mmu.c 105.4 KB
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/*
 * Kernel-based Virtual Machine driver for Linux
 *
 * This module enables machines with Intel VT-x extensions to run virtual
 * machines without emulation or binary translation.
 *
 * MMU support
 *
 * Copyright (C) 2006 Qumranet, Inc.
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 * Copyright 2010 Red Hat, Inc. and/or its affiliates.
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 *
 * Authors:
 *   Yaniv Kamay  <yaniv@qumranet.com>
 *   Avi Kivity   <avi@qumranet.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2.  See
 * the COPYING file in the top-level directory.
 *
 */
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#include "irq.h"
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#include "mmu.h"
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#include "x86.h"
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#include "kvm_cache_regs.h"
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#include <linux/kvm_host.h>
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#include <linux/types.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/module.h>
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#include <linux/swap.h>
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#include <linux/hugetlb.h>
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#include <linux/compiler.h>
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#include <linux/srcu.h>
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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#include <asm/page.h>
#include <asm/cmpxchg.h>
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#include <asm/io.h>
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#include <asm/vmx.h>
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/*
 * When setting this variable to true it enables Two-Dimensional-Paging
 * where the hardware walks 2 page tables:
 * 1. the guest-virtual to guest-physical
 * 2. while doing 1. it walks guest-physical to host-physical
 * If the hardware supports that we don't need to do shadow paging.
 */
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bool tdp_enabled = false;
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enum {
	AUDIT_PRE_PAGE_FAULT,
	AUDIT_POST_PAGE_FAULT,
	AUDIT_PRE_PTE_WRITE,
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	AUDIT_POST_PTE_WRITE,
	AUDIT_PRE_SYNC,
	AUDIT_POST_SYNC
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};
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#undef MMU_DEBUG
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#ifdef MMU_DEBUG

#define pgprintk(x...) do { if (dbg) printk(x); } while (0)
#define rmap_printk(x...) do { if (dbg) printk(x); } while (0)

#else

#define pgprintk(x...) do { } while (0)
#define rmap_printk(x...) do { } while (0)

#endif

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#ifdef MMU_DEBUG
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static bool dbg = 0;
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module_param(dbg, bool, 0644);
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#endif
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#ifndef MMU_DEBUG
#define ASSERT(x) do { } while (0)
#else
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#define ASSERT(x)							\
	if (!(x)) {							\
		printk(KERN_WARNING "assertion failed %s:%d: %s\n",	\
		       __FILE__, __LINE__, #x);				\
	}
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#endif
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#define PTE_PREFETCH_NUM		8

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#define PT_FIRST_AVAIL_BITS_SHIFT 10
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#define PT64_SECOND_AVAIL_BITS_SHIFT 52

#define PT64_LEVEL_BITS 9

#define PT64_LEVEL_SHIFT(level) \
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		(PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS)
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#define PT64_INDEX(address, level)\
	(((address) >> PT64_LEVEL_SHIFT(level)) & ((1 << PT64_LEVEL_BITS) - 1))


#define PT32_LEVEL_BITS 10

#define PT32_LEVEL_SHIFT(level) \
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		(PAGE_SHIFT + (level - 1) * PT32_LEVEL_BITS)
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#define PT32_LVL_OFFSET_MASK(level) \
	(PT32_BASE_ADDR_MASK & ((1ULL << (PAGE_SHIFT + (((level) - 1) \
						* PT32_LEVEL_BITS))) - 1))
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#define PT32_INDEX(address, level)\
	(((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1))


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#define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1))
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#define PT64_DIR_BASE_ADDR_MASK \
	(PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1))
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#define PT64_LVL_ADDR_MASK(level) \
	(PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + (((level) - 1) \
						* PT64_LEVEL_BITS))) - 1))
#define PT64_LVL_OFFSET_MASK(level) \
	(PT64_BASE_ADDR_MASK & ((1ULL << (PAGE_SHIFT + (((level) - 1) \
						* PT64_LEVEL_BITS))) - 1))
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#define PT32_BASE_ADDR_MASK PAGE_MASK
#define PT32_DIR_BASE_ADDR_MASK \
	(PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1))
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#define PT32_LVL_ADDR_MASK(level) \
	(PAGE_MASK & ~((1ULL << (PAGE_SHIFT + (((level) - 1) \
					    * PT32_LEVEL_BITS))) - 1))
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#define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK \
			| PT64_NX_MASK)
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#define ACC_EXEC_MASK    1
#define ACC_WRITE_MASK   PT_WRITABLE_MASK
#define ACC_USER_MASK    PT_USER_MASK
#define ACC_ALL          (ACC_EXEC_MASK | ACC_WRITE_MASK | ACC_USER_MASK)

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#include <trace/events/kvm.h>

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#define CREATE_TRACE_POINTS
#include "mmutrace.h"

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#define SPTE_HOST_WRITEABLE	(1ULL << PT_FIRST_AVAIL_BITS_SHIFT)
#define SPTE_MMU_WRITEABLE	(1ULL << (PT_FIRST_AVAIL_BITS_SHIFT + 1))
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#define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)

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/* make pte_list_desc fit well in cache line */
#define PTE_LIST_EXT 3

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struct pte_list_desc {
	u64 *sptes[PTE_LIST_EXT];
	struct pte_list_desc *more;
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};

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struct kvm_shadow_walk_iterator {
	u64 addr;
	hpa_t shadow_addr;
	u64 *sptep;
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	int level;
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	unsigned index;
};

#define for_each_shadow_entry(_vcpu, _addr, _walker)    \
	for (shadow_walk_init(&(_walker), _vcpu, _addr);	\
	     shadow_walk_okay(&(_walker));			\
	     shadow_walk_next(&(_walker)))

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#define for_each_shadow_entry_lockless(_vcpu, _addr, _walker, spte)	\
	for (shadow_walk_init(&(_walker), _vcpu, _addr);		\
	     shadow_walk_okay(&(_walker)) &&				\
		({ spte = mmu_spte_get_lockless(_walker.sptep); 1; });	\
	     __shadow_walk_next(&(_walker), spte))

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static struct kmem_cache *pte_list_desc_cache;
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static struct kmem_cache *mmu_page_header_cache;
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static struct percpu_counter kvm_total_used_mmu_pages;
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static u64 __read_mostly shadow_nx_mask;
static u64 __read_mostly shadow_x_mask;	/* mutual exclusive with nx_mask */
static u64 __read_mostly shadow_user_mask;
static u64 __read_mostly shadow_accessed_mask;
static u64 __read_mostly shadow_dirty_mask;
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static u64 __read_mostly shadow_mmio_mask;

static void mmu_spte_set(u64 *sptep, u64 spte);
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static void mmu_free_roots(struct kvm_vcpu *vcpu);
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void kvm_mmu_set_mmio_spte_mask(u64 mmio_mask)
{
	shadow_mmio_mask = mmio_mask;
}
EXPORT_SYMBOL_GPL(kvm_mmu_set_mmio_spte_mask);

static void mark_mmio_spte(u64 *sptep, u64 gfn, unsigned access)
{
	access &= ACC_WRITE_MASK | ACC_USER_MASK;

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	trace_mark_mmio_spte(sptep, gfn, access);
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	mmu_spte_set(sptep, shadow_mmio_mask | access | gfn << PAGE_SHIFT);
}

static bool is_mmio_spte(u64 spte)
{
	return (spte & shadow_mmio_mask) == shadow_mmio_mask;
}

static gfn_t get_mmio_spte_gfn(u64 spte)
{
	return (spte & ~shadow_mmio_mask) >> PAGE_SHIFT;
}

static unsigned get_mmio_spte_access(u64 spte)
{
	return (spte & ~shadow_mmio_mask) & ~PAGE_MASK;
}

static bool set_mmio_spte(u64 *sptep, gfn_t gfn, pfn_t pfn, unsigned access)
{
	if (unlikely(is_noslot_pfn(pfn))) {
		mark_mmio_spte(sptep, gfn, access);
		return true;
	}

	return false;
}
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static inline u64 rsvd_bits(int s, int e)
{
	return ((1ULL << (e - s + 1)) - 1) << s;
}

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void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
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		u64 dirty_mask, u64 nx_mask, u64 x_mask)
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{
	shadow_user_mask = user_mask;
	shadow_accessed_mask = accessed_mask;
	shadow_dirty_mask = dirty_mask;
	shadow_nx_mask = nx_mask;
	shadow_x_mask = x_mask;
}
EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes);

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static int is_cpuid_PSE36(void)
{
	return 1;
}

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static int is_nx(struct kvm_vcpu *vcpu)
{
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	return vcpu->arch.efer & EFER_NX;
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}

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static int is_shadow_present_pte(u64 pte)
{
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	return pte & PT_PRESENT_MASK && !is_mmio_spte(pte);
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}

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static int is_large_pte(u64 pte)
{
	return pte & PT_PAGE_SIZE_MASK;
}

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static int is_dirty_gpte(unsigned long pte)
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{
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	return pte & PT_DIRTY_MASK;
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}

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static int is_rmap_spte(u64 pte)
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{
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	return is_shadow_present_pte(pte);
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}

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static int is_last_spte(u64 pte, int level)
{
	if (level == PT_PAGE_TABLE_LEVEL)
		return 1;
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	if (is_large_pte(pte))
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		return 1;
	return 0;
}

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static pfn_t spte_to_pfn(u64 pte)
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{
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	return (pte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
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}

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static gfn_t pse36_gfn_delta(u32 gpte)
{
	int shift = 32 - PT32_DIR_PSE36_SHIFT - PAGE_SHIFT;

	return (gpte & PT32_DIR_PSE36_MASK) << shift;
}

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#ifdef CONFIG_X86_64
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static void __set_spte(u64 *sptep, u64 spte)
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{
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	*sptep = spte;
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}

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static void __update_clear_spte_fast(u64 *sptep, u64 spte)
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{
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	*sptep = spte;
}

static u64 __update_clear_spte_slow(u64 *sptep, u64 spte)
{
	return xchg(sptep, spte);
}
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static u64 __get_spte_lockless(u64 *sptep)
{
	return ACCESS_ONCE(*sptep);
}
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static bool __check_direct_spte_mmio_pf(u64 spte)
{
	/* It is valid if the spte is zapped. */
	return spte == 0ull;
}
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#else
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union split_spte {
	struct {
		u32 spte_low;
		u32 spte_high;
	};
	u64 spte;
};
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static void count_spte_clear(u64 *sptep, u64 spte)
{
	struct kvm_mmu_page *sp =  page_header(__pa(sptep));

	if (is_shadow_present_pte(spte))
		return;

	/* Ensure the spte is completely set before we increase the count */
	smp_wmb();
	sp->clear_spte_count++;
}

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static void __set_spte(u64 *sptep, u64 spte)
{
	union split_spte *ssptep, sspte;
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	ssptep = (union split_spte *)sptep;
	sspte = (union split_spte)spte;

	ssptep->spte_high = sspte.spte_high;

	/*
	 * If we map the spte from nonpresent to present, We should store
	 * the high bits firstly, then set present bit, so cpu can not
	 * fetch this spte while we are setting the spte.
	 */
	smp_wmb();

	ssptep->spte_low = sspte.spte_low;
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}

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static void __update_clear_spte_fast(u64 *sptep, u64 spte)
{
	union split_spte *ssptep, sspte;

	ssptep = (union split_spte *)sptep;
	sspte = (union split_spte)spte;

	ssptep->spte_low = sspte.spte_low;

	/*
	 * If we map the spte from present to nonpresent, we should clear
	 * present bit firstly to avoid vcpu fetch the old high bits.
	 */
	smp_wmb();

	ssptep->spte_high = sspte.spte_high;
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	count_spte_clear(sptep, spte);
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}

static u64 __update_clear_spte_slow(u64 *sptep, u64 spte)
{
	union split_spte *ssptep, sspte, orig;

	ssptep = (union split_spte *)sptep;
	sspte = (union split_spte)spte;

	/* xchg acts as a barrier before the setting of the high bits */
	orig.spte_low = xchg(&ssptep->spte_low, sspte.spte_low);
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	orig.spte_high = ssptep->spte_high;
	ssptep->spte_high = sspte.spte_high;
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	count_spte_clear(sptep, spte);
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	return orig.spte;
}
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/*
 * The idea using the light way get the spte on x86_32 guest is from
 * gup_get_pte(arch/x86/mm/gup.c).
 * The difference is we can not catch the spte tlb flush if we leave
 * guest mode, so we emulate it by increase clear_spte_count when spte
 * is cleared.
 */
static u64 __get_spte_lockless(u64 *sptep)
{
	struct kvm_mmu_page *sp =  page_header(__pa(sptep));
	union split_spte spte, *orig = (union split_spte *)sptep;
	int count;

retry:
	count = sp->clear_spte_count;
	smp_rmb();

	spte.spte_low = orig->spte_low;
	smp_rmb();

	spte.spte_high = orig->spte_high;
	smp_rmb();

	if (unlikely(spte.spte_low != orig->spte_low ||
	      count != sp->clear_spte_count))
		goto retry;

	return spte.spte;
}
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static bool __check_direct_spte_mmio_pf(u64 spte)
{
	union split_spte sspte = (union split_spte)spte;
	u32 high_mmio_mask = shadow_mmio_mask >> 32;

	/* It is valid if the spte is zapped. */
	if (spte == 0ull)
		return true;

	/* It is valid if the spte is being zapped. */
	if (sspte.spte_low == 0ull &&
	    (sspte.spte_high & high_mmio_mask) == high_mmio_mask)
		return true;

	return false;
}
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#endif

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static bool spte_is_locklessly_modifiable(u64 spte)
{
	return !(~spte & (SPTE_HOST_WRITEABLE | SPTE_MMU_WRITEABLE));
}

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static bool spte_has_volatile_bits(u64 spte)
{
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	/*
	 * Always atomicly update spte if it can be updated
	 * out of mmu-lock, it can ensure dirty bit is not lost,
	 * also, it can help us to get a stable is_writable_pte()
	 * to ensure tlb flush is not missed.
	 */
	if (spte_is_locklessly_modifiable(spte))
		return true;

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	if (!shadow_accessed_mask)
		return false;

	if (!is_shadow_present_pte(spte))
		return false;

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	if ((spte & shadow_accessed_mask) &&
	      (!is_writable_pte(spte) || (spte & shadow_dirty_mask)))
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		return false;

	return true;
}

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static bool spte_is_bit_cleared(u64 old_spte, u64 new_spte, u64 bit_mask)
{
	return (old_spte & bit_mask) && !(new_spte & bit_mask);
}

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/* Rules for using mmu_spte_set:
 * Set the sptep from nonpresent to present.
 * Note: the sptep being assigned *must* be either not present
 * or in a state where the hardware will not attempt to update
 * the spte.
 */
static void mmu_spte_set(u64 *sptep, u64 new_spte)
{
	WARN_ON(is_shadow_present_pte(*sptep));
	__set_spte(sptep, new_spte);
}

/* Rules for using mmu_spte_update:
 * Update the state bits, it means the mapped pfn is not changged.
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 *
 * Whenever we overwrite a writable spte with a read-only one we
 * should flush remote TLBs. Otherwise rmap_write_protect
 * will find a read-only spte, even though the writable spte
 * might be cached on a CPU's TLB, the return value indicates this
 * case.
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 */
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static bool mmu_spte_update(u64 *sptep, u64 new_spte)
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{
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	u64 old_spte = *sptep;
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	bool ret = false;
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	WARN_ON(!is_rmap_spte(new_spte));
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	if (!is_shadow_present_pte(old_spte)) {
		mmu_spte_set(sptep, new_spte);
		return ret;
	}
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	if (!spte_has_volatile_bits(old_spte))
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		__update_clear_spte_fast(sptep, new_spte);
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	else
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		old_spte = __update_clear_spte_slow(sptep, new_spte);
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	/*
	 * For the spte updated out of mmu-lock is safe, since
	 * we always atomicly update it, see the comments in
	 * spte_has_volatile_bits().
	 */
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	if (is_writable_pte(old_spte) && !is_writable_pte(new_spte))
		ret = true;

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	if (!shadow_accessed_mask)
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		return ret;
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	if (spte_is_bit_cleared(old_spte, new_spte, shadow_accessed_mask))
		kvm_set_pfn_accessed(spte_to_pfn(old_spte));
	if (spte_is_bit_cleared(old_spte, new_spte, shadow_dirty_mask))
		kvm_set_pfn_dirty(spte_to_pfn(old_spte));
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	return ret;
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}

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/*
 * Rules for using mmu_spte_clear_track_bits:
 * It sets the sptep from present to nonpresent, and track the
 * state bits, it is used to clear the last level sptep.
 */
static int mmu_spte_clear_track_bits(u64 *sptep)
{
	pfn_t pfn;
	u64 old_spte = *sptep;

	if (!spte_has_volatile_bits(old_spte))
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		__update_clear_spte_fast(sptep, 0ull);
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	else
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		old_spte = __update_clear_spte_slow(sptep, 0ull);
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	if (!is_rmap_spte(old_spte))
		return 0;

	pfn = spte_to_pfn(old_spte);
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	/*
	 * KVM does not hold the refcount of the page used by
	 * kvm mmu, before reclaiming the page, we should
	 * unmap it from mmu first.
	 */
	WARN_ON(!kvm_is_mmio_pfn(pfn) && !page_count(pfn_to_page(pfn)));

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	if (!shadow_accessed_mask || old_spte & shadow_accessed_mask)
		kvm_set_pfn_accessed(pfn);
	if (!shadow_dirty_mask || (old_spte & shadow_dirty_mask))
		kvm_set_pfn_dirty(pfn);
	return 1;
}

/*
 * Rules for using mmu_spte_clear_no_track:
 * Directly clear spte without caring the state bits of sptep,
 * it is used to set the upper level spte.
 */
static void mmu_spte_clear_no_track(u64 *sptep)
{
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	__update_clear_spte_fast(sptep, 0ull);
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}

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static u64 mmu_spte_get_lockless(u64 *sptep)
{
	return __get_spte_lockless(sptep);
}

static void walk_shadow_page_lockless_begin(struct kvm_vcpu *vcpu)
{
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	/*
	 * Prevent page table teardown by making any free-er wait during
	 * kvm_flush_remote_tlbs() IPI to all active vcpus.
	 */
	local_irq_disable();
	vcpu->mode = READING_SHADOW_PAGE_TABLES;
	/*
	 * Make sure a following spte read is not reordered ahead of the write
	 * to vcpu->mode.
	 */
	smp_mb();
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}

static void walk_shadow_page_lockless_end(struct kvm_vcpu *vcpu)
{
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	/*
	 * Make sure the write to vcpu->mode is not reordered in front of
	 * reads to sptes.  If it does, kvm_commit_zap_page() can see us
	 * OUTSIDE_GUEST_MODE and proceed to free the shadow page table.
	 */
	smp_mb();
	vcpu->mode = OUTSIDE_GUEST_MODE;
	local_irq_enable();
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}

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static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
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				  struct kmem_cache *base_cache, int min)
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{
	void *obj;

	if (cache->nobjs >= min)
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		return 0;
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	while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
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		obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
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		if (!obj)
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			return -ENOMEM;
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		cache->objects[cache->nobjs++] = obj;
	}
629
	return 0;
630 631
}

632 633 634 635 636
static int mmu_memory_cache_free_objects(struct kvm_mmu_memory_cache *cache)
{
	return cache->nobjs;
}

637 638
static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc,
				  struct kmem_cache *cache)
639 640
{
	while (mc->nobjs)
641
		kmem_cache_free(cache, mc->objects[--mc->nobjs]);
642 643
}

A
Avi Kivity 已提交
644
static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
645
				       int min)
A
Avi Kivity 已提交
646
{
647
	void *page;
A
Avi Kivity 已提交
648 649 650 651

	if (cache->nobjs >= min)
		return 0;
	while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
652
		page = (void *)__get_free_page(GFP_KERNEL);
A
Avi Kivity 已提交
653 654
		if (!page)
			return -ENOMEM;
655
		cache->objects[cache->nobjs++] = page;
A
Avi Kivity 已提交
656 657 658 659 660 661 662
	}
	return 0;
}

static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
{
	while (mc->nobjs)
663
		free_page((unsigned long)mc->objects[--mc->nobjs]);
A
Avi Kivity 已提交
664 665
}

666
static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
667
{
668 669
	int r;

670
	r = mmu_topup_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache,
671
				   pte_list_desc_cache, 8 + PTE_PREFETCH_NUM);
672 673
	if (r)
		goto out;
674
	r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 8);
675 676
	if (r)
		goto out;
677
	r = mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
678
				   mmu_page_header_cache, 4);
679 680
out:
	return r;
681 682 683 684
}

static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
{
685 686
	mmu_free_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache,
				pte_list_desc_cache);
687
	mmu_free_memory_cache_page(&vcpu->arch.mmu_page_cache);
688 689
	mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache,
				mmu_page_header_cache);
690 691
}

692
static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
693 694 695 696 697 698 699 700
{
	void *p;

	BUG_ON(!mc->nobjs);
	p = mc->objects[--mc->nobjs];
	return p;
}

701
static struct pte_list_desc *mmu_alloc_pte_list_desc(struct kvm_vcpu *vcpu)
702
{
703
	return mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_list_desc_cache);
704 705
}

706
static void mmu_free_pte_list_desc(struct pte_list_desc *pte_list_desc)
707
{
708
	kmem_cache_free(pte_list_desc_cache, pte_list_desc);
709 710
}

711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726
static gfn_t kvm_mmu_page_get_gfn(struct kvm_mmu_page *sp, int index)
{
	if (!sp->role.direct)
		return sp->gfns[index];

	return sp->gfn + (index << ((sp->role.level - 1) * PT64_LEVEL_BITS));
}

static void kvm_mmu_page_set_gfn(struct kvm_mmu_page *sp, int index, gfn_t gfn)
{
	if (sp->role.direct)
		BUG_ON(gfn != kvm_mmu_page_get_gfn(sp, index));
	else
		sp->gfns[index] = gfn;
}

M
Marcelo Tosatti 已提交
727
/*
728 729
 * Return the pointer to the large page information for a given gfn,
 * handling slots that are not large page aligned.
M
Marcelo Tosatti 已提交
730
 */
731 732 733
static struct kvm_lpage_info *lpage_info_slot(gfn_t gfn,
					      struct kvm_memory_slot *slot,
					      int level)
M
Marcelo Tosatti 已提交
734 735 736
{
	unsigned long idx;

737
	idx = gfn_to_index(gfn, slot->base_gfn, level);
738
	return &slot->arch.lpage_info[level - 2][idx];
M
Marcelo Tosatti 已提交
739 740 741 742
}

static void account_shadowed(struct kvm *kvm, gfn_t gfn)
{
743
	struct kvm_memory_slot *slot;
744
	struct kvm_lpage_info *linfo;
745
	int i;
M
Marcelo Tosatti 已提交
746

A
Avi Kivity 已提交
747
	slot = gfn_to_memslot(kvm, gfn);
748 749
	for (i = PT_DIRECTORY_LEVEL;
	     i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
750 751
		linfo = lpage_info_slot(gfn, slot, i);
		linfo->write_count += 1;
752
	}
753
	kvm->arch.indirect_shadow_pages++;
M
Marcelo Tosatti 已提交
754 755 756 757
}

static void unaccount_shadowed(struct kvm *kvm, gfn_t gfn)
{
758
	struct kvm_memory_slot *slot;
759
	struct kvm_lpage_info *linfo;
760
	int i;
M
Marcelo Tosatti 已提交
761

A
Avi Kivity 已提交
762
	slot = gfn_to_memslot(kvm, gfn);
763 764
	for (i = PT_DIRECTORY_LEVEL;
	     i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
765 766 767
		linfo = lpage_info_slot(gfn, slot, i);
		linfo->write_count -= 1;
		WARN_ON(linfo->write_count < 0);
768
	}
769
	kvm->arch.indirect_shadow_pages--;
M
Marcelo Tosatti 已提交
770 771
}

772 773 774
static int has_wrprotected_page(struct kvm *kvm,
				gfn_t gfn,
				int level)
M
Marcelo Tosatti 已提交
775
{
776
	struct kvm_memory_slot *slot;
777
	struct kvm_lpage_info *linfo;
M
Marcelo Tosatti 已提交
778

A
Avi Kivity 已提交
779
	slot = gfn_to_memslot(kvm, gfn);
M
Marcelo Tosatti 已提交
780
	if (slot) {
781 782
		linfo = lpage_info_slot(gfn, slot, level);
		return linfo->write_count;
M
Marcelo Tosatti 已提交
783 784 785 786 787
	}

	return 1;
}

788
static int host_mapping_level(struct kvm *kvm, gfn_t gfn)
M
Marcelo Tosatti 已提交
789
{
J
Joerg Roedel 已提交
790
	unsigned long page_size;
791
	int i, ret = 0;
M
Marcelo Tosatti 已提交
792

J
Joerg Roedel 已提交
793
	page_size = kvm_host_page_size(kvm, gfn);
M
Marcelo Tosatti 已提交
794

795 796 797 798 799 800 801 802
	for (i = PT_PAGE_TABLE_LEVEL;
	     i < (PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES); ++i) {
		if (page_size >= KVM_HPAGE_SIZE(i))
			ret = i;
		else
			break;
	}

803
	return ret;
M
Marcelo Tosatti 已提交
804 805
}

806 807 808
static struct kvm_memory_slot *
gfn_to_memslot_dirty_bitmap(struct kvm_vcpu *vcpu, gfn_t gfn,
			    bool no_dirty_log)
M
Marcelo Tosatti 已提交
809 810
{
	struct kvm_memory_slot *slot;
811 812 813 814 815 816 817 818 819 820 821

	slot = gfn_to_memslot(vcpu->kvm, gfn);
	if (!slot || slot->flags & KVM_MEMSLOT_INVALID ||
	      (no_dirty_log && slot->dirty_bitmap))
		slot = NULL;

	return slot;
}

static bool mapping_level_dirty_bitmap(struct kvm_vcpu *vcpu, gfn_t large_gfn)
{
822
	return !gfn_to_memslot_dirty_bitmap(vcpu, large_gfn, true);
823 824 825 826 827
}

static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn)
{
	int host_level, level, max_level;
M
Marcelo Tosatti 已提交
828

829 830 831 832 833
	host_level = host_mapping_level(vcpu->kvm, large_gfn);

	if (host_level == PT_PAGE_TABLE_LEVEL)
		return host_level;

834 835 836 837
	max_level = kvm_x86_ops->get_lpage_level() < host_level ?
		kvm_x86_ops->get_lpage_level() : host_level;

	for (level = PT_DIRECTORY_LEVEL; level <= max_level; ++level)
838 839 840 841
		if (has_wrprotected_page(vcpu->kvm, large_gfn, level))
			break;

	return level - 1;
M
Marcelo Tosatti 已提交
842 843
}

844
/*
845
 * Pte mapping structures:
846
 *
847
 * If pte_list bit zero is zero, then pte_list point to the spte.
848
 *
849 850
 * If pte_list bit zero is one, (then pte_list & ~1) points to a struct
 * pte_list_desc containing more mappings.
851
 *
852
 * Returns the number of pte entries before the spte was added or zero if
853 854
 * the spte was not added.
 *
855
 */
856 857
static int pte_list_add(struct kvm_vcpu *vcpu, u64 *spte,
			unsigned long *pte_list)
858
{
859
	struct pte_list_desc *desc;
860
	int i, count = 0;
861

862 863 864 865 866 867 868
	if (!*pte_list) {
		rmap_printk("pte_list_add: %p %llx 0->1\n", spte, *spte);
		*pte_list = (unsigned long)spte;
	} else if (!(*pte_list & 1)) {
		rmap_printk("pte_list_add: %p %llx 1->many\n", spte, *spte);
		desc = mmu_alloc_pte_list_desc(vcpu);
		desc->sptes[0] = (u64 *)*pte_list;
A
Avi Kivity 已提交
869
		desc->sptes[1] = spte;
870
		*pte_list = (unsigned long)desc | 1;
871
		++count;
872
	} else {
873 874 875
		rmap_printk("pte_list_add: %p %llx many->many\n", spte, *spte);
		desc = (struct pte_list_desc *)(*pte_list & ~1ul);
		while (desc->sptes[PTE_LIST_EXT-1] && desc->more) {
876
			desc = desc->more;
877
			count += PTE_LIST_EXT;
878
		}
879 880
		if (desc->sptes[PTE_LIST_EXT-1]) {
			desc->more = mmu_alloc_pte_list_desc(vcpu);
881 882
			desc = desc->more;
		}
A
Avi Kivity 已提交
883
		for (i = 0; desc->sptes[i]; ++i)
884
			++count;
A
Avi Kivity 已提交
885
		desc->sptes[i] = spte;
886
	}
887
	return count;
888 889
}

890 891 892
static void
pte_list_desc_remove_entry(unsigned long *pte_list, struct pte_list_desc *desc,
			   int i, struct pte_list_desc *prev_desc)
893 894 895
{
	int j;

896
	for (j = PTE_LIST_EXT - 1; !desc->sptes[j] && j > i; --j)
897
		;
A
Avi Kivity 已提交
898 899
	desc->sptes[i] = desc->sptes[j];
	desc->sptes[j] = NULL;
900 901 902
	if (j != 0)
		return;
	if (!prev_desc && !desc->more)
903
		*pte_list = (unsigned long)desc->sptes[0];
904 905 906 907
	else
		if (prev_desc)
			prev_desc->more = desc->more;
		else
908 909
			*pte_list = (unsigned long)desc->more | 1;
	mmu_free_pte_list_desc(desc);
910 911
}

912
static void pte_list_remove(u64 *spte, unsigned long *pte_list)
913
{
914 915
	struct pte_list_desc *desc;
	struct pte_list_desc *prev_desc;
916 917
	int i;

918 919
	if (!*pte_list) {
		printk(KERN_ERR "pte_list_remove: %p 0->BUG\n", spte);
920
		BUG();
921 922 923 924
	} else if (!(*pte_list & 1)) {
		rmap_printk("pte_list_remove:  %p 1->0\n", spte);
		if ((u64 *)*pte_list != spte) {
			printk(KERN_ERR "pte_list_remove:  %p 1->BUG\n", spte);
925 926
			BUG();
		}
927
		*pte_list = 0;
928
	} else {
929 930
		rmap_printk("pte_list_remove:  %p many->many\n", spte);
		desc = (struct pte_list_desc *)(*pte_list & ~1ul);
931 932
		prev_desc = NULL;
		while (desc) {
933
			for (i = 0; i < PTE_LIST_EXT && desc->sptes[i]; ++i)
A
Avi Kivity 已提交
934
				if (desc->sptes[i] == spte) {
935
					pte_list_desc_remove_entry(pte_list,
936
							       desc, i,
937 938 939 940 941 942
							       prev_desc);
					return;
				}
			prev_desc = desc;
			desc = desc->more;
		}
943
		pr_err("pte_list_remove: %p many->many\n", spte);
944 945 946 947
		BUG();
	}
}

948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967
typedef void (*pte_list_walk_fn) (u64 *spte);
static void pte_list_walk(unsigned long *pte_list, pte_list_walk_fn fn)
{
	struct pte_list_desc *desc;
	int i;

	if (!*pte_list)
		return;

	if (!(*pte_list & 1))
		return fn((u64 *)*pte_list);

	desc = (struct pte_list_desc *)(*pte_list & ~1ul);
	while (desc) {
		for (i = 0; i < PTE_LIST_EXT && desc->sptes[i]; ++i)
			fn(desc->sptes[i]);
		desc = desc->more;
	}
}

968
static unsigned long *__gfn_to_rmap(gfn_t gfn, int level,
969
				    struct kvm_memory_slot *slot)
970
{
971
	unsigned long idx;
972

973
	idx = gfn_to_index(gfn, slot->base_gfn, level);
974
	return &slot->arch.rmap[level - PT_PAGE_TABLE_LEVEL][idx];
975 976
}

977 978 979 980 981 982 983 984
/*
 * Take gfn and return the reverse mapping to it.
 */
static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int level)
{
	struct kvm_memory_slot *slot;

	slot = gfn_to_memslot(kvm, gfn);
985
	return __gfn_to_rmap(gfn, level, slot);
986 987
}

988 989 990 991 992 993 994 995
static bool rmap_can_add(struct kvm_vcpu *vcpu)
{
	struct kvm_mmu_memory_cache *cache;

	cache = &vcpu->arch.mmu_pte_list_desc_cache;
	return mmu_memory_cache_free_objects(cache);
}

996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018
static int rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
{
	struct kvm_mmu_page *sp;
	unsigned long *rmapp;

	sp = page_header(__pa(spte));
	kvm_mmu_page_set_gfn(sp, spte - sp->spt, gfn);
	rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level);
	return pte_list_add(vcpu, spte, rmapp);
}

static void rmap_remove(struct kvm *kvm, u64 *spte)
{
	struct kvm_mmu_page *sp;
	gfn_t gfn;
	unsigned long *rmapp;

	sp = page_header(__pa(spte));
	gfn = kvm_mmu_page_get_gfn(sp, spte - sp->spt);
	rmapp = gfn_to_rmap(kvm, gfn, sp->role.level);
	pte_list_remove(spte, rmapp);
}

1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079
/*
 * Used by the following functions to iterate through the sptes linked by a
 * rmap.  All fields are private and not assumed to be used outside.
 */
struct rmap_iterator {
	/* private fields */
	struct pte_list_desc *desc;	/* holds the sptep if not NULL */
	int pos;			/* index of the sptep */
};

/*
 * Iteration must be started by this function.  This should also be used after
 * removing/dropping sptes from the rmap link because in such cases the
 * information in the itererator may not be valid.
 *
 * Returns sptep if found, NULL otherwise.
 */
static u64 *rmap_get_first(unsigned long rmap, struct rmap_iterator *iter)
{
	if (!rmap)
		return NULL;

	if (!(rmap & 1)) {
		iter->desc = NULL;
		return (u64 *)rmap;
	}

	iter->desc = (struct pte_list_desc *)(rmap & ~1ul);
	iter->pos = 0;
	return iter->desc->sptes[iter->pos];
}

/*
 * Must be used with a valid iterator: e.g. after rmap_get_first().
 *
 * Returns sptep if found, NULL otherwise.
 */
static u64 *rmap_get_next(struct rmap_iterator *iter)
{
	if (iter->desc) {
		if (iter->pos < PTE_LIST_EXT - 1) {
			u64 *sptep;

			++iter->pos;
			sptep = iter->desc->sptes[iter->pos];
			if (sptep)
				return sptep;
		}

		iter->desc = iter->desc->more;

		if (iter->desc) {
			iter->pos = 0;
			/* desc->sptes[0] cannot be NULL */
			return iter->desc->sptes[iter->pos];
		}
	}

	return NULL;
}

1080
static void drop_spte(struct kvm *kvm, u64 *sptep)
1081
{
1082
	if (mmu_spte_clear_track_bits(sptep))
1083
		rmap_remove(kvm, sptep);
A
Avi Kivity 已提交
1084 1085
}

1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106

static bool __drop_large_spte(struct kvm *kvm, u64 *sptep)
{
	if (is_large_pte(*sptep)) {
		WARN_ON(page_header(__pa(sptep))->role.level ==
			PT_PAGE_TABLE_LEVEL);
		drop_spte(kvm, sptep);
		--kvm->stat.lpages;
		return true;
	}

	return false;
}

static void drop_large_spte(struct kvm_vcpu *vcpu, u64 *sptep)
{
	if (__drop_large_spte(vcpu->kvm, sptep))
		kvm_flush_remote_tlbs(vcpu->kvm);
}

/*
1107 1108 1109 1110 1111 1112 1113 1114 1115 1116
 * Write-protect on the specified @sptep, @pt_protect indicates whether
 * spte writ-protection is caused by protecting shadow page table.
 * @flush indicates whether tlb need be flushed.
 *
 * Note: write protection is difference between drity logging and spte
 * protection:
 * - for dirty logging, the spte can be set to writable at anytime if
 *   its dirty bitmap is properly set.
 * - for spte protection, the spte can be writable only after unsync-ing
 *   shadow page.
1117 1118 1119
 *
 * Return true if the spte is dropped.
 */
1120 1121
static bool
spte_write_protect(struct kvm *kvm, u64 *sptep, bool *flush, bool pt_protect)
1122 1123 1124
{
	u64 spte = *sptep;

1125 1126
	if (!is_writable_pte(spte) &&
	      !(pt_protect && spte_is_locklessly_modifiable(spte)))
1127 1128 1129 1130
		return false;

	rmap_printk("rmap_write_protect: spte %p %llx\n", sptep, *sptep);

1131 1132
	if (__drop_large_spte(kvm, sptep)) {
		*flush |= true;
1133
		return true;
1134
	}
1135

1136 1137
	if (pt_protect)
		spte &= ~SPTE_MMU_WRITEABLE;
1138
	spte = spte & ~PT_WRITABLE_MASK;
1139 1140

	*flush |= mmu_spte_update(sptep, spte);
1141 1142 1143
	return false;
}

1144 1145
static bool __rmap_write_protect(struct kvm *kvm, unsigned long *rmapp,
				 int level, bool pt_protect)
1146
{
1147 1148
	u64 *sptep;
	struct rmap_iterator iter;
1149
	bool flush = false;
1150

1151 1152
	for (sptep = rmap_get_first(*rmapp, &iter); sptep;) {
		BUG_ON(!(*sptep & PT_PRESENT_MASK));
1153
		if (spte_write_protect(kvm, sptep, &flush, pt_protect)) {
1154
			sptep = rmap_get_first(*rmapp, &iter);
1155
			continue;
1156
		}
1157

1158
		sptep = rmap_get_next(&iter);
1159
	}
1160

1161
	return flush;
1162 1163
}

1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176
/**
 * kvm_mmu_write_protect_pt_masked - write protect selected PT level pages
 * @kvm: kvm instance
 * @slot: slot to protect
 * @gfn_offset: start of the BITS_PER_LONG pages we care about
 * @mask: indicates which pages we should protect
 *
 * Used when we do not need to care about huge page mappings: e.g. during dirty
 * logging we do not have any such mappings.
 */
void kvm_mmu_write_protect_pt_masked(struct kvm *kvm,
				     struct kvm_memory_slot *slot,
				     gfn_t gfn_offset, unsigned long mask)
1177 1178 1179
{
	unsigned long *rmapp;

1180
	while (mask) {
1181 1182
		rmapp = __gfn_to_rmap(slot->base_gfn + gfn_offset + __ffs(mask),
				      PT_PAGE_TABLE_LEVEL, slot);
1183
		__rmap_write_protect(kvm, rmapp, PT_PAGE_TABLE_LEVEL, false);
M
Marcelo Tosatti 已提交
1184

1185 1186 1187
		/* clear the first set bit */
		mask &= mask - 1;
	}
1188 1189
}

1190
static bool rmap_write_protect(struct kvm *kvm, u64 gfn)
1191 1192
{
	struct kvm_memory_slot *slot;
1193 1194
	unsigned long *rmapp;
	int i;
1195
	bool write_protected = false;
1196 1197

	slot = gfn_to_memslot(kvm, gfn);
1198 1199 1200 1201

	for (i = PT_PAGE_TABLE_LEVEL;
	     i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
		rmapp = __gfn_to_rmap(gfn, i, slot);
1202
		write_protected |= __rmap_write_protect(kvm, rmapp, i, true);
1203 1204 1205
	}

	return write_protected;
1206 1207
}

F
Frederik Deweerdt 已提交
1208
static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp,
1209
			   struct kvm_memory_slot *slot, unsigned long data)
1210
{
1211 1212
	u64 *sptep;
	struct rmap_iterator iter;
1213 1214
	int need_tlb_flush = 0;

1215 1216 1217 1218 1219
	while ((sptep = rmap_get_first(*rmapp, &iter))) {
		BUG_ON(!(*sptep & PT_PRESENT_MASK));
		rmap_printk("kvm_rmap_unmap_hva: spte %p %llx\n", sptep, *sptep);

		drop_spte(kvm, sptep);
1220 1221
		need_tlb_flush = 1;
	}
1222

1223 1224 1225
	return need_tlb_flush;
}

F
Frederik Deweerdt 已提交
1226
static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp,
1227
			     struct kvm_memory_slot *slot, unsigned long data)
1228
{
1229 1230
	u64 *sptep;
	struct rmap_iterator iter;
1231
	int need_flush = 0;
1232
	u64 new_spte;
1233 1234 1235 1236 1237
	pte_t *ptep = (pte_t *)data;
	pfn_t new_pfn;

	WARN_ON(pte_huge(*ptep));
	new_pfn = pte_pfn(*ptep);
1238 1239 1240 1241 1242

	for (sptep = rmap_get_first(*rmapp, &iter); sptep;) {
		BUG_ON(!is_shadow_present_pte(*sptep));
		rmap_printk("kvm_set_pte_rmapp: spte %p %llx\n", sptep, *sptep);

1243
		need_flush = 1;
1244

1245
		if (pte_write(*ptep)) {
1246 1247
			drop_spte(kvm, sptep);
			sptep = rmap_get_first(*rmapp, &iter);
1248
		} else {
1249
			new_spte = *sptep & ~PT64_BASE_ADDR_MASK;
1250 1251 1252 1253
			new_spte |= (u64)new_pfn << PAGE_SHIFT;

			new_spte &= ~PT_WRITABLE_MASK;
			new_spte &= ~SPTE_HOST_WRITEABLE;
1254
			new_spte &= ~shadow_accessed_mask;
1255 1256 1257 1258

			mmu_spte_clear_track_bits(sptep);
			mmu_spte_set(sptep, new_spte);
			sptep = rmap_get_next(&iter);
1259 1260
		}
	}
1261

1262 1263 1264 1265 1266 1267
	if (need_flush)
		kvm_flush_remote_tlbs(kvm);

	return 0;
}

1268 1269 1270 1271 1272 1273
static int kvm_handle_hva_range(struct kvm *kvm,
				unsigned long start,
				unsigned long end,
				unsigned long data,
				int (*handler)(struct kvm *kvm,
					       unsigned long *rmapp,
1274
					       struct kvm_memory_slot *slot,
1275
					       unsigned long data))
1276
{
1277
	int j;
1278
	int ret = 0;
1279
	struct kvm_memslots *slots;
1280
	struct kvm_memory_slot *memslot;
1281

1282
	slots = kvm_memslots(kvm);
1283

1284
	kvm_for_each_memslot(memslot, slots) {
1285
		unsigned long hva_start, hva_end;
1286
		gfn_t gfn_start, gfn_end;
1287

1288 1289 1290 1291 1292 1293 1294
		hva_start = max(start, memslot->userspace_addr);
		hva_end = min(end, memslot->userspace_addr +
					(memslot->npages << PAGE_SHIFT));
		if (hva_start >= hva_end)
			continue;
		/*
		 * {gfn(page) | page intersects with [hva_start, hva_end)} =
1295
		 * {gfn_start, gfn_start+1, ..., gfn_end-1}.
1296
		 */
1297
		gfn_start = hva_to_gfn_memslot(hva_start, memslot);
1298
		gfn_end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, memslot);
1299

1300 1301 1302 1303
		for (j = PT_PAGE_TABLE_LEVEL;
		     j < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++j) {
			unsigned long idx, idx_end;
			unsigned long *rmapp;
1304

1305 1306 1307 1308 1309 1310
			/*
			 * {idx(page_j) | page_j intersects with
			 *  [hva_start, hva_end)} = {idx, idx+1, ..., idx_end}.
			 */
			idx = gfn_to_index(gfn_start, memslot->base_gfn, j);
			idx_end = gfn_to_index(gfn_end - 1, memslot->base_gfn, j);
1311

1312
			rmapp = __gfn_to_rmap(gfn_start, j, memslot);
1313

1314 1315
			for (; idx <= idx_end; ++idx)
				ret |= handler(kvm, rmapp++, memslot, data);
1316 1317 1318
		}
	}

1319
	return ret;
1320 1321
}

1322 1323 1324
static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
			  unsigned long data,
			  int (*handler)(struct kvm *kvm, unsigned long *rmapp,
1325
					 struct kvm_memory_slot *slot,
1326 1327 1328
					 unsigned long data))
{
	return kvm_handle_hva_range(kvm, hva, hva + 1, data, handler);
1329 1330 1331 1332
}

int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
{
1333 1334 1335
	return kvm_handle_hva(kvm, hva, 0, kvm_unmap_rmapp);
}

1336 1337 1338 1339 1340
int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end)
{
	return kvm_handle_hva_range(kvm, start, end, 0, kvm_unmap_rmapp);
}

1341 1342
void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
{
F
Frederik Deweerdt 已提交
1343
	kvm_handle_hva(kvm, hva, (unsigned long)&pte, kvm_set_pte_rmapp);
1344 1345
}

F
Frederik Deweerdt 已提交
1346
static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
1347
			 struct kvm_memory_slot *slot, unsigned long data)
1348
{
1349
	u64 *sptep;
1350
	struct rmap_iterator uninitialized_var(iter);
1351 1352
	int young = 0;

1353
	/*
1354 1355
	 * In case of absence of EPT Access and Dirty Bits supports,
	 * emulate the accessed bit for EPT, by checking if this page has
1356 1357 1358 1359 1360
	 * an EPT mapping, and clearing it if it does. On the next access,
	 * a new EPT mapping will be established.
	 * This has some overhead, but not as much as the cost of swapping
	 * out actively used pages or breaking up actively used hugepages.
	 */
1361 1362 1363 1364
	if (!shadow_accessed_mask) {
		young = kvm_unmap_rmapp(kvm, rmapp, slot, data);
		goto out;
	}
1365

1366 1367
	for (sptep = rmap_get_first(*rmapp, &iter); sptep;
	     sptep = rmap_get_next(&iter)) {
1368
		BUG_ON(!is_shadow_present_pte(*sptep));
1369

1370
		if (*sptep & shadow_accessed_mask) {
1371
			young = 1;
1372 1373
			clear_bit((ffs(shadow_accessed_mask) - 1),
				 (unsigned long *)sptep);
1374 1375
		}
	}
1376 1377 1378
out:
	/* @data has hva passed to kvm_age_hva(). */
	trace_kvm_age_page(data, slot, young);
1379 1380 1381
	return young;
}

A
Andrea Arcangeli 已提交
1382
static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
1383
			      struct kvm_memory_slot *slot, unsigned long data)
A
Andrea Arcangeli 已提交
1384
{
1385 1386
	u64 *sptep;
	struct rmap_iterator iter;
A
Andrea Arcangeli 已提交
1387 1388 1389 1390 1391 1392 1393 1394 1395 1396
	int young = 0;

	/*
	 * If there's no access bit in the secondary pte set by the
	 * hardware it's up to gup-fast/gup to set the access bit in
	 * the primary pte or in the page structure.
	 */
	if (!shadow_accessed_mask)
		goto out;

1397 1398
	for (sptep = rmap_get_first(*rmapp, &iter); sptep;
	     sptep = rmap_get_next(&iter)) {
1399
		BUG_ON(!is_shadow_present_pte(*sptep));
1400

1401
		if (*sptep & shadow_accessed_mask) {
A
Andrea Arcangeli 已提交
1402 1403 1404 1405 1406 1407 1408 1409
			young = 1;
			break;
		}
	}
out:
	return young;
}

1410 1411
#define RMAP_RECYCLE_THRESHOLD 1000

1412
static void rmap_recycle(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
1413 1414
{
	unsigned long *rmapp;
1415 1416 1417
	struct kvm_mmu_page *sp;

	sp = page_header(__pa(spte));
1418

1419
	rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level);
1420

1421
	kvm_unmap_rmapp(vcpu->kvm, rmapp, NULL, 0);
1422 1423 1424
	kvm_flush_remote_tlbs(vcpu->kvm);
}

1425 1426
int kvm_age_hva(struct kvm *kvm, unsigned long hva)
{
1427
	return kvm_handle_hva(kvm, hva, hva, kvm_age_rmapp);
1428 1429
}

A
Andrea Arcangeli 已提交
1430 1431 1432 1433 1434
int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)
{
	return kvm_handle_hva(kvm, hva, 0, kvm_test_age_rmapp);
}

1435
#ifdef MMU_DEBUG
1436
static int is_empty_shadow_page(u64 *spt)
A
Avi Kivity 已提交
1437
{
1438 1439 1440
	u64 *pos;
	u64 *end;

1441
	for (pos = spt, end = pos + PAGE_SIZE / sizeof(u64); pos != end; pos++)
1442
		if (is_shadow_present_pte(*pos)) {
1443
			printk(KERN_ERR "%s: %p %llx\n", __func__,
1444
			       pos, *pos);
A
Avi Kivity 已提交
1445
			return 0;
1446
		}
A
Avi Kivity 已提交
1447 1448
	return 1;
}
1449
#endif
A
Avi Kivity 已提交
1450

1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462
/*
 * This value is the sum of all of the kvm instances's
 * kvm->arch.n_used_mmu_pages values.  We need a global,
 * aggregate version in order to make the slab shrinker
 * faster
 */
static inline void kvm_mod_used_mmu_pages(struct kvm *kvm, int nr)
{
	kvm->arch.n_used_mmu_pages += nr;
	percpu_counter_add(&kvm_total_used_mmu_pages, nr);
}

1463 1464 1465 1466 1467 1468 1469
/*
 * Remove the sp from shadow page cache, after call it,
 * we can not find this sp from the cache, and the shadow
 * page table is still valid.
 * It should be under the protection of mmu lock.
 */
static void kvm_mmu_isolate_page(struct kvm_mmu_page *sp)
1470
{
1471
	ASSERT(is_empty_shadow_page(sp->spt));
1472
	hlist_del(&sp->hash_link);
1473
	if (!sp->role.direct)
1474
		free_page((unsigned long)sp->gfns);
1475 1476 1477 1478 1479 1480 1481 1482 1483 1484
}

/*
 * Free the shadow page table and the sp, we can do it
 * out of the protection of mmu lock.
 */
static void kvm_mmu_free_page(struct kvm_mmu_page *sp)
{
	list_del(&sp->link);
	free_page((unsigned long)sp->spt);
1485
	kmem_cache_free(mmu_page_header_cache, sp);
1486 1487
}

1488 1489
static unsigned kvm_page_table_hashfn(gfn_t gfn)
{
1490
	return gfn & ((1 << KVM_MMU_HASH_SHIFT) - 1);
1491 1492
}

1493
static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu,
1494
				    struct kvm_mmu_page *sp, u64 *parent_pte)
1495 1496 1497 1498
{
	if (!parent_pte)
		return;

1499
	pte_list_add(vcpu, parent_pte, &sp->parent_ptes);
1500 1501
}

1502
static void mmu_page_remove_parent_pte(struct kvm_mmu_page *sp,
1503 1504
				       u64 *parent_pte)
{
1505
	pte_list_remove(parent_pte, &sp->parent_ptes);
1506 1507
}

1508 1509 1510 1511
static void drop_parent_pte(struct kvm_mmu_page *sp,
			    u64 *parent_pte)
{
	mmu_page_remove_parent_pte(sp, parent_pte);
1512
	mmu_spte_clear_no_track(parent_pte);
1513 1514
}

1515 1516
static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
					       u64 *parent_pte, int direct)
M
Marcelo Tosatti 已提交
1517
{
1518
	struct kvm_mmu_page *sp;
1519 1520
	sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache);
	sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache);
1521
	if (!direct)
1522
		sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache);
1523 1524
	set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
	list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages);
1525
	bitmap_zero(sp->slot_bitmap, KVM_MEM_SLOTS_NUM);
1526 1527 1528 1529
	sp->parent_ptes = 0;
	mmu_page_add_parent_pte(vcpu, sp, parent_pte);
	kvm_mod_used_mmu_pages(vcpu->kvm, +1);
	return sp;
M
Marcelo Tosatti 已提交
1530 1531
}

1532
static void mark_unsync(u64 *spte);
1533
static void kvm_mmu_mark_parents_unsync(struct kvm_mmu_page *sp)
1534
{
1535
	pte_list_walk(&sp->parent_ptes, mark_unsync);
1536 1537
}

1538
static void mark_unsync(u64 *spte)
1539
{
1540
	struct kvm_mmu_page *sp;
1541
	unsigned int index;
1542

1543
	sp = page_header(__pa(spte));
1544 1545
	index = spte - sp->spt;
	if (__test_and_set_bit(index, sp->unsync_child_bitmap))
1546
		return;
1547
	if (sp->unsync_children++)
1548
		return;
1549
	kvm_mmu_mark_parents_unsync(sp);
1550 1551
}

1552
static int nonpaging_sync_page(struct kvm_vcpu *vcpu,
1553
			       struct kvm_mmu_page *sp)
1554 1555 1556 1557
{
	return 1;
}

M
Marcelo Tosatti 已提交
1558 1559 1560 1561
static void nonpaging_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
{
}

1562 1563
static void nonpaging_update_pte(struct kvm_vcpu *vcpu,
				 struct kvm_mmu_page *sp, u64 *spte,
1564
				 const void *pte)
1565 1566 1567 1568
{
	WARN_ON(1);
}

1569 1570 1571 1572 1573 1574 1575 1576 1577 1578
#define KVM_PAGE_ARRAY_NR 16

struct kvm_mmu_pages {
	struct mmu_page_and_offset {
		struct kvm_mmu_page *sp;
		unsigned int idx;
	} page[KVM_PAGE_ARRAY_NR];
	unsigned int nr;
};

1579 1580
static int mmu_pages_add(struct kvm_mmu_pages *pvec, struct kvm_mmu_page *sp,
			 int idx)
1581
{
1582
	int i;
1583

1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598
	if (sp->unsync)
		for (i=0; i < pvec->nr; i++)
			if (pvec->page[i].sp == sp)
				return 0;

	pvec->page[pvec->nr].sp = sp;
	pvec->page[pvec->nr].idx = idx;
	pvec->nr++;
	return (pvec->nr == KVM_PAGE_ARRAY_NR);
}

static int __mmu_unsync_walk(struct kvm_mmu_page *sp,
			   struct kvm_mmu_pages *pvec)
{
	int i, ret, nr_unsync_leaf = 0;
1599

1600
	for_each_set_bit(i, sp->unsync_child_bitmap, 512) {
1601
		struct kvm_mmu_page *child;
1602 1603
		u64 ent = sp->spt[i];

1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632
		if (!is_shadow_present_pte(ent) || is_large_pte(ent))
			goto clear_child_bitmap;

		child = page_header(ent & PT64_BASE_ADDR_MASK);

		if (child->unsync_children) {
			if (mmu_pages_add(pvec, child, i))
				return -ENOSPC;

			ret = __mmu_unsync_walk(child, pvec);
			if (!ret)
				goto clear_child_bitmap;
			else if (ret > 0)
				nr_unsync_leaf += ret;
			else
				return ret;
		} else if (child->unsync) {
			nr_unsync_leaf++;
			if (mmu_pages_add(pvec, child, i))
				return -ENOSPC;
		} else
			 goto clear_child_bitmap;

		continue;

clear_child_bitmap:
		__clear_bit(i, sp->unsync_child_bitmap);
		sp->unsync_children--;
		WARN_ON((int)sp->unsync_children < 0);
1633 1634 1635
	}


1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646
	return nr_unsync_leaf;
}

static int mmu_unsync_walk(struct kvm_mmu_page *sp,
			   struct kvm_mmu_pages *pvec)
{
	if (!sp->unsync_children)
		return 0;

	mmu_pages_add(pvec, sp, 0);
	return __mmu_unsync_walk(sp, pvec);
1647 1648 1649 1650 1651
}

static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp)
{
	WARN_ON(!sp->unsync);
1652
	trace_kvm_mmu_sync_page(sp);
1653 1654 1655 1656
	sp->unsync = 0;
	--kvm->stat.mmu_unsync;
}

1657 1658 1659 1660
static int kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
				    struct list_head *invalid_list);
static void kvm_mmu_commit_zap_page(struct kvm *kvm,
				    struct list_head *invalid_list);
1661

1662 1663
#define for_each_gfn_sp(kvm, sp, gfn, pos)				\
  hlist_for_each_entry(sp, pos,						\
1664 1665 1666
   &(kvm)->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)], hash_link)	\
	if ((sp)->gfn != (gfn)) {} else

1667 1668
#define for_each_gfn_indirect_valid_sp(kvm, sp, gfn, pos)		\
  hlist_for_each_entry(sp, pos,						\
1669 1670 1671 1672
   &(kvm)->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)], hash_link)	\
		if ((sp)->gfn != (gfn) || (sp)->role.direct ||		\
			(sp)->role.invalid) {} else

1673
/* @sp->gfn should be write-protected at the call site */
1674
static int __kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
1675
			   struct list_head *invalid_list, bool clear_unsync)
1676
{
1677
	if (sp->role.cr4_pae != !!is_pae(vcpu)) {
1678
		kvm_mmu_prepare_zap_page(vcpu->kvm, sp, invalid_list);
1679 1680 1681
		return 1;
	}

1682
	if (clear_unsync)
1683 1684
		kvm_unlink_unsync_page(vcpu->kvm, sp);

1685
	if (vcpu->arch.mmu.sync_page(vcpu, sp)) {
1686
		kvm_mmu_prepare_zap_page(vcpu->kvm, sp, invalid_list);
1687 1688 1689 1690 1691 1692 1693
		return 1;
	}

	kvm_mmu_flush_tlb(vcpu);
	return 0;
}

1694 1695 1696
static int kvm_sync_page_transient(struct kvm_vcpu *vcpu,
				   struct kvm_mmu_page *sp)
{
1697
	LIST_HEAD(invalid_list);
1698 1699
	int ret;

1700
	ret = __kvm_sync_page(vcpu, sp, &invalid_list, false);
1701
	if (ret)
1702 1703
		kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);

1704 1705 1706
	return ret;
}

1707 1708 1709 1710 1711 1712 1713
#ifdef CONFIG_KVM_MMU_AUDIT
#include "mmu_audit.c"
#else
static void kvm_mmu_audit(struct kvm_vcpu *vcpu, int point) { }
static void mmu_audit_disable(void) { }
#endif

1714 1715
static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
			 struct list_head *invalid_list)
1716
{
1717
	return __kvm_sync_page(vcpu, sp, invalid_list, true);
1718 1719
}

1720 1721 1722 1723
/* @gfn should be write-protected at the call site */
static void kvm_sync_pages(struct kvm_vcpu *vcpu,  gfn_t gfn)
{
	struct kvm_mmu_page *s;
1724
	struct hlist_node *node;
1725
	LIST_HEAD(invalid_list);
1726 1727
	bool flush = false;

1728
	for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn, node) {
1729
		if (!s->unsync)
1730 1731 1732
			continue;

		WARN_ON(s->role.level != PT_PAGE_TABLE_LEVEL);
1733
		kvm_unlink_unsync_page(vcpu->kvm, s);
1734
		if ((s->role.cr4_pae != !!is_pae(vcpu)) ||
1735
			(vcpu->arch.mmu.sync_page(vcpu, s))) {
1736
			kvm_mmu_prepare_zap_page(vcpu->kvm, s, &invalid_list);
1737 1738 1739 1740 1741
			continue;
		}
		flush = true;
	}

1742
	kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
1743 1744 1745 1746
	if (flush)
		kvm_mmu_flush_tlb(vcpu);
}

1747 1748 1749
struct mmu_page_path {
	struct kvm_mmu_page *parent[PT64_ROOT_LEVEL-1];
	unsigned int idx[PT64_ROOT_LEVEL-1];
1750 1751
};

1752 1753 1754 1755 1756 1757
#define for_each_sp(pvec, sp, parents, i)			\
		for (i = mmu_pages_next(&pvec, &parents, -1),	\
			sp = pvec.page[i].sp;			\
			i < pvec.nr && ({ sp = pvec.page[i].sp; 1;});	\
			i = mmu_pages_next(&pvec, &parents, i))

1758 1759 1760
static int mmu_pages_next(struct kvm_mmu_pages *pvec,
			  struct mmu_page_path *parents,
			  int i)
1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778
{
	int n;

	for (n = i+1; n < pvec->nr; n++) {
		struct kvm_mmu_page *sp = pvec->page[n].sp;

		if (sp->role.level == PT_PAGE_TABLE_LEVEL) {
			parents->idx[0] = pvec->page[n].idx;
			return n;
		}

		parents->parent[sp->role.level-2] = sp;
		parents->idx[sp->role.level-1] = pvec->page[n].idx;
	}

	return n;
}

1779
static void mmu_pages_clear_parents(struct mmu_page_path *parents)
1780
{
1781 1782 1783 1784 1785
	struct kvm_mmu_page *sp;
	unsigned int level = 0;

	do {
		unsigned int idx = parents->idx[level];
1786

1787 1788 1789 1790 1791 1792 1793 1794 1795
		sp = parents->parent[level];
		if (!sp)
			return;

		--sp->unsync_children;
		WARN_ON((int)sp->unsync_children < 0);
		__clear_bit(idx, sp->unsync_child_bitmap);
		level++;
	} while (level < PT64_ROOT_LEVEL-1 && !sp->unsync_children);
1796 1797
}

1798 1799 1800
static void kvm_mmu_pages_init(struct kvm_mmu_page *parent,
			       struct mmu_page_path *parents,
			       struct kvm_mmu_pages *pvec)
1801
{
1802 1803 1804
	parents->parent[parent->role.level-1] = NULL;
	pvec->nr = 0;
}
1805

1806 1807 1808 1809 1810 1811 1812
static void mmu_sync_children(struct kvm_vcpu *vcpu,
			      struct kvm_mmu_page *parent)
{
	int i;
	struct kvm_mmu_page *sp;
	struct mmu_page_path parents;
	struct kvm_mmu_pages pages;
1813
	LIST_HEAD(invalid_list);
1814 1815 1816

	kvm_mmu_pages_init(parent, &parents, &pages);
	while (mmu_unsync_walk(parent, &pages)) {
1817
		bool protected = false;
1818 1819 1820 1821 1822 1823 1824

		for_each_sp(pages, sp, parents, i)
			protected |= rmap_write_protect(vcpu->kvm, sp->gfn);

		if (protected)
			kvm_flush_remote_tlbs(vcpu->kvm);

1825
		for_each_sp(pages, sp, parents, i) {
1826
			kvm_sync_page(vcpu, sp, &invalid_list);
1827 1828
			mmu_pages_clear_parents(&parents);
		}
1829
		kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
1830
		cond_resched_lock(&vcpu->kvm->mmu_lock);
1831 1832
		kvm_mmu_pages_init(parent, &parents, &pages);
	}
1833 1834
}

1835 1836 1837 1838 1839 1840 1841 1842
static void init_shadow_page_table(struct kvm_mmu_page *sp)
{
	int i;

	for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
		sp->spt[i] = 0ull;
}

1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854
static void __clear_sp_write_flooding_count(struct kvm_mmu_page *sp)
{
	sp->write_flooding_count = 0;
}

static void clear_sp_write_flooding_count(u64 *spte)
{
	struct kvm_mmu_page *sp =  page_header(__pa(spte));

	__clear_sp_write_flooding_count(sp);
}

1855 1856 1857 1858
static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
					     gfn_t gfn,
					     gva_t gaddr,
					     unsigned level,
1859
					     int direct,
1860
					     unsigned access,
1861
					     u64 *parent_pte)
1862 1863 1864
{
	union kvm_mmu_page_role role;
	unsigned quadrant;
1865
	struct kvm_mmu_page *sp;
1866
	struct hlist_node *node;
1867
	bool need_sync = false;
1868

1869
	role = vcpu->arch.mmu.base_role;
1870
	role.level = level;
1871
	role.direct = direct;
1872
	if (role.direct)
1873
		role.cr4_pae = 0;
1874
	role.access = access;
1875 1876
	if (!vcpu->arch.mmu.direct_map
	    && vcpu->arch.mmu.root_level <= PT32_ROOT_LEVEL) {
1877 1878 1879 1880
		quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
		quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
		role.quadrant = quadrant;
	}
1881
	for_each_gfn_sp(vcpu->kvm, sp, gfn, node) {
1882 1883
		if (!need_sync && sp->unsync)
			need_sync = true;
1884

1885 1886
		if (sp->role.word != role.word)
			continue;
1887

1888 1889
		if (sp->unsync && kvm_sync_page_transient(vcpu, sp))
			break;
1890

1891 1892
		mmu_page_add_parent_pte(vcpu, sp, parent_pte);
		if (sp->unsync_children) {
1893
			kvm_make_request(KVM_REQ_MMU_SYNC, vcpu);
1894 1895 1896
			kvm_mmu_mark_parents_unsync(sp);
		} else if (sp->unsync)
			kvm_mmu_mark_parents_unsync(sp);
1897

1898
		__clear_sp_write_flooding_count(sp);
1899 1900 1901
		trace_kvm_mmu_get_page(sp, false);
		return sp;
	}
A
Avi Kivity 已提交
1902
	++vcpu->kvm->stat.mmu_cache_miss;
1903
	sp = kvm_mmu_alloc_page(vcpu, parent_pte, direct);
1904 1905 1906 1907
	if (!sp)
		return sp;
	sp->gfn = gfn;
	sp->role = role;
1908 1909
	hlist_add_head(&sp->hash_link,
		&vcpu->kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)]);
1910
	if (!direct) {
1911 1912
		if (rmap_write_protect(vcpu->kvm, gfn))
			kvm_flush_remote_tlbs(vcpu->kvm);
1913 1914 1915
		if (level > PT_PAGE_TABLE_LEVEL && need_sync)
			kvm_sync_pages(vcpu, gfn);

1916 1917
		account_shadowed(vcpu->kvm, gfn);
	}
1918
	init_shadow_page_table(sp);
A
Avi Kivity 已提交
1919
	trace_kvm_mmu_get_page(sp, true);
1920
	return sp;
1921 1922
}

1923 1924 1925 1926 1927 1928
static void shadow_walk_init(struct kvm_shadow_walk_iterator *iterator,
			     struct kvm_vcpu *vcpu, u64 addr)
{
	iterator->addr = addr;
	iterator->shadow_addr = vcpu->arch.mmu.root_hpa;
	iterator->level = vcpu->arch.mmu.shadow_root_level;
1929 1930 1931 1932 1933 1934

	if (iterator->level == PT64_ROOT_LEVEL &&
	    vcpu->arch.mmu.root_level < PT64_ROOT_LEVEL &&
	    !vcpu->arch.mmu.direct_map)
		--iterator->level;

1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948
	if (iterator->level == PT32E_ROOT_LEVEL) {
		iterator->shadow_addr
			= vcpu->arch.mmu.pae_root[(addr >> 30) & 3];
		iterator->shadow_addr &= PT64_BASE_ADDR_MASK;
		--iterator->level;
		if (!iterator->shadow_addr)
			iterator->level = 0;
	}
}

static bool shadow_walk_okay(struct kvm_shadow_walk_iterator *iterator)
{
	if (iterator->level < PT_PAGE_TABLE_LEVEL)
		return false;
1949

1950 1951 1952 1953 1954
	iterator->index = SHADOW_PT_INDEX(iterator->addr, iterator->level);
	iterator->sptep	= ((u64 *)__va(iterator->shadow_addr)) + iterator->index;
	return true;
}

1955 1956
static void __shadow_walk_next(struct kvm_shadow_walk_iterator *iterator,
			       u64 spte)
1957
{
1958
	if (is_last_spte(spte, iterator->level)) {
1959 1960 1961 1962
		iterator->level = 0;
		return;
	}

1963
	iterator->shadow_addr = spte & PT64_BASE_ADDR_MASK;
1964 1965 1966
	--iterator->level;
}

1967 1968 1969 1970 1971
static void shadow_walk_next(struct kvm_shadow_walk_iterator *iterator)
{
	return __shadow_walk_next(iterator, *iterator->sptep);
}

1972 1973 1974 1975 1976 1977 1978
static void link_shadow_page(u64 *sptep, struct kvm_mmu_page *sp)
{
	u64 spte;

	spte = __pa(sp->spt)
		| PT_PRESENT_MASK | PT_ACCESSED_MASK
		| PT_WRITABLE_MASK | PT_USER_MASK;
1979
	mmu_spte_set(sptep, spte);
1980 1981
}

1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
static void validate_direct_spte(struct kvm_vcpu *vcpu, u64 *sptep,
				   unsigned direct_access)
{
	if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep)) {
		struct kvm_mmu_page *child;

		/*
		 * For the direct sp, if the guest pte's dirty bit
		 * changed form clean to dirty, it will corrupt the
		 * sp's access: allow writable in the read-only sp,
		 * so we should update the spte at this point to get
		 * a new sp with the correct access.
		 */
		child = page_header(*sptep & PT64_BASE_ADDR_MASK);
		if (child->role.access == direct_access)
			return;

1999
		drop_parent_pte(child, sptep);
2000 2001 2002 2003
		kvm_flush_remote_tlbs(vcpu->kvm);
	}
}

X
Xiao Guangrong 已提交
2004
static bool mmu_page_zap_pte(struct kvm *kvm, struct kvm_mmu_page *sp,
2005 2006 2007 2008 2009 2010 2011
			     u64 *spte)
{
	u64 pte;
	struct kvm_mmu_page *child;

	pte = *spte;
	if (is_shadow_present_pte(pte)) {
X
Xiao Guangrong 已提交
2012
		if (is_last_spte(pte, sp->role.level)) {
2013
			drop_spte(kvm, spte);
X
Xiao Guangrong 已提交
2014 2015 2016
			if (is_large_pte(pte))
				--kvm->stat.lpages;
		} else {
2017
			child = page_header(pte & PT64_BASE_ADDR_MASK);
2018
			drop_parent_pte(child, spte);
2019
		}
X
Xiao Guangrong 已提交
2020 2021 2022 2023
		return true;
	}

	if (is_mmio_spte(pte))
2024
		mmu_spte_clear_no_track(spte);
2025

X
Xiao Guangrong 已提交
2026
	return false;
2027 2028
}

2029
static void kvm_mmu_page_unlink_children(struct kvm *kvm,
2030
					 struct kvm_mmu_page *sp)
2031
{
2032 2033
	unsigned i;

2034 2035
	for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
		mmu_page_zap_pte(kvm, sp, sp->spt + i);
2036 2037
}

2038
static void kvm_mmu_put_page(struct kvm_mmu_page *sp, u64 *parent_pte)
2039
{
2040
	mmu_page_remove_parent_pte(sp, parent_pte);
2041 2042
}

2043
static void kvm_mmu_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp)
2044
{
2045 2046
	u64 *sptep;
	struct rmap_iterator iter;
2047

2048 2049
	while ((sptep = rmap_get_first(sp->parent_ptes, &iter)))
		drop_parent_pte(sp, sptep);
2050 2051
}

2052
static int mmu_zap_unsync_children(struct kvm *kvm,
2053 2054
				   struct kvm_mmu_page *parent,
				   struct list_head *invalid_list)
2055
{
2056 2057 2058
	int i, zapped = 0;
	struct mmu_page_path parents;
	struct kvm_mmu_pages pages;
2059

2060
	if (parent->role.level == PT_PAGE_TABLE_LEVEL)
2061
		return 0;
2062 2063 2064 2065 2066 2067

	kvm_mmu_pages_init(parent, &parents, &pages);
	while (mmu_unsync_walk(parent, &pages)) {
		struct kvm_mmu_page *sp;

		for_each_sp(pages, sp, parents, i) {
2068
			kvm_mmu_prepare_zap_page(kvm, sp, invalid_list);
2069
			mmu_pages_clear_parents(&parents);
2070
			zapped++;
2071 2072 2073 2074 2075
		}
		kvm_mmu_pages_init(parent, &parents, &pages);
	}

	return zapped;
2076 2077
}

2078 2079
static int kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
				    struct list_head *invalid_list)
2080
{
2081
	int ret;
A
Avi Kivity 已提交
2082

2083
	trace_kvm_mmu_prepare_zap_page(sp);
2084
	++kvm->stat.mmu_shadow_zapped;
2085
	ret = mmu_zap_unsync_children(kvm, sp, invalid_list);
2086
	kvm_mmu_page_unlink_children(kvm, sp);
2087
	kvm_mmu_unlink_parents(kvm, sp);
2088
	if (!sp->role.invalid && !sp->role.direct)
A
Avi Kivity 已提交
2089
		unaccount_shadowed(kvm, sp->gfn);
2090 2091
	if (sp->unsync)
		kvm_unlink_unsync_page(kvm, sp);
2092
	if (!sp->root_count) {
2093 2094
		/* Count self */
		ret++;
2095
		list_move(&sp->link, invalid_list);
2096
		kvm_mod_used_mmu_pages(kvm, -1);
2097
	} else {
A
Avi Kivity 已提交
2098
		list_move(&sp->link, &kvm->arch.active_mmu_pages);
2099 2100
		kvm_reload_remote_mmus(kvm);
	}
2101 2102

	sp->role.invalid = 1;
2103
	return ret;
2104 2105
}

2106 2107 2108 2109 2110 2111 2112 2113
static void kvm_mmu_commit_zap_page(struct kvm *kvm,
				    struct list_head *invalid_list)
{
	struct kvm_mmu_page *sp;

	if (list_empty(invalid_list))
		return;

2114 2115 2116 2117 2118
	/*
	 * wmb: make sure everyone sees our modifications to the page tables
	 * rmb: make sure we see changes to vcpu->mode
	 */
	smp_mb();
X
Xiao Guangrong 已提交
2119

2120 2121 2122 2123 2124
	/*
	 * Wait for all vcpus to exit guest mode and/or lockless shadow
	 * page table walks.
	 */
	kvm_flush_remote_tlbs(kvm);
2125

2126 2127 2128
	do {
		sp = list_first_entry(invalid_list, struct kvm_mmu_page, link);
		WARN_ON(!sp->role.invalid || sp->root_count);
2129
		kvm_mmu_isolate_page(sp);
2130
		kvm_mmu_free_page(sp);
2131 2132 2133
	} while (!list_empty(invalid_list));
}

2134 2135
/*
 * Changing the number of mmu pages allocated to the vm
2136
 * Note: if goal_nr_mmu_pages is too small, you will get dead lock
2137
 */
2138
void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int goal_nr_mmu_pages)
2139
{
2140
	LIST_HEAD(invalid_list);
2141 2142 2143 2144 2145 2146
	/*
	 * If we set the number of mmu pages to be smaller be than the
	 * number of actived pages , we must to free some mmu pages before we
	 * change the value
	 */

2147 2148
	if (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages) {
		while (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages &&
2149
			!list_empty(&kvm->arch.active_mmu_pages)) {
2150 2151
			struct kvm_mmu_page *page;

2152
			page = container_of(kvm->arch.active_mmu_pages.prev,
2153
					    struct kvm_mmu_page, link);
2154
			kvm_mmu_prepare_zap_page(kvm, page, &invalid_list);
2155
		}
2156
		kvm_mmu_commit_zap_page(kvm, &invalid_list);
2157
		goal_nr_mmu_pages = kvm->arch.n_used_mmu_pages;
2158 2159
	}

2160
	kvm->arch.n_max_mmu_pages = goal_nr_mmu_pages;
2161 2162
}

2163
int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
2164
{
2165
	struct kvm_mmu_page *sp;
2166
	struct hlist_node *node;
2167
	LIST_HEAD(invalid_list);
2168 2169
	int r;

2170
	pgprintk("%s: looking for gfn %llx\n", __func__, gfn);
2171
	r = 0;
2172
	spin_lock(&kvm->mmu_lock);
2173
	for_each_gfn_indirect_valid_sp(kvm, sp, gfn, node) {
2174
		pgprintk("%s: gfn %llx role %x\n", __func__, gfn,
2175 2176
			 sp->role.word);
		r = 1;
2177
		kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list);
2178
	}
2179
	kvm_mmu_commit_zap_page(kvm, &invalid_list);
2180 2181
	spin_unlock(&kvm->mmu_lock);

2182
	return r;
2183
}
2184
EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page);
2185

2186
static void page_header_update_slot(struct kvm *kvm, void *pte, gfn_t gfn)
A
Avi Kivity 已提交
2187
{
2188
	int slot = memslot_id(kvm, gfn);
2189
	struct kvm_mmu_page *sp = page_header(__pa(pte));
A
Avi Kivity 已提交
2190

2191
	__set_bit(slot, sp->slot_bitmap);
A
Avi Kivity 已提交
2192 2193
}

2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286
/*
 * The function is based on mtrr_type_lookup() in
 * arch/x86/kernel/cpu/mtrr/generic.c
 */
static int get_mtrr_type(struct mtrr_state_type *mtrr_state,
			 u64 start, u64 end)
{
	int i;
	u64 base, mask;
	u8 prev_match, curr_match;
	int num_var_ranges = KVM_NR_VAR_MTRR;

	if (!mtrr_state->enabled)
		return 0xFF;

	/* Make end inclusive end, instead of exclusive */
	end--;

	/* Look in fixed ranges. Just return the type as per start */
	if (mtrr_state->have_fixed && (start < 0x100000)) {
		int idx;

		if (start < 0x80000) {
			idx = 0;
			idx += (start >> 16);
			return mtrr_state->fixed_ranges[idx];
		} else if (start < 0xC0000) {
			idx = 1 * 8;
			idx += ((start - 0x80000) >> 14);
			return mtrr_state->fixed_ranges[idx];
		} else if (start < 0x1000000) {
			idx = 3 * 8;
			idx += ((start - 0xC0000) >> 12);
			return mtrr_state->fixed_ranges[idx];
		}
	}

	/*
	 * Look in variable ranges
	 * Look of multiple ranges matching this address and pick type
	 * as per MTRR precedence
	 */
	if (!(mtrr_state->enabled & 2))
		return mtrr_state->def_type;

	prev_match = 0xFF;
	for (i = 0; i < num_var_ranges; ++i) {
		unsigned short start_state, end_state;

		if (!(mtrr_state->var_ranges[i].mask_lo & (1 << 11)))
			continue;

		base = (((u64)mtrr_state->var_ranges[i].base_hi) << 32) +
		       (mtrr_state->var_ranges[i].base_lo & PAGE_MASK);
		mask = (((u64)mtrr_state->var_ranges[i].mask_hi) << 32) +
		       (mtrr_state->var_ranges[i].mask_lo & PAGE_MASK);

		start_state = ((start & mask) == (base & mask));
		end_state = ((end & mask) == (base & mask));
		if (start_state != end_state)
			return 0xFE;

		if ((start & mask) != (base & mask))
			continue;

		curr_match = mtrr_state->var_ranges[i].base_lo & 0xff;
		if (prev_match == 0xFF) {
			prev_match = curr_match;
			continue;
		}

		if (prev_match == MTRR_TYPE_UNCACHABLE ||
		    curr_match == MTRR_TYPE_UNCACHABLE)
			return MTRR_TYPE_UNCACHABLE;

		if ((prev_match == MTRR_TYPE_WRBACK &&
		     curr_match == MTRR_TYPE_WRTHROUGH) ||
		    (prev_match == MTRR_TYPE_WRTHROUGH &&
		     curr_match == MTRR_TYPE_WRBACK)) {
			prev_match = MTRR_TYPE_WRTHROUGH;
			curr_match = MTRR_TYPE_WRTHROUGH;
		}

		if (prev_match != curr_match)
			return MTRR_TYPE_UNCACHABLE;
	}

	if (prev_match != 0xFF)
		return prev_match;

	return mtrr_state->def_type;
}

2287
u8 kvm_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn)
2288 2289 2290 2291 2292 2293 2294 2295 2296
{
	u8 mtrr;

	mtrr = get_mtrr_type(&vcpu->arch.mtrr_state, gfn << PAGE_SHIFT,
			     (gfn << PAGE_SHIFT) + PAGE_SIZE);
	if (mtrr == 0xfe || mtrr == 0xff)
		mtrr = MTRR_TYPE_WRBACK;
	return mtrr;
}
2297
EXPORT_SYMBOL_GPL(kvm_get_guest_memory_type);
2298

2299 2300 2301 2302 2303 2304 2305 2306 2307 2308
static void __kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
{
	trace_kvm_mmu_unsync_page(sp);
	++vcpu->kvm->stat.mmu_unsync;
	sp->unsync = 1;

	kvm_mmu_mark_parents_unsync(sp);
}

static void kvm_unsync_pages(struct kvm_vcpu *vcpu,  gfn_t gfn)
2309 2310
{
	struct kvm_mmu_page *s;
2311
	struct hlist_node *node;
2312

2313
	for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn, node) {
2314
		if (s->unsync)
2315
			continue;
2316 2317
		WARN_ON(s->role.level != PT_PAGE_TABLE_LEVEL);
		__kvm_unsync_page(vcpu, s);
2318 2319 2320 2321 2322 2323
	}
}

static int mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn,
				  bool can_unsync)
{
2324
	struct kvm_mmu_page *s;
2325
	struct hlist_node *node;
2326 2327
	bool need_unsync = false;

2328
	for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn, node) {
2329 2330 2331
		if (!can_unsync)
			return 1;

2332
		if (s->role.level != PT_PAGE_TABLE_LEVEL)
2333
			return 1;
2334 2335 2336 2337

		if (!need_unsync && !s->unsync) {
			need_unsync = true;
		}
2338
	}
2339 2340
	if (need_unsync)
		kvm_unsync_pages(vcpu, gfn);
2341 2342 2343
	return 0;
}

A
Avi Kivity 已提交
2344
static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
M
Marcelo Tosatti 已提交
2345
		    unsigned pte_access, int user_fault,
2346
		    int write_fault, int level,
2347
		    gfn_t gfn, pfn_t pfn, bool speculative,
2348
		    bool can_unsync, bool host_writable)
2349
{
2350
	u64 spte;
M
Marcelo Tosatti 已提交
2351
	int ret = 0;
S
Sheng Yang 已提交
2352

2353 2354 2355
	if (set_mmio_spte(sptep, gfn, pfn, pte_access))
		return 0;

2356
	spte = PT_PRESENT_MASK;
2357
	if (!speculative)
2358
		spte |= shadow_accessed_mask;
2359

S
Sheng Yang 已提交
2360 2361 2362 2363
	if (pte_access & ACC_EXEC_MASK)
		spte |= shadow_x_mask;
	else
		spte |= shadow_nx_mask;
2364

2365
	if (pte_access & ACC_USER_MASK)
S
Sheng Yang 已提交
2366
		spte |= shadow_user_mask;
2367

2368
	if (level > PT_PAGE_TABLE_LEVEL)
M
Marcelo Tosatti 已提交
2369
		spte |= PT_PAGE_SIZE_MASK;
2370
	if (tdp_enabled)
2371 2372
		spte |= kvm_x86_ops->get_mt_mask(vcpu, gfn,
			kvm_is_mmio_pfn(pfn));
2373

2374
	if (host_writable)
2375
		spte |= SPTE_HOST_WRITEABLE;
2376 2377
	else
		pte_access &= ~ACC_WRITE_MASK;
2378

2379
	spte |= (u64)pfn << PAGE_SHIFT;
2380 2381

	if ((pte_access & ACC_WRITE_MASK)
2382 2383
	    || (!vcpu->arch.mmu.direct_map && write_fault
		&& !is_write_protection(vcpu) && !user_fault)) {
2384

2385 2386
		if (level > PT_PAGE_TABLE_LEVEL &&
		    has_wrprotected_page(vcpu->kvm, gfn, level)) {
2387
			ret = 1;
2388
			drop_spte(vcpu->kvm, sptep);
A
Avi Kivity 已提交
2389
			goto done;
2390 2391
		}

2392
		spte |= PT_WRITABLE_MASK | SPTE_MMU_WRITEABLE;
2393

2394
		if (!vcpu->arch.mmu.direct_map
2395
		    && !(pte_access & ACC_WRITE_MASK)) {
2396
			spte &= ~PT_USER_MASK;
2397 2398 2399 2400 2401 2402 2403 2404 2405
			/*
			 * If we converted a user page to a kernel page,
			 * so that the kernel can write to it when cr0.wp=0,
			 * then we should prevent the kernel from executing it
			 * if SMEP is enabled.
			 */
			if (kvm_read_cr4_bits(vcpu, X86_CR4_SMEP))
				spte |= PT64_NX_MASK;
		}
2406

2407 2408 2409 2410 2411 2412
		/*
		 * Optimization: for pte sync, if spte was writable the hash
		 * lookup is unnecessary (and expensive). Write protection
		 * is responsibility of mmu_get_page / kvm_sync_page.
		 * Same reasoning can be applied to dirty page accounting.
		 */
2413
		if (!can_unsync && is_writable_pte(*sptep))
2414 2415
			goto set_pte;

2416
		if (mmu_need_write_protect(vcpu, gfn, can_unsync)) {
2417
			pgprintk("%s: found shadow page for %llx, marking ro\n",
2418
				 __func__, gfn);
M
Marcelo Tosatti 已提交
2419
			ret = 1;
2420
			pte_access &= ~ACC_WRITE_MASK;
2421
			spte &= ~(PT_WRITABLE_MASK | SPTE_MMU_WRITEABLE);
2422 2423 2424 2425 2426 2427
		}
	}

	if (pte_access & ACC_WRITE_MASK)
		mark_page_dirty(vcpu->kvm, gfn);

2428
set_pte:
2429
	if (mmu_spte_update(sptep, spte))
2430
		kvm_flush_remote_tlbs(vcpu->kvm);
A
Avi Kivity 已提交
2431
done:
M
Marcelo Tosatti 已提交
2432 2433 2434
	return ret;
}

A
Avi Kivity 已提交
2435
static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
M
Marcelo Tosatti 已提交
2436
			 unsigned pt_access, unsigned pte_access,
2437
			 int user_fault, int write_fault,
2438
			 int *emulate, int level, gfn_t gfn,
2439
			 pfn_t pfn, bool speculative,
2440
			 bool host_writable)
M
Marcelo Tosatti 已提交
2441 2442
{
	int was_rmapped = 0;
2443
	int rmap_count;
M
Marcelo Tosatti 已提交
2444 2445

	pgprintk("%s: spte %llx access %x write_fault %d"
2446
		 " user_fault %d gfn %llx\n",
A
Avi Kivity 已提交
2447
		 __func__, *sptep, pt_access,
M
Marcelo Tosatti 已提交
2448 2449
		 write_fault, user_fault, gfn);

A
Avi Kivity 已提交
2450
	if (is_rmap_spte(*sptep)) {
M
Marcelo Tosatti 已提交
2451 2452 2453 2454
		/*
		 * If we overwrite a PTE page pointer with a 2MB PMD, unlink
		 * the parent of the now unreachable PTE.
		 */
2455 2456
		if (level > PT_PAGE_TABLE_LEVEL &&
		    !is_large_pte(*sptep)) {
M
Marcelo Tosatti 已提交
2457
			struct kvm_mmu_page *child;
A
Avi Kivity 已提交
2458
			u64 pte = *sptep;
M
Marcelo Tosatti 已提交
2459 2460

			child = page_header(pte & PT64_BASE_ADDR_MASK);
2461
			drop_parent_pte(child, sptep);
2462
			kvm_flush_remote_tlbs(vcpu->kvm);
A
Avi Kivity 已提交
2463
		} else if (pfn != spte_to_pfn(*sptep)) {
2464
			pgprintk("hfn old %llx new %llx\n",
A
Avi Kivity 已提交
2465
				 spte_to_pfn(*sptep), pfn);
2466
			drop_spte(vcpu->kvm, sptep);
2467
			kvm_flush_remote_tlbs(vcpu->kvm);
2468 2469
		} else
			was_rmapped = 1;
M
Marcelo Tosatti 已提交
2470
	}
2471

A
Avi Kivity 已提交
2472
	if (set_spte(vcpu, sptep, pte_access, user_fault, write_fault,
2473
		      level, gfn, pfn, speculative, true,
2474
		      host_writable)) {
M
Marcelo Tosatti 已提交
2475
		if (write_fault)
2476
			*emulate = 1;
2477
		kvm_mmu_flush_tlb(vcpu);
2478
	}
M
Marcelo Tosatti 已提交
2479

2480 2481 2482
	if (unlikely(is_mmio_spte(*sptep) && emulate))
		*emulate = 1;

A
Avi Kivity 已提交
2483
	pgprintk("%s: setting spte %llx\n", __func__, *sptep);
2484
	pgprintk("instantiating %s PTE (%s) at %llx (%llx) addr %p\n",
A
Avi Kivity 已提交
2485
		 is_large_pte(*sptep)? "2MB" : "4kB",
2486 2487
		 *sptep & PT_PRESENT_MASK ?"RW":"R", gfn,
		 *sptep, sptep);
A
Avi Kivity 已提交
2488
	if (!was_rmapped && is_large_pte(*sptep))
M
Marcelo Tosatti 已提交
2489 2490
		++vcpu->kvm->stat.lpages;

2491 2492 2493 2494 2495 2496 2497
	if (is_shadow_present_pte(*sptep)) {
		page_header_update_slot(vcpu->kvm, sptep, gfn);
		if (!was_rmapped) {
			rmap_count = rmap_add(vcpu, sptep, gfn);
			if (rmap_count > RMAP_RECYCLE_THRESHOLD)
				rmap_recycle(vcpu, sptep, gfn);
		}
2498
	}
2499 2500 2501

	if (!is_error_pfn(pfn))
		kvm_release_pfn_clean(pfn);
2502 2503
}

A
Avi Kivity 已提交
2504 2505
static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
{
2506
	mmu_free_roots(vcpu);
A
Avi Kivity 已提交
2507 2508
}

2509 2510 2511 2512 2513
static pfn_t pte_prefetch_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn,
				     bool no_dirty_log)
{
	struct kvm_memory_slot *slot;

2514
	slot = gfn_to_memslot_dirty_bitmap(vcpu, gfn, no_dirty_log);
2515
	if (!slot)
2516
		return KVM_PFN_ERR_FAULT;
2517

2518
	return gfn_to_pfn_memslot_atomic(slot, gfn);
2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530
}

static int direct_pte_prefetch_many(struct kvm_vcpu *vcpu,
				    struct kvm_mmu_page *sp,
				    u64 *start, u64 *end)
{
	struct page *pages[PTE_PREFETCH_NUM];
	unsigned access = sp->role.access;
	int i, ret;
	gfn_t gfn;

	gfn = kvm_mmu_page_get_gfn(sp, start - sp->spt);
2531
	if (!gfn_to_memslot_dirty_bitmap(vcpu, gfn, access & ACC_WRITE_MASK))
2532 2533 2534 2535 2536 2537 2538 2539
		return -1;

	ret = gfn_to_page_many_atomic(vcpu->kvm, gfn, pages, end - start);
	if (ret <= 0)
		return -1;

	for (i = 0; i < ret; i++, gfn++, start++)
		mmu_set_spte(vcpu, start, ACC_ALL,
2540
			     access, 0, 0, NULL,
2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558
			     sp->role.level, gfn,
			     page_to_pfn(pages[i]), true, true);

	return 0;
}

static void __direct_pte_prefetch(struct kvm_vcpu *vcpu,
				  struct kvm_mmu_page *sp, u64 *sptep)
{
	u64 *spte, *start = NULL;
	int i;

	WARN_ON(!sp->role.direct);

	i = (sptep - sp->spt) & ~(PTE_PREFETCH_NUM - 1);
	spte = sp->spt + i;

	for (i = 0; i < PTE_PREFETCH_NUM; i++, spte++) {
2559
		if (is_shadow_present_pte(*spte) || spte == sptep) {
2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589
			if (!start)
				continue;
			if (direct_pte_prefetch_many(vcpu, sp, start, spte) < 0)
				break;
			start = NULL;
		} else if (!start)
			start = spte;
	}
}

static void direct_pte_prefetch(struct kvm_vcpu *vcpu, u64 *sptep)
{
	struct kvm_mmu_page *sp;

	/*
	 * Since it's no accessed bit on EPT, it's no way to
	 * distinguish between actually accessed translations
	 * and prefetched, so disable pte prefetch if EPT is
	 * enabled.
	 */
	if (!shadow_accessed_mask)
		return;

	sp = page_header(__pa(sptep));
	if (sp->role.level > PT_PAGE_TABLE_LEVEL)
		return;

	__direct_pte_prefetch(vcpu, sp, sptep);
}

2590
static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
2591 2592
			int map_writable, int level, gfn_t gfn, pfn_t pfn,
			bool prefault)
2593
{
2594
	struct kvm_shadow_walk_iterator iterator;
2595
	struct kvm_mmu_page *sp;
2596
	int emulate = 0;
2597
	gfn_t pseudo_gfn;
A
Avi Kivity 已提交
2598

2599
	for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) {
2600
		if (iterator.level == level) {
2601 2602 2603
			unsigned pte_access = ACC_ALL;

			mmu_set_spte(vcpu, iterator.sptep, ACC_ALL, pte_access,
2604
				     0, write, &emulate,
2605
				     level, gfn, pfn, prefault, map_writable);
2606
			direct_pte_prefetch(vcpu, iterator.sptep);
2607 2608
			++vcpu->stat.pf_fixed;
			break;
A
Avi Kivity 已提交
2609 2610
		}

2611
		if (!is_shadow_present_pte(*iterator.sptep)) {
2612 2613 2614 2615
			u64 base_addr = iterator.addr;

			base_addr &= PT64_LVL_ADDR_MASK(iterator.level);
			pseudo_gfn = base_addr >> PAGE_SHIFT;
2616 2617 2618
			sp = kvm_mmu_get_page(vcpu, pseudo_gfn, iterator.addr,
					      iterator.level - 1,
					      1, ACC_ALL, iterator.sptep);
2619

2620 2621 2622 2623 2624
			mmu_spte_set(iterator.sptep,
				     __pa(sp->spt)
				     | PT_PRESENT_MASK | PT_WRITABLE_MASK
				     | shadow_user_mask | shadow_x_mask
				     | shadow_accessed_mask);
2625 2626
		}
	}
2627
	return emulate;
A
Avi Kivity 已提交
2628 2629
}

H
Huang Ying 已提交
2630
static void kvm_send_hwpoison_signal(unsigned long address, struct task_struct *tsk)
2631
{
H
Huang Ying 已提交
2632 2633 2634 2635 2636 2637 2638
	siginfo_t info;

	info.si_signo	= SIGBUS;
	info.si_errno	= 0;
	info.si_code	= BUS_MCEERR_AR;
	info.si_addr	= (void __user *)address;
	info.si_addr_lsb = PAGE_SHIFT;
2639

H
Huang Ying 已提交
2640
	send_sig_info(SIGBUS, &info, tsk);
2641 2642
}

2643
static int kvm_handle_bad_page(struct kvm_vcpu *vcpu, gfn_t gfn, pfn_t pfn)
2644
{
X
Xiao Guangrong 已提交
2645 2646 2647 2648 2649 2650 2651 2652 2653
	/*
	 * Do not cache the mmio info caused by writing the readonly gfn
	 * into the spte otherwise read access on readonly gfn also can
	 * caused mmio page fault and treat it as mmio access.
	 * Return 1 to tell kvm to emulate it.
	 */
	if (pfn == KVM_PFN_ERR_RO_FAULT)
		return 1;

2654
	if (pfn == KVM_PFN_ERR_HWPOISON) {
2655
		kvm_send_hwpoison_signal(gfn_to_hva(vcpu->kvm, gfn), current);
2656
		return 0;
2657
	}
2658

2659
	return -EFAULT;
2660 2661
}

2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696
static void transparent_hugepage_adjust(struct kvm_vcpu *vcpu,
					gfn_t *gfnp, pfn_t *pfnp, int *levelp)
{
	pfn_t pfn = *pfnp;
	gfn_t gfn = *gfnp;
	int level = *levelp;

	/*
	 * Check if it's a transparent hugepage. If this would be an
	 * hugetlbfs page, level wouldn't be set to
	 * PT_PAGE_TABLE_LEVEL and there would be no adjustment done
	 * here.
	 */
	if (!is_error_pfn(pfn) && !kvm_is_mmio_pfn(pfn) &&
	    level == PT_PAGE_TABLE_LEVEL &&
	    PageTransCompound(pfn_to_page(pfn)) &&
	    !has_wrprotected_page(vcpu->kvm, gfn, PT_DIRECTORY_LEVEL)) {
		unsigned long mask;
		/*
		 * mmu_notifier_retry was successful and we hold the
		 * mmu_lock here, so the pmd can't become splitting
		 * from under us, and in turn
		 * __split_huge_page_refcount() can't run from under
		 * us and we can safely transfer the refcount from
		 * PG_tail to PG_head as we switch the pfn to tail to
		 * head.
		 */
		*levelp = level = PT_DIRECTORY_LEVEL;
		mask = KVM_PAGES_PER_HPAGE(level) - 1;
		VM_BUG_ON((gfn & mask) != (pfn & mask));
		if (pfn & mask) {
			gfn &= ~mask;
			*gfnp = gfn;
			kvm_release_pfn_clean(pfn);
			pfn &= ~mask;
2697
			kvm_get_pfn(pfn);
2698 2699 2700 2701 2702
			*pfnp = pfn;
		}
	}
}

2703 2704
static bool mmu_invalid_pfn(pfn_t pfn)
{
2705
	return unlikely(is_invalid_pfn(pfn));
2706 2707 2708 2709 2710 2711 2712 2713 2714 2715 2716 2717 2718
}

static bool handle_abnormal_pfn(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn,
				pfn_t pfn, unsigned access, int *ret_val)
{
	bool ret = true;

	/* The pfn is invalid, report the error! */
	if (unlikely(is_invalid_pfn(pfn))) {
		*ret_val = kvm_handle_bad_page(vcpu, gfn, pfn);
		goto exit;
	}

2719
	if (unlikely(is_noslot_pfn(pfn)))
2720 2721 2722 2723 2724 2725 2726
		vcpu_cache_mmio_info(vcpu, gva, gfn, access);

	ret = false;
exit:
	return ret;
}

2727 2728 2729 2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817
static bool page_fault_can_be_fast(struct kvm_vcpu *vcpu, u32 error_code)
{
	/*
	 * #PF can be fast only if the shadow page table is present and it
	 * is caused by write-protect, that means we just need change the
	 * W bit of the spte which can be done out of mmu-lock.
	 */
	if (!(error_code & PFERR_PRESENT_MASK) ||
	      !(error_code & PFERR_WRITE_MASK))
		return false;

	return true;
}

static bool
fast_pf_fix_direct_spte(struct kvm_vcpu *vcpu, u64 *sptep, u64 spte)
{
	struct kvm_mmu_page *sp = page_header(__pa(sptep));
	gfn_t gfn;

	WARN_ON(!sp->role.direct);

	/*
	 * The gfn of direct spte is stable since it is calculated
	 * by sp->gfn.
	 */
	gfn = kvm_mmu_page_get_gfn(sp, sptep - sp->spt);

	if (cmpxchg64(sptep, spte, spte | PT_WRITABLE_MASK) == spte)
		mark_page_dirty(vcpu->kvm, gfn);

	return true;
}

/*
 * Return value:
 * - true: let the vcpu to access on the same address again.
 * - false: let the real page fault path to fix it.
 */
static bool fast_page_fault(struct kvm_vcpu *vcpu, gva_t gva, int level,
			    u32 error_code)
{
	struct kvm_shadow_walk_iterator iterator;
	bool ret = false;
	u64 spte = 0ull;

	if (!page_fault_can_be_fast(vcpu, error_code))
		return false;

	walk_shadow_page_lockless_begin(vcpu);
	for_each_shadow_entry_lockless(vcpu, gva, iterator, spte)
		if (!is_shadow_present_pte(spte) || iterator.level < level)
			break;

	/*
	 * If the mapping has been changed, let the vcpu fault on the
	 * same address again.
	 */
	if (!is_rmap_spte(spte)) {
		ret = true;
		goto exit;
	}

	if (!is_last_spte(spte, level))
		goto exit;

	/*
	 * Check if it is a spurious fault caused by TLB lazily flushed.
	 *
	 * Need not check the access of upper level table entries since
	 * they are always ACC_ALL.
	 */
	 if (is_writable_pte(spte)) {
		ret = true;
		goto exit;
	}

	/*
	 * Currently, to simplify the code, only the spte write-protected
	 * by dirty-log can be fast fixed.
	 */
	if (!spte_is_locklessly_modifiable(spte))
		goto exit;

	/*
	 * Currently, fast page fault only works for direct mapping since
	 * the gfn is not stable for indirect shadow page.
	 * See Documentation/virtual/kvm/locking.txt to get more detail.
	 */
	ret = fast_pf_fix_direct_spte(vcpu, iterator.sptep, spte);
exit:
X
Xiao Guangrong 已提交
2818 2819
	trace_fast_page_fault(vcpu, gva, error_code, iterator.sptep,
			      spte, ret);
2820 2821 2822 2823 2824
	walk_shadow_page_lockless_end(vcpu);

	return ret;
}

2825
static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
2826 2827
			 gva_t gva, pfn_t *pfn, bool write, bool *writable);

2828 2829
static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, u32 error_code,
			 gfn_t gfn, bool prefault)
2830 2831
{
	int r;
2832
	int level;
2833
	int force_pt_level;
2834
	pfn_t pfn;
2835
	unsigned long mmu_seq;
2836
	bool map_writable, write = error_code & PFERR_WRITE_MASK;
2837

2838 2839 2840 2841 2842 2843 2844 2845 2846 2847
	force_pt_level = mapping_level_dirty_bitmap(vcpu, gfn);
	if (likely(!force_pt_level)) {
		level = mapping_level(vcpu, gfn);
		/*
		 * This path builds a PAE pagetable - so we can map
		 * 2mb pages at maximum. Therefore check if the level
		 * is larger than that.
		 */
		if (level > PT_DIRECTORY_LEVEL)
			level = PT_DIRECTORY_LEVEL;
2848

2849 2850 2851
		gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
	} else
		level = PT_PAGE_TABLE_LEVEL;
M
Marcelo Tosatti 已提交
2852

2853 2854 2855
	if (fast_page_fault(vcpu, v, level, error_code))
		return 0;

2856
	mmu_seq = vcpu->kvm->mmu_notifier_seq;
2857
	smp_rmb();
2858

2859
	if (try_async_pf(vcpu, prefault, gfn, v, &pfn, write, &map_writable))
2860
		return 0;
2861

2862 2863
	if (handle_abnormal_pfn(vcpu, v, gfn, pfn, ACC_ALL, &r))
		return r;
2864

2865
	spin_lock(&vcpu->kvm->mmu_lock);
2866 2867
	if (mmu_notifier_retry(vcpu, mmu_seq))
		goto out_unlock;
2868
	kvm_mmu_free_some_pages(vcpu);
2869 2870
	if (likely(!force_pt_level))
		transparent_hugepage_adjust(vcpu, &gfn, &pfn, &level);
2871 2872
	r = __direct_map(vcpu, v, write, map_writable, level, gfn, pfn,
			 prefault);
2873 2874 2875
	spin_unlock(&vcpu->kvm->mmu_lock);


2876
	return r;
2877 2878 2879 2880 2881

out_unlock:
	spin_unlock(&vcpu->kvm->mmu_lock);
	kvm_release_pfn_clean(pfn);
	return 0;
2882 2883 2884
}


2885 2886 2887
static void mmu_free_roots(struct kvm_vcpu *vcpu)
{
	int i;
2888
	struct kvm_mmu_page *sp;
2889
	LIST_HEAD(invalid_list);
2890

2891
	if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
A
Avi Kivity 已提交
2892
		return;
2893
	spin_lock(&vcpu->kvm->mmu_lock);
2894 2895 2896
	if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL &&
	    (vcpu->arch.mmu.root_level == PT64_ROOT_LEVEL ||
	     vcpu->arch.mmu.direct_map)) {
2897
		hpa_t root = vcpu->arch.mmu.root_hpa;
2898

2899 2900
		sp = page_header(root);
		--sp->root_count;
2901 2902 2903 2904
		if (!sp->root_count && sp->role.invalid) {
			kvm_mmu_prepare_zap_page(vcpu->kvm, sp, &invalid_list);
			kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
		}
2905
		vcpu->arch.mmu.root_hpa = INVALID_PAGE;
2906
		spin_unlock(&vcpu->kvm->mmu_lock);
2907 2908 2909
		return;
	}
	for (i = 0; i < 4; ++i) {
2910
		hpa_t root = vcpu->arch.mmu.pae_root[i];
2911

A
Avi Kivity 已提交
2912 2913
		if (root) {
			root &= PT64_BASE_ADDR_MASK;
2914 2915
			sp = page_header(root);
			--sp->root_count;
2916
			if (!sp->root_count && sp->role.invalid)
2917 2918
				kvm_mmu_prepare_zap_page(vcpu->kvm, sp,
							 &invalid_list);
A
Avi Kivity 已提交
2919
		}
2920
		vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
2921
	}
2922
	kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
2923
	spin_unlock(&vcpu->kvm->mmu_lock);
2924
	vcpu->arch.mmu.root_hpa = INVALID_PAGE;
2925 2926
}

2927 2928 2929 2930 2931
static int mmu_check_root(struct kvm_vcpu *vcpu, gfn_t root_gfn)
{
	int ret = 0;

	if (!kvm_is_visible_gfn(vcpu->kvm, root_gfn)) {
2932
		kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
2933 2934 2935 2936 2937 2938
		ret = 1;
	}

	return ret;
}

2939 2940 2941
static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
{
	struct kvm_mmu_page *sp;
2942
	unsigned i;
2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956 2957 2958

	if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
		spin_lock(&vcpu->kvm->mmu_lock);
		kvm_mmu_free_some_pages(vcpu);
		sp = kvm_mmu_get_page(vcpu, 0, 0, PT64_ROOT_LEVEL,
				      1, ACC_ALL, NULL);
		++sp->root_count;
		spin_unlock(&vcpu->kvm->mmu_lock);
		vcpu->arch.mmu.root_hpa = __pa(sp->spt);
	} else if (vcpu->arch.mmu.shadow_root_level == PT32E_ROOT_LEVEL) {
		for (i = 0; i < 4; ++i) {
			hpa_t root = vcpu->arch.mmu.pae_root[i];

			ASSERT(!VALID_PAGE(root));
			spin_lock(&vcpu->kvm->mmu_lock);
			kvm_mmu_free_some_pages(vcpu);
2959 2960
			sp = kvm_mmu_get_page(vcpu, i << (30 - PAGE_SHIFT),
					      i << 30,
2961 2962 2963 2964 2965 2966 2967
					      PT32_ROOT_LEVEL, 1, ACC_ALL,
					      NULL);
			root = __pa(sp->spt);
			++sp->root_count;
			spin_unlock(&vcpu->kvm->mmu_lock);
			vcpu->arch.mmu.pae_root[i] = root | PT_PRESENT_MASK;
		}
2968
		vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
2969 2970 2971 2972 2973 2974 2975
	} else
		BUG();

	return 0;
}

static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
2976
{
2977
	struct kvm_mmu_page *sp;
2978 2979 2980
	u64 pdptr, pm_mask;
	gfn_t root_gfn;
	int i;
2981

2982
	root_gfn = vcpu->arch.mmu.get_cr3(vcpu) >> PAGE_SHIFT;
2983

2984 2985 2986 2987 2988 2989 2990 2991
	if (mmu_check_root(vcpu, root_gfn))
		return 1;

	/*
	 * Do we shadow a long mode page table? If so we need to
	 * write-protect the guests page table root.
	 */
	if (vcpu->arch.mmu.root_level == PT64_ROOT_LEVEL) {
2992
		hpa_t root = vcpu->arch.mmu.root_hpa;
2993 2994

		ASSERT(!VALID_PAGE(root));
2995

2996
		spin_lock(&vcpu->kvm->mmu_lock);
2997
		kvm_mmu_free_some_pages(vcpu);
2998 2999
		sp = kvm_mmu_get_page(vcpu, root_gfn, 0, PT64_ROOT_LEVEL,
				      0, ACC_ALL, NULL);
3000 3001
		root = __pa(sp->spt);
		++sp->root_count;
3002
		spin_unlock(&vcpu->kvm->mmu_lock);
3003
		vcpu->arch.mmu.root_hpa = root;
3004
		return 0;
3005
	}
3006

3007 3008
	/*
	 * We shadow a 32 bit page table. This may be a legacy 2-level
3009 3010
	 * or a PAE 3-level page table. In either case we need to be aware that
	 * the shadow page table may be a PAE or a long mode page table.
3011
	 */
3012 3013 3014 3015
	pm_mask = PT_PRESENT_MASK;
	if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL)
		pm_mask |= PT_ACCESSED_MASK | PT_WRITABLE_MASK | PT_USER_MASK;

3016
	for (i = 0; i < 4; ++i) {
3017
		hpa_t root = vcpu->arch.mmu.pae_root[i];
3018 3019

		ASSERT(!VALID_PAGE(root));
3020
		if (vcpu->arch.mmu.root_level == PT32E_ROOT_LEVEL) {
3021
			pdptr = vcpu->arch.mmu.get_pdptr(vcpu, i);
3022
			if (!is_present_gpte(pdptr)) {
3023
				vcpu->arch.mmu.pae_root[i] = 0;
A
Avi Kivity 已提交
3024 3025
				continue;
			}
A
Avi Kivity 已提交
3026
			root_gfn = pdptr >> PAGE_SHIFT;
3027 3028
			if (mmu_check_root(vcpu, root_gfn))
				return 1;
3029
		}
3030
		spin_lock(&vcpu->kvm->mmu_lock);
3031
		kvm_mmu_free_some_pages(vcpu);
3032
		sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
3033
				      PT32_ROOT_LEVEL, 0,
3034
				      ACC_ALL, NULL);
3035 3036
		root = __pa(sp->spt);
		++sp->root_count;
3037 3038
		spin_unlock(&vcpu->kvm->mmu_lock);

3039
		vcpu->arch.mmu.pae_root[i] = root | pm_mask;
3040
	}
3041
	vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058 3059 3060 3061 3062 3063 3064 3065 3066 3067

	/*
	 * If we shadow a 32 bit page table with a long mode page
	 * table we enter this path.
	 */
	if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
		if (vcpu->arch.mmu.lm_root == NULL) {
			/*
			 * The additional page necessary for this is only
			 * allocated on demand.
			 */

			u64 *lm_root;

			lm_root = (void*)get_zeroed_page(GFP_KERNEL);
			if (lm_root == NULL)
				return 1;

			lm_root[0] = __pa(vcpu->arch.mmu.pae_root) | pm_mask;

			vcpu->arch.mmu.lm_root = lm_root;
		}

		vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.lm_root);
	}

3068
	return 0;
3069 3070
}

3071 3072 3073 3074 3075 3076 3077 3078
static int mmu_alloc_roots(struct kvm_vcpu *vcpu)
{
	if (vcpu->arch.mmu.direct_map)
		return mmu_alloc_direct_roots(vcpu);
	else
		return mmu_alloc_shadow_roots(vcpu);
}

3079 3080 3081 3082 3083
static void mmu_sync_roots(struct kvm_vcpu *vcpu)
{
	int i;
	struct kvm_mmu_page *sp;

3084 3085 3086
	if (vcpu->arch.mmu.direct_map)
		return;

3087 3088
	if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
		return;
3089

3090
	vcpu_clear_mmio_info(vcpu, ~0ul);
3091
	kvm_mmu_audit(vcpu, AUDIT_PRE_SYNC);
3092
	if (vcpu->arch.mmu.root_level == PT64_ROOT_LEVEL) {
3093 3094 3095
		hpa_t root = vcpu->arch.mmu.root_hpa;
		sp = page_header(root);
		mmu_sync_children(vcpu, sp);
3096
		kvm_mmu_audit(vcpu, AUDIT_POST_SYNC);
3097 3098 3099 3100 3101
		return;
	}
	for (i = 0; i < 4; ++i) {
		hpa_t root = vcpu->arch.mmu.pae_root[i];

3102
		if (root && VALID_PAGE(root)) {
3103 3104 3105 3106 3107
			root &= PT64_BASE_ADDR_MASK;
			sp = page_header(root);
			mmu_sync_children(vcpu, sp);
		}
	}
3108
	kvm_mmu_audit(vcpu, AUDIT_POST_SYNC);
3109 3110 3111 3112 3113 3114
}

void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu)
{
	spin_lock(&vcpu->kvm->mmu_lock);
	mmu_sync_roots(vcpu);
3115
	spin_unlock(&vcpu->kvm->mmu_lock);
3116 3117
}

3118
static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr,
3119
				  u32 access, struct x86_exception *exception)
A
Avi Kivity 已提交
3120
{
3121 3122
	if (exception)
		exception->error_code = 0;
A
Avi Kivity 已提交
3123 3124 3125
	return vaddr;
}

3126
static gpa_t nonpaging_gva_to_gpa_nested(struct kvm_vcpu *vcpu, gva_t vaddr,
3127 3128
					 u32 access,
					 struct x86_exception *exception)
3129
{
3130 3131
	if (exception)
		exception->error_code = 0;
3132 3133 3134
	return vcpu->arch.nested_mmu.translate_gpa(vcpu, vaddr, access);
}

3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191
static bool quickly_check_mmio_pf(struct kvm_vcpu *vcpu, u64 addr, bool direct)
{
	if (direct)
		return vcpu_match_mmio_gpa(vcpu, addr);

	return vcpu_match_mmio_gva(vcpu, addr);
}


/*
 * On direct hosts, the last spte is only allows two states
 * for mmio page fault:
 *   - It is the mmio spte
 *   - It is zapped or it is being zapped.
 *
 * This function completely checks the spte when the last spte
 * is not the mmio spte.
 */
static bool check_direct_spte_mmio_pf(u64 spte)
{
	return __check_direct_spte_mmio_pf(spte);
}

static u64 walk_shadow_page_get_mmio_spte(struct kvm_vcpu *vcpu, u64 addr)
{
	struct kvm_shadow_walk_iterator iterator;
	u64 spte = 0ull;

	walk_shadow_page_lockless_begin(vcpu);
	for_each_shadow_entry_lockless(vcpu, addr, iterator, spte)
		if (!is_shadow_present_pte(spte))
			break;
	walk_shadow_page_lockless_end(vcpu);

	return spte;
}

/*
 * If it is a real mmio page fault, return 1 and emulat the instruction
 * directly, return 0 to let CPU fault again on the address, -1 is
 * returned if bug is detected.
 */
int handle_mmio_page_fault_common(struct kvm_vcpu *vcpu, u64 addr, bool direct)
{
	u64 spte;

	if (quickly_check_mmio_pf(vcpu, addr, direct))
		return 1;

	spte = walk_shadow_page_get_mmio_spte(vcpu, addr);

	if (is_mmio_spte(spte)) {
		gfn_t gfn = get_mmio_spte_gfn(spte);
		unsigned access = get_mmio_spte_access(spte);

		if (direct)
			addr = 0;
X
Xiao Guangrong 已提交
3192 3193

		trace_handle_mmio_page_fault(addr, gfn, access);
3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 3222
		vcpu_cache_mmio_info(vcpu, addr, gfn, access);
		return 1;
	}

	/*
	 * It's ok if the gva is remapped by other cpus on shadow guest,
	 * it's a BUG if the gfn is not a mmio page.
	 */
	if (direct && !check_direct_spte_mmio_pf(spte))
		return -1;

	/*
	 * If the page table is zapped by other cpus, let CPU fault again on
	 * the address.
	 */
	return 0;
}
EXPORT_SYMBOL_GPL(handle_mmio_page_fault_common);

static int handle_mmio_page_fault(struct kvm_vcpu *vcpu, u64 addr,
				  u32 error_code, bool direct)
{
	int ret;

	ret = handle_mmio_page_fault_common(vcpu, addr, direct);
	WARN_ON(ret < 0);
	return ret;
}

A
Avi Kivity 已提交
3223
static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
3224
				u32 error_code, bool prefault)
A
Avi Kivity 已提交
3225
{
3226
	gfn_t gfn;
3227
	int r;
A
Avi Kivity 已提交
3228

3229
	pgprintk("%s: gva %lx error %x\n", __func__, gva, error_code);
3230 3231 3232 3233

	if (unlikely(error_code & PFERR_RSVD_MASK))
		return handle_mmio_page_fault(vcpu, gva, error_code, true);

3234 3235 3236
	r = mmu_topup_memory_caches(vcpu);
	if (r)
		return r;
3237

A
Avi Kivity 已提交
3238
	ASSERT(vcpu);
3239
	ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
A
Avi Kivity 已提交
3240

3241
	gfn = gva >> PAGE_SHIFT;
A
Avi Kivity 已提交
3242

3243
	return nonpaging_map(vcpu, gva & PAGE_MASK,
3244
			     error_code, gfn, prefault);
A
Avi Kivity 已提交
3245 3246
}

3247
static int kvm_arch_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn)
3248 3249
{
	struct kvm_arch_async_pf arch;
X
Xiao Guangrong 已提交
3250

3251
	arch.token = (vcpu->arch.apf.id++ << 12) | vcpu->vcpu_id;
3252
	arch.gfn = gfn;
3253
	arch.direct_map = vcpu->arch.mmu.direct_map;
X
Xiao Guangrong 已提交
3254
	arch.cr3 = vcpu->arch.mmu.get_cr3(vcpu);
3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267

	return kvm_setup_async_pf(vcpu, gva, gfn, &arch);
}

static bool can_do_async_pf(struct kvm_vcpu *vcpu)
{
	if (unlikely(!irqchip_in_kernel(vcpu->kvm) ||
		     kvm_event_needs_reinjection(vcpu)))
		return false;

	return kvm_x86_ops->interrupt_allowed(vcpu);
}

3268
static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
3269
			 gva_t gva, pfn_t *pfn, bool write, bool *writable)
3270 3271 3272
{
	bool async;

3273
	*pfn = gfn_to_pfn_async(vcpu->kvm, gfn, &async, write, writable);
3274 3275 3276 3277

	if (!async)
		return false; /* *pfn has correct page already */

3278
	if (!prefault && can_do_async_pf(vcpu)) {
3279
		trace_kvm_try_async_get_page(gva, gfn);
3280 3281 3282 3283 3284 3285 3286 3287
		if (kvm_find_async_pf_gfn(vcpu, gfn)) {
			trace_kvm_async_pf_doublefault(gva, gfn);
			kvm_make_request(KVM_REQ_APF_HALT, vcpu);
			return true;
		} else if (kvm_arch_setup_async_pf(vcpu, gva, gfn))
			return true;
	}

3288
	*pfn = gfn_to_pfn_prot(vcpu->kvm, gfn, write, writable);
3289 3290 3291 3292

	return false;
}

G
Gleb Natapov 已提交
3293
static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
3294
			  bool prefault)
3295
{
3296
	pfn_t pfn;
3297
	int r;
3298
	int level;
3299
	int force_pt_level;
M
Marcelo Tosatti 已提交
3300
	gfn_t gfn = gpa >> PAGE_SHIFT;
3301
	unsigned long mmu_seq;
3302 3303
	int write = error_code & PFERR_WRITE_MASK;
	bool map_writable;
3304 3305 3306 3307

	ASSERT(vcpu);
	ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));

3308 3309 3310
	if (unlikely(error_code & PFERR_RSVD_MASK))
		return handle_mmio_page_fault(vcpu, gpa, error_code, true);

3311 3312 3313 3314
	r = mmu_topup_memory_caches(vcpu);
	if (r)
		return r;

3315 3316 3317 3318 3319 3320
	force_pt_level = mapping_level_dirty_bitmap(vcpu, gfn);
	if (likely(!force_pt_level)) {
		level = mapping_level(vcpu, gfn);
		gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
	} else
		level = PT_PAGE_TABLE_LEVEL;
3321

3322 3323 3324
	if (fast_page_fault(vcpu, gpa, level, error_code))
		return 0;

3325
	mmu_seq = vcpu->kvm->mmu_notifier_seq;
3326
	smp_rmb();
3327

3328
	if (try_async_pf(vcpu, prefault, gfn, gpa, &pfn, write, &map_writable))
3329 3330
		return 0;

3331 3332 3333
	if (handle_abnormal_pfn(vcpu, 0, gfn, pfn, ACC_ALL, &r))
		return r;

3334
	spin_lock(&vcpu->kvm->mmu_lock);
3335 3336
	if (mmu_notifier_retry(vcpu, mmu_seq))
		goto out_unlock;
3337
	kvm_mmu_free_some_pages(vcpu);
3338 3339
	if (likely(!force_pt_level))
		transparent_hugepage_adjust(vcpu, &gfn, &pfn, &level);
3340
	r = __direct_map(vcpu, gpa, write, map_writable,
3341
			 level, gfn, pfn, prefault);
3342 3343 3344
	spin_unlock(&vcpu->kvm->mmu_lock);

	return r;
3345 3346 3347 3348 3349

out_unlock:
	spin_unlock(&vcpu->kvm->mmu_lock);
	kvm_release_pfn_clean(pfn);
	return 0;
3350 3351
}

A
Avi Kivity 已提交
3352 3353
static void nonpaging_free(struct kvm_vcpu *vcpu)
{
3354
	mmu_free_roots(vcpu);
A
Avi Kivity 已提交
3355 3356
}

3357 3358
static int nonpaging_init_context(struct kvm_vcpu *vcpu,
				  struct kvm_mmu *context)
A
Avi Kivity 已提交
3359 3360 3361 3362 3363
{
	context->new_cr3 = nonpaging_new_cr3;
	context->page_fault = nonpaging_page_fault;
	context->gva_to_gpa = nonpaging_gva_to_gpa;
	context->free = nonpaging_free;
3364
	context->sync_page = nonpaging_sync_page;
M
Marcelo Tosatti 已提交
3365
	context->invlpg = nonpaging_invlpg;
3366
	context->update_pte = nonpaging_update_pte;
3367
	context->root_level = 0;
A
Avi Kivity 已提交
3368
	context->shadow_root_level = PT32E_ROOT_LEVEL;
A
Avi Kivity 已提交
3369
	context->root_hpa = INVALID_PAGE;
3370
	context->direct_map = true;
3371
	context->nx = false;
A
Avi Kivity 已提交
3372 3373 3374
	return 0;
}

3375
void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
A
Avi Kivity 已提交
3376
{
A
Avi Kivity 已提交
3377
	++vcpu->stat.tlb_flush;
3378
	kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
A
Avi Kivity 已提交
3379 3380 3381 3382
}

static void paging_new_cr3(struct kvm_vcpu *vcpu)
{
3383
	pgprintk("%s: cr3 %lx\n", __func__, kvm_read_cr3(vcpu));
3384
	mmu_free_roots(vcpu);
A
Avi Kivity 已提交
3385 3386
}

3387 3388
static unsigned long get_cr3(struct kvm_vcpu *vcpu)
{
3389
	return kvm_read_cr3(vcpu);
3390 3391
}

3392 3393
static void inject_page_fault(struct kvm_vcpu *vcpu,
			      struct x86_exception *fault)
A
Avi Kivity 已提交
3394
{
3395
	vcpu->arch.mmu.inject_page_fault(vcpu, fault);
A
Avi Kivity 已提交
3396 3397 3398 3399 3400 3401 3402
}

static void paging_free(struct kvm_vcpu *vcpu)
{
	nonpaging_free(vcpu);
}

3403
static bool is_rsvd_bits_set(struct kvm_mmu *mmu, u64 gpte, int level)
3404 3405 3406 3407
{
	int bit7;

	bit7 = (gpte >> 7) & 1;
3408
	return (gpte & mmu->rsvd_bits_mask[bit7][level-1]) != 0;
3409 3410
}

3411 3412 3413 3414 3415 3416 3417 3418 3419 3420 3421 3422
static inline void protect_clean_gpte(unsigned *access, unsigned gpte)
{
	unsigned mask;

	BUILD_BUG_ON(PT_WRITABLE_MASK != ACC_WRITE_MASK);

	mask = (unsigned)~ACC_WRITE_MASK;
	/* Allow write access to dirty gptes */
	mask |= (gpte >> (PT_DIRTY_SHIFT - PT_WRITABLE_SHIFT)) & PT_WRITABLE_MASK;
	*access &= mask;
}

3423 3424 3425 3426 3427 3428 3429 3430 3431 3432 3433 3434 3435 3436 3437 3438 3439
static bool sync_mmio_spte(u64 *sptep, gfn_t gfn, unsigned access,
			   int *nr_present)
{
	if (unlikely(is_mmio_spte(*sptep))) {
		if (gfn != get_mmio_spte_gfn(*sptep)) {
			mmu_spte_clear_no_track(sptep);
			return true;
		}

		(*nr_present)++;
		mark_mmio_spte(sptep, gfn, access);
		return true;
	}

	return false;
}

3440 3441 3442 3443 3444 3445 3446 3447 3448 3449
static inline unsigned gpte_access(struct kvm_vcpu *vcpu, u64 gpte)
{
	unsigned access;

	access = (gpte & (PT_WRITABLE_MASK | PT_USER_MASK)) | ACC_EXEC_MASK;
	access &= ~(gpte >> PT64_NX_SHIFT);

	return access;
}

A
Avi Kivity 已提交
3450 3451 3452 3453 3454 3455 3456 3457 3458
static inline bool is_last_gpte(struct kvm_mmu *mmu, unsigned level, unsigned gpte)
{
	unsigned index;

	index = level - 1;
	index |= (gpte & PT_PAGE_SIZE_MASK) >> (PT_PAGE_SIZE_SHIFT - 2);
	return mmu->last_pte_bitmap & (1 << index);
}

A
Avi Kivity 已提交
3459 3460 3461 3462 3463 3464 3465 3466
#define PTTYPE 64
#include "paging_tmpl.h"
#undef PTTYPE

#define PTTYPE 32
#include "paging_tmpl.h"
#undef PTTYPE

3467
static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu,
3468
				  struct kvm_mmu *context)
3469 3470 3471 3472
{
	int maxphyaddr = cpuid_maxphyaddr(vcpu);
	u64 exb_bit_rsvd = 0;

3473
	if (!context->nx)
3474
		exb_bit_rsvd = rsvd_bits(63, 63);
3475
	switch (context->root_level) {
3476 3477 3478 3479
	case PT32_ROOT_LEVEL:
		/* no rsvd bits for 2 level 4K page table entries */
		context->rsvd_bits_mask[0][1] = 0;
		context->rsvd_bits_mask[0][0] = 0;
3480 3481 3482 3483 3484 3485 3486
		context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];

		if (!is_pse(vcpu)) {
			context->rsvd_bits_mask[1][1] = 0;
			break;
		}

3487 3488 3489 3490 3491 3492 3493 3494
		if (is_cpuid_PSE36())
			/* 36bits PSE 4MB page */
			context->rsvd_bits_mask[1][1] = rsvd_bits(17, 21);
		else
			/* 32 bits PSE 4MB page */
			context->rsvd_bits_mask[1][1] = rsvd_bits(13, 21);
		break;
	case PT32E_ROOT_LEVEL:
3495 3496 3497
		context->rsvd_bits_mask[0][2] =
			rsvd_bits(maxphyaddr, 63) |
			rsvd_bits(7, 8) | rsvd_bits(1, 2);	/* PDPTE */
3498
		context->rsvd_bits_mask[0][1] = exb_bit_rsvd |
3499
			rsvd_bits(maxphyaddr, 62);	/* PDE */
3500 3501 3502 3503 3504
		context->rsvd_bits_mask[0][0] = exb_bit_rsvd |
			rsvd_bits(maxphyaddr, 62); 	/* PTE */
		context->rsvd_bits_mask[1][1] = exb_bit_rsvd |
			rsvd_bits(maxphyaddr, 62) |
			rsvd_bits(13, 20);		/* large page */
3505
		context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];
3506 3507 3508 3509 3510 3511 3512
		break;
	case PT64_ROOT_LEVEL:
		context->rsvd_bits_mask[0][3] = exb_bit_rsvd |
			rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 8);
		context->rsvd_bits_mask[0][2] = exb_bit_rsvd |
			rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 8);
		context->rsvd_bits_mask[0][1] = exb_bit_rsvd |
3513
			rsvd_bits(maxphyaddr, 51);
3514 3515 3516
		context->rsvd_bits_mask[0][0] = exb_bit_rsvd |
			rsvd_bits(maxphyaddr, 51);
		context->rsvd_bits_mask[1][3] = context->rsvd_bits_mask[0][3];
3517 3518 3519
		context->rsvd_bits_mask[1][2] = exb_bit_rsvd |
			rsvd_bits(maxphyaddr, 51) |
			rsvd_bits(13, 29);
3520
		context->rsvd_bits_mask[1][1] = exb_bit_rsvd |
3521 3522
			rsvd_bits(maxphyaddr, 51) |
			rsvd_bits(13, 20);		/* large page */
3523
		context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];
3524 3525 3526 3527
		break;
	}
}

3528 3529 3530 3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559
static void update_permission_bitmask(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu)
{
	unsigned bit, byte, pfec;
	u8 map;
	bool fault, x, w, u, wf, uf, ff, smep;

	smep = kvm_read_cr4_bits(vcpu, X86_CR4_SMEP);
	for (byte = 0; byte < ARRAY_SIZE(mmu->permissions); ++byte) {
		pfec = byte << 1;
		map = 0;
		wf = pfec & PFERR_WRITE_MASK;
		uf = pfec & PFERR_USER_MASK;
		ff = pfec & PFERR_FETCH_MASK;
		for (bit = 0; bit < 8; ++bit) {
			x = bit & ACC_EXEC_MASK;
			w = bit & ACC_WRITE_MASK;
			u = bit & ACC_USER_MASK;

			/* Not really needed: !nx will cause pte.nx to fault */
			x |= !mmu->nx;
			/* Allow supervisor writes if !cr0.wp */
			w |= !is_write_protection(vcpu) && !uf;
			/* Disallow supervisor fetches of user code if cr4.smep */
			x &= !(smep && u && !uf);

			fault = (ff && !x) || (uf && !u) || (wf && !w);
			map |= fault << bit;
		}
		mmu->permissions[byte] = map;
	}
}

A
Avi Kivity 已提交
3560 3561 3562 3563 3564 3565 3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577
static void update_last_pte_bitmap(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu)
{
	u8 map;
	unsigned level, root_level = mmu->root_level;
	const unsigned ps_set_index = 1 << 2;  /* bit 2 of index: ps */

	if (root_level == PT32E_ROOT_LEVEL)
		--root_level;
	/* PT_PAGE_TABLE_LEVEL always terminates */
	map = 1 | (1 << ps_set_index);
	for (level = PT_DIRECTORY_LEVEL; level <= root_level; ++level) {
		if (level <= PT_PDPE_LEVEL
		    && (mmu->root_level >= PT32E_ROOT_LEVEL || is_pse(vcpu)))
			map |= 1 << (ps_set_index | (level - 1));
	}
	mmu->last_pte_bitmap = map;
}

3578 3579 3580
static int paging64_init_context_common(struct kvm_vcpu *vcpu,
					struct kvm_mmu *context,
					int level)
A
Avi Kivity 已提交
3581
{
3582
	context->nx = is_nx(vcpu);
3583
	context->root_level = level;
3584

3585
	reset_rsvds_bits_mask(vcpu, context);
3586
	update_permission_bitmask(vcpu, context);
A
Avi Kivity 已提交
3587
	update_last_pte_bitmap(vcpu, context);
A
Avi Kivity 已提交
3588 3589 3590 3591 3592

	ASSERT(is_pae(vcpu));
	context->new_cr3 = paging_new_cr3;
	context->page_fault = paging64_page_fault;
	context->gva_to_gpa = paging64_gva_to_gpa;
3593
	context->sync_page = paging64_sync_page;
M
Marcelo Tosatti 已提交
3594
	context->invlpg = paging64_invlpg;
3595
	context->update_pte = paging64_update_pte;
A
Avi Kivity 已提交
3596
	context->free = paging_free;
3597
	context->shadow_root_level = level;
A
Avi Kivity 已提交
3598
	context->root_hpa = INVALID_PAGE;
3599
	context->direct_map = false;
A
Avi Kivity 已提交
3600 3601 3602
	return 0;
}

3603 3604
static int paging64_init_context(struct kvm_vcpu *vcpu,
				 struct kvm_mmu *context)
3605
{
3606
	return paging64_init_context_common(vcpu, context, PT64_ROOT_LEVEL);
3607 3608
}

3609 3610
static int paging32_init_context(struct kvm_vcpu *vcpu,
				 struct kvm_mmu *context)
A
Avi Kivity 已提交
3611
{
3612
	context->nx = false;
3613
	context->root_level = PT32_ROOT_LEVEL;
3614

3615
	reset_rsvds_bits_mask(vcpu, context);
3616
	update_permission_bitmask(vcpu, context);
A
Avi Kivity 已提交
3617
	update_last_pte_bitmap(vcpu, context);
A
Avi Kivity 已提交
3618 3619 3620 3621 3622

	context->new_cr3 = paging_new_cr3;
	context->page_fault = paging32_page_fault;
	context->gva_to_gpa = paging32_gva_to_gpa;
	context->free = paging_free;
3623
	context->sync_page = paging32_sync_page;
M
Marcelo Tosatti 已提交
3624
	context->invlpg = paging32_invlpg;
3625
	context->update_pte = paging32_update_pte;
A
Avi Kivity 已提交
3626
	context->shadow_root_level = PT32E_ROOT_LEVEL;
A
Avi Kivity 已提交
3627
	context->root_hpa = INVALID_PAGE;
3628
	context->direct_map = false;
A
Avi Kivity 已提交
3629 3630 3631
	return 0;
}

3632 3633
static int paging32E_init_context(struct kvm_vcpu *vcpu,
				  struct kvm_mmu *context)
A
Avi Kivity 已提交
3634
{
3635
	return paging64_init_context_common(vcpu, context, PT32E_ROOT_LEVEL);
A
Avi Kivity 已提交
3636 3637
}

3638 3639
static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
{
3640
	struct kvm_mmu *context = vcpu->arch.walk_mmu;
3641

3642
	context->base_role.word = 0;
3643 3644 3645
	context->new_cr3 = nonpaging_new_cr3;
	context->page_fault = tdp_page_fault;
	context->free = nonpaging_free;
3646
	context->sync_page = nonpaging_sync_page;
M
Marcelo Tosatti 已提交
3647
	context->invlpg = nonpaging_invlpg;
3648
	context->update_pte = nonpaging_update_pte;
3649
	context->shadow_root_level = kvm_x86_ops->get_tdp_level();
3650
	context->root_hpa = INVALID_PAGE;
3651
	context->direct_map = true;
3652
	context->set_cr3 = kvm_x86_ops->set_tdp_cr3;
3653
	context->get_cr3 = get_cr3;
3654
	context->get_pdptr = kvm_pdptr_read;
3655
	context->inject_page_fault = kvm_inject_page_fault;
3656 3657

	if (!is_paging(vcpu)) {
3658
		context->nx = false;
3659 3660 3661
		context->gva_to_gpa = nonpaging_gva_to_gpa;
		context->root_level = 0;
	} else if (is_long_mode(vcpu)) {
3662
		context->nx = is_nx(vcpu);
3663
		context->root_level = PT64_ROOT_LEVEL;
3664 3665
		reset_rsvds_bits_mask(vcpu, context);
		context->gva_to_gpa = paging64_gva_to_gpa;
3666
	} else if (is_pae(vcpu)) {
3667
		context->nx = is_nx(vcpu);
3668
		context->root_level = PT32E_ROOT_LEVEL;
3669 3670
		reset_rsvds_bits_mask(vcpu, context);
		context->gva_to_gpa = paging64_gva_to_gpa;
3671
	} else {
3672
		context->nx = false;
3673
		context->root_level = PT32_ROOT_LEVEL;
3674 3675
		reset_rsvds_bits_mask(vcpu, context);
		context->gva_to_gpa = paging32_gva_to_gpa;
3676 3677
	}

3678
	update_permission_bitmask(vcpu, context);
A
Avi Kivity 已提交
3679
	update_last_pte_bitmap(vcpu, context);
3680

3681 3682 3683
	return 0;
}

3684
int kvm_init_shadow_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *context)
A
Avi Kivity 已提交
3685
{
3686
	int r;
3687
	bool smep = kvm_read_cr4_bits(vcpu, X86_CR4_SMEP);
A
Avi Kivity 已提交
3688
	ASSERT(vcpu);
3689
	ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
A
Avi Kivity 已提交
3690 3691

	if (!is_paging(vcpu))
3692
		r = nonpaging_init_context(vcpu, context);
A
Avi Kivity 已提交
3693
	else if (is_long_mode(vcpu))
3694
		r = paging64_init_context(vcpu, context);
A
Avi Kivity 已提交
3695
	else if (is_pae(vcpu))
3696
		r = paging32E_init_context(vcpu, context);
A
Avi Kivity 已提交
3697
	else
3698
		r = paging32_init_context(vcpu, context);
3699

3700
	vcpu->arch.mmu.base_role.cr4_pae = !!is_pae(vcpu);
3701
	vcpu->arch.mmu.base_role.cr0_wp  = is_write_protection(vcpu);
3702 3703
	vcpu->arch.mmu.base_role.smep_andnot_wp
		= smep && !is_write_protection(vcpu);
3704 3705 3706 3707 3708 3709 3710

	return r;
}
EXPORT_SYMBOL_GPL(kvm_init_shadow_mmu);

static int init_kvm_softmmu(struct kvm_vcpu *vcpu)
{
3711
	int r = kvm_init_shadow_mmu(vcpu, vcpu->arch.walk_mmu);
3712

3713 3714
	vcpu->arch.walk_mmu->set_cr3           = kvm_x86_ops->set_cr3;
	vcpu->arch.walk_mmu->get_cr3           = get_cr3;
3715
	vcpu->arch.walk_mmu->get_pdptr         = kvm_pdptr_read;
3716
	vcpu->arch.walk_mmu->inject_page_fault = kvm_inject_page_fault;
3717 3718

	return r;
A
Avi Kivity 已提交
3719 3720
}

3721 3722 3723 3724 3725
static int init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
{
	struct kvm_mmu *g_context = &vcpu->arch.nested_mmu;

	g_context->get_cr3           = get_cr3;
3726
	g_context->get_pdptr         = kvm_pdptr_read;
3727 3728 3729 3730 3731 3732 3733 3734 3735
	g_context->inject_page_fault = kvm_inject_page_fault;

	/*
	 * Note that arch.mmu.gva_to_gpa translates l2_gva to l1_gpa. The
	 * translation of l2_gpa to l1_gpa addresses is done using the
	 * arch.nested_mmu.gva_to_gpa function. Basically the gva_to_gpa
	 * functions between mmu and nested_mmu are swapped.
	 */
	if (!is_paging(vcpu)) {
3736
		g_context->nx = false;
3737 3738 3739
		g_context->root_level = 0;
		g_context->gva_to_gpa = nonpaging_gva_to_gpa_nested;
	} else if (is_long_mode(vcpu)) {
3740
		g_context->nx = is_nx(vcpu);
3741
		g_context->root_level = PT64_ROOT_LEVEL;
3742
		reset_rsvds_bits_mask(vcpu, g_context);
3743 3744
		g_context->gva_to_gpa = paging64_gva_to_gpa_nested;
	} else if (is_pae(vcpu)) {
3745
		g_context->nx = is_nx(vcpu);
3746
		g_context->root_level = PT32E_ROOT_LEVEL;
3747
		reset_rsvds_bits_mask(vcpu, g_context);
3748 3749
		g_context->gva_to_gpa = paging64_gva_to_gpa_nested;
	} else {
3750
		g_context->nx = false;
3751
		g_context->root_level = PT32_ROOT_LEVEL;
3752
		reset_rsvds_bits_mask(vcpu, g_context);
3753 3754 3755
		g_context->gva_to_gpa = paging32_gva_to_gpa_nested;
	}

3756
	update_permission_bitmask(vcpu, g_context);
A
Avi Kivity 已提交
3757
	update_last_pte_bitmap(vcpu, g_context);
3758

3759 3760 3761
	return 0;
}

3762 3763
static int init_kvm_mmu(struct kvm_vcpu *vcpu)
{
3764 3765 3766
	if (mmu_is_nested(vcpu))
		return init_kvm_nested_mmu(vcpu);
	else if (tdp_enabled)
3767 3768 3769 3770 3771
		return init_kvm_tdp_mmu(vcpu);
	else
		return init_kvm_softmmu(vcpu);
}

A
Avi Kivity 已提交
3772 3773 3774
static void destroy_kvm_mmu(struct kvm_vcpu *vcpu)
{
	ASSERT(vcpu);
3775 3776
	if (VALID_PAGE(vcpu->arch.mmu.root_hpa))
		/* mmu.free() should set root_hpa = INVALID_PAGE */
3777
		vcpu->arch.mmu.free(vcpu);
A
Avi Kivity 已提交
3778 3779 3780
}

int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
A
Avi Kivity 已提交
3781 3782
{
	destroy_kvm_mmu(vcpu);
3783
	return init_kvm_mmu(vcpu);
A
Avi Kivity 已提交
3784
}
3785
EXPORT_SYMBOL_GPL(kvm_mmu_reset_context);
A
Avi Kivity 已提交
3786 3787

int kvm_mmu_load(struct kvm_vcpu *vcpu)
A
Avi Kivity 已提交
3788
{
3789 3790
	int r;

3791
	r = mmu_topup_memory_caches(vcpu);
A
Avi Kivity 已提交
3792 3793
	if (r)
		goto out;
3794
	r = mmu_alloc_roots(vcpu);
3795
	spin_lock(&vcpu->kvm->mmu_lock);
3796
	mmu_sync_roots(vcpu);
3797
	spin_unlock(&vcpu->kvm->mmu_lock);
3798 3799
	if (r)
		goto out;
3800
	/* set_cr3() should ensure TLB has been flushed */
3801
	vcpu->arch.mmu.set_cr3(vcpu, vcpu->arch.mmu.root_hpa);
3802 3803
out:
	return r;
A
Avi Kivity 已提交
3804
}
A
Avi Kivity 已提交
3805 3806 3807 3808 3809 3810
EXPORT_SYMBOL_GPL(kvm_mmu_load);

void kvm_mmu_unload(struct kvm_vcpu *vcpu)
{
	mmu_free_roots(vcpu);
}
3811
EXPORT_SYMBOL_GPL(kvm_mmu_unload);
A
Avi Kivity 已提交
3812

3813
static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
3814 3815
				  struct kvm_mmu_page *sp, u64 *spte,
				  const void *new)
3816
{
3817
	if (sp->role.level != PT_PAGE_TABLE_LEVEL) {
3818 3819
		++vcpu->kvm->stat.mmu_pde_zapped;
		return;
3820
        }
3821

A
Avi Kivity 已提交
3822
	++vcpu->kvm->stat.mmu_pte_updated;
3823
	vcpu->arch.mmu.update_pte(vcpu, sp, spte, new);
3824 3825
}

3826 3827 3828 3829 3830 3831 3832 3833 3834 3835 3836 3837 3838
static bool need_remote_flush(u64 old, u64 new)
{
	if (!is_shadow_present_pte(old))
		return false;
	if (!is_shadow_present_pte(new))
		return true;
	if ((old ^ new) & PT64_BASE_ADDR_MASK)
		return true;
	old ^= PT64_NX_MASK;
	new ^= PT64_NX_MASK;
	return (old & ~new & PT64_PERM_MASK) != 0;
}

3839 3840
static void mmu_pte_write_flush_tlb(struct kvm_vcpu *vcpu, bool zap_page,
				    bool remote_flush, bool local_flush)
3841
{
3842 3843 3844 3845
	if (zap_page)
		return;

	if (remote_flush)
3846
		kvm_flush_remote_tlbs(vcpu->kvm);
3847
	else if (local_flush)
3848 3849 3850
		kvm_mmu_flush_tlb(vcpu);
}

3851 3852
static u64 mmu_pte_write_fetch_gpte(struct kvm_vcpu *vcpu, gpa_t *gpa,
				    const u8 *new, int *bytes)
3853
{
3854 3855
	u64 gentry;
	int r;
3856 3857 3858

	/*
	 * Assume that the pte write on a page table of the same type
3859 3860
	 * as the current vcpu paging mode since we update the sptes only
	 * when they have the same mode.
3861
	 */
3862
	if (is_pae(vcpu) && *bytes == 4) {
3863
		/* Handle a 32-bit guest writing two halves of a 64-bit gpte */
3864 3865 3866
		*gpa &= ~(gpa_t)7;
		*bytes = 8;
		r = kvm_read_guest(vcpu->kvm, *gpa, &gentry, min(*bytes, 8));
3867 3868
		if (r)
			gentry = 0;
3869 3870 3871
		new = (const u8 *)&gentry;
	}

3872
	switch (*bytes) {
3873 3874 3875 3876 3877 3878 3879 3880 3881
	case 4:
		gentry = *(const u32 *)new;
		break;
	case 8:
		gentry = *(const u64 *)new;
		break;
	default:
		gentry = 0;
		break;
3882 3883
	}

3884 3885 3886 3887 3888 3889 3890
	return gentry;
}

/*
 * If we're seeing too many writes to a page, it may no longer be a page table,
 * or we may be forking, in which case it is better to unmap the page.
 */
3891
static bool detect_write_flooding(struct kvm_mmu_page *sp)
3892
{
3893 3894 3895 3896
	/*
	 * Skip write-flooding detected for the sp whose level is 1, because
	 * it can become unsync, then the guest page is not write-protected.
	 */
3897
	if (sp->role.level == PT_PAGE_TABLE_LEVEL)
3898
		return false;
3899

3900
	return ++sp->write_flooding_count >= 3;
3901 3902 3903 3904 3905 3906 3907 3908 3909 3910 3911 3912 3913 3914 3915 3916
}

/*
 * Misaligned accesses are too much trouble to fix up; also, they usually
 * indicate a page is not used as a page table.
 */
static bool detect_write_misaligned(struct kvm_mmu_page *sp, gpa_t gpa,
				    int bytes)
{
	unsigned offset, pte_size, misaligned;

	pgprintk("misaligned: gpa %llx bytes %d role %x\n",
		 gpa, bytes, sp->role.word);

	offset = offset_in_page(gpa);
	pte_size = sp->role.cr4_pae ? 8 : 4;
3917 3918 3919 3920 3921 3922 3923 3924

	/*
	 * Sometimes, the OS only writes the last one bytes to update status
	 * bits, for example, in linux, andb instruction is used in clear_bit().
	 */
	if (!(offset & (pte_size - 1)) && bytes == 1)
		return false;

3925 3926 3927 3928 3929 3930 3931 3932 3933 3934 3935 3936 3937 3938 3939 3940 3941 3942 3943 3944 3945 3946 3947 3948 3949 3950 3951 3952 3953 3954 3955 3956 3957 3958 3959 3960 3961 3962 3963 3964 3965 3966 3967 3968 3969 3970 3971
	misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
	misaligned |= bytes < 4;

	return misaligned;
}

static u64 *get_written_sptes(struct kvm_mmu_page *sp, gpa_t gpa, int *nspte)
{
	unsigned page_offset, quadrant;
	u64 *spte;
	int level;

	page_offset = offset_in_page(gpa);
	level = sp->role.level;
	*nspte = 1;
	if (!sp->role.cr4_pae) {
		page_offset <<= 1;	/* 32->64 */
		/*
		 * A 32-bit pde maps 4MB while the shadow pdes map
		 * only 2MB.  So we need to double the offset again
		 * and zap two pdes instead of one.
		 */
		if (level == PT32_ROOT_LEVEL) {
			page_offset &= ~7; /* kill rounding error */
			page_offset <<= 1;
			*nspte = 2;
		}
		quadrant = page_offset >> PAGE_SHIFT;
		page_offset &= ~PAGE_MASK;
		if (quadrant != sp->role.quadrant)
			return NULL;
	}

	spte = &sp->spt[page_offset / sizeof(*spte)];
	return spte;
}

void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
		       const u8 *new, int bytes)
{
	gfn_t gfn = gpa >> PAGE_SHIFT;
	union kvm_mmu_page_role mask = { .word = 0 };
	struct kvm_mmu_page *sp;
	struct hlist_node *node;
	LIST_HEAD(invalid_list);
	u64 entry, gentry, *spte;
	int npte;
3972
	bool remote_flush, local_flush, zap_page;
3973 3974 3975 3976 3977 3978 3979 3980 3981 3982 3983 3984 3985 3986 3987 3988 3989 3990 3991 3992 3993 3994 3995

	/*
	 * If we don't have indirect shadow pages, it means no page is
	 * write-protected, so we can exit simply.
	 */
	if (!ACCESS_ONCE(vcpu->kvm->arch.indirect_shadow_pages))
		return;

	zap_page = remote_flush = local_flush = false;

	pgprintk("%s: gpa %llx bytes %d\n", __func__, gpa, bytes);

	gentry = mmu_pte_write_fetch_gpte(vcpu, &gpa, new, &bytes);

	/*
	 * No need to care whether allocation memory is successful
	 * or not since pte prefetch is skiped if it does not have
	 * enough objects in the cache.
	 */
	mmu_topup_memory_caches(vcpu);

	spin_lock(&vcpu->kvm->mmu_lock);
	++vcpu->kvm->stat.mmu_pte_write;
3996
	kvm_mmu_audit(vcpu, AUDIT_PRE_PTE_WRITE);
3997

3998
	mask.cr0_wp = mask.cr4_pae = mask.nxe = 1;
3999
	for_each_gfn_indirect_valid_sp(vcpu->kvm, sp, gfn, node) {
4000
		if (detect_write_misaligned(sp, gpa, bytes) ||
4001
		      detect_write_flooding(sp)) {
4002
			zap_page |= !!kvm_mmu_prepare_zap_page(vcpu->kvm, sp,
4003
						     &invalid_list);
A
Avi Kivity 已提交
4004
			++vcpu->kvm->stat.mmu_flooded;
4005 4006
			continue;
		}
4007 4008 4009 4010 4011

		spte = get_written_sptes(sp, gpa, &npte);
		if (!spte)
			continue;

4012
		local_flush = true;
4013
		while (npte--) {
4014
			entry = *spte;
4015
			mmu_page_zap_pte(vcpu->kvm, sp, spte);
4016 4017
			if (gentry &&
			      !((sp->role.word ^ vcpu->arch.mmu.base_role.word)
4018
			      & mask.word) && rmap_can_add(vcpu))
4019
				mmu_pte_write_new_pte(vcpu, sp, spte, &gentry);
4020 4021
			if (!remote_flush && need_remote_flush(entry, *spte))
				remote_flush = true;
4022
			++spte;
4023 4024
		}
	}
4025
	mmu_pte_write_flush_tlb(vcpu, zap_page, remote_flush, local_flush);
4026
	kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
4027
	kvm_mmu_audit(vcpu, AUDIT_POST_PTE_WRITE);
4028
	spin_unlock(&vcpu->kvm->mmu_lock);
4029 4030
}

4031 4032
int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
{
4033 4034
	gpa_t gpa;
	int r;
4035

4036
	if (vcpu->arch.mmu.direct_map)
4037 4038
		return 0;

4039
	gpa = kvm_mmu_gva_to_gpa_read(vcpu, gva, NULL);
4040 4041

	r = kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT);
4042

4043
	return r;
4044
}
4045
EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page_virt);
4046

4047
void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
A
Avi Kivity 已提交
4048
{
4049
	LIST_HEAD(invalid_list);
4050

4051
	while (kvm_mmu_available_pages(vcpu->kvm) < KVM_REFILL_PAGES &&
4052
	       !list_empty(&vcpu->kvm->arch.active_mmu_pages)) {
4053
		struct kvm_mmu_page *sp;
A
Avi Kivity 已提交
4054

4055
		sp = container_of(vcpu->kvm->arch.active_mmu_pages.prev,
4056
				  struct kvm_mmu_page, link);
4057
		kvm_mmu_prepare_zap_page(vcpu->kvm, sp, &invalid_list);
A
Avi Kivity 已提交
4058
		++vcpu->kvm->stat.mmu_recycled;
A
Avi Kivity 已提交
4059
	}
4060
	kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
A
Avi Kivity 已提交
4061 4062
}

4063 4064 4065 4066 4067 4068 4069 4070
static bool is_mmio_page_fault(struct kvm_vcpu *vcpu, gva_t addr)
{
	if (vcpu->arch.mmu.direct_map || mmu_is_nested(vcpu))
		return vcpu_match_mmio_gpa(vcpu, addr);

	return vcpu_match_mmio_gva(vcpu, addr);
}

4071 4072
int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code,
		       void *insn, int insn_len)
4073
{
4074
	int r, emulation_type = EMULTYPE_RETRY;
4075 4076
	enum emulation_result er;

G
Gleb Natapov 已提交
4077
	r = vcpu->arch.mmu.page_fault(vcpu, cr2, error_code, false);
4078 4079 4080 4081 4082 4083 4084 4085
	if (r < 0)
		goto out;

	if (!r) {
		r = 1;
		goto out;
	}

4086 4087 4088 4089
	if (is_mmio_page_fault(vcpu, cr2))
		emulation_type = 0;

	er = x86_emulate_instruction(vcpu, cr2, emulation_type, insn, insn_len);
4090 4091 4092 4093 4094 4095

	switch (er) {
	case EMULATE_DONE:
		return 1;
	case EMULATE_DO_MMIO:
		++vcpu->stat.mmio_exits;
4096
		/* fall through */
4097
	case EMULATE_FAIL:
4098
		return 0;
4099 4100 4101 4102 4103 4104 4105 4106
	default:
		BUG();
	}
out:
	return r;
}
EXPORT_SYMBOL_GPL(kvm_mmu_page_fault);

M
Marcelo Tosatti 已提交
4107 4108 4109 4110 4111 4112 4113 4114
void kvm_mmu_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
{
	vcpu->arch.mmu.invlpg(vcpu, gva);
	kvm_mmu_flush_tlb(vcpu);
	++vcpu->stat.invlpg;
}
EXPORT_SYMBOL_GPL(kvm_mmu_invlpg);

4115 4116 4117 4118 4119 4120
void kvm_enable_tdp(void)
{
	tdp_enabled = true;
}
EXPORT_SYMBOL_GPL(kvm_enable_tdp);

4121 4122 4123 4124 4125 4126
void kvm_disable_tdp(void)
{
	tdp_enabled = false;
}
EXPORT_SYMBOL_GPL(kvm_disable_tdp);

A
Avi Kivity 已提交
4127 4128
static void free_mmu_pages(struct kvm_vcpu *vcpu)
{
4129
	free_page((unsigned long)vcpu->arch.mmu.pae_root);
4130 4131
	if (vcpu->arch.mmu.lm_root != NULL)
		free_page((unsigned long)vcpu->arch.mmu.lm_root);
A
Avi Kivity 已提交
4132 4133 4134 4135
}

static int alloc_mmu_pages(struct kvm_vcpu *vcpu)
{
4136
	struct page *page;
A
Avi Kivity 已提交
4137 4138 4139 4140
	int i;

	ASSERT(vcpu);

4141 4142 4143 4144 4145 4146 4147
	/*
	 * When emulating 32-bit mode, cr3 is only 32 bits even on x86_64.
	 * Therefore we need to allocate shadow page tables in the first
	 * 4GB of memory, which happens to fit the DMA32 zone.
	 */
	page = alloc_page(GFP_KERNEL | __GFP_DMA32);
	if (!page)
4148 4149
		return -ENOMEM;

4150
	vcpu->arch.mmu.pae_root = page_address(page);
4151
	for (i = 0; i < 4; ++i)
4152
		vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
4153

A
Avi Kivity 已提交
4154 4155 4156
	return 0;
}

4157
int kvm_mmu_create(struct kvm_vcpu *vcpu)
A
Avi Kivity 已提交
4158 4159
{
	ASSERT(vcpu);
4160 4161 4162 4163 4164

	vcpu->arch.walk_mmu = &vcpu->arch.mmu;
	vcpu->arch.mmu.root_hpa = INVALID_PAGE;
	vcpu->arch.mmu.translate_gpa = translate_gpa;
	vcpu->arch.nested_mmu.translate_gpa = translate_nested_gpa;
A
Avi Kivity 已提交
4165

4166 4167
	return alloc_mmu_pages(vcpu);
}
A
Avi Kivity 已提交
4168

4169 4170 4171
int kvm_mmu_setup(struct kvm_vcpu *vcpu)
{
	ASSERT(vcpu);
4172
	ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
4173

4174
	return init_kvm_mmu(vcpu);
A
Avi Kivity 已提交
4175 4176
}

4177
void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
A
Avi Kivity 已提交
4178
{
4179
	struct kvm_mmu_page *sp;
4180
	bool flush = false;
A
Avi Kivity 已提交
4181

4182
	list_for_each_entry(sp, &kvm->arch.active_mmu_pages, link) {
A
Avi Kivity 已提交
4183 4184 4185
		int i;
		u64 *pt;

4186
		if (!test_bit(slot, sp->slot_bitmap))
A
Avi Kivity 已提交
4187 4188
			continue;

4189
		pt = sp->spt;
4190
		for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
4191 4192 4193 4194
			if (!is_shadow_present_pte(pt[i]) ||
			      !is_last_spte(pt[i], sp->role.level))
				continue;

4195
			spte_write_protect(kvm, &pt[i], &flush, false);
4196
		}
A
Avi Kivity 已提交
4197
	}
4198
	kvm_flush_remote_tlbs(kvm);
A
Avi Kivity 已提交
4199
}
4200

4201
void kvm_mmu_zap_all(struct kvm *kvm)
D
Dor Laor 已提交
4202
{
4203
	struct kvm_mmu_page *sp, *node;
4204
	LIST_HEAD(invalid_list);
D
Dor Laor 已提交
4205

4206
	spin_lock(&kvm->mmu_lock);
4207
restart:
4208
	list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link)
4209
		if (kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list))
4210 4211
			goto restart;

4212
	kvm_mmu_commit_zap_page(kvm, &invalid_list);
4213
	spin_unlock(&kvm->mmu_lock);
D
Dor Laor 已提交
4214 4215
}

4216 4217
static void kvm_mmu_remove_some_alloc_mmu_pages(struct kvm *kvm,
						struct list_head *invalid_list)
4218 4219 4220
{
	struct kvm_mmu_page *page;

4221 4222 4223
	if (list_empty(&kvm->arch.active_mmu_pages))
		return;

4224 4225
	page = container_of(kvm->arch.active_mmu_pages.prev,
			    struct kvm_mmu_page, link);
4226
	kvm_mmu_prepare_zap_page(kvm, page, invalid_list);
4227 4228
}

4229
static int mmu_shrink(struct shrinker *shrink, struct shrink_control *sc)
4230 4231
{
	struct kvm *kvm;
4232
	int nr_to_scan = sc->nr_to_scan;
4233 4234 4235

	if (nr_to_scan == 0)
		goto out;
4236

4237
	raw_spin_lock(&kvm_lock);
4238 4239

	list_for_each_entry(kvm, &vm_list, vm_list) {
4240
		int idx;
4241
		LIST_HEAD(invalid_list);
4242

4243 4244 4245 4246 4247 4248 4249 4250
		/*
		 * Never scan more than sc->nr_to_scan VM instances.
		 * Will not hit this condition practically since we do not try
		 * to shrink more than one VM and it is very unlikely to see
		 * !n_used_mmu_pages so many times.
		 */
		if (!nr_to_scan--)
			break;
4251 4252 4253 4254 4255 4256
		/*
		 * n_used_mmu_pages is accessed without holding kvm->mmu_lock
		 * here. We may skip a VM instance errorneosly, but we do not
		 * want to shrink a VM that only started to populate its MMU
		 * anyway.
		 */
4257
		if (!kvm->arch.n_used_mmu_pages)
4258 4259
			continue;

4260
		idx = srcu_read_lock(&kvm->srcu);
4261 4262
		spin_lock(&kvm->mmu_lock);

4263
		kvm_mmu_remove_some_alloc_mmu_pages(kvm, &invalid_list);
4264
		kvm_mmu_commit_zap_page(kvm, &invalid_list);
4265

4266
		spin_unlock(&kvm->mmu_lock);
4267
		srcu_read_unlock(&kvm->srcu, idx);
4268 4269 4270

		list_move_tail(&kvm->vm_list, &vm_list);
		break;
4271 4272
	}

4273
	raw_spin_unlock(&kvm_lock);
4274

4275 4276
out:
	return percpu_counter_read_positive(&kvm_total_used_mmu_pages);
4277 4278 4279 4280 4281 4282 4283
}

static struct shrinker mmu_shrinker = {
	.shrink = mmu_shrink,
	.seeks = DEFAULT_SEEKS * 10,
};

I
Ingo Molnar 已提交
4284
static void mmu_destroy_caches(void)
4285
{
4286 4287
	if (pte_list_desc_cache)
		kmem_cache_destroy(pte_list_desc_cache);
4288 4289
	if (mmu_page_header_cache)
		kmem_cache_destroy(mmu_page_header_cache);
4290 4291 4292 4293
}

int kvm_mmu_module_init(void)
{
4294 4295
	pte_list_desc_cache = kmem_cache_create("pte_list_desc",
					    sizeof(struct pte_list_desc),
4296
					    0, 0, NULL);
4297
	if (!pte_list_desc_cache)
4298 4299
		goto nomem;

4300 4301
	mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
						  sizeof(struct kvm_mmu_page),
4302
						  0, 0, NULL);
4303 4304 4305
	if (!mmu_page_header_cache)
		goto nomem;

4306 4307 4308
	if (percpu_counter_init(&kvm_total_used_mmu_pages, 0))
		goto nomem;

4309 4310
	register_shrinker(&mmu_shrinker);

4311 4312 4313
	return 0;

nomem:
4314
	mmu_destroy_caches();
4315 4316 4317
	return -ENOMEM;
}

4318 4319 4320 4321 4322 4323 4324
/*
 * Caculate mmu pages needed for kvm.
 */
unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
{
	unsigned int nr_mmu_pages;
	unsigned int  nr_pages = 0;
4325
	struct kvm_memslots *slots;
4326
	struct kvm_memory_slot *memslot;
4327

4328 4329
	slots = kvm_memslots(kvm);

4330 4331
	kvm_for_each_memslot(memslot, slots)
		nr_pages += memslot->npages;
4332 4333 4334 4335 4336 4337 4338 4339

	nr_mmu_pages = nr_pages * KVM_PERMILLE_MMU_PAGES / 1000;
	nr_mmu_pages = max(nr_mmu_pages,
			(unsigned int) KVM_MIN_ALLOC_MMU_PAGES);

	return nr_mmu_pages;
}

4340 4341 4342
int kvm_mmu_get_spte_hierarchy(struct kvm_vcpu *vcpu, u64 addr, u64 sptes[4])
{
	struct kvm_shadow_walk_iterator iterator;
4343
	u64 spte;
4344 4345
	int nr_sptes = 0;

4346 4347 4348
	walk_shadow_page_lockless_begin(vcpu);
	for_each_shadow_entry_lockless(vcpu, addr, iterator, spte) {
		sptes[iterator.level-1] = spte;
4349
		nr_sptes++;
4350
		if (!is_shadow_present_pte(spte))
4351 4352
			break;
	}
4353
	walk_shadow_page_lockless_end(vcpu);
4354 4355 4356 4357 4358

	return nr_sptes;
}
EXPORT_SYMBOL_GPL(kvm_mmu_get_spte_hierarchy);

4359 4360 4361 4362 4363 4364 4365
void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
{
	ASSERT(vcpu);

	destroy_kvm_mmu(vcpu);
	free_mmu_pages(vcpu);
	mmu_free_memory_caches(vcpu);
4366 4367 4368 4369 4370 4371 4372
}

void kvm_mmu_module_exit(void)
{
	mmu_destroy_caches();
	percpu_counter_destroy(&kvm_total_used_mmu_pages);
	unregister_shrinker(&mmu_shrinker);
4373 4374
	mmu_audit_disable();
}