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)
{
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	return (spte & (SPTE_HOST_WRITEABLE | SPTE_MMU_WRITEABLE)) ==
		(SPTE_HOST_WRITEABLE | SPTE_MMU_WRITEABLE);
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}

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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);
626
		if (!obj)
627
			return -ENOMEM;
628 629
		cache->objects[cache->nobjs++] = obj;
	}
630
	return 0;
631 632
}

633 634 635 636 637
static int mmu_memory_cache_free_objects(struct kvm_mmu_memory_cache *cache)
{
	return cache->nobjs;
}

638 639
static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc,
				  struct kmem_cache *cache)
640 641
{
	while (mc->nobjs)
642
		kmem_cache_free(cache, mc->objects[--mc->nobjs]);
643 644
}

A
Avi Kivity 已提交
645
static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
646
				       int min)
A
Avi Kivity 已提交
647
{
648
	void *page;
A
Avi Kivity 已提交
649 650 651 652

	if (cache->nobjs >= min)
		return 0;
	while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
653
		page = (void *)__get_free_page(GFP_KERNEL);
A
Avi Kivity 已提交
654 655
		if (!page)
			return -ENOMEM;
656
		cache->objects[cache->nobjs++] = page;
A
Avi Kivity 已提交
657 658 659 660 661 662 663
	}
	return 0;
}

static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
{
	while (mc->nobjs)
664
		free_page((unsigned long)mc->objects[--mc->nobjs]);
A
Avi Kivity 已提交
665 666
}

667
static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
668
{
669 670
	int r;

671
	r = mmu_topup_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache,
672
				   pte_list_desc_cache, 8 + PTE_PREFETCH_NUM);
673 674
	if (r)
		goto out;
675
	r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 8);
676 677
	if (r)
		goto out;
678
	r = mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
679
				   mmu_page_header_cache, 4);
680 681
out:
	return r;
682 683 684 685
}

static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
{
686 687
	mmu_free_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache,
				pte_list_desc_cache);
688
	mmu_free_memory_cache_page(&vcpu->arch.mmu_page_cache);
689 690
	mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache,
				mmu_page_header_cache);
691 692
}

693
static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
694 695 696 697 698 699 700 701
{
	void *p;

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

702
static struct pte_list_desc *mmu_alloc_pte_list_desc(struct kvm_vcpu *vcpu)
703
{
704
	return mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_list_desc_cache);
705 706
}

707
static void mmu_free_pte_list_desc(struct pte_list_desc *pte_list_desc)
708
{
709
	kmem_cache_free(pte_list_desc_cache, pte_list_desc);
710 711
}

712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727
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
728
/*
729 730
 * 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
731
 */
732 733 734
static struct kvm_lpage_info *lpage_info_slot(gfn_t gfn,
					      struct kvm_memory_slot *slot,
					      int level)
M
Marcelo Tosatti 已提交
735 736 737
{
	unsigned long idx;

738
	idx = gfn_to_index(gfn, slot->base_gfn, level);
739
	return &slot->arch.lpage_info[level - 2][idx];
M
Marcelo Tosatti 已提交
740 741 742 743
}

static void account_shadowed(struct kvm *kvm, gfn_t gfn)
{
744
	struct kvm_memory_slot *slot;
745
	struct kvm_lpage_info *linfo;
746
	int i;
M
Marcelo Tosatti 已提交
747

A
Avi Kivity 已提交
748
	slot = gfn_to_memslot(kvm, gfn);
749 750
	for (i = PT_DIRECTORY_LEVEL;
	     i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
751 752
		linfo = lpage_info_slot(gfn, slot, i);
		linfo->write_count += 1;
753
	}
754
	kvm->arch.indirect_shadow_pages++;
M
Marcelo Tosatti 已提交
755 756 757 758
}

static void unaccount_shadowed(struct kvm *kvm, gfn_t gfn)
{
759
	struct kvm_memory_slot *slot;
760
	struct kvm_lpage_info *linfo;
761
	int i;
M
Marcelo Tosatti 已提交
762

A
Avi Kivity 已提交
763
	slot = gfn_to_memslot(kvm, gfn);
764 765
	for (i = PT_DIRECTORY_LEVEL;
	     i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
766 767 768
		linfo = lpage_info_slot(gfn, slot, i);
		linfo->write_count -= 1;
		WARN_ON(linfo->write_count < 0);
769
	}
770
	kvm->arch.indirect_shadow_pages--;
M
Marcelo Tosatti 已提交
771 772
}

773 774 775
static int has_wrprotected_page(struct kvm *kvm,
				gfn_t gfn,
				int level)
M
Marcelo Tosatti 已提交
776
{
777
	struct kvm_memory_slot *slot;
778
	struct kvm_lpage_info *linfo;
M
Marcelo Tosatti 已提交
779

A
Avi Kivity 已提交
780
	slot = gfn_to_memslot(kvm, gfn);
M
Marcelo Tosatti 已提交
781
	if (slot) {
782 783
		linfo = lpage_info_slot(gfn, slot, level);
		return linfo->write_count;
M
Marcelo Tosatti 已提交
784 785 786 787 788
	}

	return 1;
}

789
static int host_mapping_level(struct kvm *kvm, gfn_t gfn)
M
Marcelo Tosatti 已提交
790
{
J
Joerg Roedel 已提交
791
	unsigned long page_size;
792
	int i, ret = 0;
M
Marcelo Tosatti 已提交
793

J
Joerg Roedel 已提交
794
	page_size = kvm_host_page_size(kvm, gfn);
M
Marcelo Tosatti 已提交
795

796 797 798 799 800 801 802 803
	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;
	}

804
	return ret;
M
Marcelo Tosatti 已提交
805 806
}

807 808 809
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
810 811
{
	struct kvm_memory_slot *slot;
812 813 814 815 816 817 818 819 820 821 822

	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)
{
823
	return !gfn_to_memslot_dirty_bitmap(vcpu, large_gfn, true);
824 825 826 827 828
}

static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn)
{
	int host_level, level, max_level;
M
Marcelo Tosatti 已提交
829

830 831 832 833 834
	host_level = host_mapping_level(vcpu->kvm, large_gfn);

	if (host_level == PT_PAGE_TABLE_LEVEL)
		return host_level;

835 836 837 838
	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)
839 840 841 842
		if (has_wrprotected_page(vcpu->kvm, large_gfn, level))
			break;

	return level - 1;
M
Marcelo Tosatti 已提交
843 844
}

845
/*
846
 * Pte mapping structures:
847
 *
848
 * If pte_list bit zero is zero, then pte_list point to the spte.
849
 *
850 851
 * If pte_list bit zero is one, (then pte_list & ~1) points to a struct
 * pte_list_desc containing more mappings.
852
 *
853
 * Returns the number of pte entries before the spte was added or zero if
854 855
 * the spte was not added.
 *
856
 */
857 858
static int pte_list_add(struct kvm_vcpu *vcpu, u64 *spte,
			unsigned long *pte_list)
859
{
860
	struct pte_list_desc *desc;
861
	int i, count = 0;
862

863 864 865 866 867 868 869
	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
870
		desc->sptes[1] = spte;
871
		*pte_list = (unsigned long)desc | 1;
872
		++count;
873
	} else {
874 875 876
		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) {
877
			desc = desc->more;
878
			count += PTE_LIST_EXT;
879
		}
880 881
		if (desc->sptes[PTE_LIST_EXT-1]) {
			desc->more = mmu_alloc_pte_list_desc(vcpu);
882 883
			desc = desc->more;
		}
A
Avi Kivity 已提交
884
		for (i = 0; desc->sptes[i]; ++i)
885
			++count;
A
Avi Kivity 已提交
886
		desc->sptes[i] = spte;
887
	}
888
	return count;
889 890
}

891 892 893
static void
pte_list_desc_remove_entry(unsigned long *pte_list, struct pte_list_desc *desc,
			   int i, struct pte_list_desc *prev_desc)
894 895 896
{
	int j;

897
	for (j = PTE_LIST_EXT - 1; !desc->sptes[j] && j > i; --j)
898
		;
A
Avi Kivity 已提交
899 900
	desc->sptes[i] = desc->sptes[j];
	desc->sptes[j] = NULL;
901 902 903
	if (j != 0)
		return;
	if (!prev_desc && !desc->more)
904
		*pte_list = (unsigned long)desc->sptes[0];
905 906 907 908
	else
		if (prev_desc)
			prev_desc->more = desc->more;
		else
909 910
			*pte_list = (unsigned long)desc->more | 1;
	mmu_free_pte_list_desc(desc);
911 912
}

913
static void pte_list_remove(u64 *spte, unsigned long *pte_list)
914
{
915 916
	struct pte_list_desc *desc;
	struct pte_list_desc *prev_desc;
917 918
	int i;

919 920
	if (!*pte_list) {
		printk(KERN_ERR "pte_list_remove: %p 0->BUG\n", spte);
921
		BUG();
922 923 924 925
	} 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);
926 927
			BUG();
		}
928
		*pte_list = 0;
929
	} else {
930 931
		rmap_printk("pte_list_remove:  %p many->many\n", spte);
		desc = (struct pte_list_desc *)(*pte_list & ~1ul);
932 933
		prev_desc = NULL;
		while (desc) {
934
			for (i = 0; i < PTE_LIST_EXT && desc->sptes[i]; ++i)
A
Avi Kivity 已提交
935
				if (desc->sptes[i] == spte) {
936
					pte_list_desc_remove_entry(pte_list,
937
							       desc, i,
938 939 940 941 942 943
							       prev_desc);
					return;
				}
			prev_desc = desc;
			desc = desc->more;
		}
944
		pr_err("pte_list_remove: %p many->many\n", spte);
945 946 947 948
		BUG();
	}
}

949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968
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;
	}
}

969
static unsigned long *__gfn_to_rmap(gfn_t gfn, int level,
970
				    struct kvm_memory_slot *slot)
971
{
972
	unsigned long idx;
973

974
	idx = gfn_to_index(gfn, slot->base_gfn, level);
975
	return &slot->arch.rmap[level - PT_PAGE_TABLE_LEVEL][idx];
976 977
}

978 979 980 981 982 983 984 985
/*
 * 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);
986
	return __gfn_to_rmap(gfn, level, slot);
987 988
}

989 990 991 992 993 994 995 996
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);
}

997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019
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);
}

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 1080
/*
 * 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;
}

1081
static void drop_spte(struct kvm *kvm, u64 *sptep)
1082
{
1083
	if (mmu_spte_clear_track_bits(sptep))
1084
		rmap_remove(kvm, sptep);
A
Avi Kivity 已提交
1085 1086
}

1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107

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);
}

/*
1108 1109 1110 1111 1112 1113 1114 1115 1116 1117
 * 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.
1118 1119 1120
 *
 * Return true if the spte is dropped.
 */
1121 1122
static bool
spte_write_protect(struct kvm *kvm, u64 *sptep, bool *flush, bool pt_protect)
1123 1124 1125
{
	u64 spte = *sptep;

1126 1127
	if (!is_writable_pte(spte) &&
	      !(pt_protect && spte_is_locklessly_modifiable(spte)))
1128 1129 1130 1131
		return false;

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

1132 1133
	if (__drop_large_spte(kvm, sptep)) {
		*flush |= true;
1134
		return true;
1135
	}
1136

1137 1138
	if (pt_protect)
		spte &= ~SPTE_MMU_WRITEABLE;
1139
	spte = spte & ~PT_WRITABLE_MASK;
1140 1141

	*flush |= mmu_spte_update(sptep, spte);
1142 1143 1144
	return false;
}

1145
static bool __rmap_write_protect(struct kvm *kvm, unsigned long *rmapp,
1146
				 bool pt_protect)
1147
{
1148 1149
	u64 *sptep;
	struct rmap_iterator iter;
1150
	bool flush = false;
1151

1152 1153
	for (sptep = rmap_get_first(*rmapp, &iter); sptep;) {
		BUG_ON(!(*sptep & PT_PRESENT_MASK));
1154
		if (spte_write_protect(kvm, sptep, &flush, pt_protect)) {
1155
			sptep = rmap_get_first(*rmapp, &iter);
1156
			continue;
1157
		}
1158

1159
		sptep = rmap_get_next(&iter);
1160
	}
1161

1162
	return flush;
1163 1164
}

1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177
/**
 * 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)
1178 1179 1180
{
	unsigned long *rmapp;

1181
	while (mask) {
1182 1183
		rmapp = __gfn_to_rmap(slot->base_gfn + gfn_offset + __ffs(mask),
				      PT_PAGE_TABLE_LEVEL, slot);
1184
		__rmap_write_protect(kvm, rmapp, false);
M
Marcelo Tosatti 已提交
1185

1186 1187 1188
		/* clear the first set bit */
		mask &= mask - 1;
	}
1189 1190
}

1191
static bool rmap_write_protect(struct kvm *kvm, u64 gfn)
1192 1193
{
	struct kvm_memory_slot *slot;
1194 1195
	unsigned long *rmapp;
	int i;
1196
	bool write_protected = false;
1197 1198

	slot = gfn_to_memslot(kvm, gfn);
1199 1200 1201 1202

	for (i = PT_PAGE_TABLE_LEVEL;
	     i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
		rmapp = __gfn_to_rmap(gfn, i, slot);
1203
		write_protected |= __rmap_write_protect(kvm, rmapp, true);
1204 1205 1206
	}

	return write_protected;
1207 1208
}

F
Frederik Deweerdt 已提交
1209
static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp,
1210
			   struct kvm_memory_slot *slot, unsigned long data)
1211
{
1212 1213
	u64 *sptep;
	struct rmap_iterator iter;
1214 1215
	int need_tlb_flush = 0;

1216 1217 1218 1219 1220
	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);
1221 1222
		need_tlb_flush = 1;
	}
1223

1224 1225 1226
	return need_tlb_flush;
}

F
Frederik Deweerdt 已提交
1227
static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp,
1228
			     struct kvm_memory_slot *slot, unsigned long data)
1229
{
1230 1231
	u64 *sptep;
	struct rmap_iterator iter;
1232
	int need_flush = 0;
1233
	u64 new_spte;
1234 1235 1236 1237 1238
	pte_t *ptep = (pte_t *)data;
	pfn_t new_pfn;

	WARN_ON(pte_huge(*ptep));
	new_pfn = pte_pfn(*ptep);
1239 1240 1241 1242 1243

	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);

1244
		need_flush = 1;
1245

1246
		if (pte_write(*ptep)) {
1247 1248
			drop_spte(kvm, sptep);
			sptep = rmap_get_first(*rmapp, &iter);
1249
		} else {
1250
			new_spte = *sptep & ~PT64_BASE_ADDR_MASK;
1251 1252 1253 1254
			new_spte |= (u64)new_pfn << PAGE_SHIFT;

			new_spte &= ~PT_WRITABLE_MASK;
			new_spte &= ~SPTE_HOST_WRITEABLE;
1255
			new_spte &= ~shadow_accessed_mask;
1256 1257 1258 1259

			mmu_spte_clear_track_bits(sptep);
			mmu_spte_set(sptep, new_spte);
			sptep = rmap_get_next(&iter);
1260 1261
		}
	}
1262

1263 1264 1265 1266 1267 1268
	if (need_flush)
		kvm_flush_remote_tlbs(kvm);

	return 0;
}

1269 1270 1271 1272 1273 1274
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,
1275
					       struct kvm_memory_slot *slot,
1276
					       unsigned long data))
1277
{
1278
	int j;
1279
	int ret = 0;
1280
	struct kvm_memslots *slots;
1281
	struct kvm_memory_slot *memslot;
1282

1283
	slots = kvm_memslots(kvm);
1284

1285
	kvm_for_each_memslot(memslot, slots) {
1286
		unsigned long hva_start, hva_end;
1287
		gfn_t gfn_start, gfn_end;
1288

1289 1290 1291 1292 1293 1294 1295
		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)} =
1296
		 * {gfn_start, gfn_start+1, ..., gfn_end-1}.
1297
		 */
1298
		gfn_start = hva_to_gfn_memslot(hva_start, memslot);
1299
		gfn_end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, memslot);
1300

1301 1302 1303 1304
		for (j = PT_PAGE_TABLE_LEVEL;
		     j < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++j) {
			unsigned long idx, idx_end;
			unsigned long *rmapp;
1305

1306 1307 1308 1309 1310 1311
			/*
			 * {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);
1312

1313
			rmapp = __gfn_to_rmap(gfn_start, j, memslot);
1314

1315 1316
			for (; idx <= idx_end; ++idx)
				ret |= handler(kvm, rmapp++, memslot, data);
1317 1318 1319
		}
	}

1320
	return ret;
1321 1322
}

1323 1324 1325
static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
			  unsigned long data,
			  int (*handler)(struct kvm *kvm, unsigned long *rmapp,
1326
					 struct kvm_memory_slot *slot,
1327 1328 1329
					 unsigned long data))
{
	return kvm_handle_hva_range(kvm, hva, hva + 1, data, handler);
1330 1331 1332 1333
}

int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
{
1334 1335 1336
	return kvm_handle_hva(kvm, hva, 0, kvm_unmap_rmapp);
}

1337 1338 1339 1340 1341
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);
}

1342 1343
void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
{
F
Frederik Deweerdt 已提交
1344
	kvm_handle_hva(kvm, hva, (unsigned long)&pte, kvm_set_pte_rmapp);
1345 1346
}

F
Frederik Deweerdt 已提交
1347
static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
1348
			 struct kvm_memory_slot *slot, unsigned long data)
1349
{
1350
	u64 *sptep;
1351
	struct rmap_iterator uninitialized_var(iter);
1352 1353
	int young = 0;

1354
	/*
1355 1356
	 * In case of absence of EPT Access and Dirty Bits supports,
	 * emulate the accessed bit for EPT, by checking if this page has
1357 1358 1359 1360 1361
	 * 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.
	 */
1362 1363 1364 1365
	if (!shadow_accessed_mask) {
		young = kvm_unmap_rmapp(kvm, rmapp, slot, data);
		goto out;
	}
1366

1367 1368
	for (sptep = rmap_get_first(*rmapp, &iter); sptep;
	     sptep = rmap_get_next(&iter)) {
1369
		BUG_ON(!is_shadow_present_pte(*sptep));
1370

1371
		if (*sptep & shadow_accessed_mask) {
1372
			young = 1;
1373 1374
			clear_bit((ffs(shadow_accessed_mask) - 1),
				 (unsigned long *)sptep);
1375 1376
		}
	}
1377 1378 1379
out:
	/* @data has hva passed to kvm_age_hva(). */
	trace_kvm_age_page(data, slot, young);
1380 1381 1382
	return young;
}

A
Andrea Arcangeli 已提交
1383
static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
1384
			      struct kvm_memory_slot *slot, unsigned long data)
A
Andrea Arcangeli 已提交
1385
{
1386 1387
	u64 *sptep;
	struct rmap_iterator iter;
A
Andrea Arcangeli 已提交
1388 1389 1390 1391 1392 1393 1394 1395 1396 1397
	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;

1398 1399
	for (sptep = rmap_get_first(*rmapp, &iter); sptep;
	     sptep = rmap_get_next(&iter)) {
1400
		BUG_ON(!is_shadow_present_pte(*sptep));
1401

1402
		if (*sptep & shadow_accessed_mask) {
A
Andrea Arcangeli 已提交
1403 1404 1405 1406 1407 1408 1409 1410
			young = 1;
			break;
		}
	}
out:
	return young;
}

1411 1412
#define RMAP_RECYCLE_THRESHOLD 1000

1413
static void rmap_recycle(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
1414 1415
{
	unsigned long *rmapp;
1416 1417 1418
	struct kvm_mmu_page *sp;

	sp = page_header(__pa(spte));
1419

1420
	rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level);
1421

1422
	kvm_unmap_rmapp(vcpu->kvm, rmapp, NULL, 0);
1423 1424 1425
	kvm_flush_remote_tlbs(vcpu->kvm);
}

1426 1427
int kvm_age_hva(struct kvm *kvm, unsigned long hva)
{
1428
	return kvm_handle_hva(kvm, hva, hva, kvm_age_rmapp);
1429 1430
}

A
Andrea Arcangeli 已提交
1431 1432 1433 1434 1435
int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)
{
	return kvm_handle_hva(kvm, hva, 0, kvm_test_age_rmapp);
}

1436
#ifdef MMU_DEBUG
1437
static int is_empty_shadow_page(u64 *spt)
A
Avi Kivity 已提交
1438
{
1439 1440 1441
	u64 *pos;
	u64 *end;

1442
	for (pos = spt, end = pos + PAGE_SIZE / sizeof(u64); pos != end; pos++)
1443
		if (is_shadow_present_pte(*pos)) {
1444
			printk(KERN_ERR "%s: %p %llx\n", __func__,
1445
			       pos, *pos);
A
Avi Kivity 已提交
1446
			return 0;
1447
		}
A
Avi Kivity 已提交
1448 1449
	return 1;
}
1450
#endif
A
Avi Kivity 已提交
1451

1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463
/*
 * 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);
}

1464 1465 1466 1467 1468 1469 1470
/*
 * 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)
1471
{
1472
	ASSERT(is_empty_shadow_page(sp->spt));
1473
	hlist_del(&sp->hash_link);
1474
	if (!sp->role.direct)
1475
		free_page((unsigned long)sp->gfns);
1476 1477 1478 1479 1480 1481 1482 1483 1484 1485
}

/*
 * 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);
1486
	kmem_cache_free(mmu_page_header_cache, sp);
1487 1488
}

1489 1490
static unsigned kvm_page_table_hashfn(gfn_t gfn)
{
1491
	return gfn & ((1 << KVM_MMU_HASH_SHIFT) - 1);
1492 1493
}

1494
static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu,
1495
				    struct kvm_mmu_page *sp, u64 *parent_pte)
1496 1497 1498 1499
{
	if (!parent_pte)
		return;

1500
	pte_list_add(vcpu, parent_pte, &sp->parent_ptes);
1501 1502
}

1503
static void mmu_page_remove_parent_pte(struct kvm_mmu_page *sp,
1504 1505
				       u64 *parent_pte)
{
1506
	pte_list_remove(parent_pte, &sp->parent_ptes);
1507 1508
}

1509 1510 1511 1512
static void drop_parent_pte(struct kvm_mmu_page *sp,
			    u64 *parent_pte)
{
	mmu_page_remove_parent_pte(sp, parent_pte);
1513
	mmu_spte_clear_no_track(parent_pte);
1514 1515
}

1516 1517
static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
					       u64 *parent_pte, int direct)
M
Marcelo Tosatti 已提交
1518
{
1519
	struct kvm_mmu_page *sp;
1520 1521
	sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache);
	sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache);
1522
	if (!direct)
1523
		sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache);
1524 1525 1526 1527 1528 1529
	set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
	list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages);
	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
	spin_lock(&kvm->mmu_lock);

2149 2150
	if (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages) {
		while (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages &&
2151
			!list_empty(&kvm->arch.active_mmu_pages)) {
2152 2153
			struct kvm_mmu_page *page;

2154
			page = container_of(kvm->arch.active_mmu_pages.prev,
2155
					    struct kvm_mmu_page, link);
2156
			kvm_mmu_prepare_zap_page(kvm, page, &invalid_list);
2157
		}
2158
		kvm_mmu_commit_zap_page(kvm, &invalid_list);
2159
		goal_nr_mmu_pages = kvm->arch.n_used_mmu_pages;
2160 2161
	}

2162
	kvm->arch.n_max_mmu_pages = goal_nr_mmu_pages;
2163 2164

	spin_unlock(&kvm->mmu_lock);
2165 2166
}

2167
int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
2168
{
2169
	struct kvm_mmu_page *sp;
2170
	struct hlist_node *node;
2171
	LIST_HEAD(invalid_list);
2172 2173
	int r;

2174
	pgprintk("%s: looking for gfn %llx\n", __func__, gfn);
2175
	r = 0;
2176
	spin_lock(&kvm->mmu_lock);
2177
	for_each_gfn_indirect_valid_sp(kvm, sp, gfn, node) {
2178
		pgprintk("%s: gfn %llx role %x\n", __func__, gfn,
2179 2180
			 sp->role.word);
		r = 1;
2181
		kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list);
2182
	}
2183
	kvm_mmu_commit_zap_page(kvm, &invalid_list);
2184 2185
	spin_unlock(&kvm->mmu_lock);

2186
	return r;
2187
}
2188
EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page);
2189

2190 2191 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
/*
 * 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;
}

2283
u8 kvm_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn)
2284 2285 2286 2287 2288 2289 2290 2291 2292
{
	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;
}
2293
EXPORT_SYMBOL_GPL(kvm_get_guest_memory_type);
2294

2295 2296 2297 2298 2299 2300 2301 2302 2303 2304
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)
2305 2306
{
	struct kvm_mmu_page *s;
2307
	struct hlist_node *node;
2308

2309
	for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn, node) {
2310
		if (s->unsync)
2311
			continue;
2312 2313
		WARN_ON(s->role.level != PT_PAGE_TABLE_LEVEL);
		__kvm_unsync_page(vcpu, s);
2314 2315 2316 2317 2318 2319
	}
}

static int mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn,
				  bool can_unsync)
{
2320
	struct kvm_mmu_page *s;
2321
	struct hlist_node *node;
2322 2323
	bool need_unsync = false;

2324
	for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn, node) {
2325 2326 2327
		if (!can_unsync)
			return 1;

2328
		if (s->role.level != PT_PAGE_TABLE_LEVEL)
2329
			return 1;
2330 2331 2332 2333

		if (!need_unsync && !s->unsync) {
			need_unsync = true;
		}
2334
	}
2335 2336
	if (need_unsync)
		kvm_unsync_pages(vcpu, gfn);
2337 2338 2339
	return 0;
}

A
Avi Kivity 已提交
2340
static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
2341
		    unsigned pte_access, int level,
2342
		    gfn_t gfn, pfn_t pfn, bool speculative,
2343
		    bool can_unsync, bool host_writable)
2344
{
2345
	u64 spte;
M
Marcelo Tosatti 已提交
2346
	int ret = 0;
S
Sheng Yang 已提交
2347

2348 2349 2350
	if (set_mmio_spte(sptep, gfn, pfn, pte_access))
		return 0;

2351
	spte = PT_PRESENT_MASK;
2352
	if (!speculative)
2353
		spte |= shadow_accessed_mask;
2354

S
Sheng Yang 已提交
2355 2356 2357 2358
	if (pte_access & ACC_EXEC_MASK)
		spte |= shadow_x_mask;
	else
		spte |= shadow_nx_mask;
2359

2360
	if (pte_access & ACC_USER_MASK)
S
Sheng Yang 已提交
2361
		spte |= shadow_user_mask;
2362

2363
	if (level > PT_PAGE_TABLE_LEVEL)
M
Marcelo Tosatti 已提交
2364
		spte |= PT_PAGE_SIZE_MASK;
2365
	if (tdp_enabled)
2366 2367
		spte |= kvm_x86_ops->get_mt_mask(vcpu, gfn,
			kvm_is_mmio_pfn(pfn));
2368

2369
	if (host_writable)
2370
		spte |= SPTE_HOST_WRITEABLE;
2371 2372
	else
		pte_access &= ~ACC_WRITE_MASK;
2373

2374
	spte |= (u64)pfn << PAGE_SHIFT;
2375

2376
	if (pte_access & ACC_WRITE_MASK) {
2377

X
Xiao Guangrong 已提交
2378
		/*
2379 2380 2381 2382
		 * Other vcpu creates new sp in the window between
		 * mapping_level() and acquiring mmu-lock. We can
		 * allow guest to retry the access, the mapping can
		 * be fixed if guest refault.
X
Xiao Guangrong 已提交
2383
		 */
2384
		if (level > PT_PAGE_TABLE_LEVEL &&
X
Xiao Guangrong 已提交
2385
		    has_wrprotected_page(vcpu->kvm, gfn, level))
A
Avi Kivity 已提交
2386
			goto done;
2387

2388
		spte |= PT_WRITABLE_MASK | SPTE_MMU_WRITEABLE;
2389

2390 2391 2392 2393 2394 2395
		/*
		 * 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.
		 */
2396
		if (!can_unsync && is_writable_pte(*sptep))
2397 2398
			goto set_pte;

2399
		if (mmu_need_write_protect(vcpu, gfn, can_unsync)) {
2400
			pgprintk("%s: found shadow page for %llx, marking ro\n",
2401
				 __func__, gfn);
M
Marcelo Tosatti 已提交
2402
			ret = 1;
2403
			pte_access &= ~ACC_WRITE_MASK;
2404
			spte &= ~(PT_WRITABLE_MASK | SPTE_MMU_WRITEABLE);
2405 2406 2407 2408 2409 2410
		}
	}

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

2411
set_pte:
2412
	if (mmu_spte_update(sptep, spte))
2413
		kvm_flush_remote_tlbs(vcpu->kvm);
A
Avi Kivity 已提交
2414
done:
M
Marcelo Tosatti 已提交
2415 2416 2417
	return ret;
}

A
Avi Kivity 已提交
2418
static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
M
Marcelo Tosatti 已提交
2419
			 unsigned pt_access, unsigned pte_access,
2420 2421
			 int write_fault, int *emulate, int level, gfn_t gfn,
			 pfn_t pfn, bool speculative, bool host_writable)
M
Marcelo Tosatti 已提交
2422 2423
{
	int was_rmapped = 0;
2424
	int rmap_count;
M
Marcelo Tosatti 已提交
2425

2426
	pgprintk("%s: spte %llx access %x write_fault %d gfn %llx\n",
A
Avi Kivity 已提交
2427
		 __func__, *sptep, pt_access,
2428
		 write_fault, gfn);
M
Marcelo Tosatti 已提交
2429

A
Avi Kivity 已提交
2430
	if (is_rmap_spte(*sptep)) {
M
Marcelo Tosatti 已提交
2431 2432 2433 2434
		/*
		 * If we overwrite a PTE page pointer with a 2MB PMD, unlink
		 * the parent of the now unreachable PTE.
		 */
2435 2436
		if (level > PT_PAGE_TABLE_LEVEL &&
		    !is_large_pte(*sptep)) {
M
Marcelo Tosatti 已提交
2437
			struct kvm_mmu_page *child;
A
Avi Kivity 已提交
2438
			u64 pte = *sptep;
M
Marcelo Tosatti 已提交
2439 2440

			child = page_header(pte & PT64_BASE_ADDR_MASK);
2441
			drop_parent_pte(child, sptep);
2442
			kvm_flush_remote_tlbs(vcpu->kvm);
A
Avi Kivity 已提交
2443
		} else if (pfn != spte_to_pfn(*sptep)) {
2444
			pgprintk("hfn old %llx new %llx\n",
A
Avi Kivity 已提交
2445
				 spte_to_pfn(*sptep), pfn);
2446
			drop_spte(vcpu->kvm, sptep);
2447
			kvm_flush_remote_tlbs(vcpu->kvm);
2448 2449
		} else
			was_rmapped = 1;
M
Marcelo Tosatti 已提交
2450
	}
2451

2452 2453
	if (set_spte(vcpu, sptep, pte_access, level, gfn, pfn, speculative,
	      true, host_writable)) {
M
Marcelo Tosatti 已提交
2454
		if (write_fault)
2455
			*emulate = 1;
2456
		kvm_mmu_flush_tlb(vcpu);
2457
	}
M
Marcelo Tosatti 已提交
2458

2459 2460 2461
	if (unlikely(is_mmio_spte(*sptep) && emulate))
		*emulate = 1;

A
Avi Kivity 已提交
2462
	pgprintk("%s: setting spte %llx\n", __func__, *sptep);
2463
	pgprintk("instantiating %s PTE (%s) at %llx (%llx) addr %p\n",
A
Avi Kivity 已提交
2464
		 is_large_pte(*sptep)? "2MB" : "4kB",
2465 2466
		 *sptep & PT_PRESENT_MASK ?"RW":"R", gfn,
		 *sptep, sptep);
A
Avi Kivity 已提交
2467
	if (!was_rmapped && is_large_pte(*sptep))
M
Marcelo Tosatti 已提交
2468 2469
		++vcpu->kvm->stat.lpages;

2470 2471 2472 2473 2474 2475
	if (is_shadow_present_pte(*sptep)) {
		if (!was_rmapped) {
			rmap_count = rmap_add(vcpu, sptep, gfn);
			if (rmap_count > RMAP_RECYCLE_THRESHOLD)
				rmap_recycle(vcpu, sptep, gfn);
		}
2476
	}
2477

X
Xiao Guangrong 已提交
2478
	kvm_release_pfn_clean(pfn);
2479 2480
}

A
Avi Kivity 已提交
2481 2482
static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
{
2483
	mmu_free_roots(vcpu);
A
Avi Kivity 已提交
2484 2485
}

2486 2487 2488 2489 2490 2491 2492 2493
static bool is_rsvd_bits_set(struct kvm_mmu *mmu, u64 gpte, int level)
{
	int bit7;

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

2494 2495 2496 2497 2498
static pfn_t pte_prefetch_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn,
				     bool no_dirty_log)
{
	struct kvm_memory_slot *slot;

2499
	slot = gfn_to_memslot_dirty_bitmap(vcpu, gfn, no_dirty_log);
2500
	if (!slot)
2501
		return KVM_PFN_ERR_FAULT;
2502

2503
	return gfn_to_pfn_memslot_atomic(slot, gfn);
2504 2505
}

2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525
static bool prefetch_invalid_gpte(struct kvm_vcpu *vcpu,
				  struct kvm_mmu_page *sp, u64 *spte,
				  u64 gpte)
{
	if (is_rsvd_bits_set(&vcpu->arch.mmu, gpte, PT_PAGE_TABLE_LEVEL))
		goto no_present;

	if (!is_present_gpte(gpte))
		goto no_present;

	if (!(gpte & PT_ACCESSED_MASK))
		goto no_present;

	return false;

no_present:
	drop_spte(vcpu->kvm, spte);
	return true;
}

2526 2527 2528 2529 2530 2531 2532 2533 2534 2535
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);
2536
	if (!gfn_to_memslot_dirty_bitmap(vcpu, gfn, access & ACC_WRITE_MASK))
2537 2538 2539 2540 2541 2542 2543
		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++)
2544 2545 2546
		mmu_set_spte(vcpu, start, ACC_ALL, access, 0, NULL,
			     sp->role.level, gfn, page_to_pfn(pages[i]),
			     true, true);
2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562

	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++) {
2563
		if (is_shadow_present_pte(*spte) || spte == sptep) {
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 2590 2591 2592 2593
			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);
}

2594
static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
2595 2596
			int map_writable, int level, gfn_t gfn, pfn_t pfn,
			bool prefault)
2597
{
2598
	struct kvm_shadow_walk_iterator iterator;
2599
	struct kvm_mmu_page *sp;
2600
	int emulate = 0;
2601
	gfn_t pseudo_gfn;
A
Avi Kivity 已提交
2602

2603
	for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) {
2604
		if (iterator.level == level) {
2605 2606 2607
			unsigned pte_access = ACC_ALL;

			mmu_set_spte(vcpu, iterator.sptep, ACC_ALL, pte_access,
2608 2609
				     write, &emulate, level, gfn, pfn,
				     prefault, map_writable);
2610
			direct_pte_prefetch(vcpu, iterator.sptep);
2611 2612
			++vcpu->stat.pf_fixed;
			break;
A
Avi Kivity 已提交
2613 2614
		}

2615
		if (!is_shadow_present_pte(*iterator.sptep)) {
2616 2617 2618 2619
			u64 base_addr = iterator.addr;

			base_addr &= PT64_LVL_ADDR_MASK(iterator.level);
			pseudo_gfn = base_addr >> PAGE_SHIFT;
2620 2621 2622
			sp = kvm_mmu_get_page(vcpu, pseudo_gfn, iterator.addr,
					      iterator.level - 1,
					      1, ACC_ALL, iterator.sptep);
2623

2624 2625 2626 2627 2628
			mmu_spte_set(iterator.sptep,
				     __pa(sp->spt)
				     | PT_PRESENT_MASK | PT_WRITABLE_MASK
				     | shadow_user_mask | shadow_x_mask
				     | shadow_accessed_mask);
2629 2630
		}
	}
2631
	return emulate;
A
Avi Kivity 已提交
2632 2633
}

H
Huang Ying 已提交
2634
static void kvm_send_hwpoison_signal(unsigned long address, struct task_struct *tsk)
2635
{
H
Huang Ying 已提交
2636 2637 2638 2639 2640 2641 2642
	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;
2643

H
Huang Ying 已提交
2644
	send_sig_info(SIGBUS, &info, tsk);
2645 2646
}

2647
static int kvm_handle_bad_page(struct kvm_vcpu *vcpu, gfn_t gfn, pfn_t pfn)
2648
{
X
Xiao Guangrong 已提交
2649 2650 2651 2652 2653 2654 2655 2656 2657
	/*
	 * 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;

2658
	if (pfn == KVM_PFN_ERR_HWPOISON) {
2659
		kvm_send_hwpoison_signal(gfn_to_hva(vcpu->kvm, gfn), current);
2660
		return 0;
2661
	}
2662

2663
	return -EFAULT;
2664 2665
}

2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678
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.
	 */
2679
	if (!is_error_noslot_pfn(pfn) && !kvm_is_mmio_pfn(pfn) &&
2680 2681 2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700
	    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;
2701
			kvm_get_pfn(pfn);
2702 2703 2704 2705 2706
			*pfnp = pfn;
		}
	}
}

2707 2708 2709 2710 2711 2712
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! */
2713
	if (unlikely(is_error_pfn(pfn))) {
2714 2715 2716 2717
		*ret_val = kvm_handle_bad_page(vcpu, gfn, pfn);
		goto exit;
	}

2718
	if (unlikely(is_noslot_pfn(pfn)))
2719 2720 2721 2722 2723 2724 2725
		vcpu_cache_mmio_info(vcpu, gva, gfn, access);

	ret = false;
exit:
	return ret;
}

2726 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
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
2817 2818
	trace_fast_page_fault(vcpu, gva, error_code, iterator.sptep,
			      spte, ret);
2819 2820 2821 2822 2823
	walk_shadow_page_lockless_end(vcpu);

	return ret;
}

2824
static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
2825 2826
			 gva_t gva, pfn_t *pfn, bool write, bool *writable);

2827 2828
static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, u32 error_code,
			 gfn_t gfn, bool prefault)
2829 2830
{
	int r;
2831
	int level;
2832
	int force_pt_level;
2833
	pfn_t pfn;
2834
	unsigned long mmu_seq;
2835
	bool map_writable, write = error_code & PFERR_WRITE_MASK;
2836

2837 2838 2839 2840 2841 2842 2843 2844 2845 2846
	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;
2847

2848 2849 2850
		gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
	} else
		level = PT_PAGE_TABLE_LEVEL;
M
Marcelo Tosatti 已提交
2851

2852 2853 2854
	if (fast_page_fault(vcpu, v, level, error_code))
		return 0;

2855
	mmu_seq = vcpu->kvm->mmu_notifier_seq;
2856
	smp_rmb();
2857

2858
	if (try_async_pf(vcpu, prefault, gfn, v, &pfn, write, &map_writable))
2859
		return 0;
2860

2861 2862
	if (handle_abnormal_pfn(vcpu, v, gfn, pfn, ACC_ALL, &r))
		return r;
2863

2864
	spin_lock(&vcpu->kvm->mmu_lock);
2865
	if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
2866
		goto out_unlock;
2867
	kvm_mmu_free_some_pages(vcpu);
2868 2869
	if (likely(!force_pt_level))
		transparent_hugepage_adjust(vcpu, &gfn, &pfn, &level);
2870 2871
	r = __direct_map(vcpu, v, write, map_writable, level, gfn, pfn,
			 prefault);
2872 2873 2874
	spin_unlock(&vcpu->kvm->mmu_lock);


2875
	return r;
2876 2877 2878 2879 2880

out_unlock:
	spin_unlock(&vcpu->kvm->mmu_lock);
	kvm_release_pfn_clean(pfn);
	return 0;
2881 2882 2883
}


2884 2885 2886
static void mmu_free_roots(struct kvm_vcpu *vcpu)
{
	int i;
2887
	struct kvm_mmu_page *sp;
2888
	LIST_HEAD(invalid_list);
2889

2890
	if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
A
Avi Kivity 已提交
2891
		return;
2892
	spin_lock(&vcpu->kvm->mmu_lock);
2893 2894 2895
	if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL &&
	    (vcpu->arch.mmu.root_level == PT64_ROOT_LEVEL ||
	     vcpu->arch.mmu.direct_map)) {
2896
		hpa_t root = vcpu->arch.mmu.root_hpa;
2897

2898 2899
		sp = page_header(root);
		--sp->root_count;
2900 2901 2902 2903
		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);
		}
2904
		vcpu->arch.mmu.root_hpa = INVALID_PAGE;
2905
		spin_unlock(&vcpu->kvm->mmu_lock);
2906 2907 2908
		return;
	}
	for (i = 0; i < 4; ++i) {
2909
		hpa_t root = vcpu->arch.mmu.pae_root[i];
2910

A
Avi Kivity 已提交
2911 2912
		if (root) {
			root &= PT64_BASE_ADDR_MASK;
2913 2914
			sp = page_header(root);
			--sp->root_count;
2915
			if (!sp->root_count && sp->role.invalid)
2916 2917
				kvm_mmu_prepare_zap_page(vcpu->kvm, sp,
							 &invalid_list);
A
Avi Kivity 已提交
2918
		}
2919
		vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
2920
	}
2921
	kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
2922
	spin_unlock(&vcpu->kvm->mmu_lock);
2923
	vcpu->arch.mmu.root_hpa = INVALID_PAGE;
2924 2925
}

2926 2927 2928 2929 2930
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)) {
2931
		kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
2932 2933 2934 2935 2936 2937
		ret = 1;
	}

	return ret;
}

2938 2939 2940
static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
{
	struct kvm_mmu_page *sp;
2941
	unsigned i;
2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956 2957

	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);
2958 2959
			sp = kvm_mmu_get_page(vcpu, i << (30 - PAGE_SHIFT),
					      i << 30,
2960 2961 2962 2963 2964 2965 2966
					      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;
		}
2967
		vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
2968 2969 2970 2971 2972 2973 2974
	} else
		BUG();

	return 0;
}

static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
2975
{
2976
	struct kvm_mmu_page *sp;
2977 2978 2979
	u64 pdptr, pm_mask;
	gfn_t root_gfn;
	int i;
2980

2981
	root_gfn = vcpu->arch.mmu.get_cr3(vcpu) >> PAGE_SHIFT;
2982

2983 2984 2985 2986 2987 2988 2989 2990
	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) {
2991
		hpa_t root = vcpu->arch.mmu.root_hpa;
2992 2993

		ASSERT(!VALID_PAGE(root));
2994

2995
		spin_lock(&vcpu->kvm->mmu_lock);
2996
		kvm_mmu_free_some_pages(vcpu);
2997 2998
		sp = kvm_mmu_get_page(vcpu, root_gfn, 0, PT64_ROOT_LEVEL,
				      0, ACC_ALL, NULL);
2999 3000
		root = __pa(sp->spt);
		++sp->root_count;
3001
		spin_unlock(&vcpu->kvm->mmu_lock);
3002
		vcpu->arch.mmu.root_hpa = root;
3003
		return 0;
3004
	}
3005

3006 3007
	/*
	 * We shadow a 32 bit page table. This may be a legacy 2-level
3008 3009
	 * 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.
3010
	 */
3011 3012 3013 3014
	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;

3015
	for (i = 0; i < 4; ++i) {
3016
		hpa_t root = vcpu->arch.mmu.pae_root[i];
3017 3018

		ASSERT(!VALID_PAGE(root));
3019
		if (vcpu->arch.mmu.root_level == PT32E_ROOT_LEVEL) {
3020
			pdptr = vcpu->arch.mmu.get_pdptr(vcpu, i);
3021
			if (!is_present_gpte(pdptr)) {
3022
				vcpu->arch.mmu.pae_root[i] = 0;
A
Avi Kivity 已提交
3023 3024
				continue;
			}
A
Avi Kivity 已提交
3025
			root_gfn = pdptr >> PAGE_SHIFT;
3026 3027
			if (mmu_check_root(vcpu, root_gfn))
				return 1;
3028
		}
3029
		spin_lock(&vcpu->kvm->mmu_lock);
3030
		kvm_mmu_free_some_pages(vcpu);
3031
		sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
3032
				      PT32_ROOT_LEVEL, 0,
3033
				      ACC_ALL, NULL);
3034 3035
		root = __pa(sp->spt);
		++sp->root_count;
3036 3037
		spin_unlock(&vcpu->kvm->mmu_lock);

3038
		vcpu->arch.mmu.pae_root[i] = root | pm_mask;
3039
	}
3040
	vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
3041 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

	/*
	 * 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);
	}

3067
	return 0;
3068 3069
}

3070 3071 3072 3073 3074 3075 3076 3077
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);
}

3078 3079 3080 3081 3082
static void mmu_sync_roots(struct kvm_vcpu *vcpu)
{
	int i;
	struct kvm_mmu_page *sp;

3083 3084 3085
	if (vcpu->arch.mmu.direct_map)
		return;

3086 3087
	if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
		return;
3088

3089
	vcpu_clear_mmio_info(vcpu, ~0ul);
3090
	kvm_mmu_audit(vcpu, AUDIT_PRE_SYNC);
3091
	if (vcpu->arch.mmu.root_level == PT64_ROOT_LEVEL) {
3092 3093 3094
		hpa_t root = vcpu->arch.mmu.root_hpa;
		sp = page_header(root);
		mmu_sync_children(vcpu, sp);
3095
		kvm_mmu_audit(vcpu, AUDIT_POST_SYNC);
3096 3097 3098 3099 3100
		return;
	}
	for (i = 0; i < 4; ++i) {
		hpa_t root = vcpu->arch.mmu.pae_root[i];

3101
		if (root && VALID_PAGE(root)) {
3102 3103 3104 3105 3106
			root &= PT64_BASE_ADDR_MASK;
			sp = page_header(root);
			mmu_sync_children(vcpu, sp);
		}
	}
3107
	kvm_mmu_audit(vcpu, AUDIT_POST_SYNC);
3108 3109 3110 3111 3112 3113
}

void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu)
{
	spin_lock(&vcpu->kvm->mmu_lock);
	mmu_sync_roots(vcpu);
3114
	spin_unlock(&vcpu->kvm->mmu_lock);
3115 3116
}

3117
static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr,
3118
				  u32 access, struct x86_exception *exception)
A
Avi Kivity 已提交
3119
{
3120 3121
	if (exception)
		exception->error_code = 0;
A
Avi Kivity 已提交
3122 3123 3124
	return vaddr;
}

3125
static gpa_t nonpaging_gva_to_gpa_nested(struct kvm_vcpu *vcpu, gva_t vaddr,
3126 3127
					 u32 access,
					 struct x86_exception *exception)
3128
{
3129 3130
	if (exception)
		exception->error_code = 0;
3131 3132 3133
	return vcpu->arch.nested_mmu.translate_gpa(vcpu, vaddr, access);
}

3134 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
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
3191 3192

		trace_handle_mmio_page_fault(addr, gfn, access);
3193 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
		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
3222
static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
3223
				u32 error_code, bool prefault)
A
Avi Kivity 已提交
3224
{
3225
	gfn_t gfn;
3226
	int r;
A
Avi Kivity 已提交
3227

3228
	pgprintk("%s: gva %lx error %x\n", __func__, gva, error_code);
3229 3230 3231 3232

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

3233 3234 3235
	r = mmu_topup_memory_caches(vcpu);
	if (r)
		return r;
3236

A
Avi Kivity 已提交
3237
	ASSERT(vcpu);
3238
	ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
A
Avi Kivity 已提交
3239

3240
	gfn = gva >> PAGE_SHIFT;
A
Avi Kivity 已提交
3241

3242
	return nonpaging_map(vcpu, gva & PAGE_MASK,
3243
			     error_code, gfn, prefault);
A
Avi Kivity 已提交
3244 3245
}

3246
static int kvm_arch_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn)
3247 3248
{
	struct kvm_arch_async_pf arch;
X
Xiao Guangrong 已提交
3249

3250
	arch.token = (vcpu->arch.apf.id++ << 12) | vcpu->vcpu_id;
3251
	arch.gfn = gfn;
3252
	arch.direct_map = vcpu->arch.mmu.direct_map;
X
Xiao Guangrong 已提交
3253
	arch.cr3 = vcpu->arch.mmu.get_cr3(vcpu);
3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266

	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);
}

3267
static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
3268
			 gva_t gva, pfn_t *pfn, bool write, bool *writable)
3269 3270 3271
{
	bool async;

3272
	*pfn = gfn_to_pfn_async(vcpu->kvm, gfn, &async, write, writable);
3273 3274 3275 3276

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

3277
	if (!prefault && can_do_async_pf(vcpu)) {
3278
		trace_kvm_try_async_get_page(gva, gfn);
3279 3280 3281 3282 3283 3284 3285 3286
		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;
	}

3287
	*pfn = gfn_to_pfn_prot(vcpu->kvm, gfn, write, writable);
3288 3289 3290 3291

	return false;
}

G
Gleb Natapov 已提交
3292
static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
3293
			  bool prefault)
3294
{
3295
	pfn_t pfn;
3296
	int r;
3297
	int level;
3298
	int force_pt_level;
M
Marcelo Tosatti 已提交
3299
	gfn_t gfn = gpa >> PAGE_SHIFT;
3300
	unsigned long mmu_seq;
3301 3302
	int write = error_code & PFERR_WRITE_MASK;
	bool map_writable;
3303 3304 3305 3306

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

3307 3308 3309
	if (unlikely(error_code & PFERR_RSVD_MASK))
		return handle_mmio_page_fault(vcpu, gpa, error_code, true);

3310 3311 3312 3313
	r = mmu_topup_memory_caches(vcpu);
	if (r)
		return r;

3314 3315 3316 3317 3318 3319
	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;
3320

3321 3322 3323
	if (fast_page_fault(vcpu, gpa, level, error_code))
		return 0;

3324
	mmu_seq = vcpu->kvm->mmu_notifier_seq;
3325
	smp_rmb();
3326

3327
	if (try_async_pf(vcpu, prefault, gfn, gpa, &pfn, write, &map_writable))
3328 3329
		return 0;

3330 3331 3332
	if (handle_abnormal_pfn(vcpu, 0, gfn, pfn, ACC_ALL, &r))
		return r;

3333
	spin_lock(&vcpu->kvm->mmu_lock);
3334
	if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
3335
		goto out_unlock;
3336
	kvm_mmu_free_some_pages(vcpu);
3337 3338
	if (likely(!force_pt_level))
		transparent_hugepage_adjust(vcpu, &gfn, &pfn, &level);
3339
	r = __direct_map(vcpu, gpa, write, map_writable,
3340
			 level, gfn, pfn, prefault);
3341 3342 3343
	spin_unlock(&vcpu->kvm->mmu_lock);

	return r;
3344 3345 3346 3347 3348

out_unlock:
	spin_unlock(&vcpu->kvm->mmu_lock);
	kvm_release_pfn_clean(pfn);
	return 0;
3349 3350
}

A
Avi Kivity 已提交
3351 3352
static void nonpaging_free(struct kvm_vcpu *vcpu)
{
3353
	mmu_free_roots(vcpu);
A
Avi Kivity 已提交
3354 3355
}

3356 3357
static int nonpaging_init_context(struct kvm_vcpu *vcpu,
				  struct kvm_mmu *context)
A
Avi Kivity 已提交
3358 3359 3360 3361 3362
{
	context->new_cr3 = nonpaging_new_cr3;
	context->page_fault = nonpaging_page_fault;
	context->gva_to_gpa = nonpaging_gva_to_gpa;
	context->free = nonpaging_free;
3363
	context->sync_page = nonpaging_sync_page;
M
Marcelo Tosatti 已提交
3364
	context->invlpg = nonpaging_invlpg;
3365
	context->update_pte = nonpaging_update_pte;
3366
	context->root_level = 0;
A
Avi Kivity 已提交
3367
	context->shadow_root_level = PT32E_ROOT_LEVEL;
A
Avi Kivity 已提交
3368
	context->root_hpa = INVALID_PAGE;
3369
	context->direct_map = true;
3370
	context->nx = false;
A
Avi Kivity 已提交
3371 3372 3373
	return 0;
}

3374
void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
A
Avi Kivity 已提交
3375
{
A
Avi Kivity 已提交
3376
	++vcpu->stat.tlb_flush;
3377
	kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
A
Avi Kivity 已提交
3378 3379 3380 3381
}

static void paging_new_cr3(struct kvm_vcpu *vcpu)
{
3382
	pgprintk("%s: cr3 %lx\n", __func__, kvm_read_cr3(vcpu));
3383
	mmu_free_roots(vcpu);
A
Avi Kivity 已提交
3384 3385
}

3386 3387
static unsigned long get_cr3(struct kvm_vcpu *vcpu)
{
3388
	return kvm_read_cr3(vcpu);
3389 3390
}

3391 3392
static void inject_page_fault(struct kvm_vcpu *vcpu,
			      struct x86_exception *fault)
A
Avi Kivity 已提交
3393
{
3394
	vcpu->arch.mmu.inject_page_fault(vcpu, fault);
A
Avi Kivity 已提交
3395 3396 3397 3398 3399 3400 3401
}

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

3402 3403 3404 3405 3406 3407 3408 3409 3410 3411 3412 3413
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;
}

3414 3415 3416 3417 3418 3419 3420 3421 3422 3423 3424 3425 3426 3427 3428 3429 3430
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;
}

3431 3432 3433 3434 3435 3436 3437 3438 3439 3440
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
3441 3442 3443 3444 3445 3446 3447 3448 3449
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
3450 3451 3452 3453 3454 3455 3456 3457
#define PTTYPE 64
#include "paging_tmpl.h"
#undef PTTYPE

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

3458
static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu,
3459
				  struct kvm_mmu *context)
3460 3461 3462 3463
{
	int maxphyaddr = cpuid_maxphyaddr(vcpu);
	u64 exb_bit_rsvd = 0;

3464
	if (!context->nx)
3465
		exb_bit_rsvd = rsvd_bits(63, 63);
3466
	switch (context->root_level) {
3467 3468 3469 3470
	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;
3471 3472 3473 3474 3475 3476 3477
		context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];

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

3478 3479 3480 3481 3482 3483 3484 3485
		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:
3486 3487 3488
		context->rsvd_bits_mask[0][2] =
			rsvd_bits(maxphyaddr, 63) |
			rsvd_bits(7, 8) | rsvd_bits(1, 2);	/* PDPTE */
3489
		context->rsvd_bits_mask[0][1] = exb_bit_rsvd |
3490
			rsvd_bits(maxphyaddr, 62);	/* PDE */
3491 3492 3493 3494 3495
		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 */
3496
		context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];
3497 3498 3499 3500 3501 3502 3503
		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 |
3504
			rsvd_bits(maxphyaddr, 51);
3505 3506 3507
		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];
3508 3509 3510
		context->rsvd_bits_mask[1][2] = exb_bit_rsvd |
			rsvd_bits(maxphyaddr, 51) |
			rsvd_bits(13, 29);
3511
		context->rsvd_bits_mask[1][1] = exb_bit_rsvd |
3512 3513
			rsvd_bits(maxphyaddr, 51) |
			rsvd_bits(13, 20);		/* large page */
3514
		context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];
3515 3516 3517 3518
		break;
	}
}

3519 3520 3521 3522 3523 3524 3525 3526 3527 3528 3529 3530 3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549 3550
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
3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565 3566 3567 3568
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;
}

3569 3570 3571
static int paging64_init_context_common(struct kvm_vcpu *vcpu,
					struct kvm_mmu *context,
					int level)
A
Avi Kivity 已提交
3572
{
3573
	context->nx = is_nx(vcpu);
3574
	context->root_level = level;
3575

3576
	reset_rsvds_bits_mask(vcpu, context);
3577
	update_permission_bitmask(vcpu, context);
A
Avi Kivity 已提交
3578
	update_last_pte_bitmap(vcpu, context);
A
Avi Kivity 已提交
3579 3580 3581 3582 3583

	ASSERT(is_pae(vcpu));
	context->new_cr3 = paging_new_cr3;
	context->page_fault = paging64_page_fault;
	context->gva_to_gpa = paging64_gva_to_gpa;
3584
	context->sync_page = paging64_sync_page;
M
Marcelo Tosatti 已提交
3585
	context->invlpg = paging64_invlpg;
3586
	context->update_pte = paging64_update_pte;
A
Avi Kivity 已提交
3587
	context->free = paging_free;
3588
	context->shadow_root_level = level;
A
Avi Kivity 已提交
3589
	context->root_hpa = INVALID_PAGE;
3590
	context->direct_map = false;
A
Avi Kivity 已提交
3591 3592 3593
	return 0;
}

3594 3595
static int paging64_init_context(struct kvm_vcpu *vcpu,
				 struct kvm_mmu *context)
3596
{
3597
	return paging64_init_context_common(vcpu, context, PT64_ROOT_LEVEL);
3598 3599
}

3600 3601
static int paging32_init_context(struct kvm_vcpu *vcpu,
				 struct kvm_mmu *context)
A
Avi Kivity 已提交
3602
{
3603
	context->nx = false;
3604
	context->root_level = PT32_ROOT_LEVEL;
3605

3606
	reset_rsvds_bits_mask(vcpu, context);
3607
	update_permission_bitmask(vcpu, context);
A
Avi Kivity 已提交
3608
	update_last_pte_bitmap(vcpu, context);
A
Avi Kivity 已提交
3609 3610 3611 3612 3613

	context->new_cr3 = paging_new_cr3;
	context->page_fault = paging32_page_fault;
	context->gva_to_gpa = paging32_gva_to_gpa;
	context->free = paging_free;
3614
	context->sync_page = paging32_sync_page;
M
Marcelo Tosatti 已提交
3615
	context->invlpg = paging32_invlpg;
3616
	context->update_pte = paging32_update_pte;
A
Avi Kivity 已提交
3617
	context->shadow_root_level = PT32E_ROOT_LEVEL;
A
Avi Kivity 已提交
3618
	context->root_hpa = INVALID_PAGE;
3619
	context->direct_map = false;
A
Avi Kivity 已提交
3620 3621 3622
	return 0;
}

3623 3624
static int paging32E_init_context(struct kvm_vcpu *vcpu,
				  struct kvm_mmu *context)
A
Avi Kivity 已提交
3625
{
3626
	return paging64_init_context_common(vcpu, context, PT32E_ROOT_LEVEL);
A
Avi Kivity 已提交
3627 3628
}

3629 3630
static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
{
3631
	struct kvm_mmu *context = vcpu->arch.walk_mmu;
3632

3633
	context->base_role.word = 0;
3634 3635 3636
	context->new_cr3 = nonpaging_new_cr3;
	context->page_fault = tdp_page_fault;
	context->free = nonpaging_free;
3637
	context->sync_page = nonpaging_sync_page;
M
Marcelo Tosatti 已提交
3638
	context->invlpg = nonpaging_invlpg;
3639
	context->update_pte = nonpaging_update_pte;
3640
	context->shadow_root_level = kvm_x86_ops->get_tdp_level();
3641
	context->root_hpa = INVALID_PAGE;
3642
	context->direct_map = true;
3643
	context->set_cr3 = kvm_x86_ops->set_tdp_cr3;
3644
	context->get_cr3 = get_cr3;
3645
	context->get_pdptr = kvm_pdptr_read;
3646
	context->inject_page_fault = kvm_inject_page_fault;
3647 3648

	if (!is_paging(vcpu)) {
3649
		context->nx = false;
3650 3651 3652
		context->gva_to_gpa = nonpaging_gva_to_gpa;
		context->root_level = 0;
	} else if (is_long_mode(vcpu)) {
3653
		context->nx = is_nx(vcpu);
3654
		context->root_level = PT64_ROOT_LEVEL;
3655 3656
		reset_rsvds_bits_mask(vcpu, context);
		context->gva_to_gpa = paging64_gva_to_gpa;
3657
	} else if (is_pae(vcpu)) {
3658
		context->nx = is_nx(vcpu);
3659
		context->root_level = PT32E_ROOT_LEVEL;
3660 3661
		reset_rsvds_bits_mask(vcpu, context);
		context->gva_to_gpa = paging64_gva_to_gpa;
3662
	} else {
3663
		context->nx = false;
3664
		context->root_level = PT32_ROOT_LEVEL;
3665 3666
		reset_rsvds_bits_mask(vcpu, context);
		context->gva_to_gpa = paging32_gva_to_gpa;
3667 3668
	}

3669
	update_permission_bitmask(vcpu, context);
A
Avi Kivity 已提交
3670
	update_last_pte_bitmap(vcpu, context);
3671

3672 3673 3674
	return 0;
}

3675
int kvm_init_shadow_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *context)
A
Avi Kivity 已提交
3676
{
3677
	int r;
3678
	bool smep = kvm_read_cr4_bits(vcpu, X86_CR4_SMEP);
A
Avi Kivity 已提交
3679
	ASSERT(vcpu);
3680
	ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
A
Avi Kivity 已提交
3681 3682

	if (!is_paging(vcpu))
3683
		r = nonpaging_init_context(vcpu, context);
A
Avi Kivity 已提交
3684
	else if (is_long_mode(vcpu))
3685
		r = paging64_init_context(vcpu, context);
A
Avi Kivity 已提交
3686
	else if (is_pae(vcpu))
3687
		r = paging32E_init_context(vcpu, context);
A
Avi Kivity 已提交
3688
	else
3689
		r = paging32_init_context(vcpu, context);
3690

3691
	vcpu->arch.mmu.base_role.cr4_pae = !!is_pae(vcpu);
3692
	vcpu->arch.mmu.base_role.cr0_wp  = is_write_protection(vcpu);
3693 3694
	vcpu->arch.mmu.base_role.smep_andnot_wp
		= smep && !is_write_protection(vcpu);
3695 3696 3697 3698 3699 3700 3701

	return r;
}
EXPORT_SYMBOL_GPL(kvm_init_shadow_mmu);

static int init_kvm_softmmu(struct kvm_vcpu *vcpu)
{
3702
	int r = kvm_init_shadow_mmu(vcpu, vcpu->arch.walk_mmu);
3703

3704 3705
	vcpu->arch.walk_mmu->set_cr3           = kvm_x86_ops->set_cr3;
	vcpu->arch.walk_mmu->get_cr3           = get_cr3;
3706
	vcpu->arch.walk_mmu->get_pdptr         = kvm_pdptr_read;
3707
	vcpu->arch.walk_mmu->inject_page_fault = kvm_inject_page_fault;
3708 3709

	return r;
A
Avi Kivity 已提交
3710 3711
}

3712 3713 3714 3715 3716
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;
3717
	g_context->get_pdptr         = kvm_pdptr_read;
3718 3719 3720 3721 3722 3723 3724 3725 3726
	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)) {
3727
		g_context->nx = false;
3728 3729 3730
		g_context->root_level = 0;
		g_context->gva_to_gpa = nonpaging_gva_to_gpa_nested;
	} else if (is_long_mode(vcpu)) {
3731
		g_context->nx = is_nx(vcpu);
3732
		g_context->root_level = PT64_ROOT_LEVEL;
3733
		reset_rsvds_bits_mask(vcpu, g_context);
3734 3735
		g_context->gva_to_gpa = paging64_gva_to_gpa_nested;
	} else if (is_pae(vcpu)) {
3736
		g_context->nx = is_nx(vcpu);
3737
		g_context->root_level = PT32E_ROOT_LEVEL;
3738
		reset_rsvds_bits_mask(vcpu, g_context);
3739 3740
		g_context->gva_to_gpa = paging64_gva_to_gpa_nested;
	} else {
3741
		g_context->nx = false;
3742
		g_context->root_level = PT32_ROOT_LEVEL;
3743
		reset_rsvds_bits_mask(vcpu, g_context);
3744 3745 3746
		g_context->gva_to_gpa = paging32_gva_to_gpa_nested;
	}

3747
	update_permission_bitmask(vcpu, g_context);
A
Avi Kivity 已提交
3748
	update_last_pte_bitmap(vcpu, g_context);
3749

3750 3751 3752
	return 0;
}

3753 3754
static int init_kvm_mmu(struct kvm_vcpu *vcpu)
{
3755 3756 3757
	if (mmu_is_nested(vcpu))
		return init_kvm_nested_mmu(vcpu);
	else if (tdp_enabled)
3758 3759 3760 3761 3762
		return init_kvm_tdp_mmu(vcpu);
	else
		return init_kvm_softmmu(vcpu);
}

A
Avi Kivity 已提交
3763 3764 3765
static void destroy_kvm_mmu(struct kvm_vcpu *vcpu)
{
	ASSERT(vcpu);
3766 3767
	if (VALID_PAGE(vcpu->arch.mmu.root_hpa))
		/* mmu.free() should set root_hpa = INVALID_PAGE */
3768
		vcpu->arch.mmu.free(vcpu);
A
Avi Kivity 已提交
3769 3770 3771
}

int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
A
Avi Kivity 已提交
3772 3773
{
	destroy_kvm_mmu(vcpu);
3774
	return init_kvm_mmu(vcpu);
A
Avi Kivity 已提交
3775
}
3776
EXPORT_SYMBOL_GPL(kvm_mmu_reset_context);
A
Avi Kivity 已提交
3777 3778

int kvm_mmu_load(struct kvm_vcpu *vcpu)
A
Avi Kivity 已提交
3779
{
3780 3781
	int r;

3782
	r = mmu_topup_memory_caches(vcpu);
A
Avi Kivity 已提交
3783 3784
	if (r)
		goto out;
3785
	r = mmu_alloc_roots(vcpu);
3786
	spin_lock(&vcpu->kvm->mmu_lock);
3787
	mmu_sync_roots(vcpu);
3788
	spin_unlock(&vcpu->kvm->mmu_lock);
3789 3790
	if (r)
		goto out;
3791
	/* set_cr3() should ensure TLB has been flushed */
3792
	vcpu->arch.mmu.set_cr3(vcpu, vcpu->arch.mmu.root_hpa);
3793 3794
out:
	return r;
A
Avi Kivity 已提交
3795
}
A
Avi Kivity 已提交
3796 3797 3798 3799 3800 3801
EXPORT_SYMBOL_GPL(kvm_mmu_load);

void kvm_mmu_unload(struct kvm_vcpu *vcpu)
{
	mmu_free_roots(vcpu);
}
3802
EXPORT_SYMBOL_GPL(kvm_mmu_unload);
A
Avi Kivity 已提交
3803

3804
static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
3805 3806
				  struct kvm_mmu_page *sp, u64 *spte,
				  const void *new)
3807
{
3808
	if (sp->role.level != PT_PAGE_TABLE_LEVEL) {
3809 3810
		++vcpu->kvm->stat.mmu_pde_zapped;
		return;
3811
        }
3812

A
Avi Kivity 已提交
3813
	++vcpu->kvm->stat.mmu_pte_updated;
3814
	vcpu->arch.mmu.update_pte(vcpu, sp, spte, new);
3815 3816
}

3817 3818 3819 3820 3821 3822 3823 3824 3825 3826 3827 3828 3829
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;
}

3830 3831
static void mmu_pte_write_flush_tlb(struct kvm_vcpu *vcpu, bool zap_page,
				    bool remote_flush, bool local_flush)
3832
{
3833 3834 3835 3836
	if (zap_page)
		return;

	if (remote_flush)
3837
		kvm_flush_remote_tlbs(vcpu->kvm);
3838
	else if (local_flush)
3839 3840 3841
		kvm_mmu_flush_tlb(vcpu);
}

3842 3843
static u64 mmu_pte_write_fetch_gpte(struct kvm_vcpu *vcpu, gpa_t *gpa,
				    const u8 *new, int *bytes)
3844
{
3845 3846
	u64 gentry;
	int r;
3847 3848 3849

	/*
	 * Assume that the pte write on a page table of the same type
3850 3851
	 * as the current vcpu paging mode since we update the sptes only
	 * when they have the same mode.
3852
	 */
3853
	if (is_pae(vcpu) && *bytes == 4) {
3854
		/* Handle a 32-bit guest writing two halves of a 64-bit gpte */
3855 3856 3857
		*gpa &= ~(gpa_t)7;
		*bytes = 8;
		r = kvm_read_guest(vcpu->kvm, *gpa, &gentry, min(*bytes, 8));
3858 3859
		if (r)
			gentry = 0;
3860 3861 3862
		new = (const u8 *)&gentry;
	}

3863
	switch (*bytes) {
3864 3865 3866 3867 3868 3869 3870 3871 3872
	case 4:
		gentry = *(const u32 *)new;
		break;
	case 8:
		gentry = *(const u64 *)new;
		break;
	default:
		gentry = 0;
		break;
3873 3874
	}

3875 3876 3877 3878 3879 3880 3881
	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.
 */
3882
static bool detect_write_flooding(struct kvm_mmu_page *sp)
3883
{
3884 3885 3886 3887
	/*
	 * Skip write-flooding detected for the sp whose level is 1, because
	 * it can become unsync, then the guest page is not write-protected.
	 */
3888
	if (sp->role.level == PT_PAGE_TABLE_LEVEL)
3889
		return false;
3890

3891
	return ++sp->write_flooding_count >= 3;
3892 3893 3894 3895 3896 3897 3898 3899 3900 3901 3902 3903 3904 3905 3906 3907
}

/*
 * 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;
3908 3909 3910 3911 3912 3913 3914 3915

	/*
	 * 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;

3916 3917 3918 3919 3920 3921 3922 3923 3924 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
	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;
3963
	bool remote_flush, local_flush, zap_page;
3964 3965 3966 3967 3968 3969 3970 3971 3972 3973 3974 3975 3976 3977 3978 3979 3980 3981 3982 3983 3984 3985 3986

	/*
	 * 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;
3987
	kvm_mmu_audit(vcpu, AUDIT_PRE_PTE_WRITE);
3988

3989
	mask.cr0_wp = mask.cr4_pae = mask.nxe = 1;
3990
	for_each_gfn_indirect_valid_sp(vcpu->kvm, sp, gfn, node) {
3991
		if (detect_write_misaligned(sp, gpa, bytes) ||
3992
		      detect_write_flooding(sp)) {
3993
			zap_page |= !!kvm_mmu_prepare_zap_page(vcpu->kvm, sp,
3994
						     &invalid_list);
A
Avi Kivity 已提交
3995
			++vcpu->kvm->stat.mmu_flooded;
3996 3997
			continue;
		}
3998 3999 4000 4001 4002

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

4003
		local_flush = true;
4004
		while (npte--) {
4005
			entry = *spte;
4006
			mmu_page_zap_pte(vcpu->kvm, sp, spte);
4007 4008
			if (gentry &&
			      !((sp->role.word ^ vcpu->arch.mmu.base_role.word)
4009
			      & mask.word) && rmap_can_add(vcpu))
4010
				mmu_pte_write_new_pte(vcpu, sp, spte, &gentry);
4011 4012
			if (!remote_flush && need_remote_flush(entry, *spte))
				remote_flush = true;
4013
			++spte;
4014 4015
		}
	}
4016
	mmu_pte_write_flush_tlb(vcpu, zap_page, remote_flush, local_flush);
4017
	kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
4018
	kvm_mmu_audit(vcpu, AUDIT_POST_PTE_WRITE);
4019
	spin_unlock(&vcpu->kvm->mmu_lock);
4020 4021
}

4022 4023
int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
{
4024 4025
	gpa_t gpa;
	int r;
4026

4027
	if (vcpu->arch.mmu.direct_map)
4028 4029
		return 0;

4030
	gpa = kvm_mmu_gva_to_gpa_read(vcpu, gva, NULL);
4031 4032

	r = kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT);
4033

4034
	return r;
4035
}
4036
EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page_virt);
4037

4038
void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
A
Avi Kivity 已提交
4039
{
4040
	LIST_HEAD(invalid_list);
4041

4042
	while (kvm_mmu_available_pages(vcpu->kvm) < KVM_REFILL_PAGES &&
4043
	       !list_empty(&vcpu->kvm->arch.active_mmu_pages)) {
4044
		struct kvm_mmu_page *sp;
A
Avi Kivity 已提交
4045

4046
		sp = container_of(vcpu->kvm->arch.active_mmu_pages.prev,
4047
				  struct kvm_mmu_page, link);
4048
		kvm_mmu_prepare_zap_page(vcpu->kvm, sp, &invalid_list);
A
Avi Kivity 已提交
4049
		++vcpu->kvm->stat.mmu_recycled;
A
Avi Kivity 已提交
4050
	}
4051
	kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
A
Avi Kivity 已提交
4052 4053
}

4054 4055 4056 4057 4058 4059 4060 4061
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);
}

4062 4063
int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code,
		       void *insn, int insn_len)
4064
{
4065
	int r, emulation_type = EMULTYPE_RETRY;
4066 4067
	enum emulation_result er;

G
Gleb Natapov 已提交
4068
	r = vcpu->arch.mmu.page_fault(vcpu, cr2, error_code, false);
4069 4070 4071 4072 4073 4074 4075 4076
	if (r < 0)
		goto out;

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

4077 4078 4079 4080
	if (is_mmio_page_fault(vcpu, cr2))
		emulation_type = 0;

	er = x86_emulate_instruction(vcpu, cr2, emulation_type, insn, insn_len);
4081 4082 4083 4084 4085 4086

	switch (er) {
	case EMULATE_DONE:
		return 1;
	case EMULATE_DO_MMIO:
		++vcpu->stat.mmio_exits;
4087
		/* fall through */
4088
	case EMULATE_FAIL:
4089
		return 0;
4090 4091 4092 4093 4094 4095 4096 4097
	default:
		BUG();
	}
out:
	return r;
}
EXPORT_SYMBOL_GPL(kvm_mmu_page_fault);

M
Marcelo Tosatti 已提交
4098 4099 4100 4101 4102 4103 4104 4105
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);

4106 4107 4108 4109 4110 4111
void kvm_enable_tdp(void)
{
	tdp_enabled = true;
}
EXPORT_SYMBOL_GPL(kvm_enable_tdp);

4112 4113 4114 4115 4116 4117
void kvm_disable_tdp(void)
{
	tdp_enabled = false;
}
EXPORT_SYMBOL_GPL(kvm_disable_tdp);

A
Avi Kivity 已提交
4118 4119
static void free_mmu_pages(struct kvm_vcpu *vcpu)
{
4120
	free_page((unsigned long)vcpu->arch.mmu.pae_root);
4121 4122
	if (vcpu->arch.mmu.lm_root != NULL)
		free_page((unsigned long)vcpu->arch.mmu.lm_root);
A
Avi Kivity 已提交
4123 4124 4125 4126
}

static int alloc_mmu_pages(struct kvm_vcpu *vcpu)
{
4127
	struct page *page;
A
Avi Kivity 已提交
4128 4129 4130 4131
	int i;

	ASSERT(vcpu);

4132 4133 4134 4135 4136 4137 4138
	/*
	 * 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)
4139 4140
		return -ENOMEM;

4141
	vcpu->arch.mmu.pae_root = page_address(page);
4142
	for (i = 0; i < 4; ++i)
4143
		vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
4144

A
Avi Kivity 已提交
4145 4146 4147
	return 0;
}

4148
int kvm_mmu_create(struct kvm_vcpu *vcpu)
A
Avi Kivity 已提交
4149 4150
{
	ASSERT(vcpu);
4151 4152 4153 4154 4155

	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
4156

4157 4158
	return alloc_mmu_pages(vcpu);
}
A
Avi Kivity 已提交
4159

4160 4161 4162
int kvm_mmu_setup(struct kvm_vcpu *vcpu)
{
	ASSERT(vcpu);
4163
	ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
4164

4165
	return init_kvm_mmu(vcpu);
A
Avi Kivity 已提交
4166 4167
}

4168
void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
A
Avi Kivity 已提交
4169
{
4170 4171 4172
	struct kvm_memory_slot *memslot;
	gfn_t last_gfn;
	int i;
A
Avi Kivity 已提交
4173

4174 4175
	memslot = id_to_memslot(kvm->memslots, slot);
	last_gfn = memslot->base_gfn + memslot->npages - 1;
A
Avi Kivity 已提交
4176

4177 4178
	spin_lock(&kvm->mmu_lock);

4179 4180 4181 4182
	for (i = PT_PAGE_TABLE_LEVEL;
	     i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
		unsigned long *rmapp;
		unsigned long last_index, index;
A
Avi Kivity 已提交
4183

4184 4185
		rmapp = memslot->arch.rmap[i - PT_PAGE_TABLE_LEVEL];
		last_index = gfn_to_index(last_gfn, memslot->base_gfn, i);
4186

4187 4188 4189
		for (index = 0; index <= last_index; ++index, ++rmapp) {
			if (*rmapp)
				__rmap_write_protect(kvm, rmapp, false);
4190 4191 4192 4193 4194

			if (need_resched() || spin_needbreak(&kvm->mmu_lock)) {
				kvm_flush_remote_tlbs(kvm);
				cond_resched_lock(&kvm->mmu_lock);
			}
4195
		}
A
Avi Kivity 已提交
4196
	}
4197

4198
	kvm_flush_remote_tlbs(kvm);
4199
	spin_unlock(&kvm->mmu_lock);
A
Avi Kivity 已提交
4200
}
4201

4202
void kvm_mmu_zap_all(struct kvm *kvm)
D
Dor Laor 已提交
4203
{
4204
	struct kvm_mmu_page *sp, *node;
4205
	LIST_HEAD(invalid_list);
D
Dor Laor 已提交
4206

4207
	spin_lock(&kvm->mmu_lock);
4208
restart:
4209
	list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link)
4210
		if (kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list))
4211 4212
			goto restart;

4213
	kvm_mmu_commit_zap_page(kvm, &invalid_list);
4214
	spin_unlock(&kvm->mmu_lock);
D
Dor Laor 已提交
4215 4216
}

4217 4218
static void kvm_mmu_remove_some_alloc_mmu_pages(struct kvm *kvm,
						struct list_head *invalid_list)
4219 4220 4221
{
	struct kvm_mmu_page *page;

4222 4223 4224
	if (list_empty(&kvm->arch.active_mmu_pages))
		return;

4225 4226
	page = container_of(kvm->arch.active_mmu_pages.prev,
			    struct kvm_mmu_page, link);
4227
	kvm_mmu_prepare_zap_page(kvm, page, invalid_list);
4228 4229
}

4230
static int mmu_shrink(struct shrinker *shrink, struct shrink_control *sc)
4231 4232
{
	struct kvm *kvm;
4233
	int nr_to_scan = sc->nr_to_scan;
4234 4235 4236

	if (nr_to_scan == 0)
		goto out;
4237

4238
	raw_spin_lock(&kvm_lock);
4239 4240

	list_for_each_entry(kvm, &vm_list, vm_list) {
4241
		int idx;
4242
		LIST_HEAD(invalid_list);
4243

4244 4245 4246 4247 4248 4249 4250 4251
		/*
		 * 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;
4252 4253 4254 4255 4256 4257
		/*
		 * 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.
		 */
4258
		if (!kvm->arch.n_used_mmu_pages)
4259 4260
			continue;

4261
		idx = srcu_read_lock(&kvm->srcu);
4262 4263
		spin_lock(&kvm->mmu_lock);

4264
		kvm_mmu_remove_some_alloc_mmu_pages(kvm, &invalid_list);
4265
		kvm_mmu_commit_zap_page(kvm, &invalid_list);
4266

4267
		spin_unlock(&kvm->mmu_lock);
4268
		srcu_read_unlock(&kvm->srcu, idx);
4269 4270 4271

		list_move_tail(&kvm->vm_list, &vm_list);
		break;
4272 4273
	}

4274
	raw_spin_unlock(&kvm_lock);
4275

4276 4277
out:
	return percpu_counter_read_positive(&kvm_total_used_mmu_pages);
4278 4279 4280 4281 4282 4283 4284
}

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

I
Ingo Molnar 已提交
4285
static void mmu_destroy_caches(void)
4286
{
4287 4288
	if (pte_list_desc_cache)
		kmem_cache_destroy(pte_list_desc_cache);
4289 4290
	if (mmu_page_header_cache)
		kmem_cache_destroy(mmu_page_header_cache);
4291 4292 4293 4294
}

int kvm_mmu_module_init(void)
{
4295 4296
	pte_list_desc_cache = kmem_cache_create("pte_list_desc",
					    sizeof(struct pte_list_desc),
4297
					    0, 0, NULL);
4298
	if (!pte_list_desc_cache)
4299 4300
		goto nomem;

4301 4302
	mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
						  sizeof(struct kvm_mmu_page),
4303
						  0, 0, NULL);
4304 4305 4306
	if (!mmu_page_header_cache)
		goto nomem;

4307 4308 4309
	if (percpu_counter_init(&kvm_total_used_mmu_pages, 0))
		goto nomem;

4310 4311
	register_shrinker(&mmu_shrinker);

4312 4313 4314
	return 0;

nomem:
4315
	mmu_destroy_caches();
4316 4317 4318
	return -ENOMEM;
}

4319 4320 4321 4322 4323 4324 4325
/*
 * 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;
4326
	struct kvm_memslots *slots;
4327
	struct kvm_memory_slot *memslot;
4328

4329 4330
	slots = kvm_memslots(kvm);

4331 4332
	kvm_for_each_memslot(memslot, slots)
		nr_pages += memslot->npages;
4333 4334 4335 4336 4337 4338 4339 4340

	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;
}

4341 4342 4343
int kvm_mmu_get_spte_hierarchy(struct kvm_vcpu *vcpu, u64 addr, u64 sptes[4])
{
	struct kvm_shadow_walk_iterator iterator;
4344
	u64 spte;
4345 4346
	int nr_sptes = 0;

4347 4348 4349
	walk_shadow_page_lockless_begin(vcpu);
	for_each_shadow_entry_lockless(vcpu, addr, iterator, spte) {
		sptes[iterator.level-1] = spte;
4350
		nr_sptes++;
4351
		if (!is_shadow_present_pte(spte))
4352 4353
			break;
	}
4354
	walk_shadow_page_lockless_end(vcpu);
4355 4356 4357 4358 4359

	return nr_sptes;
}
EXPORT_SYMBOL_GPL(kvm_mmu_get_spte_hierarchy);

4360 4361 4362 4363 4364 4365 4366
void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
{
	ASSERT(vcpu);

	destroy_kvm_mmu(vcpu);
	free_mmu_pages(vcpu);
	mmu_free_memory_caches(vcpu);
4367 4368 4369 4370 4371 4372 4373
}

void kvm_mmu_module_exit(void)
{
	mmu_destroy_caches();
	percpu_counter_destroy(&kvm_total_used_mmu_pages);
	unregister_shrinker(&mmu_shrinker);
4374 4375
	mmu_audit_disable();
}