mmu.c 50.2 KB
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/*
 * Copyright (C) 2012 - Virtual Open Systems and Columbia University
 * Author: Christoffer Dall <c.dall@virtualopensystems.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2, as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
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#include <linux/mman.h>
#include <linux/kvm_host.h>
#include <linux/io.h>
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#include <linux/hugetlb.h>
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#include <trace/events/kvm.h>
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#include <asm/pgalloc.h>
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#include <asm/cacheflush.h>
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#include <asm/kvm_arm.h>
#include <asm/kvm_mmu.h>
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#include <asm/kvm_mmio.h>
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#include <asm/kvm_asm.h>
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#include <asm/kvm_emulate.h>
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#include "trace.h"
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extern char  __hyp_idmap_text_start[], __hyp_idmap_text_end[];

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static pgd_t *boot_hyp_pgd;
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static pgd_t *hyp_pgd;
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static pgd_t *merged_hyp_pgd;
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static DEFINE_MUTEX(kvm_hyp_pgd_mutex);

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static unsigned long hyp_idmap_start;
static unsigned long hyp_idmap_end;
static phys_addr_t hyp_idmap_vector;

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#define hyp_pgd_order get_order(PTRS_PER_PGD * sizeof(pgd_t))
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#define kvm_pmd_huge(_x)	(pmd_huge(_x) || pmd_trans_huge(_x))
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#define kvm_pud_huge(_x)	pud_huge(_x)
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#define KVM_S2PTE_FLAG_IS_IOMAP		(1UL << 0)
#define KVM_S2_FLAG_LOGGING_ACTIVE	(1UL << 1)

static bool memslot_is_logging(struct kvm_memory_slot *memslot)
{
	return memslot->dirty_bitmap && !(memslot->flags & KVM_MEM_READONLY);
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}

/**
 * kvm_flush_remote_tlbs() - flush all VM TLB entries for v7/8
 * @kvm:	pointer to kvm structure.
 *
 * Interface to HYP function to flush all VM TLB entries
 */
void kvm_flush_remote_tlbs(struct kvm *kvm)
{
	kvm_call_hyp(__kvm_tlb_flush_vmid, kvm);
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}
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static void kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)
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{
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	/*
	 * This function also gets called when dealing with HYP page
	 * tables. As HYP doesn't have an associated struct kvm (and
	 * the HYP page tables are fairly static), we don't do
	 * anything there.
	 */
	if (kvm)
		kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, kvm, ipa);
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}

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/*
 * D-Cache management functions. They take the page table entries by
 * value, as they are flushing the cache using the kernel mapping (or
 * kmap on 32bit).
 */
static void kvm_flush_dcache_pte(pte_t pte)
{
	__kvm_flush_dcache_pte(pte);
}

static void kvm_flush_dcache_pmd(pmd_t pmd)
{
	__kvm_flush_dcache_pmd(pmd);
}

static void kvm_flush_dcache_pud(pud_t pud)
{
	__kvm_flush_dcache_pud(pud);
}

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static bool kvm_is_device_pfn(unsigned long pfn)
{
	return !pfn_valid(pfn);
}

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/**
 * stage2_dissolve_pmd() - clear and flush huge PMD entry
 * @kvm:	pointer to kvm structure.
 * @addr:	IPA
 * @pmd:	pmd pointer for IPA
 *
 * Function clears a PMD entry, flushes addr 1st and 2nd stage TLBs. Marks all
 * pages in the range dirty.
 */
static void stage2_dissolve_pmd(struct kvm *kvm, phys_addr_t addr, pmd_t *pmd)
{
	if (!kvm_pmd_huge(*pmd))
		return;

	pmd_clear(pmd);
	kvm_tlb_flush_vmid_ipa(kvm, addr);
	put_page(virt_to_page(pmd));
}

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static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
				  int min, int max)
{
	void *page;

	BUG_ON(max > KVM_NR_MEM_OBJS);
	if (cache->nobjs >= min)
		return 0;
	while (cache->nobjs < max) {
		page = (void *)__get_free_page(PGALLOC_GFP);
		if (!page)
			return -ENOMEM;
		cache->objects[cache->nobjs++] = page;
	}
	return 0;
}

static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
{
	while (mc->nobjs)
		free_page((unsigned long)mc->objects[--mc->nobjs]);
}

static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
{
	void *p;

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

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static void clear_pgd_entry(struct kvm *kvm, pgd_t *pgd, phys_addr_t addr)
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{
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	pud_t *pud_table __maybe_unused = pud_offset(pgd, 0);
	pgd_clear(pgd);
	kvm_tlb_flush_vmid_ipa(kvm, addr);
	pud_free(NULL, pud_table);
	put_page(virt_to_page(pgd));
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}

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static void clear_pud_entry(struct kvm *kvm, pud_t *pud, phys_addr_t addr)
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{
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	pmd_t *pmd_table = pmd_offset(pud, 0);
	VM_BUG_ON(pud_huge(*pud));
	pud_clear(pud);
	kvm_tlb_flush_vmid_ipa(kvm, addr);
	pmd_free(NULL, pmd_table);
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	put_page(virt_to_page(pud));
}
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static void clear_pmd_entry(struct kvm *kvm, pmd_t *pmd, phys_addr_t addr)
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{
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	pte_t *pte_table = pte_offset_kernel(pmd, 0);
	VM_BUG_ON(kvm_pmd_huge(*pmd));
	pmd_clear(pmd);
	kvm_tlb_flush_vmid_ipa(kvm, addr);
	pte_free_kernel(NULL, pte_table);
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	put_page(virt_to_page(pmd));
}

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/*
 * Unmapping vs dcache management:
 *
 * If a guest maps certain memory pages as uncached, all writes will
 * bypass the data cache and go directly to RAM.  However, the CPUs
 * can still speculate reads (not writes) and fill cache lines with
 * data.
 *
 * Those cache lines will be *clean* cache lines though, so a
 * clean+invalidate operation is equivalent to an invalidate
 * operation, because no cache lines are marked dirty.
 *
 * Those clean cache lines could be filled prior to an uncached write
 * by the guest, and the cache coherent IO subsystem would therefore
 * end up writing old data to disk.
 *
 * This is why right after unmapping a page/section and invalidating
 * the corresponding TLBs, we call kvm_flush_dcache_p*() to make sure
 * the IO subsystem will never hit in the cache.
 */
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static void unmap_ptes(struct kvm *kvm, pmd_t *pmd,
		       phys_addr_t addr, phys_addr_t end)
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{
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	phys_addr_t start_addr = addr;
	pte_t *pte, *start_pte;

	start_pte = pte = pte_offset_kernel(pmd, addr);
	do {
		if (!pte_none(*pte)) {
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			pte_t old_pte = *pte;

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			kvm_set_pte(pte, __pte(0));
			kvm_tlb_flush_vmid_ipa(kvm, addr);
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			/* No need to invalidate the cache for device mappings */
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			if (!kvm_is_device_pfn(pte_pfn(old_pte)))
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				kvm_flush_dcache_pte(old_pte);

			put_page(virt_to_page(pte));
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		}
	} while (pte++, addr += PAGE_SIZE, addr != end);

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	if (kvm_pte_table_empty(kvm, start_pte))
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		clear_pmd_entry(kvm, pmd, start_addr);
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}

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static void unmap_pmds(struct kvm *kvm, pud_t *pud,
		       phys_addr_t addr, phys_addr_t end)
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{
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	phys_addr_t next, start_addr = addr;
	pmd_t *pmd, *start_pmd;
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	start_pmd = pmd = pmd_offset(pud, addr);
	do {
		next = kvm_pmd_addr_end(addr, end);
		if (!pmd_none(*pmd)) {
			if (kvm_pmd_huge(*pmd)) {
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				pmd_t old_pmd = *pmd;

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				pmd_clear(pmd);
				kvm_tlb_flush_vmid_ipa(kvm, addr);
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				kvm_flush_dcache_pmd(old_pmd);

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				put_page(virt_to_page(pmd));
			} else {
				unmap_ptes(kvm, pmd, addr, next);
			}
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		}
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	} while (pmd++, addr = next, addr != end);
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	if (kvm_pmd_table_empty(kvm, start_pmd))
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		clear_pud_entry(kvm, pud, start_addr);
}
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static void unmap_puds(struct kvm *kvm, pgd_t *pgd,
		       phys_addr_t addr, phys_addr_t end)
{
	phys_addr_t next, start_addr = addr;
	pud_t *pud, *start_pud;
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	start_pud = pud = pud_offset(pgd, addr);
	do {
		next = kvm_pud_addr_end(addr, end);
		if (!pud_none(*pud)) {
			if (pud_huge(*pud)) {
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				pud_t old_pud = *pud;

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				pud_clear(pud);
				kvm_tlb_flush_vmid_ipa(kvm, addr);
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				kvm_flush_dcache_pud(old_pud);

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				put_page(virt_to_page(pud));
			} else {
				unmap_pmds(kvm, pud, addr, next);
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			}
		}
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	} while (pud++, addr = next, addr != end);
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	if (kvm_pud_table_empty(kvm, start_pud))
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		clear_pgd_entry(kvm, pgd, start_addr);
}


static void unmap_range(struct kvm *kvm, pgd_t *pgdp,
			phys_addr_t start, u64 size)
{
	pgd_t *pgd;
	phys_addr_t addr = start, end = start + size;
	phys_addr_t next;

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	pgd = pgdp + kvm_pgd_index(addr);
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	do {
		next = kvm_pgd_addr_end(addr, end);
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		if (!pgd_none(*pgd))
			unmap_puds(kvm, pgd, addr, next);
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	} while (pgd++, addr = next, addr != end);
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}

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static void stage2_flush_ptes(struct kvm *kvm, pmd_t *pmd,
			      phys_addr_t addr, phys_addr_t end)
{
	pte_t *pte;

	pte = pte_offset_kernel(pmd, addr);
	do {
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		if (!pte_none(*pte) && !kvm_is_device_pfn(pte_pfn(*pte)))
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			kvm_flush_dcache_pte(*pte);
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	} while (pte++, addr += PAGE_SIZE, addr != end);
}

static void stage2_flush_pmds(struct kvm *kvm, pud_t *pud,
			      phys_addr_t addr, phys_addr_t end)
{
	pmd_t *pmd;
	phys_addr_t next;

	pmd = pmd_offset(pud, addr);
	do {
		next = kvm_pmd_addr_end(addr, end);
		if (!pmd_none(*pmd)) {
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			if (kvm_pmd_huge(*pmd))
				kvm_flush_dcache_pmd(*pmd);
			else
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				stage2_flush_ptes(kvm, pmd, addr, next);
		}
	} while (pmd++, addr = next, addr != end);
}

static void stage2_flush_puds(struct kvm *kvm, pgd_t *pgd,
			      phys_addr_t addr, phys_addr_t end)
{
	pud_t *pud;
	phys_addr_t next;

	pud = pud_offset(pgd, addr);
	do {
		next = kvm_pud_addr_end(addr, end);
		if (!pud_none(*pud)) {
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			if (pud_huge(*pud))
				kvm_flush_dcache_pud(*pud);
			else
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				stage2_flush_pmds(kvm, pud, addr, next);
		}
	} while (pud++, addr = next, addr != end);
}

static void stage2_flush_memslot(struct kvm *kvm,
				 struct kvm_memory_slot *memslot)
{
	phys_addr_t addr = memslot->base_gfn << PAGE_SHIFT;
	phys_addr_t end = addr + PAGE_SIZE * memslot->npages;
	phys_addr_t next;
	pgd_t *pgd;

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	pgd = kvm->arch.pgd + kvm_pgd_index(addr);
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	do {
		next = kvm_pgd_addr_end(addr, end);
		stage2_flush_puds(kvm, pgd, addr, next);
	} while (pgd++, addr = next, addr != end);
}

/**
 * stage2_flush_vm - Invalidate cache for pages mapped in stage 2
 * @kvm: The struct kvm pointer
 *
 * Go through the stage 2 page tables and invalidate any cache lines
 * backing memory already mapped to the VM.
 */
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static void stage2_flush_vm(struct kvm *kvm)
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{
	struct kvm_memslots *slots;
	struct kvm_memory_slot *memslot;
	int idx;

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

	slots = kvm_memslots(kvm);
	kvm_for_each_memslot(memslot, slots)
		stage2_flush_memslot(kvm, memslot);

	spin_unlock(&kvm->mmu_lock);
	srcu_read_unlock(&kvm->srcu, idx);
}

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/**
 * free_boot_hyp_pgd - free HYP boot page tables
 *
 * Free the HYP boot page tables. The bounce page is also freed.
 */
void free_boot_hyp_pgd(void)
{
	mutex_lock(&kvm_hyp_pgd_mutex);

	if (boot_hyp_pgd) {
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		unmap_range(NULL, boot_hyp_pgd, hyp_idmap_start, PAGE_SIZE);
		unmap_range(NULL, boot_hyp_pgd, TRAMPOLINE_VA, PAGE_SIZE);
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		free_pages((unsigned long)boot_hyp_pgd, hyp_pgd_order);
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		boot_hyp_pgd = NULL;
	}

	if (hyp_pgd)
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		unmap_range(NULL, hyp_pgd, TRAMPOLINE_VA, PAGE_SIZE);
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	mutex_unlock(&kvm_hyp_pgd_mutex);
}

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/**
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 * free_hyp_pgds - free Hyp-mode page tables
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 *
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 * Assumes hyp_pgd is a page table used strictly in Hyp-mode and
 * therefore contains either mappings in the kernel memory area (above
 * PAGE_OFFSET), or device mappings in the vmalloc range (from
 * VMALLOC_START to VMALLOC_END).
 *
 * boot_hyp_pgd should only map two pages for the init code.
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 */
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void free_hyp_pgds(void)
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{
	unsigned long addr;

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	free_boot_hyp_pgd();
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	mutex_lock(&kvm_hyp_pgd_mutex);
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	if (hyp_pgd) {
		for (addr = PAGE_OFFSET; virt_addr_valid(addr); addr += PGDIR_SIZE)
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			unmap_range(NULL, hyp_pgd, KERN_TO_HYP(addr), PGDIR_SIZE);
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		for (addr = VMALLOC_START; is_vmalloc_addr((void*)addr); addr += PGDIR_SIZE)
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			unmap_range(NULL, hyp_pgd, KERN_TO_HYP(addr), PGDIR_SIZE);

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		free_pages((unsigned long)hyp_pgd, hyp_pgd_order);
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		hyp_pgd = NULL;
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	}
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	if (merged_hyp_pgd) {
		clear_page(merged_hyp_pgd);
		free_page((unsigned long)merged_hyp_pgd);
		merged_hyp_pgd = NULL;
	}
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	mutex_unlock(&kvm_hyp_pgd_mutex);
}

static void create_hyp_pte_mappings(pmd_t *pmd, unsigned long start,
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				    unsigned long end, unsigned long pfn,
				    pgprot_t prot)
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{
	pte_t *pte;
	unsigned long addr;

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	addr = start;
	do {
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		pte = pte_offset_kernel(pmd, addr);
		kvm_set_pte(pte, pfn_pte(pfn, prot));
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		get_page(virt_to_page(pte));
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		kvm_flush_dcache_to_poc(pte, sizeof(*pte));
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		pfn++;
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	} while (addr += PAGE_SIZE, addr != end);
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}

static int create_hyp_pmd_mappings(pud_t *pud, unsigned long start,
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				   unsigned long end, unsigned long pfn,
				   pgprot_t prot)
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{
	pmd_t *pmd;
	pte_t *pte;
	unsigned long addr, next;

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	addr = start;
	do {
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		pmd = pmd_offset(pud, addr);
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		BUG_ON(pmd_sect(*pmd));

		if (pmd_none(*pmd)) {
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			pte = pte_alloc_one_kernel(NULL, addr);
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			if (!pte) {
				kvm_err("Cannot allocate Hyp pte\n");
				return -ENOMEM;
			}
			pmd_populate_kernel(NULL, pmd, pte);
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			get_page(virt_to_page(pmd));
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			kvm_flush_dcache_to_poc(pmd, sizeof(*pmd));
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		}

		next = pmd_addr_end(addr, end);

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		create_hyp_pte_mappings(pmd, addr, next, pfn, prot);
		pfn += (next - addr) >> PAGE_SHIFT;
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	} while (addr = next, addr != end);
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	return 0;
}

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static int create_hyp_pud_mappings(pgd_t *pgd, unsigned long start,
				   unsigned long end, unsigned long pfn,
				   pgprot_t prot)
{
	pud_t *pud;
	pmd_t *pmd;
	unsigned long addr, next;
	int ret;

	addr = start;
	do {
		pud = pud_offset(pgd, addr);

		if (pud_none_or_clear_bad(pud)) {
			pmd = pmd_alloc_one(NULL, addr);
			if (!pmd) {
				kvm_err("Cannot allocate Hyp pmd\n");
				return -ENOMEM;
			}
			pud_populate(NULL, pud, pmd);
			get_page(virt_to_page(pud));
			kvm_flush_dcache_to_poc(pud, sizeof(*pud));
		}

		next = pud_addr_end(addr, end);
		ret = create_hyp_pmd_mappings(pud, addr, next, pfn, prot);
		if (ret)
			return ret;
		pfn += (next - addr) >> PAGE_SHIFT;
	} while (addr = next, addr != end);

	return 0;
}

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static int __create_hyp_mappings(pgd_t *pgdp,
				 unsigned long start, unsigned long end,
				 unsigned long pfn, pgprot_t prot)
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{
	pgd_t *pgd;
	pud_t *pud;
	unsigned long addr, next;
	int err = 0;

	mutex_lock(&kvm_hyp_pgd_mutex);
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	addr = start & PAGE_MASK;
	end = PAGE_ALIGN(end);
	do {
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		pgd = pgdp + pgd_index(addr);
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		if (pgd_none(*pgd)) {
			pud = pud_alloc_one(NULL, addr);
			if (!pud) {
				kvm_err("Cannot allocate Hyp pud\n");
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				err = -ENOMEM;
				goto out;
			}
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			pgd_populate(NULL, pgd, pud);
			get_page(virt_to_page(pgd));
			kvm_flush_dcache_to_poc(pgd, sizeof(*pgd));
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		}

		next = pgd_addr_end(addr, end);
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		err = create_hyp_pud_mappings(pgd, addr, next, pfn, prot);
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		if (err)
			goto out;
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		pfn += (next - addr) >> PAGE_SHIFT;
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	} while (addr = next, addr != end);
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out:
	mutex_unlock(&kvm_hyp_pgd_mutex);
	return err;
}

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static phys_addr_t kvm_kaddr_to_phys(void *kaddr)
{
	if (!is_vmalloc_addr(kaddr)) {
		BUG_ON(!virt_addr_valid(kaddr));
		return __pa(kaddr);
	} else {
		return page_to_phys(vmalloc_to_page(kaddr)) +
		       offset_in_page(kaddr);
	}
}

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/**
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 * create_hyp_mappings - duplicate a kernel virtual address range in Hyp mode
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 * @from:	The virtual kernel start address of the range
 * @to:		The virtual kernel end address of the range (exclusive)
 *
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 * The same virtual address as the kernel virtual address is also used
 * in Hyp-mode mapping (modulo HYP_PAGE_OFFSET) to the same underlying
 * physical pages.
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 */
int create_hyp_mappings(void *from, void *to)
{
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	phys_addr_t phys_addr;
	unsigned long virt_addr;
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	unsigned long start = KERN_TO_HYP((unsigned long)from);
	unsigned long end = KERN_TO_HYP((unsigned long)to);

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	start = start & PAGE_MASK;
	end = PAGE_ALIGN(end);
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	for (virt_addr = start; virt_addr < end; virt_addr += PAGE_SIZE) {
		int err;
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		phys_addr = kvm_kaddr_to_phys(from + virt_addr - start);
		err = __create_hyp_mappings(hyp_pgd, virt_addr,
					    virt_addr + PAGE_SIZE,
					    __phys_to_pfn(phys_addr),
					    PAGE_HYP);
		if (err)
			return err;
	}

	return 0;
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}

/**
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 * create_hyp_io_mappings - duplicate a kernel IO mapping into Hyp mode
 * @from:	The kernel start VA of the range
 * @to:		The kernel end VA of the range (exclusive)
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 * @phys_addr:	The physical start address which gets mapped
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 *
 * The resulting HYP VA is the same as the kernel VA, modulo
 * HYP_PAGE_OFFSET.
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 */
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int create_hyp_io_mappings(void *from, void *to, phys_addr_t phys_addr)
629
{
630 631 632 633 634 635 636 637 638
	unsigned long start = KERN_TO_HYP((unsigned long)from);
	unsigned long end = KERN_TO_HYP((unsigned long)to);

	/* Check for a valid kernel IO mapping */
	if (!is_vmalloc_addr(from) || !is_vmalloc_addr(to - 1))
		return -EINVAL;

	return __create_hyp_mappings(hyp_pgd, start, end,
				     __phys_to_pfn(phys_addr), PAGE_HYP_DEVICE);
639 640
}

641 642 643 644 645 646 647 648 649 650 651 652 653 654
/* Free the HW pgd, one page at a time */
static void kvm_free_hwpgd(void *hwpgd)
{
	free_pages_exact(hwpgd, kvm_get_hwpgd_size());
}

/* Allocate the HW PGD, making sure that each page gets its own refcount */
static void *kvm_alloc_hwpgd(void)
{
	unsigned int size = kvm_get_hwpgd_size();

	return alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
}

655 656 657 658 659 660 661 662 663 664 665 666 667 668
/**
 * kvm_alloc_stage2_pgd - allocate level-1 table for stage-2 translation.
 * @kvm:	The KVM struct pointer for the VM.
 *
 * Allocates the 1st level table only of size defined by S2_PGD_ORDER (can
 * support either full 40-bit input addresses or limited to 32-bit input
 * addresses). Clears the allocated pages.
 *
 * Note we don't need locking here as this is only called when the VM is
 * created, which can only be done once.
 */
int kvm_alloc_stage2_pgd(struct kvm *kvm)
{
	pgd_t *pgd;
669
	void *hwpgd;
670 671 672 673 674 675

	if (kvm->arch.pgd != NULL) {
		kvm_err("kvm_arch already initialized?\n");
		return -EINVAL;
	}

676 677 678 679 680 681 682 683 684 685 686 687 688 689
	hwpgd = kvm_alloc_hwpgd();
	if (!hwpgd)
		return -ENOMEM;

	/* When the kernel uses more levels of page tables than the
	 * guest, we allocate a fake PGD and pre-populate it to point
	 * to the next-level page table, which will be the real
	 * initial page table pointed to by the VTTBR.
	 *
	 * When KVM_PREALLOC_LEVEL==2, we allocate a single page for
	 * the PMD and the kernel will use folded pud.
	 * When KVM_PREALLOC_LEVEL==1, we allocate 2 consecutive PUD
	 * pages.
	 */
690
	if (KVM_PREALLOC_LEVEL > 0) {
691 692
		int i;

693 694 695 696 697
		/*
		 * Allocate fake pgd for the page table manipulation macros to
		 * work.  This is not used by the hardware and we have no
		 * alignment requirement for this allocation.
		 */
698 699
		pgd = kmalloc(PTRS_PER_S2_PGD * sizeof(pgd_t),
				GFP_KERNEL | __GFP_ZERO);
700 701 702 703 704 705 706 707 708 709 710 711 712 713 714

		if (!pgd) {
			kvm_free_hwpgd(hwpgd);
			return -ENOMEM;
		}

		/* Plug the HW PGD into the fake one. */
		for (i = 0; i < PTRS_PER_S2_PGD; i++) {
			if (KVM_PREALLOC_LEVEL == 1)
				pgd_populate(NULL, pgd + i,
					     (pud_t *)hwpgd + i * PTRS_PER_PUD);
			else if (KVM_PREALLOC_LEVEL == 2)
				pud_populate(NULL, pud_offset(pgd, 0) + i,
					     (pmd_t *)hwpgd + i * PTRS_PER_PMD);
		}
715 716 717 718 719
	} else {
		/*
		 * Allocate actual first-level Stage-2 page table used by the
		 * hardware for Stage-2 page table walks.
		 */
720
		pgd = (pgd_t *)hwpgd;
721 722
	}

723
	kvm_clean_pgd(pgd);
724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740
	kvm->arch.pgd = pgd;
	return 0;
}

/**
 * unmap_stage2_range -- Clear stage2 page table entries to unmap a range
 * @kvm:   The VM pointer
 * @start: The intermediate physical base address of the range to unmap
 * @size:  The size of the area to unmap
 *
 * Clear a range of stage-2 mappings, lowering the various ref-counts.  Must
 * be called while holding mmu_lock (unless for freeing the stage2 pgd before
 * destroying the VM), otherwise another faulting VCPU may come in and mess
 * with things behind our backs.
 */
static void unmap_stage2_range(struct kvm *kvm, phys_addr_t start, u64 size)
{
741
	unmap_range(kvm, kvm->arch.pgd, start, size);
742 743
}

744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808
static void stage2_unmap_memslot(struct kvm *kvm,
				 struct kvm_memory_slot *memslot)
{
	hva_t hva = memslot->userspace_addr;
	phys_addr_t addr = memslot->base_gfn << PAGE_SHIFT;
	phys_addr_t size = PAGE_SIZE * memslot->npages;
	hva_t reg_end = hva + size;

	/*
	 * A memory region could potentially cover multiple VMAs, and any holes
	 * between them, so iterate over all of them to find out if we should
	 * unmap any of them.
	 *
	 *     +--------------------------------------------+
	 * +---------------+----------------+   +----------------+
	 * |   : VMA 1     |      VMA 2     |   |    VMA 3  :    |
	 * +---------------+----------------+   +----------------+
	 *     |               memory region                |
	 *     +--------------------------------------------+
	 */
	do {
		struct vm_area_struct *vma = find_vma(current->mm, hva);
		hva_t vm_start, vm_end;

		if (!vma || vma->vm_start >= reg_end)
			break;

		/*
		 * Take the intersection of this VMA with the memory region
		 */
		vm_start = max(hva, vma->vm_start);
		vm_end = min(reg_end, vma->vm_end);

		if (!(vma->vm_flags & VM_PFNMAP)) {
			gpa_t gpa = addr + (vm_start - memslot->userspace_addr);
			unmap_stage2_range(kvm, gpa, vm_end - vm_start);
		}
		hva = vm_end;
	} while (hva < reg_end);
}

/**
 * stage2_unmap_vm - Unmap Stage-2 RAM mappings
 * @kvm: The struct kvm pointer
 *
 * Go through the memregions and unmap any reguler RAM
 * backing memory already mapped to the VM.
 */
void stage2_unmap_vm(struct kvm *kvm)
{
	struct kvm_memslots *slots;
	struct kvm_memory_slot *memslot;
	int idx;

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

	slots = kvm_memslots(kvm);
	kvm_for_each_memslot(memslot, slots)
		stage2_unmap_memslot(kvm, memslot);

	spin_unlock(&kvm->mmu_lock);
	srcu_read_unlock(&kvm->srcu, idx);
}

809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825
/**
 * kvm_free_stage2_pgd - free all stage-2 tables
 * @kvm:	The KVM struct pointer for the VM.
 *
 * Walks the level-1 page table pointed to by kvm->arch.pgd and frees all
 * underlying level-2 and level-3 tables before freeing the actual level-1 table
 * and setting the struct pointer to NULL.
 *
 * Note we don't need locking here as this is only called when the VM is
 * destroyed, which can only be done once.
 */
void kvm_free_stage2_pgd(struct kvm *kvm)
{
	if (kvm->arch.pgd == NULL)
		return;

	unmap_stage2_range(kvm, 0, KVM_PHYS_SIZE);
826
	kvm_free_hwpgd(kvm_get_hwpgd(kvm));
827 828
	if (KVM_PREALLOC_LEVEL > 0)
		kfree(kvm->arch.pgd);
829

830 831 832
	kvm->arch.pgd = NULL;
}

833
static pud_t *stage2_get_pud(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
834
			     phys_addr_t addr)
835 836 837 838
{
	pgd_t *pgd;
	pud_t *pud;

839
	pgd = kvm->arch.pgd + kvm_pgd_index(addr);
840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857
	if (WARN_ON(pgd_none(*pgd))) {
		if (!cache)
			return NULL;
		pud = mmu_memory_cache_alloc(cache);
		pgd_populate(NULL, pgd, pud);
		get_page(virt_to_page(pgd));
	}

	return pud_offset(pgd, addr);
}

static pmd_t *stage2_get_pmd(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
			     phys_addr_t addr)
{
	pud_t *pud;
	pmd_t *pmd;

	pud = stage2_get_pud(kvm, cache, addr);
858 859
	if (pud_none(*pud)) {
		if (!cache)
860
			return NULL;
861 862 863
		pmd = mmu_memory_cache_alloc(cache);
		pud_populate(NULL, pud, pmd);
		get_page(virt_to_page(pud));
864 865
	}

866 867 868 869 870 871 872 873 874 875
	return pmd_offset(pud, addr);
}

static int stage2_set_pmd_huge(struct kvm *kvm, struct kvm_mmu_memory_cache
			       *cache, phys_addr_t addr, const pmd_t *new_pmd)
{
	pmd_t *pmd, old_pmd;

	pmd = stage2_get_pmd(kvm, cache, addr);
	VM_BUG_ON(!pmd);
876

877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897
	/*
	 * Mapping in huge pages should only happen through a fault.  If a
	 * page is merged into a transparent huge page, the individual
	 * subpages of that huge page should be unmapped through MMU
	 * notifiers before we get here.
	 *
	 * Merging of CompoundPages is not supported; they should become
	 * splitting first, unmapped, merged, and mapped back in on-demand.
	 */
	VM_BUG_ON(pmd_present(*pmd) && pmd_pfn(*pmd) != pmd_pfn(*new_pmd));

	old_pmd = *pmd;
	kvm_set_pmd(pmd, *new_pmd);
	if (pmd_present(old_pmd))
		kvm_tlb_flush_vmid_ipa(kvm, addr);
	else
		get_page(virt_to_page(pmd));
	return 0;
}

static int stage2_set_pte(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
898 899
			  phys_addr_t addr, const pte_t *new_pte,
			  unsigned long flags)
900 901 902
{
	pmd_t *pmd;
	pte_t *pte, old_pte;
903 904 905 906
	bool iomap = flags & KVM_S2PTE_FLAG_IS_IOMAP;
	bool logging_active = flags & KVM_S2_FLAG_LOGGING_ACTIVE;

	VM_BUG_ON(logging_active && !cache);
907

908
	/* Create stage-2 page table mapping - Levels 0 and 1 */
909 910 911 912 913 914 915 916 917
	pmd = stage2_get_pmd(kvm, cache, addr);
	if (!pmd) {
		/*
		 * Ignore calls from kvm_set_spte_hva for unallocated
		 * address ranges.
		 */
		return 0;
	}

918 919 920 921 922 923 924
	/*
	 * While dirty page logging - dissolve huge PMD, then continue on to
	 * allocate page.
	 */
	if (logging_active)
		stage2_dissolve_pmd(kvm, addr, pmd);

925
	/* Create stage-2 page mappings - Level 2 */
926 927 928 929
	if (pmd_none(*pmd)) {
		if (!cache)
			return 0; /* ignore calls from kvm_set_spte_hva */
		pte = mmu_memory_cache_alloc(cache);
930
		kvm_clean_pte(pte);
931 932
		pmd_populate_kernel(NULL, pmd, pte);
		get_page(virt_to_page(pmd));
933 934 935
	}

	pte = pte_offset_kernel(pmd, addr);
936 937 938 939 940 941 942 943

	if (iomap && pte_present(*pte))
		return -EFAULT;

	/* Create 2nd stage page table mapping - Level 3 */
	old_pte = *pte;
	kvm_set_pte(pte, *new_pte);
	if (pte_present(old_pte))
944
		kvm_tlb_flush_vmid_ipa(kvm, addr);
945 946 947 948 949 950 951 952 953 954 955 956 957 958 959
	else
		get_page(virt_to_page(pte));

	return 0;
}

/**
 * kvm_phys_addr_ioremap - map a device range to guest IPA
 *
 * @kvm:	The KVM pointer
 * @guest_ipa:	The IPA at which to insert the mapping
 * @pa:		The physical address of the device
 * @size:	The size of the mapping
 */
int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
960
			  phys_addr_t pa, unsigned long size, bool writable)
961 962 963 964 965 966 967 968 969 970
{
	phys_addr_t addr, end;
	int ret = 0;
	unsigned long pfn;
	struct kvm_mmu_memory_cache cache = { 0, };

	end = (guest_ipa + size + PAGE_SIZE - 1) & PAGE_MASK;
	pfn = __phys_to_pfn(pa);

	for (addr = guest_ipa; addr < end; addr += PAGE_SIZE) {
971
		pte_t pte = pfn_pte(pfn, PAGE_S2_DEVICE);
972

973 974 975
		if (writable)
			kvm_set_s2pte_writable(&pte);

976 977
		ret = mmu_topup_memory_cache(&cache, KVM_MMU_CACHE_MIN_PAGES,
						KVM_NR_MEM_OBJS);
978 979 980
		if (ret)
			goto out;
		spin_lock(&kvm->mmu_lock);
981 982
		ret = stage2_set_pte(kvm, &cache, addr, &pte,
						KVM_S2PTE_FLAG_IS_IOMAP);
983 984 985 986 987 988 989 990 991 992 993 994
		spin_unlock(&kvm->mmu_lock);
		if (ret)
			goto out;

		pfn++;
	}

out:
	mmu_free_memory_cache(&cache);
	return ret;
}

995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035
static bool transparent_hugepage_adjust(pfn_t *pfnp, phys_addr_t *ipap)
{
	pfn_t pfn = *pfnp;
	gfn_t gfn = *ipap >> PAGE_SHIFT;

	if (PageTransCompound(pfn_to_page(pfn))) {
		unsigned long mask;
		/*
		 * The address we faulted on is backed by a transparent huge
		 * page.  However, because we map the compound huge page and
		 * not the individual tail page, we need to transfer the
		 * refcount to the head page.  We have to be careful that the
		 * THP doesn't start to split while we are adjusting the
		 * refcounts.
		 *
		 * We are sure this doesn't happen, because mmu_notifier_retry
		 * was successful and we are holding the mmu_lock, so if this
		 * THP is trying to split, it will be blocked in the mmu
		 * notifier before touching any of the pages, specifically
		 * before being able to call __split_huge_page_refcount().
		 *
		 * We can therefore safely transfer the refcount from PG_tail
		 * to PG_head and switch the pfn from a tail page to the head
		 * page accordingly.
		 */
		mask = PTRS_PER_PMD - 1;
		VM_BUG_ON((gfn & mask) != (pfn & mask));
		if (pfn & mask) {
			*ipap &= PMD_MASK;
			kvm_release_pfn_clean(pfn);
			pfn &= ~mask;
			kvm_get_pfn(pfn);
			*pfnp = pfn;
		}

		return true;
	}

	return false;
}

1036 1037 1038 1039 1040 1041 1042 1043
static bool kvm_is_write_fault(struct kvm_vcpu *vcpu)
{
	if (kvm_vcpu_trap_is_iabt(vcpu))
		return false;

	return kvm_vcpu_dabt_iswrite(vcpu);
}

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 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123
/**
 * stage2_wp_ptes - write protect PMD range
 * @pmd:	pointer to pmd entry
 * @addr:	range start address
 * @end:	range end address
 */
static void stage2_wp_ptes(pmd_t *pmd, phys_addr_t addr, phys_addr_t end)
{
	pte_t *pte;

	pte = pte_offset_kernel(pmd, addr);
	do {
		if (!pte_none(*pte)) {
			if (!kvm_s2pte_readonly(pte))
				kvm_set_s2pte_readonly(pte);
		}
	} while (pte++, addr += PAGE_SIZE, addr != end);
}

/**
 * stage2_wp_pmds - write protect PUD range
 * @pud:	pointer to pud entry
 * @addr:	range start address
 * @end:	range end address
 */
static void stage2_wp_pmds(pud_t *pud, phys_addr_t addr, phys_addr_t end)
{
	pmd_t *pmd;
	phys_addr_t next;

	pmd = pmd_offset(pud, addr);

	do {
		next = kvm_pmd_addr_end(addr, end);
		if (!pmd_none(*pmd)) {
			if (kvm_pmd_huge(*pmd)) {
				if (!kvm_s2pmd_readonly(pmd))
					kvm_set_s2pmd_readonly(pmd);
			} else {
				stage2_wp_ptes(pmd, addr, next);
			}
		}
	} while (pmd++, addr = next, addr != end);
}

/**
  * stage2_wp_puds - write protect PGD range
  * @pgd:	pointer to pgd entry
  * @addr:	range start address
  * @end:	range end address
  *
  * Process PUD entries, for a huge PUD we cause a panic.
  */
static void  stage2_wp_puds(pgd_t *pgd, phys_addr_t addr, phys_addr_t end)
{
	pud_t *pud;
	phys_addr_t next;

	pud = pud_offset(pgd, addr);
	do {
		next = kvm_pud_addr_end(addr, end);
		if (!pud_none(*pud)) {
			/* TODO:PUD not supported, revisit later if supported */
			BUG_ON(kvm_pud_huge(*pud));
			stage2_wp_pmds(pud, addr, next);
		}
	} while (pud++, addr = next, addr != end);
}

/**
 * stage2_wp_range() - write protect stage2 memory region range
 * @kvm:	The KVM pointer
 * @addr:	Start address of range
 * @end:	End address of range
 */
static void stage2_wp_range(struct kvm *kvm, phys_addr_t addr, phys_addr_t end)
{
	pgd_t *pgd;
	phys_addr_t next;

1124
	pgd = kvm->arch.pgd + kvm_pgd_index(addr);
1125 1126 1127 1128
	do {
		/*
		 * Release kvm_mmu_lock periodically if the memory region is
		 * large. Otherwise, we may see kernel panics with
1129 1130
		 * CONFIG_DETECT_HUNG_TASK, CONFIG_LOCKUP_DETECTOR,
		 * CONFIG_LOCKDEP. Additionally, holding the lock too long
1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156
		 * will also starve other vCPUs.
		 */
		if (need_resched() || spin_needbreak(&kvm->mmu_lock))
			cond_resched_lock(&kvm->mmu_lock);

		next = kvm_pgd_addr_end(addr, end);
		if (pgd_present(*pgd))
			stage2_wp_puds(pgd, addr, next);
	} while (pgd++, addr = next, addr != end);
}

/**
 * kvm_mmu_wp_memory_region() - write protect stage 2 entries for memory slot
 * @kvm:	The KVM pointer
 * @slot:	The memory slot to write protect
 *
 * Called to start logging dirty pages after memory region
 * KVM_MEM_LOG_DIRTY_PAGES operation is called. After this function returns
 * all present PMD and PTEs are write protected in the memory region.
 * Afterwards read of dirty page log can be called.
 *
 * Acquires kvm_mmu_lock. Called with kvm->slots_lock mutex acquired,
 * serializing operations for VM memory regions.
 */
void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot)
{
1157 1158
	struct kvm_memslots *slots = kvm_memslots(kvm);
	struct kvm_memory_slot *memslot = id_to_memslot(slots, slot);
1159 1160 1161 1162 1163 1164 1165 1166
	phys_addr_t start = memslot->base_gfn << PAGE_SHIFT;
	phys_addr_t end = (memslot->base_gfn + memslot->npages) << PAGE_SHIFT;

	spin_lock(&kvm->mmu_lock);
	stage2_wp_range(kvm, start, end);
	spin_unlock(&kvm->mmu_lock);
	kvm_flush_remote_tlbs(kvm);
}
1167 1168

/**
1169
 * kvm_mmu_write_protect_pt_masked() - write protect dirty pages
1170 1171 1172 1173 1174 1175 1176 1177 1178
 * @kvm:	The KVM pointer
 * @slot:	The memory slot associated with mask
 * @gfn_offset:	The gfn offset in memory slot
 * @mask:	The mask of dirty pages at offset 'gfn_offset' in this memory
 *		slot to be write protected
 *
 * Walks bits set in mask write protects the associated pte's. Caller must
 * acquire kvm_mmu_lock.
 */
1179
static void kvm_mmu_write_protect_pt_masked(struct kvm *kvm,
1180 1181 1182 1183 1184 1185 1186 1187 1188
		struct kvm_memory_slot *slot,
		gfn_t gfn_offset, unsigned long mask)
{
	phys_addr_t base_gfn = slot->base_gfn + gfn_offset;
	phys_addr_t start = (base_gfn +  __ffs(mask)) << PAGE_SHIFT;
	phys_addr_t end = (base_gfn + __fls(mask) + 1) << PAGE_SHIFT;

	stage2_wp_range(kvm, start, end);
}
1189

1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203
/*
 * kvm_arch_mmu_enable_log_dirty_pt_masked - enable dirty logging for selected
 * dirty pages.
 *
 * It calls kvm_mmu_write_protect_pt_masked to write protect selected pages to
 * enable dirty logging for them.
 */
void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
		struct kvm_memory_slot *slot,
		gfn_t gfn_offset, unsigned long mask)
{
	kvm_mmu_write_protect_pt_masked(kvm, slot, gfn_offset, mask);
}

1204 1205 1206 1207 1208 1209
static void coherent_cache_guest_page(struct kvm_vcpu *vcpu, pfn_t pfn,
				      unsigned long size, bool uncached)
{
	__coherent_cache_guest_page(vcpu, pfn, size, uncached);
}

1210
static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
1211
			  struct kvm_memory_slot *memslot, unsigned long hva,
1212 1213 1214
			  unsigned long fault_status)
{
	int ret;
1215
	bool write_fault, writable, hugetlb = false, force_pte = false;
1216
	unsigned long mmu_seq;
1217 1218
	gfn_t gfn = fault_ipa >> PAGE_SHIFT;
	struct kvm *kvm = vcpu->kvm;
1219
	struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
1220 1221
	struct vm_area_struct *vma;
	pfn_t pfn;
1222
	pgprot_t mem_type = PAGE_S2;
1223
	bool fault_ipa_uncached;
1224 1225
	bool logging_active = memslot_is_logging(memslot);
	unsigned long flags = 0;
1226

1227
	write_fault = kvm_is_write_fault(vcpu);
1228 1229 1230 1231 1232
	if (fault_status == FSC_PERM && !write_fault) {
		kvm_err("Unexpected L2 read permission error\n");
		return -EFAULT;
	}

1233 1234 1235
	/* Let's check if we will get back a huge page backed by hugetlbfs */
	down_read(&current->mm->mmap_sem);
	vma = find_vma_intersection(current->mm, hva, hva + 1);
1236 1237 1238 1239 1240 1241
	if (unlikely(!vma)) {
		kvm_err("Failed to find VMA for hva 0x%lx\n", hva);
		up_read(&current->mm->mmap_sem);
		return -EFAULT;
	}

1242
	if (is_vm_hugetlb_page(vma) && !logging_active) {
1243 1244
		hugetlb = true;
		gfn = (fault_ipa & PMD_MASK) >> PAGE_SHIFT;
1245 1246
	} else {
		/*
1247 1248 1249 1250 1251 1252 1253
		 * Pages belonging to memslots that don't have the same
		 * alignment for userspace and IPA cannot be mapped using
		 * block descriptors even if the pages belong to a THP for
		 * the process, because the stage-2 block descriptor will
		 * cover more than a single THP and we loose atomicity for
		 * unmapping, updates, and splits of the THP or other pages
		 * in the stage-2 block range.
1254
		 */
1255 1256
		if ((memslot->userspace_addr & ~PMD_MASK) !=
		    ((memslot->base_gfn << PAGE_SHIFT) & ~PMD_MASK))
1257
			force_pte = true;
1258 1259 1260
	}
	up_read(&current->mm->mmap_sem);

1261
	/* We need minimum second+third level pages */
1262 1263
	ret = mmu_topup_memory_cache(memcache, KVM_MMU_CACHE_MIN_PAGES,
				     KVM_NR_MEM_OBJS);
1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278
	if (ret)
		return ret;

	mmu_seq = vcpu->kvm->mmu_notifier_seq;
	/*
	 * Ensure the read of mmu_notifier_seq happens before we call
	 * gfn_to_pfn_prot (which calls get_user_pages), so that we don't risk
	 * the page we just got a reference to gets unmapped before we have a
	 * chance to grab the mmu_lock, which ensure that if the page gets
	 * unmapped afterwards, the call to kvm_unmap_hva will take it away
	 * from us again properly. This smp_rmb() interacts with the smp_wmb()
	 * in kvm_mmu_notifier_invalidate_<page|range_end>.
	 */
	smp_rmb();

1279
	pfn = gfn_to_pfn_prot(kvm, gfn, write_fault, &writable);
1280 1281 1282
	if (is_error_pfn(pfn))
		return -EFAULT;

1283
	if (kvm_is_device_pfn(pfn)) {
1284
		mem_type = PAGE_S2_DEVICE;
1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301
		flags |= KVM_S2PTE_FLAG_IS_IOMAP;
	} else if (logging_active) {
		/*
		 * Faults on pages in a memslot with logging enabled
		 * should not be mapped with huge pages (it introduces churn
		 * and performance degradation), so force a pte mapping.
		 */
		force_pte = true;
		flags |= KVM_S2_FLAG_LOGGING_ACTIVE;

		/*
		 * Only actually map the page as writable if this was a write
		 * fault.
		 */
		if (!write_fault)
			writable = false;
	}
1302

1303 1304
	spin_lock(&kvm->mmu_lock);
	if (mmu_notifier_retry(kvm, mmu_seq))
1305
		goto out_unlock;
1306

1307 1308
	if (!hugetlb && !force_pte)
		hugetlb = transparent_hugepage_adjust(&pfn, &fault_ipa);
1309

1310
	fault_ipa_uncached = memslot->flags & KVM_MEMSLOT_INCOHERENT;
1311

1312
	if (hugetlb) {
1313
		pmd_t new_pmd = pfn_pmd(pfn, mem_type);
1314 1315 1316 1317 1318
		new_pmd = pmd_mkhuge(new_pmd);
		if (writable) {
			kvm_set_s2pmd_writable(&new_pmd);
			kvm_set_pfn_dirty(pfn);
		}
1319
		coherent_cache_guest_page(vcpu, pfn, PMD_SIZE, fault_ipa_uncached);
1320 1321
		ret = stage2_set_pmd_huge(kvm, memcache, fault_ipa, &new_pmd);
	} else {
1322
		pte_t new_pte = pfn_pte(pfn, mem_type);
1323

1324 1325 1326
		if (writable) {
			kvm_set_s2pte_writable(&new_pte);
			kvm_set_pfn_dirty(pfn);
1327
			mark_page_dirty(kvm, gfn);
1328
		}
1329
		coherent_cache_guest_page(vcpu, pfn, PAGE_SIZE, fault_ipa_uncached);
1330
		ret = stage2_set_pte(kvm, memcache, fault_ipa, &new_pte, flags);
1331
	}
1332

1333
out_unlock:
1334
	spin_unlock(&kvm->mmu_lock);
1335
	kvm_set_pfn_accessed(pfn);
1336
	kvm_release_pfn_clean(pfn);
1337
	return ret;
1338 1339
}

1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379
/*
 * Resolve the access fault by making the page young again.
 * Note that because the faulting entry is guaranteed not to be
 * cached in the TLB, we don't need to invalidate anything.
 */
static void handle_access_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa)
{
	pmd_t *pmd;
	pte_t *pte;
	pfn_t pfn;
	bool pfn_valid = false;

	trace_kvm_access_fault(fault_ipa);

	spin_lock(&vcpu->kvm->mmu_lock);

	pmd = stage2_get_pmd(vcpu->kvm, NULL, fault_ipa);
	if (!pmd || pmd_none(*pmd))	/* Nothing there */
		goto out;

	if (kvm_pmd_huge(*pmd)) {	/* THP, HugeTLB */
		*pmd = pmd_mkyoung(*pmd);
		pfn = pmd_pfn(*pmd);
		pfn_valid = true;
		goto out;
	}

	pte = pte_offset_kernel(pmd, fault_ipa);
	if (pte_none(*pte))		/* Nothing there either */
		goto out;

	*pte = pte_mkyoung(*pte);	/* Just a page... */
	pfn = pte_pfn(*pte);
	pfn_valid = true;
out:
	spin_unlock(&vcpu->kvm->mmu_lock);
	if (pfn_valid)
		kvm_set_pfn_accessed(pfn);
}

1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391
/**
 * kvm_handle_guest_abort - handles all 2nd stage aborts
 * @vcpu:	the VCPU pointer
 * @run:	the kvm_run structure
 *
 * Any abort that gets to the host is almost guaranteed to be caused by a
 * missing second stage translation table entry, which can mean that either the
 * guest simply needs more memory and we must allocate an appropriate page or it
 * can mean that the guest tried to access I/O memory, which is emulated by user
 * space. The distinction is based on the IPA causing the fault and whether this
 * memory region has been registered as standard RAM by user space.
 */
1392 1393
int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
1394 1395 1396
	unsigned long fault_status;
	phys_addr_t fault_ipa;
	struct kvm_memory_slot *memslot;
1397 1398
	unsigned long hva;
	bool is_iabt, write_fault, writable;
1399 1400 1401
	gfn_t gfn;
	int ret, idx;

1402
	is_iabt = kvm_vcpu_trap_is_iabt(vcpu);
1403
	fault_ipa = kvm_vcpu_get_fault_ipa(vcpu);
1404

1405 1406
	trace_kvm_guest_fault(*vcpu_pc(vcpu), kvm_vcpu_get_hsr(vcpu),
			      kvm_vcpu_get_hfar(vcpu), fault_ipa);
1407 1408

	/* Check the stage-2 fault is trans. fault or write fault */
1409
	fault_status = kvm_vcpu_trap_get_fault_type(vcpu);
1410 1411
	if (fault_status != FSC_FAULT && fault_status != FSC_PERM &&
	    fault_status != FSC_ACCESS) {
1412 1413 1414 1415
		kvm_err("Unsupported FSC: EC=%#x xFSC=%#lx ESR_EL2=%#lx\n",
			kvm_vcpu_trap_get_class(vcpu),
			(unsigned long)kvm_vcpu_trap_get_fault(vcpu),
			(unsigned long)kvm_vcpu_get_hsr(vcpu));
1416 1417 1418 1419 1420 1421
		return -EFAULT;
	}

	idx = srcu_read_lock(&vcpu->kvm->srcu);

	gfn = fault_ipa >> PAGE_SHIFT;
1422 1423
	memslot = gfn_to_memslot(vcpu->kvm, gfn);
	hva = gfn_to_hva_memslot_prot(memslot, gfn, &writable);
1424
	write_fault = kvm_is_write_fault(vcpu);
1425
	if (kvm_is_error_hva(hva) || (write_fault && !writable)) {
1426 1427
		if (is_iabt) {
			/* Prefetch Abort on I/O address */
1428
			kvm_inject_pabt(vcpu, kvm_vcpu_get_hfar(vcpu));
1429 1430 1431 1432
			ret = 1;
			goto out_unlock;
		}

M
Marc Zyngier 已提交
1433 1434 1435 1436 1437 1438 1439
		/*
		 * The IPA is reported as [MAX:12], so we need to
		 * complement it with the bottom 12 bits from the
		 * faulting VA. This is always 12 bits, irrespective
		 * of the page size.
		 */
		fault_ipa |= kvm_vcpu_get_hfar(vcpu) & ((1 << 12) - 1);
C
Christoffer Dall 已提交
1440
		ret = io_mem_abort(vcpu, run, fault_ipa);
1441 1442 1443
		goto out_unlock;
	}

1444 1445 1446
	/* Userspace should not be able to register out-of-bounds IPAs */
	VM_BUG_ON(fault_ipa >= KVM_PHYS_SIZE);

1447 1448 1449 1450 1451 1452
	if (fault_status == FSC_ACCESS) {
		handle_access_fault(vcpu, fault_ipa);
		ret = 1;
		goto out_unlock;
	}

1453
	ret = user_mem_abort(vcpu, fault_ipa, memslot, hva, fault_status);
1454 1455 1456 1457 1458
	if (ret == 0)
		ret = 1;
out_unlock:
	srcu_read_unlock(&vcpu->kvm->srcu, idx);
	return ret;
1459 1460
}

1461 1462 1463 1464 1465 1466
static int handle_hva_to_gpa(struct kvm *kvm,
			     unsigned long start,
			     unsigned long end,
			     int (*handler)(struct kvm *kvm,
					    gpa_t gpa, void *data),
			     void *data)
1467 1468 1469
{
	struct kvm_memslots *slots;
	struct kvm_memory_slot *memslot;
1470
	int ret = 0;
1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493

	slots = kvm_memslots(kvm);

	/* we only care about the pages that the guest sees */
	kvm_for_each_memslot(memslot, slots) {
		unsigned long hva_start, hva_end;
		gfn_t gfn, gfn_end;

		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)} =
		 * {gfn_start, gfn_start+1, ..., gfn_end-1}.
		 */
		gfn = hva_to_gfn_memslot(hva_start, memslot);
		gfn_end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, memslot);

		for (; gfn < gfn_end; ++gfn) {
			gpa_t gpa = gfn << PAGE_SHIFT;
1494
			ret |= handler(kvm, gpa, data);
1495 1496
		}
	}
1497 1498

	return ret;
1499 1500
}

1501
static int kvm_unmap_hva_handler(struct kvm *kvm, gpa_t gpa, void *data)
1502 1503
{
	unmap_stage2_range(kvm, gpa, PAGE_SIZE);
1504
	return 0;
1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529
}

int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
{
	unsigned long end = hva + PAGE_SIZE;

	if (!kvm->arch.pgd)
		return 0;

	trace_kvm_unmap_hva(hva);
	handle_hva_to_gpa(kvm, hva, end, &kvm_unmap_hva_handler, NULL);
	return 0;
}

int kvm_unmap_hva_range(struct kvm *kvm,
			unsigned long start, unsigned long end)
{
	if (!kvm->arch.pgd)
		return 0;

	trace_kvm_unmap_hva_range(start, end);
	handle_hva_to_gpa(kvm, start, end, &kvm_unmap_hva_handler, NULL);
	return 0;
}

1530
static int kvm_set_spte_handler(struct kvm *kvm, gpa_t gpa, void *data)
1531 1532 1533
{
	pte_t *pte = (pte_t *)data;

1534 1535 1536 1537 1538 1539 1540 1541
	/*
	 * We can always call stage2_set_pte with KVM_S2PTE_FLAG_LOGGING_ACTIVE
	 * flag clear because MMU notifiers will have unmapped a huge PMD before
	 * calling ->change_pte() (which in turn calls kvm_set_spte_hva()) and
	 * therefore stage2_set_pte() never needs to clear out a huge PMD
	 * through this calling path.
	 */
	stage2_set_pte(kvm, NULL, gpa, pte, 0);
1542
	return 0;
1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558
}


void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
{
	unsigned long end = hva + PAGE_SIZE;
	pte_t stage2_pte;

	if (!kvm->arch.pgd)
		return;

	trace_kvm_set_spte_hva(hva);
	stage2_pte = pfn_pte(pte_pfn(pte), PAGE_S2);
	handle_hva_to_gpa(kvm, hva, end, &kvm_set_spte_handler, &stage2_pte);
}

1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619
static int kvm_age_hva_handler(struct kvm *kvm, gpa_t gpa, void *data)
{
	pmd_t *pmd;
	pte_t *pte;

	pmd = stage2_get_pmd(kvm, NULL, gpa);
	if (!pmd || pmd_none(*pmd))	/* Nothing there */
		return 0;

	if (kvm_pmd_huge(*pmd)) {	/* THP, HugeTLB */
		if (pmd_young(*pmd)) {
			*pmd = pmd_mkold(*pmd);
			return 1;
		}

		return 0;
	}

	pte = pte_offset_kernel(pmd, gpa);
	if (pte_none(*pte))
		return 0;

	if (pte_young(*pte)) {
		*pte = pte_mkold(*pte);	/* Just a page... */
		return 1;
	}

	return 0;
}

static int kvm_test_age_hva_handler(struct kvm *kvm, gpa_t gpa, void *data)
{
	pmd_t *pmd;
	pte_t *pte;

	pmd = stage2_get_pmd(kvm, NULL, gpa);
	if (!pmd || pmd_none(*pmd))	/* Nothing there */
		return 0;

	if (kvm_pmd_huge(*pmd))		/* THP, HugeTLB */
		return pmd_young(*pmd);

	pte = pte_offset_kernel(pmd, gpa);
	if (!pte_none(*pte))		/* Just a page... */
		return pte_young(*pte);

	return 0;
}

int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end)
{
	trace_kvm_age_hva(start, end);
	return handle_hva_to_gpa(kvm, start, end, kvm_age_hva_handler, NULL);
}

int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)
{
	trace_kvm_test_age_hva(hva);
	return handle_hva_to_gpa(kvm, hva, hva, kvm_test_age_hva_handler, NULL);
}

1620 1621 1622 1623 1624
void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu)
{
	mmu_free_memory_cache(&vcpu->arch.mmu_page_cache);
}

1625 1626
phys_addr_t kvm_mmu_get_httbr(void)
{
1627 1628 1629 1630
	if (__kvm_cpu_uses_extended_idmap())
		return virt_to_phys(merged_hyp_pgd);
	else
		return virt_to_phys(hyp_pgd);
1631 1632
}

1633 1634
phys_addr_t kvm_mmu_get_boot_httbr(void)
{
1635 1636 1637 1638
	if (__kvm_cpu_uses_extended_idmap())
		return virt_to_phys(merged_hyp_pgd);
	else
		return virt_to_phys(boot_hyp_pgd);
1639 1640 1641 1642 1643 1644 1645
}

phys_addr_t kvm_get_idmap_vector(void)
{
	return hyp_idmap_vector;
}

1646 1647
int kvm_mmu_init(void)
{
1648 1649
	int err;

1650 1651 1652
	hyp_idmap_start = kvm_virt_to_phys(__hyp_idmap_text_start);
	hyp_idmap_end = kvm_virt_to_phys(__hyp_idmap_text_end);
	hyp_idmap_vector = kvm_virt_to_phys(__kvm_hyp_init);
1653

1654 1655 1656 1657 1658
	/*
	 * We rely on the linker script to ensure at build time that the HYP
	 * init code does not cross a page boundary.
	 */
	BUG_ON((hyp_idmap_start ^ (hyp_idmap_end - 1)) & PAGE_MASK);
1659

1660 1661
	hyp_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, hyp_pgd_order);
	boot_hyp_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, hyp_pgd_order);
1662

1663
	if (!hyp_pgd || !boot_hyp_pgd) {
1664
		kvm_err("Hyp mode PGD not allocated\n");
1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678
		err = -ENOMEM;
		goto out;
	}

	/* Create the idmap in the boot page tables */
	err = 	__create_hyp_mappings(boot_hyp_pgd,
				      hyp_idmap_start, hyp_idmap_end,
				      __phys_to_pfn(hyp_idmap_start),
				      PAGE_HYP);

	if (err) {
		kvm_err("Failed to idmap %lx-%lx\n",
			hyp_idmap_start, hyp_idmap_end);
		goto out;
1679 1680
	}

1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691
	if (__kvm_cpu_uses_extended_idmap()) {
		merged_hyp_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
		if (!merged_hyp_pgd) {
			kvm_err("Failed to allocate extra HYP pgd\n");
			goto out;
		}
		__kvm_extend_hypmap(boot_hyp_pgd, hyp_pgd, merged_hyp_pgd,
				    hyp_idmap_start);
		return 0;
	}

1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713
	/* Map the very same page at the trampoline VA */
	err = 	__create_hyp_mappings(boot_hyp_pgd,
				      TRAMPOLINE_VA, TRAMPOLINE_VA + PAGE_SIZE,
				      __phys_to_pfn(hyp_idmap_start),
				      PAGE_HYP);
	if (err) {
		kvm_err("Failed to map trampoline @%lx into boot HYP pgd\n",
			TRAMPOLINE_VA);
		goto out;
	}

	/* Map the same page again into the runtime page tables */
	err = 	__create_hyp_mappings(hyp_pgd,
				      TRAMPOLINE_VA, TRAMPOLINE_VA + PAGE_SIZE,
				      __phys_to_pfn(hyp_idmap_start),
				      PAGE_HYP);
	if (err) {
		kvm_err("Failed to map trampoline @%lx into runtime HYP pgd\n",
			TRAMPOLINE_VA);
		goto out;
	}

1714
	return 0;
1715
out:
1716
	free_hyp_pgds();
1717
	return err;
1718
}
1719 1720

void kvm_arch_commit_memory_region(struct kvm *kvm,
1721
				   const struct kvm_userspace_memory_region *mem,
1722
				   const struct kvm_memory_slot *old,
1723
				   const struct kvm_memory_slot *new,
1724 1725
				   enum kvm_mr_change change)
{
1726 1727 1728 1729 1730 1731 1732
	/*
	 * At this point memslot has been committed and there is an
	 * allocated dirty_bitmap[], dirty pages will be be tracked while the
	 * memory slot is write protected.
	 */
	if (change != KVM_MR_DELETE && mem->flags & KVM_MEM_LOG_DIRTY_PAGES)
		kvm_mmu_wp_memory_region(kvm, mem->slot);
1733 1734 1735 1736
}

int kvm_arch_prepare_memory_region(struct kvm *kvm,
				   struct kvm_memory_slot *memslot,
1737
				   const struct kvm_userspace_memory_region *mem,
1738 1739
				   enum kvm_mr_change change)
{
1740 1741 1742 1743 1744
	hva_t hva = mem->userspace_addr;
	hva_t reg_end = hva + mem->memory_size;
	bool writable = !(mem->flags & KVM_MEM_READONLY);
	int ret = 0;

1745 1746
	if (change != KVM_MR_CREATE && change != KVM_MR_MOVE &&
			change != KVM_MR_FLAGS_ONLY)
1747 1748
		return 0;

1749 1750 1751 1752 1753 1754 1755 1756
	/*
	 * Prevent userspace from creating a memory region outside of the IPA
	 * space addressable by the KVM guest IPA space.
	 */
	if (memslot->base_gfn + memslot->npages >=
	    (KVM_PHYS_SIZE >> PAGE_SHIFT))
		return -EFAULT;

1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793
	/*
	 * A memory region could potentially cover multiple VMAs, and any holes
	 * between them, so iterate over all of them to find out if we can map
	 * any of them right now.
	 *
	 *     +--------------------------------------------+
	 * +---------------+----------------+   +----------------+
	 * |   : VMA 1     |      VMA 2     |   |    VMA 3  :    |
	 * +---------------+----------------+   +----------------+
	 *     |               memory region                |
	 *     +--------------------------------------------+
	 */
	do {
		struct vm_area_struct *vma = find_vma(current->mm, hva);
		hva_t vm_start, vm_end;

		if (!vma || vma->vm_start >= reg_end)
			break;

		/*
		 * Mapping a read-only VMA is only allowed if the
		 * memory region is configured as read-only.
		 */
		if (writable && !(vma->vm_flags & VM_WRITE)) {
			ret = -EPERM;
			break;
		}

		/*
		 * Take the intersection of this VMA with the memory region
		 */
		vm_start = max(hva, vma->vm_start);
		vm_end = min(reg_end, vma->vm_end);

		if (vma->vm_flags & VM_PFNMAP) {
			gpa_t gpa = mem->guest_phys_addr +
				    (vm_start - mem->userspace_addr);
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			phys_addr_t pa;

			pa = (phys_addr_t)vma->vm_pgoff << PAGE_SHIFT;
			pa += vm_start - vma->vm_start;
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			/* IO region dirty page logging not allowed */
			if (memslot->flags & KVM_MEM_LOG_DIRTY_PAGES)
				return -EINVAL;

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			ret = kvm_phys_addr_ioremap(kvm, gpa, pa,
						    vm_end - vm_start,
						    writable);
			if (ret)
				break;
		}
		hva = vm_end;
	} while (hva < reg_end);

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	if (change == KVM_MR_FLAGS_ONLY)
		return ret;

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	spin_lock(&kvm->mmu_lock);
	if (ret)
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		unmap_stage2_range(kvm, mem->guest_phys_addr, mem->memory_size);
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	else
		stage2_flush_memslot(kvm, memslot);
	spin_unlock(&kvm->mmu_lock);
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	return ret;
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}

void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free,
			   struct kvm_memory_slot *dont)
{
}

int kvm_arch_create_memslot(struct kvm *kvm, struct kvm_memory_slot *slot,
			    unsigned long npages)
{
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	/*
	 * Readonly memslots are not incoherent with the caches by definition,
	 * but in practice, they are used mostly to emulate ROMs or NOR flashes
	 * that the guest may consider devices and hence map as uncached.
	 * To prevent incoherency issues in these cases, tag all readonly
	 * regions as incoherent.
	 */
	if (slot->flags & KVM_MEM_READONLY)
		slot->flags |= KVM_MEMSLOT_INCOHERENT;
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	return 0;
}

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void kvm_arch_memslots_updated(struct kvm *kvm, struct kvm_memslots *slots)
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{
}

void kvm_arch_flush_shadow_all(struct kvm *kvm)
{
}

void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
				   struct kvm_memory_slot *slot)
{
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	gpa_t gpa = slot->base_gfn << PAGE_SHIFT;
	phys_addr_t size = slot->npages << PAGE_SHIFT;

	spin_lock(&kvm->mmu_lock);
	unmap_stage2_range(kvm, gpa, size);
	spin_unlock(&kvm->mmu_lock);
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}
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/*
 * See note at ARMv7 ARM B1.14.4 (TL;DR: S/W ops are not easily virtualized).
 *
 * Main problems:
 * - S/W ops are local to a CPU (not broadcast)
 * - We have line migration behind our back (speculation)
 * - System caches don't support S/W at all (damn!)
 *
 * In the face of the above, the best we can do is to try and convert
 * S/W ops to VA ops. Because the guest is not allowed to infer the
 * S/W to PA mapping, it can only use S/W to nuke the whole cache,
 * which is a rather good thing for us.
 *
 * Also, it is only used when turning caches on/off ("The expected
 * usage of the cache maintenance instructions that operate by set/way
 * is associated with the cache maintenance instructions associated
 * with the powerdown and powerup of caches, if this is required by
 * the implementation.").
 *
 * We use the following policy:
 *
 * - If we trap a S/W operation, we enable VM trapping to detect
 *   caches being turned on/off, and do a full clean.
 *
 * - We flush the caches on both caches being turned on and off.
 *
 * - Once the caches are enabled, we stop trapping VM ops.
 */
void kvm_set_way_flush(struct kvm_vcpu *vcpu)
{
	unsigned long hcr = vcpu_get_hcr(vcpu);

	/*
	 * If this is the first time we do a S/W operation
	 * (i.e. HCR_TVM not set) flush the whole memory, and set the
	 * VM trapping.
	 *
	 * Otherwise, rely on the VM trapping to wait for the MMU +
	 * Caches to be turned off. At that point, we'll be able to
	 * clean the caches again.
	 */
	if (!(hcr & HCR_TVM)) {
		trace_kvm_set_way_flush(*vcpu_pc(vcpu),
					vcpu_has_cache_enabled(vcpu));
		stage2_flush_vm(vcpu->kvm);
		vcpu_set_hcr(vcpu, hcr | HCR_TVM);
	}
}

void kvm_toggle_cache(struct kvm_vcpu *vcpu, bool was_enabled)
{
	bool now_enabled = vcpu_has_cache_enabled(vcpu);

	/*
	 * If switching the MMU+caches on, need to invalidate the caches.
	 * If switching it off, need to clean the caches.
	 * Clean + invalidate does the trick always.
	 */
	if (now_enabled != was_enabled)
		stage2_flush_vm(vcpu->kvm);

	/* Caches are now on, stop trapping VM ops (until a S/W op) */
	if (now_enabled)
		vcpu_set_hcr(vcpu, vcpu_get_hcr(vcpu) & ~HCR_TVM);

	trace_kvm_toggle_cache(*vcpu_pc(vcpu), was_enabled, now_enabled);
}