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linux/arch/x86/kvm/mmu.c

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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.
*
* 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.
*
*/
#include "mmu.h"
#include "kvm_cache_regs.h"
#include <linux/kvm_host.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/module.h>
#include <linux/swap.h>
#include <linux/hugetlb.h>
#include <linux/compiler.h>
#include <asm/page.h>
#include <asm/cmpxchg.h>
#include <asm/io.h>
#include <asm/vmx.h>
/*
* 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.
*/
bool tdp_enabled = false;
#undef MMU_DEBUG
#undef AUDIT
#ifdef AUDIT
static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg);
#else
static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg) {}
#endif
#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
#if defined(MMU_DEBUG) || defined(AUDIT)
static int dbg = 0;
module_param(dbg, bool, 0644);
#endif
static int oos_shadow = 1;
module_param(oos_shadow, bool, 0644);
#ifndef MMU_DEBUG
#define ASSERT(x) do { } while (0)
#else
#define ASSERT(x) \
if (!(x)) { \
printk(KERN_WARNING "assertion failed %s:%d: %s\n", \
__FILE__, __LINE__, #x); \
}
#endif
#define PT_FIRST_AVAIL_BITS_SHIFT 9
#define PT64_SECOND_AVAIL_BITS_SHIFT 52
#define VALID_PAGE(x) ((x) != INVALID_PAGE)
#define PT64_LEVEL_BITS 9
#define PT64_LEVEL_SHIFT(level) \
(PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS)
#define PT64_LEVEL_MASK(level) \
(((1ULL << PT64_LEVEL_BITS) - 1) << PT64_LEVEL_SHIFT(level))
#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) \
(PAGE_SHIFT + (level - 1) * PT32_LEVEL_BITS)
#define PT32_LEVEL_MASK(level) \
(((1ULL << PT32_LEVEL_BITS) - 1) << PT32_LEVEL_SHIFT(level))
#define PT32_LVL_OFFSET_MASK(level) \
(PT32_BASE_ADDR_MASK & ((1ULL << (PAGE_SHIFT + (((level) - 1) \
* PT32_LEVEL_BITS))) - 1))
#define PT32_INDEX(address, level)\
(((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1))
#define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1))
#define PT64_DIR_BASE_ADDR_MASK \
(PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1))
#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))
#define PT32_BASE_ADDR_MASK PAGE_MASK
#define PT32_DIR_BASE_ADDR_MASK \
(PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1))
#define PT32_LVL_ADDR_MASK(level) \
(PAGE_MASK & ~((1ULL << (PAGE_SHIFT + (((level) - 1) \
* PT32_LEVEL_BITS))) - 1))
#define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK \
| PT64_NX_MASK)
#define PFERR_PRESENT_MASK (1U << 0)
#define PFERR_WRITE_MASK (1U << 1)
#define PFERR_USER_MASK (1U << 2)
#define PFERR_RSVD_MASK (1U << 3)
#define PFERR_FETCH_MASK (1U << 4)
#define PT_PDPE_LEVEL 3
#define PT_DIRECTORY_LEVEL 2
#define PT_PAGE_TABLE_LEVEL 1
#define RMAP_EXT 4
#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)
#define CREATE_TRACE_POINTS
#include "mmutrace.h"
#define SPTE_HOST_WRITEABLE (1ULL << PT_FIRST_AVAIL_BITS_SHIFT)
#define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)
struct kvm_rmap_desc {
u64 *sptes[RMAP_EXT];
struct kvm_rmap_desc *more;
};
struct kvm_shadow_walk_iterator {
u64 addr;
hpa_t shadow_addr;
int level;
u64 *sptep;
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)))
struct kvm_unsync_walk {
int (*entry) (struct kvm_mmu_page *sp, struct kvm_unsync_walk *walk);
};
typedef int (*mmu_parent_walk_fn) (struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp);
static struct kmem_cache *pte_chain_cache;
static struct kmem_cache *rmap_desc_cache;
static struct kmem_cache *mmu_page_header_cache;
static u64 __read_mostly shadow_trap_nonpresent_pte;
static u64 __read_mostly shadow_notrap_nonpresent_pte;
static u64 __read_mostly shadow_base_present_pte;
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;
static inline u64 rsvd_bits(int s, int e)
{
return ((1ULL << (e - s + 1)) - 1) << s;
}
void kvm_mmu_set_nonpresent_ptes(u64 trap_pte, u64 notrap_pte)
{
shadow_trap_nonpresent_pte = trap_pte;
shadow_notrap_nonpresent_pte = notrap_pte;
}
EXPORT_SYMBOL_GPL(kvm_mmu_set_nonpresent_ptes);
void kvm_mmu_set_base_ptes(u64 base_pte)
{
shadow_base_present_pte = base_pte;
}
EXPORT_SYMBOL_GPL(kvm_mmu_set_base_ptes);
void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
u64 dirty_mask, u64 nx_mask, u64 x_mask)
{
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);
static int is_write_protection(struct kvm_vcpu *vcpu)
{
return vcpu->arch.cr0 & X86_CR0_WP;
}
static int is_cpuid_PSE36(void)
{
return 1;
}
static int is_nx(struct kvm_vcpu *vcpu)
{
return vcpu->arch.shadow_efer & EFER_NX;
}
static int is_shadow_present_pte(u64 pte)
{
return pte != shadow_trap_nonpresent_pte
&& pte != shadow_notrap_nonpresent_pte;
}
static int is_large_pte(u64 pte)
{
return pte & PT_PAGE_SIZE_MASK;
}
static int is_writeble_pte(unsigned long pte)
{
return pte & PT_WRITABLE_MASK;
}
static int is_dirty_gpte(unsigned long pte)
{
return pte & PT_DIRTY_MASK;
}
static int is_rmap_spte(u64 pte)
{
return is_shadow_present_pte(pte);
}
static int is_last_spte(u64 pte, int level)
{
if (level == PT_PAGE_TABLE_LEVEL)
return 1;
if (is_large_pte(pte))
return 1;
return 0;
}
static pfn_t spte_to_pfn(u64 pte)
{
return (pte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
}
static gfn_t pse36_gfn_delta(u32 gpte)
{
int shift = 32 - PT32_DIR_PSE36_SHIFT - PAGE_SHIFT;
return (gpte & PT32_DIR_PSE36_MASK) << shift;
}
static void __set_spte(u64 *sptep, u64 spte)
{
#ifdef CONFIG_X86_64
set_64bit((unsigned long *)sptep, spte);
#else
set_64bit((unsigned long long *)sptep, spte);
#endif
}
static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
struct kmem_cache *base_cache, int min)
{
void *obj;
if (cache->nobjs >= min)
return 0;
while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
if (!obj)
return -ENOMEM;
cache->objects[cache->nobjs++] = obj;
}
return 0;
}
static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
{
while (mc->nobjs)
kfree(mc->objects[--mc->nobjs]);
}
static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
int min)
{
struct page *page;
if (cache->nobjs >= min)
return 0;
while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
page = alloc_page(GFP_KERNEL);
if (!page)
return -ENOMEM;
set_page_private(page, 0);
cache->objects[cache->nobjs++] = page_address(page);
}
return 0;
}
static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
{
while (mc->nobjs)
free_page((unsigned long)mc->objects[--mc->nobjs]);
}
static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
{
int r;
r = mmu_topup_memory_cache(&vcpu->arch.mmu_pte_chain_cache,
pte_chain_cache, 4);
if (r)
goto out;
r = mmu_topup_memory_cache(&vcpu->arch.mmu_rmap_desc_cache,
rmap_desc_cache, 4);
if (r)
goto out;
r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 8);
if (r)
goto out;
r = mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
mmu_page_header_cache, 4);
out:
return r;
}
static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
{
mmu_free_memory_cache(&vcpu->arch.mmu_pte_chain_cache);
mmu_free_memory_cache(&vcpu->arch.mmu_rmap_desc_cache);
mmu_free_memory_cache_page(&vcpu->arch.mmu_page_cache);
mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache);
}
static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc,
size_t size)
{
void *p;
BUG_ON(!mc->nobjs);
p = mc->objects[--mc->nobjs];
return p;
}
static struct kvm_pte_chain *mmu_alloc_pte_chain(struct kvm_vcpu *vcpu)
{
return mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_chain_cache,
sizeof(struct kvm_pte_chain));
}
static void mmu_free_pte_chain(struct kvm_pte_chain *pc)
{
kfree(pc);
}
static struct kvm_rmap_desc *mmu_alloc_rmap_desc(struct kvm_vcpu *vcpu)
{
return mmu_memory_cache_alloc(&vcpu->arch.mmu_rmap_desc_cache,
sizeof(struct kvm_rmap_desc));
}
static void mmu_free_rmap_desc(struct kvm_rmap_desc *rd)
{
kfree(rd);
}
/*
* Return the pointer to the largepage write count for a given
* gfn, handling slots that are not large page aligned.
*/
static int *slot_largepage_idx(gfn_t gfn,
struct kvm_memory_slot *slot,
int level)
{
unsigned long idx;
idx = (gfn / KVM_PAGES_PER_HPAGE(level)) -
(slot->base_gfn / KVM_PAGES_PER_HPAGE(level));
return &slot->lpage_info[level - 2][idx].write_count;
}
static void account_shadowed(struct kvm *kvm, gfn_t gfn)
{
struct kvm_memory_slot *slot;
int *write_count;
int i;
gfn = unalias_gfn(kvm, gfn);
slot = gfn_to_memslot_unaliased(kvm, gfn);
for (i = PT_DIRECTORY_LEVEL;
i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
write_count = slot_largepage_idx(gfn, slot, i);
*write_count += 1;
}
}
static void unaccount_shadowed(struct kvm *kvm, gfn_t gfn)
{
struct kvm_memory_slot *slot;
int *write_count;
int i;
gfn = unalias_gfn(kvm, gfn);
for (i = PT_DIRECTORY_LEVEL;
i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
slot = gfn_to_memslot_unaliased(kvm, gfn);
write_count = slot_largepage_idx(gfn, slot, i);
*write_count -= 1;
WARN_ON(*write_count < 0);
}
}
static int has_wrprotected_page(struct kvm *kvm,
gfn_t gfn,
int level)
{
struct kvm_memory_slot *slot;
int *largepage_idx;
gfn = unalias_gfn(kvm, gfn);
slot = gfn_to_memslot_unaliased(kvm, gfn);
if (slot) {
largepage_idx = slot_largepage_idx(gfn, slot, level);
return *largepage_idx;
}
return 1;
}
static int host_mapping_level(struct kvm *kvm, gfn_t gfn)
{
unsigned long page_size = PAGE_SIZE;
struct vm_area_struct *vma;
unsigned long addr;
int i, ret = 0;
addr = gfn_to_hva(kvm, gfn);
if (kvm_is_error_hva(addr))
return page_size;
down_read(&current->mm->mmap_sem);
vma = find_vma(current->mm, addr);
if (!vma)
goto out;
page_size = vma_kernel_pagesize(vma);
out:
up_read(&current->mm->mmap_sem);
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;
}
return ret;
}
static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn)
{
struct kvm_memory_slot *slot;
int host_level;
int level = PT_PAGE_TABLE_LEVEL;
slot = gfn_to_memslot(vcpu->kvm, large_gfn);
if (slot && slot->dirty_bitmap)
return PT_PAGE_TABLE_LEVEL;
host_level = host_mapping_level(vcpu->kvm, large_gfn);
if (host_level == PT_PAGE_TABLE_LEVEL)
return host_level;
for (level = PT_DIRECTORY_LEVEL; level <= host_level; ++level) {
if (has_wrprotected_page(vcpu->kvm, large_gfn, level))
break;
}
return level - 1;
}
/*
* Take gfn and return the reverse mapping to it.
* Note: gfn must be unaliased before this function get called
*/
static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int level)
{
struct kvm_memory_slot *slot;
unsigned long idx;
slot = gfn_to_memslot(kvm, gfn);
if (likely(level == PT_PAGE_TABLE_LEVEL))
return &slot->rmap[gfn - slot->base_gfn];
idx = (gfn / KVM_PAGES_PER_HPAGE(level)) -
(slot->base_gfn / KVM_PAGES_PER_HPAGE(level));
return &slot->lpage_info[level - 2][idx].rmap_pde;
}
/*
* Reverse mapping data structures:
*
* If rmapp bit zero is zero, then rmapp point to the shadw page table entry
* that points to page_address(page).
*
* If rmapp bit zero is one, (then rmap & ~1) points to a struct kvm_rmap_desc
* containing more mappings.
*
* Returns the number of rmap entries before the spte was added or zero if
* the spte was not added.
*
*/
static int rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
{
struct kvm_mmu_page *sp;
struct kvm_rmap_desc *desc;
unsigned long *rmapp;
int i, count = 0;
if (!is_rmap_spte(*spte))
return count;
gfn = unalias_gfn(vcpu->kvm, gfn);
sp = page_header(__pa(spte));
sp->gfns[spte - sp->spt] = gfn;
rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level);
if (!*rmapp) {
rmap_printk("rmap_add: %p %llx 0->1\n", spte, *spte);
*rmapp = (unsigned long)spte;
} else if (!(*rmapp & 1)) {
rmap_printk("rmap_add: %p %llx 1->many\n", spte, *spte);
desc = mmu_alloc_rmap_desc(vcpu);
desc->sptes[0] = (u64 *)*rmapp;
desc->sptes[1] = spte;
*rmapp = (unsigned long)desc | 1;
} else {
rmap_printk("rmap_add: %p %llx many->many\n", spte, *spte);
desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
while (desc->sptes[RMAP_EXT-1] && desc->more) {
desc = desc->more;
count += RMAP_EXT;
}
if (desc->sptes[RMAP_EXT-1]) {
desc->more = mmu_alloc_rmap_desc(vcpu);
desc = desc->more;
}
for (i = 0; desc->sptes[i]; ++i)
;
desc->sptes[i] = spte;
}
return count;
}
static void rmap_desc_remove_entry(unsigned long *rmapp,
struct kvm_rmap_desc *desc,
int i,
struct kvm_rmap_desc *prev_desc)
{
int j;
for (j = RMAP_EXT - 1; !desc->sptes[j] && j > i; --j)
;
desc->sptes[i] = desc->sptes[j];
desc->sptes[j] = NULL;
if (j != 0)
return;
if (!prev_desc && !desc->more)
*rmapp = (unsigned long)desc->sptes[0];
else
if (prev_desc)
prev_desc->more = desc->more;
else
*rmapp = (unsigned long)desc->more | 1;
mmu_free_rmap_desc(desc);
}
static void rmap_remove(struct kvm *kvm, u64 *spte)
{
struct kvm_rmap_desc *desc;
struct kvm_rmap_desc *prev_desc;
struct kvm_mmu_page *sp;
pfn_t pfn;
unsigned long *rmapp;
int i;
if (!is_rmap_spte(*spte))
return;
sp = page_header(__pa(spte));
pfn = spte_to_pfn(*spte);
if (*spte & shadow_accessed_mask)
kvm_set_pfn_accessed(pfn);
if (is_writeble_pte(*spte))
kvm_set_pfn_dirty(pfn);
rmapp = gfn_to_rmap(kvm, sp->gfns[spte - sp->spt], sp->role.level);
if (!*rmapp) {
printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte);
BUG();
} else if (!(*rmapp & 1)) {
rmap_printk("rmap_remove: %p %llx 1->0\n", spte, *spte);
if ((u64 *)*rmapp != spte) {
printk(KERN_ERR "rmap_remove: %p %llx 1->BUG\n",
spte, *spte);
BUG();
}
*rmapp = 0;
} else {
rmap_printk("rmap_remove: %p %llx many->many\n", spte, *spte);
desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
prev_desc = NULL;
while (desc) {
for (i = 0; i < RMAP_EXT && desc->sptes[i]; ++i)
if (desc->sptes[i] == spte) {
rmap_desc_remove_entry(rmapp,
desc, i,
prev_desc);
return;
}
prev_desc = desc;
desc = desc->more;
}
BUG();
}
}
static u64 *rmap_next(struct kvm *kvm, unsigned long *rmapp, u64 *spte)
{
struct kvm_rmap_desc *desc;
struct kvm_rmap_desc *prev_desc;
u64 *prev_spte;
int i;
if (!*rmapp)
return NULL;
else if (!(*rmapp & 1)) {
if (!spte)
return (u64 *)*rmapp;
return NULL;
}
desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
prev_desc = NULL;
prev_spte = NULL;
while (desc) {
for (i = 0; i < RMAP_EXT && desc->sptes[i]; ++i) {
if (prev_spte == spte)
return desc->sptes[i];
prev_spte = desc->sptes[i];
}
desc = desc->more;
}
return NULL;
}
static int rmap_write_protect(struct kvm *kvm, u64 gfn)
{
unsigned long *rmapp;
u64 *spte;
int i, write_protected = 0;
gfn = unalias_gfn(kvm, gfn);
rmapp = gfn_to_rmap(kvm, gfn, PT_PAGE_TABLE_LEVEL);
spte = rmap_next(kvm, rmapp, NULL);
while (spte) {
BUG_ON(!spte);
BUG_ON(!(*spte & PT_PRESENT_MASK));
rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
if (is_writeble_pte(*spte)) {
__set_spte(spte, *spte & ~PT_WRITABLE_MASK);
write_protected = 1;
}
spte = rmap_next(kvm, rmapp, spte);
}
if (write_protected) {
pfn_t pfn;
spte = rmap_next(kvm, rmapp, NULL);
pfn = spte_to_pfn(*spte);
kvm_set_pfn_dirty(pfn);
}
/* check for huge page mappings */
for (i = PT_DIRECTORY_LEVEL;
i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
rmapp = gfn_to_rmap(kvm, gfn, i);
spte = rmap_next(kvm, rmapp, NULL);
while (spte) {
BUG_ON(!spte);
BUG_ON(!(*spte & PT_PRESENT_MASK));
BUG_ON((*spte & (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK)) != (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK));
pgprintk("rmap_write_protect(large): spte %p %llx %lld\n", spte, *spte, gfn);
if (is_writeble_pte(*spte)) {
rmap_remove(kvm, spte);
--kvm->stat.lpages;
__set_spte(spte, shadow_trap_nonpresent_pte);
spte = NULL;
write_protected = 1;
}
spte = rmap_next(kvm, rmapp, spte);
}
}
return write_protected;
}
static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp, u64 data)
{
u64 *spte;
int need_tlb_flush = 0;
while ((spte = rmap_next(kvm, rmapp, NULL))) {
BUG_ON(!(*spte & PT_PRESENT_MASK));
rmap_printk("kvm_rmap_unmap_hva: spte %p %llx\n", spte, *spte);
rmap_remove(kvm, spte);
__set_spte(spte, shadow_trap_nonpresent_pte);
need_tlb_flush = 1;
}
return need_tlb_flush;
}
static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp, u64 data)
{
int need_flush = 0;
u64 *spte, new_spte;
pte_t *ptep = (pte_t *)data;
pfn_t new_pfn;
WARN_ON(pte_huge(*ptep));
new_pfn = pte_pfn(*ptep);
spte = rmap_next(kvm, rmapp, NULL);
while (spte) {
BUG_ON(!is_shadow_present_pte(*spte));
rmap_printk("kvm_set_pte_rmapp: spte %p %llx\n", spte, *spte);
need_flush = 1;
if (pte_write(*ptep)) {
rmap_remove(kvm, spte);
__set_spte(spte, shadow_trap_nonpresent_pte);
spte = rmap_next(kvm, rmapp, NULL);
} else {
new_spte = *spte &~ (PT64_BASE_ADDR_MASK);
new_spte |= (u64)new_pfn << PAGE_SHIFT;
new_spte &= ~PT_WRITABLE_MASK;
new_spte &= ~SPTE_HOST_WRITEABLE;
if (is_writeble_pte(*spte))
kvm_set_pfn_dirty(spte_to_pfn(*spte));
__set_spte(spte, new_spte);
spte = rmap_next(kvm, rmapp, spte);
}
}
if (need_flush)
kvm_flush_remote_tlbs(kvm);
return 0;
}
static int kvm_handle_hva(struct kvm *kvm, unsigned long hva, u64 data,
int (*handler)(struct kvm *kvm, unsigned long *rmapp,
u64 data))
{
int i, j;
int retval = 0;
/*
* If mmap_sem isn't taken, we can look the memslots with only
* the mmu_lock by skipping over the slots with userspace_addr == 0.
*/
for (i = 0; i < kvm->nmemslots; i++) {
struct kvm_memory_slot *memslot = &kvm->memslots[i];
unsigned long start = memslot->userspace_addr;
unsigned long end;
/* mmu_lock protects userspace_addr */
if (!start)
continue;
end = start + (memslot->npages << PAGE_SHIFT);
if (hva >= start && hva < end) {
gfn_t gfn_offset = (hva - start) >> PAGE_SHIFT;
retval |= handler(kvm, &memslot->rmap[gfn_offset],
data);
for (j = 0; j < KVM_NR_PAGE_SIZES - 1; ++j) {
int idx = gfn_offset;
idx /= KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL + j);
retval |= handler(kvm,
&memslot->lpage_info[j][idx].rmap_pde,
data);
}
}
}
return retval;
}
int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
{
return kvm_handle_hva(kvm, hva, 0, kvm_unmap_rmapp);
}
void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
{
kvm_handle_hva(kvm, hva, (u64)&pte, kvm_set_pte_rmapp);
}
static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp, u64 data)
{
u64 *spte;
int young = 0;
/* always return old for EPT */
if (!shadow_accessed_mask)
return 0;
spte = rmap_next(kvm, rmapp, NULL);
while (spte) {
int _young;
u64 _spte = *spte;
BUG_ON(!(_spte & PT_PRESENT_MASK));
_young = _spte & PT_ACCESSED_MASK;
if (_young) {
young = 1;
clear_bit(PT_ACCESSED_SHIFT, (unsigned long *)spte);
}
spte = rmap_next(kvm, rmapp, spte);
}
return young;
}
#define RMAP_RECYCLE_THRESHOLD 1000
static void rmap_recycle(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
{
unsigned long *rmapp;
struct kvm_mmu_page *sp;
sp = page_header(__pa(spte));
gfn = unalias_gfn(vcpu->kvm, gfn);
rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level);
kvm_unmap_rmapp(vcpu->kvm, rmapp, 0);
kvm_flush_remote_tlbs(vcpu->kvm);
}
int kvm_age_hva(struct kvm *kvm, unsigned long hva)
{
return kvm_handle_hva(kvm, hva, 0, kvm_age_rmapp);
}
#ifdef MMU_DEBUG
static int is_empty_shadow_page(u64 *spt)
{
u64 *pos;
u64 *end;
for (pos = spt, end = pos + PAGE_SIZE / sizeof(u64); pos != end; pos++)
if (is_shadow_present_pte(*pos)) {
printk(KERN_ERR "%s: %p %llx\n", __func__,
pos, *pos);
return 0;
}
return 1;
}
#endif
static void kvm_mmu_free_page(struct kvm *kvm, struct kvm_mmu_page *sp)
{
ASSERT(is_empty_shadow_page(sp->spt));
list_del(&sp->link);
__free_page(virt_to_page(sp->spt));
__free_page(virt_to_page(sp->gfns));
kfree(sp);
++kvm->arch.n_free_mmu_pages;
}
static unsigned kvm_page_table_hashfn(gfn_t gfn)
{
return gfn & ((1 << KVM_MMU_HASH_SHIFT) - 1);
}
static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
u64 *parent_pte)
{
struct kvm_mmu_page *sp;
sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache, sizeof *sp);
sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE);
sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE);
set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages);
INIT_LIST_HEAD(&sp->oos_link);
bitmap_zero(sp->slot_bitmap, KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS);
sp->multimapped = 0;
sp->parent_pte = parent_pte;
--vcpu->kvm->arch.n_free_mmu_pages;
return sp;
}
static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *sp, u64 *parent_pte)
{
struct kvm_pte_chain *pte_chain;
struct hlist_node *node;
int i;
if (!parent_pte)
return;
if (!sp->multimapped) {
u64 *old = sp->parent_pte;
if (!old) {
sp->parent_pte = parent_pte;
return;
}
sp->multimapped = 1;
pte_chain = mmu_alloc_pte_chain(vcpu);
INIT_HLIST_HEAD(&sp->parent_ptes);
hlist_add_head(&pte_chain->link, &sp->parent_ptes);
pte_chain->parent_ptes[0] = old;
}
hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link) {
if (pte_chain->parent_ptes[NR_PTE_CHAIN_ENTRIES-1])
continue;
for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i)
if (!pte_chain->parent_ptes[i]) {
pte_chain->parent_ptes[i] = parent_pte;
return;
}
}
pte_chain = mmu_alloc_pte_chain(vcpu);
BUG_ON(!pte_chain);
hlist_add_head(&pte_chain->link, &sp->parent_ptes);
pte_chain->parent_ptes[0] = parent_pte;
}
static void mmu_page_remove_parent_pte(struct kvm_mmu_page *sp,
u64 *parent_pte)
{
struct kvm_pte_chain *pte_chain;
struct hlist_node *node;
int i;
if (!sp->multimapped) {
BUG_ON(sp->parent_pte != parent_pte);
sp->parent_pte = NULL;
return;
}
hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link)
for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
if (!pte_chain->parent_ptes[i])
break;
if (pte_chain->parent_ptes[i] != parent_pte)
continue;
while (i + 1 < NR_PTE_CHAIN_ENTRIES
&& pte_chain->parent_ptes[i + 1]) {
pte_chain->parent_ptes[i]
= pte_chain->parent_ptes[i + 1];
++i;
}
pte_chain->parent_ptes[i] = NULL;
if (i == 0) {
hlist_del(&pte_chain->link);
mmu_free_pte_chain(pte_chain);
if (hlist_empty(&sp->parent_ptes)) {
sp->multimapped = 0;
sp->parent_pte = NULL;
}
}
return;
}
BUG();
}
static void mmu_parent_walk(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
mmu_parent_walk_fn fn)
{
struct kvm_pte_chain *pte_chain;
struct hlist_node *node;
struct kvm_mmu_page *parent_sp;
int i;
if (!sp->multimapped && sp->parent_pte) {
parent_sp = page_header(__pa(sp->parent_pte));
fn(vcpu, parent_sp);
mmu_parent_walk(vcpu, parent_sp, fn);
return;
}
hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link)
for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
if (!pte_chain->parent_ptes[i])
break;
parent_sp = page_header(__pa(pte_chain->parent_ptes[i]));
fn(vcpu, parent_sp);
mmu_parent_walk(vcpu, parent_sp, fn);
}
}
static void kvm_mmu_update_unsync_bitmap(u64 *spte)
{
unsigned int index;
struct kvm_mmu_page *sp = page_header(__pa(spte));
index = spte - sp->spt;
if (!__test_and_set_bit(index, sp->unsync_child_bitmap))
sp->unsync_children++;
WARN_ON(!sp->unsync_children);
}
static void kvm_mmu_update_parents_unsync(struct kvm_mmu_page *sp)
{
struct kvm_pte_chain *pte_chain;
struct hlist_node *node;
int i;
if (!sp->parent_pte)
return;
if (!sp->multimapped) {
kvm_mmu_update_unsync_bitmap(sp->parent_pte);
return;
}
hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link)
for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
if (!pte_chain->parent_ptes[i])
break;
kvm_mmu_update_unsync_bitmap(pte_chain->parent_ptes[i]);
}
}
static int unsync_walk_fn(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
{
kvm_mmu_update_parents_unsync(sp);
return 1;
}
static void kvm_mmu_mark_parents_unsync(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *sp)
{
mmu_parent_walk(vcpu, sp, unsync_walk_fn);
kvm_mmu_update_parents_unsync(sp);
}
static void nonpaging_prefetch_page(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *sp)
{
int i;
for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
sp->spt[i] = shadow_trap_nonpresent_pte;
}
static int nonpaging_sync_page(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *sp)
{
return 1;
}
static void nonpaging_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
{
}
#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;
};
#define for_each_unsync_children(bitmap, idx) \
for (idx = find_first_bit(bitmap, 512); \
idx < 512; \
idx = find_next_bit(bitmap, 512, idx+1))
static int mmu_pages_add(struct kvm_mmu_pages *pvec, struct kvm_mmu_page *sp,
int idx)
{
int i;
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;
for_each_unsync_children(sp->unsync_child_bitmap, i) {
u64 ent = sp->spt[i];
if (is_shadow_present_pte(ent) && !is_large_pte(ent)) {
struct kvm_mmu_page *child;
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)
__clear_bit(i, sp->unsync_child_bitmap);
else if (ret > 0)
nr_unsync_leaf += ret;
else
return ret;
}
if (child->unsync) {
nr_unsync_leaf++;
if (mmu_pages_add(pvec, child, i))
return -ENOSPC;
}
}
}
if (find_first_bit(sp->unsync_child_bitmap, 512) == 512)
sp->unsync_children = 0;
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);
}
static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm *kvm, gfn_t gfn)
{
unsigned index;
struct hlist_head *bucket;
struct kvm_mmu_page *sp;
struct hlist_node *node;
pgprintk("%s: looking for gfn %lx\n", __func__, gfn);
index = kvm_page_table_hashfn(gfn);
bucket = &kvm->arch.mmu_page_hash[index];
hlist_for_each_entry(sp, node, bucket, hash_link)
if (sp->gfn == gfn && !sp->role.direct
&& !sp->role.invalid) {
pgprintk("%s: found role %x\n",
__func__, sp->role.word);
return sp;
}
return NULL;
}
static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp)
{
WARN_ON(!sp->unsync);
sp->unsync = 0;
--kvm->stat.mmu_unsync;
}
static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp);
static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
{
if (sp->role.glevels != vcpu->arch.mmu.root_level) {
kvm_mmu_zap_page(vcpu->kvm, sp);
return 1;
}
trace_kvm_mmu_sync_page(sp);
if (rmap_write_protect(vcpu->kvm, sp->gfn))
kvm_flush_remote_tlbs(vcpu->kvm);
kvm_unlink_unsync_page(vcpu->kvm, sp);
if (vcpu->arch.mmu.sync_page(vcpu, sp)) {
kvm_mmu_zap_page(vcpu->kvm, sp);
return 1;
}
kvm_mmu_flush_tlb(vcpu);
return 0;
}
struct mmu_page_path {
struct kvm_mmu_page *parent[PT64_ROOT_LEVEL-1];
unsigned int idx[PT64_ROOT_LEVEL-1];
};
#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))
static int mmu_pages_next(struct kvm_mmu_pages *pvec,
struct mmu_page_path *parents,
int i)
{
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;
}
static void mmu_pages_clear_parents(struct mmu_page_path *parents)
{
struct kvm_mmu_page *sp;
unsigned int level = 0;
do {
unsigned int idx = parents->idx[level];
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);
}
static void kvm_mmu_pages_init(struct kvm_mmu_page *parent,
struct mmu_page_path *parents,
struct kvm_mmu_pages *pvec)
{
parents->parent[parent->role.level-1] = NULL;
pvec->nr = 0;
}
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;
kvm_mmu_pages_init(parent, &parents, &pages);
while (mmu_unsync_walk(parent, &pages)) {
int protected = 0;
for_each_sp(pages, sp, parents, i)
protected |= rmap_write_protect(vcpu->kvm, sp->gfn);
if (protected)
kvm_flush_remote_tlbs(vcpu->kvm);
for_each_sp(pages, sp, parents, i) {
kvm_sync_page(vcpu, sp);
mmu_pages_clear_parents(&parents);
}
cond_resched_lock(&vcpu->kvm->mmu_lock);
kvm_mmu_pages_init(parent, &parents, &pages);
}
}
static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
gfn_t gfn,
gva_t gaddr,
unsigned level,
int direct,
unsigned access,
u64 *parent_pte)
{
union kvm_mmu_page_role role;
unsigned index;
unsigned quadrant;
struct hlist_head *bucket;
struct kvm_mmu_page *sp;
struct hlist_node *node, *tmp;
role = vcpu->arch.mmu.base_role;
role.level = level;
role.direct = direct;
role.access = access;
if (vcpu->arch.mmu.root_level <= PT32_ROOT_LEVEL) {
quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
role.quadrant = quadrant;
}
index = kvm_page_table_hashfn(gfn);
bucket = &vcpu->kvm->arch.mmu_page_hash[index];
hlist_for_each_entry_safe(sp, node, tmp, bucket, hash_link)
if (sp->gfn == gfn) {
if (sp->unsync)
if (kvm_sync_page(vcpu, sp))
continue;
if (sp->role.word != role.word)
continue;
mmu_page_add_parent_pte(vcpu, sp, parent_pte);
if (sp->unsync_children) {
set_bit(KVM_REQ_MMU_SYNC, &vcpu->requests);
kvm_mmu_mark_parents_unsync(vcpu, sp);
}
trace_kvm_mmu_get_page(sp, false);
return sp;
}
++vcpu->kvm->stat.mmu_cache_miss;
sp = kvm_mmu_alloc_page(vcpu, parent_pte);
if (!sp)
return sp;
sp->gfn = gfn;
sp->role = role;
hlist_add_head(&sp->hash_link, bucket);
if (!direct) {
if (rmap_write_protect(vcpu->kvm, gfn))
kvm_flush_remote_tlbs(vcpu->kvm);
account_shadowed(vcpu->kvm, gfn);
}
if (shadow_trap_nonpresent_pte != shadow_notrap_nonpresent_pte)
vcpu->arch.mmu.prefetch_page(vcpu, sp);
else
nonpaging_prefetch_page(vcpu, sp);
trace_kvm_mmu_get_page(sp, true);
return sp;
}
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;
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;
if (iterator->level == PT_PAGE_TABLE_LEVEL)
if (is_large_pte(*iterator->sptep))
return false;
iterator->index = SHADOW_PT_INDEX(iterator->addr, iterator->level);
iterator->sptep = ((u64 *)__va(iterator->shadow_addr)) + iterator->index;
return true;
}
static void shadow_walk_next(struct kvm_shadow_walk_iterator *iterator)
{
iterator->shadow_addr = *iterator->sptep & PT64_BASE_ADDR_MASK;
--iterator->level;
}
static void kvm_mmu_page_unlink_children(struct kvm *kvm,
struct kvm_mmu_page *sp)
{
unsigned i;
u64 *pt;
u64 ent;
pt = sp->spt;
for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
ent = pt[i];
if (is_shadow_present_pte(ent)) {
if (!is_last_spte(ent, sp->role.level)) {
ent &= PT64_BASE_ADDR_MASK;
mmu_page_remove_parent_pte(page_header(ent),
&pt[i]);
} else {
if (is_large_pte(ent))
--kvm->stat.lpages;
rmap_remove(kvm, &pt[i]);
}
}
pt[i] = shadow_trap_nonpresent_pte;
}
}
static void kvm_mmu_put_page(struct kvm_mmu_page *sp, u64 *parent_pte)
{
mmu_page_remove_parent_pte(sp, parent_pte);
}
static void kvm_mmu_reset_last_pte_updated(struct kvm *kvm)
{
int i;
struct kvm_vcpu *vcpu;
kvm_for_each_vcpu(i, vcpu, kvm)
vcpu->arch.last_pte_updated = NULL;
}
static void kvm_mmu_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp)
{
u64 *parent_pte;
while (sp->multimapped || sp->parent_pte) {
if (!sp->multimapped)
parent_pte = sp->parent_pte;
else {
struct kvm_pte_chain *chain;
chain = container_of(sp->parent_ptes.first,
struct kvm_pte_chain, link);
parent_pte = chain->parent_ptes[0];
}
BUG_ON(!parent_pte);
kvm_mmu_put_page(sp, parent_pte);
__set_spte(parent_pte, shadow_trap_nonpresent_pte);
}
}
static int mmu_zap_unsync_children(struct kvm *kvm,
struct kvm_mmu_page *parent)
{
int i, zapped = 0;
struct mmu_page_path parents;
struct kvm_mmu_pages pages;
if (parent->role.level == PT_PAGE_TABLE_LEVEL)
return 0;
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) {
kvm_mmu_zap_page(kvm, sp);
mmu_pages_clear_parents(&parents);
}
zapped += pages.nr;
kvm_mmu_pages_init(parent, &parents, &pages);
}
return zapped;
}
static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp)
{
int ret;
trace_kvm_mmu_zap_page(sp);
++kvm->stat.mmu_shadow_zapped;
ret = mmu_zap_unsync_children(kvm, sp);
kvm_mmu_page_unlink_children(kvm, sp);
kvm_mmu_unlink_parents(kvm, sp);
kvm_flush_remote_tlbs(kvm);
if (!sp->role.invalid && !sp->role.direct)
unaccount_shadowed(kvm, sp->gfn);
if (sp->unsync)
kvm_unlink_unsync_page(kvm, sp);
if (!sp->root_count) {
hlist_del(&sp->hash_link);
kvm_mmu_free_page(kvm, sp);
} else {
sp->role.invalid = 1;
list_move(&sp->link, &kvm->arch.active_mmu_pages);
kvm_reload_remote_mmus(kvm);
}
kvm_mmu_reset_last_pte_updated(kvm);
return ret;
}
/*
* Changing the number of mmu pages allocated to the vm
* Note: if kvm_nr_mmu_pages is too small, you will get dead lock
*/
void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages)
{
int used_pages;
used_pages = kvm->arch.n_alloc_mmu_pages - kvm->arch.n_free_mmu_pages;
used_pages = max(0, used_pages);
/*
* 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
*/
if (used_pages > kvm_nr_mmu_pages) {
while (used_pages > kvm_nr_mmu_pages) {
struct kvm_mmu_page *page;
page = container_of(kvm->arch.active_mmu_pages.prev,
struct kvm_mmu_page, link);
kvm_mmu_zap_page(kvm, page);
used_pages--;
}
kvm->arch.n_free_mmu_pages = 0;
}
else
kvm->arch.n_free_mmu_pages += kvm_nr_mmu_pages
- kvm->arch.n_alloc_mmu_pages;
kvm->arch.n_alloc_mmu_pages = kvm_nr_mmu_pages;
}
static int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
{
unsigned index;
struct hlist_head *bucket;
struct kvm_mmu_page *sp;
struct hlist_node *node, *n;
int r;
pgprintk("%s: looking for gfn %lx\n", __func__, gfn);
r = 0;
index = kvm_page_table_hashfn(gfn);
bucket = &kvm->arch.mmu_page_hash[index];
hlist_for_each_entry_safe(sp, node, n, bucket, hash_link)
if (sp->gfn == gfn && !sp->role.direct) {
pgprintk("%s: gfn %lx role %x\n", __func__, gfn,
sp->role.word);
r = 1;
if (kvm_mmu_zap_page(kvm, sp))
n = bucket->first;
}
return r;
}
static void mmu_unshadow(struct kvm *kvm, gfn_t gfn)
{
unsigned index;
struct hlist_head *bucket;
struct kvm_mmu_page *sp;
struct hlist_node *node, *nn;
index = kvm_page_table_hashfn(gfn);
bucket = &kvm->arch.mmu_page_hash[index];
hlist_for_each_entry_safe(sp, node, nn, bucket, hash_link) {
if (sp->gfn == gfn && !sp->role.direct
&& !sp->role.invalid) {
pgprintk("%s: zap %lx %x\n",
__func__, gfn, sp->role.word);
kvm_mmu_zap_page(kvm, sp);
}
}
}
static void page_header_update_slot(struct kvm *kvm, void *pte, gfn_t gfn)
{
int slot = memslot_id(kvm, gfn_to_memslot(kvm, gfn));
struct kvm_mmu_page *sp = page_header(__pa(pte));
__set_bit(slot, sp->slot_bitmap);
}
static void mmu_convert_notrap(struct kvm_mmu_page *sp)
{
int i;
u64 *pt = sp->spt;
if (shadow_trap_nonpresent_pte == shadow_notrap_nonpresent_pte)
return;
for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
if (pt[i] == shadow_notrap_nonpresent_pte)
__set_spte(&pt[i], shadow_trap_nonpresent_pte);
}
}
struct page *gva_to_page(struct kvm_vcpu *vcpu, gva_t gva)
{
struct page *page;
gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gva);
if (gpa == UNMAPPED_GVA)
return NULL;
page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT);
return page;
}
/*
* 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;
}
u8 kvm_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn)
{
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;
}
EXPORT_SYMBOL_GPL(kvm_get_guest_memory_type);
static int kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
{
unsigned index;
struct hlist_head *bucket;
struct kvm_mmu_page *s;
struct hlist_node *node, *n;
trace_kvm_mmu_unsync_page(sp);
index = kvm_page_table_hashfn(sp->gfn);
bucket = &vcpu->kvm->arch.mmu_page_hash[index];
/* don't unsync if pagetable is shadowed with multiple roles */
hlist_for_each_entry_safe(s, node, n, bucket, hash_link) {
if (s->gfn != sp->gfn || s->role.direct)
continue;
if (s->role.word != sp->role.word)
return 1;
}
++vcpu->kvm->stat.mmu_unsync;
sp->unsync = 1;
kvm_mmu_mark_parents_unsync(vcpu, sp);
mmu_convert_notrap(sp);
return 0;
}
static int mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn,
bool can_unsync)
{
struct kvm_mmu_page *shadow;
shadow = kvm_mmu_lookup_page(vcpu->kvm, gfn);
if (shadow) {
if (shadow->role.level != PT_PAGE_TABLE_LEVEL)
return 1;
if (shadow->unsync)
return 0;
if (can_unsync && oos_shadow)
return kvm_unsync_page(vcpu, shadow);
return 1;
}
return 0;
}
static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
unsigned pte_access, int user_fault,
int write_fault, int dirty, int level,
gfn_t gfn, pfn_t pfn, bool speculative,
bool can_unsync, bool reset_host_protection)
{
u64 spte;
int ret = 0;
/*
* We don't set the accessed bit, since we sometimes want to see
* whether the guest actually used the pte (in order to detect
* demand paging).
*/
spte = shadow_base_present_pte | shadow_dirty_mask;
if (!speculative)
spte |= shadow_accessed_mask;
if (!dirty)
pte_access &= ~ACC_WRITE_MASK;
if (pte_access & ACC_EXEC_MASK)
spte |= shadow_x_mask;
else
spte |= shadow_nx_mask;
if (pte_access & ACC_USER_MASK)
spte |= shadow_user_mask;
if (level > PT_PAGE_TABLE_LEVEL)
spte |= PT_PAGE_SIZE_MASK;
if (tdp_enabled)
spte |= kvm_x86_ops->get_mt_mask(vcpu, gfn,
kvm_is_mmio_pfn(pfn));
if (reset_host_protection)
spte |= SPTE_HOST_WRITEABLE;
spte |= (u64)pfn << PAGE_SHIFT;
if ((pte_access & ACC_WRITE_MASK)
|| (write_fault && !is_write_protection(vcpu) && !user_fault)) {
if (level > PT_PAGE_TABLE_LEVEL &&
has_wrprotected_page(vcpu->kvm, gfn, level)) {
ret = 1;
spte = shadow_trap_nonpresent_pte;
goto set_pte;
}
spte |= PT_WRITABLE_MASK;
/*
* 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.
*/
if (!can_unsync && is_writeble_pte(*sptep))
goto set_pte;
if (mmu_need_write_protect(vcpu, gfn, can_unsync)) {
pgprintk("%s: found shadow page for %lx, marking ro\n",
__func__, gfn);
ret = 1;
pte_access &= ~ACC_WRITE_MASK;
if (is_writeble_pte(spte))
spte &= ~PT_WRITABLE_MASK;
}
}
if (pte_access & ACC_WRITE_MASK)
mark_page_dirty(vcpu->kvm, gfn);
set_pte:
__set_spte(sptep, spte);
return ret;
}
static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
unsigned pt_access, unsigned pte_access,
int user_fault, int write_fault, int dirty,
int *ptwrite, int level, gfn_t gfn,
pfn_t pfn, bool speculative,
bool reset_host_protection)
{
int was_rmapped = 0;
int was_writeble = is_writeble_pte(*sptep);
int rmap_count;
pgprintk("%s: spte %llx access %x write_fault %d"
" user_fault %d gfn %lx\n",
__func__, *sptep, pt_access,
write_fault, user_fault, gfn);
if (is_rmap_spte(*sptep)) {
/*
* If we overwrite a PTE page pointer with a 2MB PMD, unlink
* the parent of the now unreachable PTE.
*/
if (level > PT_PAGE_TABLE_LEVEL &&
!is_large_pte(*sptep)) {
struct kvm_mmu_page *child;
u64 pte = *sptep;
child = page_header(pte & PT64_BASE_ADDR_MASK);
mmu_page_remove_parent_pte(child, sptep);
} else if (pfn != spte_to_pfn(*sptep)) {
pgprintk("hfn old %lx new %lx\n",
spte_to_pfn(*sptep), pfn);
rmap_remove(vcpu->kvm, sptep);
} else
was_rmapped = 1;
}
if (set_spte(vcpu, sptep, pte_access, user_fault, write_fault,
dirty, level, gfn, pfn, speculative, true,
reset_host_protection)) {
if (write_fault)
*ptwrite = 1;
kvm_x86_ops->tlb_flush(vcpu);
}
pgprintk("%s: setting spte %llx\n", __func__, *sptep);
pgprintk("instantiating %s PTE (%s) at %ld (%llx) addr %p\n",
is_large_pte(*sptep)? "2MB" : "4kB",
*sptep & PT_PRESENT_MASK ?"RW":"R", gfn,
*sptep, sptep);
if (!was_rmapped && is_large_pte(*sptep))
++vcpu->kvm->stat.lpages;
page_header_update_slot(vcpu->kvm, sptep, gfn);
if (!was_rmapped) {
rmap_count = rmap_add(vcpu, sptep, gfn);
kvm_release_pfn_clean(pfn);
if (rmap_count > RMAP_RECYCLE_THRESHOLD)
rmap_recycle(vcpu, sptep, gfn);
} else {
if (was_writeble)
kvm_release_pfn_dirty(pfn);
else
kvm_release_pfn_clean(pfn);
}
if (speculative) {
vcpu->arch.last_pte_updated = sptep;
vcpu->arch.last_pte_gfn = gfn;
}
}
static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
{
}
static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
int level, gfn_t gfn, pfn_t pfn)
{
struct kvm_shadow_walk_iterator iterator;
struct kvm_mmu_page *sp;
int pt_write = 0;
gfn_t pseudo_gfn;
for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) {
if (iterator.level == level) {
mmu_set_spte(vcpu, iterator.sptep, ACC_ALL, ACC_ALL,
0, write, 1, &pt_write,
level, gfn, pfn, false, true);
++vcpu->stat.pf_fixed;
break;
}
if (*iterator.sptep == shadow_trap_nonpresent_pte) {
pseudo_gfn = (iterator.addr & PT64_DIR_BASE_ADDR_MASK) >> PAGE_SHIFT;
sp = kvm_mmu_get_page(vcpu, pseudo_gfn, iterator.addr,
iterator.level - 1,
1, ACC_ALL, iterator.sptep);
if (!sp) {
pgprintk("nonpaging_map: ENOMEM\n");
kvm_release_pfn_clean(pfn);
return -ENOMEM;
}
__set_spte(iterator.sptep,
__pa(sp->spt)
| PT_PRESENT_MASK | PT_WRITABLE_MASK
| shadow_user_mask | shadow_x_mask);
}
}
return pt_write;
}
static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
{
int r;
int level;
pfn_t pfn;
unsigned long mmu_seq;
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;
gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
mmu_seq = vcpu->kvm->mmu_notifier_seq;
smp_rmb();
pfn = gfn_to_pfn(vcpu->kvm, gfn);
/* mmio */
if (is_error_pfn(pfn)) {
kvm_release_pfn_clean(pfn);
return 1;
}
spin_lock(&vcpu->kvm->mmu_lock);
if (mmu_notifier_retry(vcpu, mmu_seq))
goto out_unlock;
kvm_mmu_free_some_pages(vcpu);
r = __direct_map(vcpu, v, write, level, gfn, pfn);
spin_unlock(&vcpu->kvm->mmu_lock);
return r;
out_unlock:
spin_unlock(&vcpu->kvm->mmu_lock);
kvm_release_pfn_clean(pfn);
return 0;
}
static void mmu_free_roots(struct kvm_vcpu *vcpu)
{
int i;
struct kvm_mmu_page *sp;
if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
return;
spin_lock(&vcpu->kvm->mmu_lock);
if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
hpa_t root = vcpu->arch.mmu.root_hpa;
sp = page_header(root);
--sp->root_count;
if (!sp->root_count && sp->role.invalid)
kvm_mmu_zap_page(vcpu->kvm, sp);
vcpu->arch.mmu.root_hpa = INVALID_PAGE;
spin_unlock(&vcpu->kvm->mmu_lock);
return;
}
for (i = 0; i < 4; ++i) {
hpa_t root = vcpu->arch.mmu.pae_root[i];
if (root) {
root &= PT64_BASE_ADDR_MASK;
sp = page_header(root);
--sp->root_count;
if (!sp->root_count && sp->role.invalid)
kvm_mmu_zap_page(vcpu->kvm, sp);
}
vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
}
spin_unlock(&vcpu->kvm->mmu_lock);
vcpu->arch.mmu.root_hpa = INVALID_PAGE;
}
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)) {
set_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests);
ret = 1;
}
return ret;
}
static int mmu_alloc_roots(struct kvm_vcpu *vcpu)
{
int i;
gfn_t root_gfn;
struct kvm_mmu_page *sp;
int direct = 0;
u64 pdptr;
root_gfn = vcpu->arch.cr3 >> PAGE_SHIFT;
if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
hpa_t root = vcpu->arch.mmu.root_hpa;
ASSERT(!VALID_PAGE(root));
if (tdp_enabled)
direct = 1;
if (mmu_check_root(vcpu, root_gfn))
return 1;
sp = kvm_mmu_get_page(vcpu, root_gfn, 0,
PT64_ROOT_LEVEL, direct,
ACC_ALL, NULL);
root = __pa(sp->spt);
++sp->root_count;
vcpu->arch.mmu.root_hpa = root;
return 0;
}
direct = !is_paging(vcpu);
if (tdp_enabled)
direct = 1;
for (i = 0; i < 4; ++i) {
hpa_t root = vcpu->arch.mmu.pae_root[i];
ASSERT(!VALID_PAGE(root));
if (vcpu->arch.mmu.root_level == PT32E_ROOT_LEVEL) {
pdptr = kvm_pdptr_read(vcpu, i);
if (!is_present_gpte(pdptr)) {
vcpu->arch.mmu.pae_root[i] = 0;
continue;
}
root_gfn = pdptr >> PAGE_SHIFT;
} else if (vcpu->arch.mmu.root_level == 0)
root_gfn = 0;
if (mmu_check_root(vcpu, root_gfn))
return 1;
sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
PT32_ROOT_LEVEL, direct,
ACC_ALL, NULL);
root = __pa(sp->spt);
++sp->root_count;
vcpu->arch.mmu.pae_root[i] = root | PT_PRESENT_MASK;
}
vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
return 0;
}
static void mmu_sync_roots(struct kvm_vcpu *vcpu)
{
int i;
struct kvm_mmu_page *sp;
if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
return;
if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
hpa_t root = vcpu->arch.mmu.root_hpa;
sp = page_header(root);
mmu_sync_children(vcpu, sp);
return;
}
for (i = 0; i < 4; ++i) {
hpa_t root = vcpu->arch.mmu.pae_root[i];
if (root && VALID_PAGE(root)) {
root &= PT64_BASE_ADDR_MASK;
sp = page_header(root);
mmu_sync_children(vcpu, sp);
}
}
}
void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu)
{
spin_lock(&vcpu->kvm->mmu_lock);
mmu_sync_roots(vcpu);
spin_unlock(&vcpu->kvm->mmu_lock);
}
static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr)
{
return vaddr;
}
static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
u32 error_code)
{
gfn_t gfn;
int r;
pgprintk("%s: gva %lx error %x\n", __func__, gva, error_code);
r = mmu_topup_memory_caches(vcpu);
if (r)
return r;
ASSERT(vcpu);
ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
gfn = gva >> PAGE_SHIFT;
return nonpaging_map(vcpu, gva & PAGE_MASK,
error_code & PFERR_WRITE_MASK, gfn);
}
static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
u32 error_code)
{
pfn_t pfn;
int r;
int level;
gfn_t gfn = gpa >> PAGE_SHIFT;
unsigned long mmu_seq;
ASSERT(vcpu);
ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
r = mmu_topup_memory_caches(vcpu);
if (r)
return r;
level = mapping_level(vcpu, gfn);
gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
mmu_seq = vcpu->kvm->mmu_notifier_seq;
smp_rmb();
pfn = gfn_to_pfn(vcpu->kvm, gfn);
if (is_error_pfn(pfn)) {
kvm_release_pfn_clean(pfn);
return 1;
}
spin_lock(&vcpu->kvm->mmu_lock);
if (mmu_notifier_retry(vcpu, mmu_seq))
goto out_unlock;
kvm_mmu_free_some_pages(vcpu);
r = __direct_map(vcpu, gpa, error_code & PFERR_WRITE_MASK,
level, gfn, pfn);
spin_unlock(&vcpu->kvm->mmu_lock);
return r;
out_unlock:
spin_unlock(&vcpu->kvm->mmu_lock);
kvm_release_pfn_clean(pfn);
return 0;
}
static void nonpaging_free(struct kvm_vcpu *vcpu)
{
mmu_free_roots(vcpu);
}
static int nonpaging_init_context(struct kvm_vcpu *vcpu)
{
struct kvm_mmu *context = &vcpu->arch.mmu;
context->new_cr3 = nonpaging_new_cr3;
context->page_fault = nonpaging_page_fault;
context->gva_to_gpa = nonpaging_gva_to_gpa;
context->free = nonpaging_free;
context->prefetch_page = nonpaging_prefetch_page;
context->sync_page = nonpaging_sync_page;
context->invlpg = nonpaging_invlpg;
context->root_level = 0;
context->shadow_root_level = PT32E_ROOT_LEVEL;
context->root_hpa = INVALID_PAGE;
return 0;
}
void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
{
++vcpu->stat.tlb_flush;
kvm_x86_ops->tlb_flush(vcpu);
}
static void paging_new_cr3(struct kvm_vcpu *vcpu)
{
pgprintk("%s: cr3 %lx\n", __func__, vcpu->arch.cr3);
mmu_free_roots(vcpu);
}
static void inject_page_fault(struct kvm_vcpu *vcpu,
u64 addr,
u32 err_code)
{
kvm_inject_page_fault(vcpu, addr, err_code);
}
static void paging_free(struct kvm_vcpu *vcpu)
{
nonpaging_free(vcpu);
}
static bool is_rsvd_bits_set(struct kvm_vcpu *vcpu, u64 gpte, int level)
{
int bit7;
bit7 = (gpte >> 7) & 1;
return (gpte & vcpu->arch.mmu.rsvd_bits_mask[bit7][level-1]) != 0;
}
#define PTTYPE 64
#include "paging_tmpl.h"
#undef PTTYPE
#define PTTYPE 32
#include "paging_tmpl.h"
#undef PTTYPE
static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu, int level)
{
struct kvm_mmu *context = &vcpu->arch.mmu;
int maxphyaddr = cpuid_maxphyaddr(vcpu);
u64 exb_bit_rsvd = 0;
if (!is_nx(vcpu))
exb_bit_rsvd = rsvd_bits(63, 63);
switch (level) {
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;
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);
context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[1][0];
break;
case PT32E_ROOT_LEVEL:
context->rsvd_bits_mask[0][2] =
rsvd_bits(maxphyaddr, 63) |
rsvd_bits(7, 8) | rsvd_bits(1, 2); /* PDPTE */
context->rsvd_bits_mask[0][1] = exb_bit_rsvd |
rsvd_bits(maxphyaddr, 62); /* PDE */
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 */
context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[1][0];
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 |
rsvd_bits(maxphyaddr, 51);
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];
context->rsvd_bits_mask[1][2] = exb_bit_rsvd |
rsvd_bits(maxphyaddr, 51) |
rsvd_bits(13, 29);
context->rsvd_bits_mask[1][1] = exb_bit_rsvd |
rsvd_bits(maxphyaddr, 51) |
rsvd_bits(13, 20); /* large page */
context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[1][0];
break;
}
}
static int paging64_init_context_common(struct kvm_vcpu *vcpu, int level)
{
struct kvm_mmu *context = &vcpu->arch.mmu;
ASSERT(is_pae(vcpu));
context->new_cr3 = paging_new_cr3;
context->page_fault = paging64_page_fault;
context->gva_to_gpa = paging64_gva_to_gpa;
context->prefetch_page = paging64_prefetch_page;
context->sync_page = paging64_sync_page;
context->invlpg = paging64_invlpg;
context->free = paging_free;
context->root_level = level;
context->shadow_root_level = level;
context->root_hpa = INVALID_PAGE;
return 0;
}
static int paging64_init_context(struct kvm_vcpu *vcpu)
{
reset_rsvds_bits_mask(vcpu, PT64_ROOT_LEVEL);
return paging64_init_context_common(vcpu, PT64_ROOT_LEVEL);
}
static int paging32_init_context(struct kvm_vcpu *vcpu)
{
struct kvm_mmu *context = &vcpu->arch.mmu;
reset_rsvds_bits_mask(vcpu, PT32_ROOT_LEVEL);
context->new_cr3 = paging_new_cr3;
context->page_fault = paging32_page_fault;
context->gva_to_gpa = paging32_gva_to_gpa;
context->free = paging_free;
context->prefetch_page = paging32_prefetch_page;
context->sync_page = paging32_sync_page;
context->invlpg = paging32_invlpg;
context->root_level = PT32_ROOT_LEVEL;
context->shadow_root_level = PT32E_ROOT_LEVEL;
context->root_hpa = INVALID_PAGE;
return 0;
}
static int paging32E_init_context(struct kvm_vcpu *vcpu)
{
reset_rsvds_bits_mask(vcpu, PT32E_ROOT_LEVEL);
return paging64_init_context_common(vcpu, PT32E_ROOT_LEVEL);
}
static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
{
struct kvm_mmu *context = &vcpu->arch.mmu;
context->new_cr3 = nonpaging_new_cr3;
context->page_fault = tdp_page_fault;
context->free = nonpaging_free;
context->prefetch_page = nonpaging_prefetch_page;
context->sync_page = nonpaging_sync_page;
context->invlpg = nonpaging_invlpg;
context->shadow_root_level = kvm_x86_ops->get_tdp_level();
context->root_hpa = INVALID_PAGE;
if (!is_paging(vcpu)) {
context->gva_to_gpa = nonpaging_gva_to_gpa;
context->root_level = 0;
} else if (is_long_mode(vcpu)) {
reset_rsvds_bits_mask(vcpu, PT64_ROOT_LEVEL);
context->gva_to_gpa = paging64_gva_to_gpa;
context->root_level = PT64_ROOT_LEVEL;
} else if (is_pae(vcpu)) {
reset_rsvds_bits_mask(vcpu, PT32E_ROOT_LEVEL);
context->gva_to_gpa = paging64_gva_to_gpa;
context->root_level = PT32E_ROOT_LEVEL;
} else {
reset_rsvds_bits_mask(vcpu, PT32_ROOT_LEVEL);
context->gva_to_gpa = paging32_gva_to_gpa;
context->root_level = PT32_ROOT_LEVEL;
}
return 0;
}
static int init_kvm_softmmu(struct kvm_vcpu *vcpu)
{
int r;
ASSERT(vcpu);
ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
if (!is_paging(vcpu))
r = nonpaging_init_context(vcpu);
else if (is_long_mode(vcpu))
r = paging64_init_context(vcpu);
else if (is_pae(vcpu))
r = paging32E_init_context(vcpu);
else
r = paging32_init_context(vcpu);
vcpu->arch.mmu.base_role.glevels = vcpu->arch.mmu.root_level;
return r;
}
static int init_kvm_mmu(struct kvm_vcpu *vcpu)
{
vcpu->arch.update_pte.pfn = bad_pfn;
if (tdp_enabled)
return init_kvm_tdp_mmu(vcpu);
else
return init_kvm_softmmu(vcpu);
}
static void destroy_kvm_mmu(struct kvm_vcpu *vcpu)
{
ASSERT(vcpu);
if (VALID_PAGE(vcpu->arch.mmu.root_hpa)) {
vcpu->arch.mmu.free(vcpu);
vcpu->arch.mmu.root_hpa = INVALID_PAGE;
}
}
int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
{
destroy_kvm_mmu(vcpu);
return init_kvm_mmu(vcpu);
}
EXPORT_SYMBOL_GPL(kvm_mmu_reset_context);
int kvm_mmu_load(struct kvm_vcpu *vcpu)
{
int r;
r = mmu_topup_memory_caches(vcpu);
if (r)
goto out;
spin_lock(&vcpu->kvm->mmu_lock);
kvm_mmu_free_some_pages(vcpu);
r = mmu_alloc_roots(vcpu);
mmu_sync_roots(vcpu);
spin_unlock(&vcpu->kvm->mmu_lock);
if (r)
goto out;
/* set_cr3() should ensure TLB has been flushed */
kvm_x86_ops->set_cr3(vcpu, vcpu->arch.mmu.root_hpa);
out:
return r;
}
EXPORT_SYMBOL_GPL(kvm_mmu_load);
void kvm_mmu_unload(struct kvm_vcpu *vcpu)
{
mmu_free_roots(vcpu);
}
static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *sp,
u64 *spte)
{
u64 pte;
struct kvm_mmu_page *child;
pte = *spte;
if (is_shadow_present_pte(pte)) {
if (is_last_spte(pte, sp->role.level))
rmap_remove(vcpu->kvm, spte);
else {
child = page_header(pte & PT64_BASE_ADDR_MASK);
mmu_page_remove_parent_pte(child, spte);
}
}
__set_spte(spte, shadow_trap_nonpresent_pte);
if (is_large_pte(pte))
--vcpu->kvm->stat.lpages;
}
static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *sp,
u64 *spte,
const void *new)
{
if (sp->role.level != PT_PAGE_TABLE_LEVEL) {
++vcpu->kvm->stat.mmu_pde_zapped;
return;
}
++vcpu->kvm->stat.mmu_pte_updated;
if (sp->role.glevels == PT32_ROOT_LEVEL)
paging32_update_pte(vcpu, sp, spte, new);
else
paging64_update_pte(vcpu, sp, spte, new);
}
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;
}
static void mmu_pte_write_flush_tlb(struct kvm_vcpu *vcpu, u64 old, u64 new)
{
if (need_remote_flush(old, new))
kvm_flush_remote_tlbs(vcpu->kvm);
else
kvm_mmu_flush_tlb(vcpu);
}
static bool last_updated_pte_accessed(struct kvm_vcpu *vcpu)
{
u64 *spte = vcpu->arch.last_pte_updated;
return !!(spte && (*spte & shadow_accessed_mask));
}
static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
const u8 *new, int bytes)
{
gfn_t gfn;
int r;
u64 gpte = 0;
pfn_t pfn;
if (bytes != 4 && bytes != 8)
return;
/*
* Assume that the pte write on a page table of the same type
* as the current vcpu paging mode. This is nearly always true
* (might be false while changing modes). Note it is verified later
* by update_pte().
*/
if (is_pae(vcpu)) {
/* Handle a 32-bit guest writing two halves of a 64-bit gpte */
if ((bytes == 4) && (gpa % 4 == 0)) {
r = kvm_read_guest(vcpu->kvm, gpa & ~(u64)7, &gpte, 8);
if (r)
return;
memcpy((void *)&gpte + (gpa % 8), new, 4);
} else if ((bytes == 8) && (gpa % 8 == 0)) {
memcpy((void *)&gpte, new, 8);
}
} else {
if ((bytes == 4) && (gpa % 4 == 0))
memcpy((void *)&gpte, new, 4);
}
if (!is_present_gpte(gpte))
return;
gfn = (gpte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
vcpu->arch.update_pte.mmu_seq = vcpu->kvm->mmu_notifier_seq;
smp_rmb();
pfn = gfn_to_pfn(vcpu->kvm, gfn);
if (is_error_pfn(pfn)) {
kvm_release_pfn_clean(pfn);
return;
}
vcpu->arch.update_pte.gfn = gfn;
vcpu->arch.update_pte.pfn = pfn;
}
static void kvm_mmu_access_page(struct kvm_vcpu *vcpu, gfn_t gfn)
{
u64 *spte = vcpu->arch.last_pte_updated;
if (spte
&& vcpu->arch.last_pte_gfn == gfn
&& shadow_accessed_mask
&& !(*spte & shadow_accessed_mask)
&& is_shadow_present_pte(*spte))
set_bit(PT_ACCESSED_SHIFT, (unsigned long *)spte);
}
void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
const u8 *new, int bytes,
bool guest_initiated)
{
gfn_t gfn = gpa >> PAGE_SHIFT;
struct kvm_mmu_page *sp;
struct hlist_node *node, *n;
struct hlist_head *bucket;
unsigned index;
u64 entry, gentry;
u64 *spte;
unsigned offset = offset_in_page(gpa);
unsigned pte_size;
unsigned page_offset;
unsigned misaligned;
unsigned quadrant;
int level;
int flooded = 0;
int npte;
int r;
pgprintk("%s: gpa %llx bytes %d\n", __func__, gpa, bytes);
mmu_guess_page_from_pte_write(vcpu, gpa, new, bytes);
spin_lock(&vcpu->kvm->mmu_lock);
kvm_mmu_access_page(vcpu, gfn);
kvm_mmu_free_some_pages(vcpu);
++vcpu->kvm->stat.mmu_pte_write;
kvm_mmu_audit(vcpu, "pre pte write");
if (guest_initiated) {
if (gfn == vcpu->arch.last_pt_write_gfn
&& !last_updated_pte_accessed(vcpu)) {
++vcpu->arch.last_pt_write_count;
if (vcpu->arch.last_pt_write_count >= 3)
flooded = 1;
} else {
vcpu->arch.last_pt_write_gfn = gfn;
vcpu->arch.last_pt_write_count = 1;
vcpu->arch.last_pte_updated = NULL;
}
}
index = kvm_page_table_hashfn(gfn);
bucket = &vcpu->kvm->arch.mmu_page_hash[index];
hlist_for_each_entry_safe(sp, node, n, bucket, hash_link) {
if (sp->gfn != gfn || sp->role.direct || sp->role.invalid)
continue;
pte_size = sp->role.glevels == PT32_ROOT_LEVEL ? 4 : 8;
misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
misaligned |= bytes < 4;
if (misaligned || flooded) {
/*
* Misaligned accesses are too much trouble to fix
* up; also, they usually indicate a page is not used
* as a page table.
*
* 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.
*/
pgprintk("misaligned: gpa %llx bytes %d role %x\n",
gpa, bytes, sp->role.word);
if (kvm_mmu_zap_page(vcpu->kvm, sp))
n = bucket->first;
++vcpu->kvm->stat.mmu_flooded;
continue;
}
page_offset = offset;
level = sp->role.level;
npte = 1;
if (sp->role.glevels == PT32_ROOT_LEVEL) {
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;
npte = 2;
}
quadrant = page_offset >> PAGE_SHIFT;
page_offset &= ~PAGE_MASK;
if (quadrant != sp->role.quadrant)
continue;
}
spte = &sp->spt[page_offset / sizeof(*spte)];
if ((gpa & (pte_size - 1)) || (bytes < pte_size)) {
gentry = 0;
r = kvm_read_guest_atomic(vcpu->kvm,
gpa & ~(u64)(pte_size - 1),
&gentry, pte_size);
new = (const void *)&gentry;
if (r < 0)
new = NULL;
}
while (npte--) {
entry = *spte;
mmu_pte_write_zap_pte(vcpu, sp, spte);
if (new)
mmu_pte_write_new_pte(vcpu, sp, spte, new);
mmu_pte_write_flush_tlb(vcpu, entry, *spte);
++spte;
}
}
kvm_mmu_audit(vcpu, "post pte write");
spin_unlock(&vcpu->kvm->mmu_lock);
if (!is_error_pfn(vcpu->arch.update_pte.pfn)) {
kvm_release_pfn_clean(vcpu->arch.update_pte.pfn);
vcpu->arch.update_pte.pfn = bad_pfn;
}
}
int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
{
gpa_t gpa;
int r;
if (tdp_enabled)
return 0;
gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gva);
spin_lock(&vcpu->kvm->mmu_lock);
r = kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT);
spin_unlock(&vcpu->kvm->mmu_lock);
return r;
}
EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page_virt);
void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
{
while (vcpu->kvm->arch.n_free_mmu_pages < KVM_REFILL_PAGES &&
!list_empty(&vcpu->kvm->arch.active_mmu_pages)) {
struct kvm_mmu_page *sp;
sp = container_of(vcpu->kvm->arch.active_mmu_pages.prev,
struct kvm_mmu_page, link);
kvm_mmu_zap_page(vcpu->kvm, sp);
++vcpu->kvm->stat.mmu_recycled;
}
}
int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code)
{
int r;
enum emulation_result er;
r = vcpu->arch.mmu.page_fault(vcpu, cr2, error_code);
if (r < 0)
goto out;
if (!r) {
r = 1;
goto out;
}
r = mmu_topup_memory_caches(vcpu);
if (r)
goto out;
er = emulate_instruction(vcpu, vcpu->run, cr2, error_code, 0);
switch (er) {
case EMULATE_DONE:
return 1;
case EMULATE_DO_MMIO:
++vcpu->stat.mmio_exits;
return 0;
case EMULATE_FAIL:
vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
return 0;
default:
BUG();
}
out:
return r;
}
EXPORT_SYMBOL_GPL(kvm_mmu_page_fault);
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);
void kvm_enable_tdp(void)
{
tdp_enabled = true;
}
EXPORT_SYMBOL_GPL(kvm_enable_tdp);
void kvm_disable_tdp(void)
{
tdp_enabled = false;
}
EXPORT_SYMBOL_GPL(kvm_disable_tdp);
static void free_mmu_pages(struct kvm_vcpu *vcpu)
{
free_page((unsigned long)vcpu->arch.mmu.pae_root);
}
static int alloc_mmu_pages(struct kvm_vcpu *vcpu)
{
struct page *page;
int i;
ASSERT(vcpu);
/*
* 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)
goto error_1;
vcpu->arch.mmu.pae_root = page_address(page);
for (i = 0; i < 4; ++i)
vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
return 0;
error_1:
free_mmu_pages(vcpu);
return -ENOMEM;
}
int kvm_mmu_create(struct kvm_vcpu *vcpu)
{
ASSERT(vcpu);
ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
return alloc_mmu_pages(vcpu);
}
int kvm_mmu_setup(struct kvm_vcpu *vcpu)
{
ASSERT(vcpu);
ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
return init_kvm_mmu(vcpu);
}
void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
{
ASSERT(vcpu);
destroy_kvm_mmu(vcpu);
free_mmu_pages(vcpu);
mmu_free_memory_caches(vcpu);
}
void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
{
struct kvm_mmu_page *sp;
list_for_each_entry(sp, &kvm->arch.active_mmu_pages, link) {
int i;
u64 *pt;
if (!test_bit(slot, sp->slot_bitmap))
continue;
pt = sp->spt;
for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
/* avoid RMW */
if (pt[i] & PT_WRITABLE_MASK)
pt[i] &= ~PT_WRITABLE_MASK;
}
kvm_flush_remote_tlbs(kvm);
}
void kvm_mmu_zap_all(struct kvm *kvm)
{
struct kvm_mmu_page *sp, *node;
spin_lock(&kvm->mmu_lock);
list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link)
if (kvm_mmu_zap_page(kvm, sp))
node = container_of(kvm->arch.active_mmu_pages.next,
struct kvm_mmu_page, link);
spin_unlock(&kvm->mmu_lock);
kvm_flush_remote_tlbs(kvm);
}
static void kvm_mmu_remove_one_alloc_mmu_page(struct kvm *kvm)
{
struct kvm_mmu_page *page;
page = container_of(kvm->arch.active_mmu_pages.prev,
struct kvm_mmu_page, link);
kvm_mmu_zap_page(kvm, page);
}
static int mmu_shrink(int nr_to_scan, gfp_t gfp_mask)
{
struct kvm *kvm;
struct kvm *kvm_freed = NULL;
int cache_count = 0;
spin_lock(&kvm_lock);
list_for_each_entry(kvm, &vm_list, vm_list) {
int npages;
if (!down_read_trylock(&kvm->slots_lock))
continue;
spin_lock(&kvm->mmu_lock);
npages = kvm->arch.n_alloc_mmu_pages -
kvm->arch.n_free_mmu_pages;
cache_count += npages;
if (!kvm_freed && nr_to_scan > 0 && npages > 0) {
kvm_mmu_remove_one_alloc_mmu_page(kvm);
cache_count--;
kvm_freed = kvm;
}
nr_to_scan--;
spin_unlock(&kvm->mmu_lock);
up_read(&kvm->slots_lock);
}
if (kvm_freed)
list_move_tail(&kvm_freed->vm_list, &vm_list);
spin_unlock(&kvm_lock);
return cache_count;
}
static struct shrinker mmu_shrinker = {
.shrink = mmu_shrink,
.seeks = DEFAULT_SEEKS * 10,
};
static void mmu_destroy_caches(void)
{
if (pte_chain_cache)
kmem_cache_destroy(pte_chain_cache);
if (rmap_desc_cache)
kmem_cache_destroy(rmap_desc_cache);
if (mmu_page_header_cache)
kmem_cache_destroy(mmu_page_header_cache);
}
void kvm_mmu_module_exit(void)
{
mmu_destroy_caches();
unregister_shrinker(&mmu_shrinker);
}
int kvm_mmu_module_init(void)
{
pte_chain_cache = kmem_cache_create("kvm_pte_chain",
sizeof(struct kvm_pte_chain),
0, 0, NULL);
if (!pte_chain_cache)
goto nomem;
rmap_desc_cache = kmem_cache_create("kvm_rmap_desc",
sizeof(struct kvm_rmap_desc),
0, 0, NULL);
if (!rmap_desc_cache)
goto nomem;
mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
sizeof(struct kvm_mmu_page),
0, 0, NULL);
if (!mmu_page_header_cache)
goto nomem;
register_shrinker(&mmu_shrinker);
return 0;
nomem:
mmu_destroy_caches();
return -ENOMEM;
}
/*
* Caculate mmu pages needed for kvm.
*/
unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
{
int i;
unsigned int nr_mmu_pages;
unsigned int nr_pages = 0;
for (i = 0; i < kvm->nmemslots; i++)
nr_pages += kvm->memslots[i].npages;
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;
}
static void *pv_mmu_peek_buffer(struct kvm_pv_mmu_op_buffer *buffer,
unsigned len)
{
if (len > buffer->len)
return NULL;
return buffer->ptr;
}
static void *pv_mmu_read_buffer(struct kvm_pv_mmu_op_buffer *buffer,
unsigned len)
{
void *ret;
ret = pv_mmu_peek_buffer(buffer, len);
if (!ret)
return ret;
buffer->ptr += len;
buffer->len -= len;
buffer->processed += len;
return ret;
}
static int kvm_pv_mmu_write(struct kvm_vcpu *vcpu,
gpa_t addr, gpa_t value)
{
int bytes = 8;
int r;
if (!is_long_mode(vcpu) && !is_pae(vcpu))
bytes = 4;
r = mmu_topup_memory_caches(vcpu);
if (r)
return r;
if (!emulator_write_phys(vcpu, addr, &value, bytes))
return -EFAULT;
return 1;
}
static int kvm_pv_mmu_flush_tlb(struct kvm_vcpu *vcpu)
{
kvm_set_cr3(vcpu, vcpu->arch.cr3);
return 1;
}
static int kvm_pv_mmu_release_pt(struct kvm_vcpu *vcpu, gpa_t addr)
{
spin_lock(&vcpu->kvm->mmu_lock);
mmu_unshadow(vcpu->kvm, addr >> PAGE_SHIFT);
spin_unlock(&vcpu->kvm->mmu_lock);
return 1;
}
static int kvm_pv_mmu_op_one(struct kvm_vcpu *vcpu,
struct kvm_pv_mmu_op_buffer *buffer)
{
struct kvm_mmu_op_header *header;
header = pv_mmu_peek_buffer(buffer, sizeof *header);
if (!header)
return 0;
switch (header->op) {
case KVM_MMU_OP_WRITE_PTE: {
struct kvm_mmu_op_write_pte *wpte;
wpte = pv_mmu_read_buffer(buffer, sizeof *wpte);
if (!wpte)
return 0;
return kvm_pv_mmu_write(vcpu, wpte->pte_phys,
wpte->pte_val);
}
case KVM_MMU_OP_FLUSH_TLB: {
struct kvm_mmu_op_flush_tlb *ftlb;
ftlb = pv_mmu_read_buffer(buffer, sizeof *ftlb);
if (!ftlb)
return 0;
return kvm_pv_mmu_flush_tlb(vcpu);
}
case KVM_MMU_OP_RELEASE_PT: {
struct kvm_mmu_op_release_pt *rpt;
rpt = pv_mmu_read_buffer(buffer, sizeof *rpt);
if (!rpt)
return 0;
return kvm_pv_mmu_release_pt(vcpu, rpt->pt_phys);
}
default: return 0;
}
}
int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes,
gpa_t addr, unsigned long *ret)
{
int r;
struct kvm_pv_mmu_op_buffer *buffer = &vcpu->arch.mmu_op_buffer;
buffer->ptr = buffer->buf;
buffer->len = min_t(unsigned long, bytes, sizeof buffer->buf);
buffer->processed = 0;
r = kvm_read_guest(vcpu->kvm, addr, buffer->buf, buffer->len);
if (r)
goto out;
while (buffer->len) {
r = kvm_pv_mmu_op_one(vcpu, buffer);
if (r < 0)
goto out;
if (r == 0)
break;
}
r = 1;
out:
*ret = buffer->processed;
return r;
}
int kvm_mmu_get_spte_hierarchy(struct kvm_vcpu *vcpu, u64 addr, u64 sptes[4])
{
struct kvm_shadow_walk_iterator iterator;
int nr_sptes = 0;
spin_lock(&vcpu->kvm->mmu_lock);
for_each_shadow_entry(vcpu, addr, iterator) {
sptes[iterator.level-1] = *iterator.sptep;
nr_sptes++;
if (!is_shadow_present_pte(*iterator.sptep))
break;
}
spin_unlock(&vcpu->kvm->mmu_lock);
return nr_sptes;
}
EXPORT_SYMBOL_GPL(kvm_mmu_get_spte_hierarchy);
#ifdef AUDIT
static const char *audit_msg;
static gva_t canonicalize(gva_t gva)
{
#ifdef CONFIG_X86_64
gva = (long long)(gva << 16) >> 16;
#endif
return gva;
}
typedef void (*inspect_spte_fn) (struct kvm *kvm, struct kvm_mmu_page *sp,
u64 *sptep);
static void __mmu_spte_walk(struct kvm *kvm, struct kvm_mmu_page *sp,
inspect_spte_fn fn)
{
int i;
for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
u64 ent = sp->spt[i];
if (is_shadow_present_pte(ent)) {
if (!is_last_spte(ent, sp->role.level)) {
struct kvm_mmu_page *child;
child = page_header(ent & PT64_BASE_ADDR_MASK);
__mmu_spte_walk(kvm, child, fn);
} else
fn(kvm, sp, &sp->spt[i]);
}
}
}
static void mmu_spte_walk(struct kvm_vcpu *vcpu, inspect_spte_fn fn)
{
int i;
struct kvm_mmu_page *sp;
if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
return;
if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
hpa_t root = vcpu->arch.mmu.root_hpa;
sp = page_header(root);
__mmu_spte_walk(vcpu->kvm, sp, fn);
return;
}
for (i = 0; i < 4; ++i) {
hpa_t root = vcpu->arch.mmu.pae_root[i];
if (root && VALID_PAGE(root)) {
root &= PT64_BASE_ADDR_MASK;
sp = page_header(root);
__mmu_spte_walk(vcpu->kvm, sp, fn);
}
}
return;
}
static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte,
gva_t va, int level)
{
u64 *pt = __va(page_pte & PT64_BASE_ADDR_MASK);
int i;
gva_t va_delta = 1ul << (PAGE_SHIFT + 9 * (level - 1));
for (i = 0; i < PT64_ENT_PER_PAGE; ++i, va += va_delta) {
u64 ent = pt[i];
if (ent == shadow_trap_nonpresent_pte)
continue;
va = canonicalize(va);
if (is_shadow_present_pte(ent) && !is_last_spte(ent, level))
audit_mappings_page(vcpu, ent, va, level - 1);
else {
gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, va);
gfn_t gfn = gpa >> PAGE_SHIFT;
pfn_t pfn = gfn_to_pfn(vcpu->kvm, gfn);
hpa_t hpa = (hpa_t)pfn << PAGE_SHIFT;
if (is_error_pfn(pfn)) {
kvm_release_pfn_clean(pfn);
continue;
}
if (is_shadow_present_pte(ent)
&& (ent & PT64_BASE_ADDR_MASK) != hpa)
printk(KERN_ERR "xx audit error: (%s) levels %d"
" gva %lx gpa %llx hpa %llx ent %llx %d\n",
audit_msg, vcpu->arch.mmu.root_level,
va, gpa, hpa, ent,
is_shadow_present_pte(ent));
else if (ent == shadow_notrap_nonpresent_pte
&& !is_error_hpa(hpa))
printk(KERN_ERR "audit: (%s) notrap shadow,"
" valid guest gva %lx\n", audit_msg, va);
kvm_release_pfn_clean(pfn);
}
}
}
static void audit_mappings(struct kvm_vcpu *vcpu)
{
unsigned i;
if (vcpu->arch.mmu.root_level == 4)
audit_mappings_page(vcpu, vcpu->arch.mmu.root_hpa, 0, 4);
else
for (i = 0; i < 4; ++i)
if (vcpu->arch.mmu.pae_root[i] & PT_PRESENT_MASK)
audit_mappings_page(vcpu,
vcpu->arch.mmu.pae_root[i],
i << 30,
2);
}
static int count_rmaps(struct kvm_vcpu *vcpu)
{
int nmaps = 0;
int i, j, k;
for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
struct kvm_memory_slot *m = &vcpu->kvm->memslots[i];
struct kvm_rmap_desc *d;
for (j = 0; j < m->npages; ++j) {
unsigned long *rmapp = &m->rmap[j];
if (!*rmapp)
continue;
if (!(*rmapp & 1)) {
++nmaps;
continue;
}
d = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
while (d) {
for (k = 0; k < RMAP_EXT; ++k)
if (d->sptes[k])
++nmaps;
else
break;
d = d->more;
}
}
}
return nmaps;
}
void inspect_spte_has_rmap(struct kvm *kvm, struct kvm_mmu_page *sp, u64 *sptep)
{
unsigned long *rmapp;
struct kvm_mmu_page *rev_sp;
gfn_t gfn;
if (*sptep & PT_WRITABLE_MASK) {
rev_sp = page_header(__pa(sptep));
gfn = rev_sp->gfns[sptep - rev_sp->spt];
if (!gfn_to_memslot(kvm, gfn)) {
if (!printk_ratelimit())
return;
printk(KERN_ERR "%s: no memslot for gfn %ld\n",
audit_msg, gfn);
printk(KERN_ERR "%s: index %ld of sp (gfn=%lx)\n",
audit_msg, sptep - rev_sp->spt,
rev_sp->gfn);
dump_stack();
return;
}
rmapp = gfn_to_rmap(kvm, rev_sp->gfns[sptep - rev_sp->spt],
is_large_pte(*sptep));
if (!*rmapp) {
if (!printk_ratelimit())
return;
printk(KERN_ERR "%s: no rmap for writable spte %llx\n",
audit_msg, *sptep);
dump_stack();
}
}
}
void audit_writable_sptes_have_rmaps(struct kvm_vcpu *vcpu)
{
mmu_spte_walk(vcpu, inspect_spte_has_rmap);
}
static void check_writable_mappings_rmap(struct kvm_vcpu *vcpu)
{
struct kvm_mmu_page *sp;
int i;
list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
u64 *pt = sp->spt;
if (sp->role.level != PT_PAGE_TABLE_LEVEL)
continue;
for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
u64 ent = pt[i];
if (!(ent & PT_PRESENT_MASK))
continue;
if (!(ent & PT_WRITABLE_MASK))
continue;
inspect_spte_has_rmap(vcpu->kvm, sp, &pt[i]);
}
}
return;
}
static void audit_rmap(struct kvm_vcpu *vcpu)
{
check_writable_mappings_rmap(vcpu);
count_rmaps(vcpu);
}
static void audit_write_protection(struct kvm_vcpu *vcpu)
{
struct kvm_mmu_page *sp;
struct kvm_memory_slot *slot;
unsigned long *rmapp;
u64 *spte;
gfn_t gfn;
list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
if (sp->role.direct)
continue;
if (sp->unsync)
continue;
gfn = unalias_gfn(vcpu->kvm, sp->gfn);
slot = gfn_to_memslot_unaliased(vcpu->kvm, sp->gfn);
rmapp = &slot->rmap[gfn - slot->base_gfn];
spte = rmap_next(vcpu->kvm, rmapp, NULL);
while (spte) {
if (*spte & PT_WRITABLE_MASK)
printk(KERN_ERR "%s: (%s) shadow page has "
"writable mappings: gfn %lx role %x\n",
__func__, audit_msg, sp->gfn,
sp->role.word);
spte = rmap_next(vcpu->kvm, rmapp, spte);
}
}
}
static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg)
{
int olddbg = dbg;
dbg = 0;
audit_msg = msg;
audit_rmap(vcpu);
audit_write_protection(vcpu);
if (strcmp("pre pte write", audit_msg) != 0)
audit_mappings(vcpu);
audit_writable_sptes_have_rmaps(vcpu);
dbg = olddbg;
}
#endif
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