- 根目录:
- arch
- x86
- kvm
- paging_tmpl.h
/*
* 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.
* Copyright 2010 Red Hat, Inc. and/or its affiliates.
*
* 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.
*
*/
/*
* We need the mmu code to access both 32-bit and 64-bit guest ptes,
* so the code in this file is compiled twice, once per pte size.
*/
#if PTTYPE == 64
#define pt_element_t u64
#define guest_walker guest_walker64
#define FNAME(name) paging##64_##name
#define PT_BASE_ADDR_MASK PT64_BASE_ADDR_MASK
#define PT_LVL_ADDR_MASK(lvl) PT64_LVL_ADDR_MASK(lvl)
#define PT_LVL_OFFSET_MASK(lvl) PT64_LVL_OFFSET_MASK(lvl)
#define PT_INDEX(addr, level) PT64_INDEX(addr, level)
#define PT_LEVEL_BITS PT64_LEVEL_BITS
#ifdef CONFIG_X86_64
#define PT_MAX_FULL_LEVELS 4
#define CMPXCHG cmpxchg
#else
#define CMPXCHG cmpxchg64
#define PT_MAX_FULL_LEVELS 2
#endif
#elif PTTYPE == 32
#define pt_element_t u32
#define guest_walker guest_walker32
#define FNAME(name) paging##32_##name
#define PT_BASE_ADDR_MASK PT32_BASE_ADDR_MASK
#define PT_LVL_ADDR_MASK(lvl) PT32_LVL_ADDR_MASK(lvl)
#define PT_LVL_OFFSET_MASK(lvl) PT32_LVL_OFFSET_MASK(lvl)
#define PT_INDEX(addr, level) PT32_INDEX(addr, level)
#define PT_LEVEL_BITS PT32_LEVEL_BITS
#define PT_MAX_FULL_LEVELS 2
#define CMPXCHG cmpxchg
#else
#error Invalid PTTYPE value
#endif
#define gpte_to_gfn_lvl FNAME(gpte_to_gfn_lvl)
#define gpte_to_gfn(pte) gpte_to_gfn_lvl((pte), PT_PAGE_TABLE_LEVEL)
/*
* The guest_walker structure emulates the behavior of the hardware page
* table walker.
*/
struct guest_walker {
int level;
gfn_t table_gfn[PT_MAX_FULL_LEVELS];
pt_element_t ptes[PT_MAX_FULL_LEVELS];
pt_element_t prefetch_ptes[PTE_PREFETCH_NUM];
gpa_t pte_gpa[PT_MAX_FULL_LEVELS];
unsigned pt_access;
unsigned pte_access;
gfn_t gfn;
struct x86_exception fault;
};
static gfn_t gpte_to_gfn_lvl(pt_element_t gpte, int lvl)
{
return (gpte & PT_LVL_ADDR_MASK(lvl)) >> PAGE_SHIFT;
}
static int FNAME(cmpxchg_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
pt_element_t __user *ptep_user, unsigned index,
pt_element_t orig_pte, pt_element_t new_pte)
{
int npages;
pt_element_t ret;
pt_element_t *table;
struct page *page;
npages = get_user_pages_fast((unsigned long)ptep_user, 1, 1, &page);
/* Check if the user is doing something meaningless. */
if (unlikely(npages != 1))
return -EFAULT;
table = kmap_atomic(page, KM_USER0);
ret = CMPXCHG(&table[index], orig_pte, new_pte);
kunmap_atomic(table, KM_USER0);
kvm_release_page_dirty(page);
return (ret != orig_pte);
}
static unsigned FNAME(gpte_access)(struct kvm_vcpu *vcpu, pt_element_t gpte,
bool last)
{
unsigned access;
access = (gpte & (PT_WRITABLE_MASK | PT_USER_MASK)) | ACC_EXEC_MASK;
if (last && !is_dirty_gpte(gpte))
access &= ~ACC_WRITE_MASK;
#if PTTYPE == 64
if (vcpu->arch.mmu.nx)
access &= ~(gpte >> PT64_NX_SHIFT);
#endif
return access;
}
static bool FNAME(is_last_gpte)(struct guest_walker *walker,
struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
pt_element_t gpte)
{
if (walker->level == PT_PAGE_TABLE_LEVEL)
return true;
if ((walker->level == PT_DIRECTORY_LEVEL) && is_large_pte(gpte) &&
(PTTYPE == 64 || is_pse(vcpu)))
return true;
if ((walker->level == PT_PDPE_LEVEL) && is_large_pte(gpte) &&
(mmu->root_level == PT64_ROOT_LEVEL))
return true;
return false;
}
/*
* Fetch a guest pte for a guest virtual address
*/
static int FNAME(walk_addr_generic)(struct guest_walker *walker,
struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
gva_t addr, u32 access)
{
pt_element_t pte;
pt_element_t __user *uninitialized_var(ptep_user);
gfn_t table_gfn;
unsigned index, pt_access, uninitialized_var(pte_access);
gpa_t pte_gpa;
bool eperm, last_gpte;
int offset;
const int write_fault = access & PFERR_WRITE_MASK;
const int user_fault = access & PFERR_USER_MASK;
const int fetch_fault = access & PFERR_FETCH_MASK;
u16 errcode = 0;
trace_kvm_mmu_pagetable_walk(addr, write_fault, user_fault,
fetch_fault);
retry_walk:
eperm = false;
walker->level = mmu->root_level;
pte = mmu->get_cr3(vcpu);
#if PTTYPE == 64
if (walker->level == PT32E_ROOT_LEVEL) {
pte = mmu->get_pdptr(vcpu, (addr >> 30) & 3);
trace_kvm_mmu_paging_element(pte, walker->level);
if (!is_present_gpte(pte))
goto error;
--walker->level;
}
#endif
ASSERT((!is_long_mode(vcpu) && is_pae(vcpu)) ||
(mmu->get_cr3(vcpu) & CR3_NONPAE_RESERVED_BITS) == 0);
pt_access = ACC_ALL;
for (;;) {
gfn_t real_gfn;
unsigned long host_addr;
index = PT_INDEX(addr, walker->level);
table_gfn = gpte_to_gfn(pte);
offset = index * sizeof(pt_element_t);
pte_gpa = gfn_to_gpa(table_gfn) + offset;
walker->table_gfn[walker->level - 1] = table_gfn;
walker->pte_gpa[walker->level - 1] = pte_gpa;
real_gfn = mmu->translate_gpa(vcpu, gfn_to_gpa(table_gfn),
PFERR_USER_MASK|PFERR_WRITE_MASK);
if (unlikely(real_gfn == UNMAPPED_GVA))
goto error;
real_gfn = gpa_to_gfn(real_gfn);
host_addr = gfn_to_hva(vcpu->kvm, real_gfn);
if (unlikely(kvm_is_error_hva(host_addr)))
goto error;
ptep_user = (pt_element_t __user *)((void *)host_addr + offset);
if (unlikely(__copy_from_user(&pte, ptep_user, sizeof(pte))))
goto error;
trace_kvm_mmu_paging_element(pte, walker->level);
if (unlikely(!is_present_gpte(pte)))
goto error;
if (unlikely(is_rsvd_bits_set(&vcpu->arch.mmu, pte,
walker->level))) {
errcode |= PFERR_RSVD_MASK | PFERR_PRESENT_MASK;
goto error;
}
if (!check_write_user_access(vcpu, write_fault, user_fault,
pte))
eperm = true;
#if PTTYPE == 64
if (unlikely(fetch_fault && (pte & PT64_NX_MASK)))
eperm = true;
#endif
last_gpte = FNAME(is_last_gpte)(walker, vcpu, mmu, pte);
if (last_gpte) {
pte_access = pt_access &
FNAME(gpte_access)(vcpu, pte, true);
/* check if the kernel is fetching from user page */
if (unlikely(pte_access & PT_USER_MASK) &&
kvm_read_cr4_bits(vcpu, X86_CR4_SMEP))
if (fetch_fault && !user_fault)
eperm = true;
}
if (!eperm && unlikely(!(pte & PT_ACCESSED_MASK))) {
int ret;
trace_kvm_mmu_set_accessed_bit(table_gfn, index,
sizeof(pte));
ret = FNAME(cmpxchg_gpte)(vcpu, mmu, ptep_user, index,
pte, pte|PT_ACCESSED_MASK);
if (unlikely(ret < 0))
goto error;
else if (ret)
goto retry_walk;
mark_page_dirty(vcpu->kvm, table_gfn);
pte |= PT_ACCESSED_MASK;
}
walker->ptes[walker->level - 1] = pte;
if (last_gpte) {
int lvl = walker->level;
gpa_t real_gpa;
gfn_t gfn;
u32 ac;
gfn = gpte_to_gfn_lvl(pte, lvl);
gfn += (addr & PT_LVL_OFFSET_MASK(lvl)) >> PAGE_SHIFT;
if (PTTYPE == 32 &&
walker->level == PT_DIRECTORY_LEVEL &&
is_cpuid_PSE36())
gfn += pse36_gfn_delta(pte);
ac = write_fault | fetch_fault | user_fault;
real_gpa = mmu->translate_gpa(vcpu, gfn_to_gpa(gfn),
ac);
if (real_gpa == UNMAPPED_GVA)
return 0;
walker->gfn = real_gpa >> PAGE_SHIFT;
break;
}
pt_access &= FNAME(gpte_access)(vcpu, pte, false);
--walker->level;
}
if (unlikely(eperm)) {
errcode |= PFERR_PRESENT_MASK;
goto error;
}
if (write_fault && unlikely(!is_dirty_gpte(pte))) {
int ret;
trace_kvm_mmu_set_dirty_bit(table_gfn, index, sizeof(pte));
ret = FNAME(cmpxchg_gpte)(vcpu, mmu, ptep_user, index,
pte, pte|PT_DIRTY_MASK);
if (unlikely(ret < 0))
goto error;
else if (ret)
goto retry_walk;
mark_page_dirty(vcpu->kvm, table_gfn);
pte |= PT_DIRTY_MASK;
walker->ptes[walker->level - 1] = pte;
}
walker->pt_access = pt_access;
walker->pte_access = pte_access;
pgprintk("%s: pte %llx pte_access %x pt_access %x\n",
__func__, (u64)pte, pte_access, pt_access);
return 1;
error:
errcode |= write_fault | user_fault;
if (fetch_fault && (mmu->nx ||
kvm_read_cr4_bits(vcpu, X86_CR4_SMEP)))
errcode |= PFERR_FETCH_MASK;
walker->fault.vector = PF_VECTOR;
walker->fault.error_code_valid = true;
walker->fault.error_code = errcode;
walker->fault.address = addr;
walker->fault.nested_page_fault = mmu != vcpu->arch.walk_mmu;
trace_kvm_mmu_walker_error(walker->fault.error_code);
return 0;
}
static int FNAME(walk_addr)(struct guest_walker *walker,
struct kvm_vcpu *vcpu, gva_t addr, u32 access)
{
return FNAME(walk_addr_generic)(walker, vcpu, &vcpu->arch.mmu, addr,
access);
}
static int FNAME(walk_addr_nested)(struct guest_walker *walker,
struct kvm_vcpu *vcpu, gva_t addr,
u32 access)
{
return FNAME(walk_addr_generic)(walker, vcpu, &vcpu->arch.nested_mmu,
addr, access);
}
static bool FNAME(prefetch_invalid_gpte)(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *sp, u64 *spte,
pt_element_t gpte)
{
if (is_rsvd_bits_set(&vcpu->arch.mmu, gpte, PT_PAGE_TABLE_LEVEL))
goto no_present;
if (!is_present_gpte(gpte))
goto no_present;
if (!(gpte & PT_ACCESSED_MASK))
goto no_present;
return false;
no_present:
drop_spte(vcpu->kvm, spte);
return true;
}
static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
u64 *spte, const void *pte)
{
pt_element_t gpte;
unsigned pte_access;
pfn_t pfn;
gpte = *(const pt_element_t *)pte;
if (FNAME(prefetch_invalid_gpte)(vcpu, sp, spte, gpte))
return;
pgprintk("%s: gpte %llx spte %p\n", __func__, (u64)gpte, spte);
pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte, true);
pfn = gfn_to_pfn_atomic(vcpu->kvm, gpte_to_gfn(gpte));
if (mmu_invalid_pfn(pfn)) {
kvm_release_pfn_clean(pfn);
return;
}
/*
* we call mmu_set_spte() with host_writable = true because that
* vcpu->arch.update_pte.pfn was fetched from get_user_pages(write = 1).
*/
mmu_set_spte(vcpu, spte, sp->role.access, pte_access, 0, 0,
NULL, PT_PAGE_TABLE_LEVEL,
gpte_to_gfn(gpte), pfn, true, true);
}
static bool FNAME(gpte_changed)(struct kvm_vcpu *vcpu,
struct guest_walker *gw, int level)
{
pt_element_t curr_pte;
gpa_t base_gpa, pte_gpa = gw->pte_gpa[level - 1];
u64 mask;
int r, index;
if (level == PT_PAGE_TABLE_LEVEL) {
mask = PTE_PREFETCH_NUM * sizeof(pt_element_t) - 1;
base_gpa = pte_gpa & ~mask;
index = (pte_gpa - base_gpa) / sizeof(pt_element_t);
r = kvm_read_guest_atomic(vcpu->kvm, base_gpa,
gw->prefetch_ptes, sizeof(gw->prefetch_ptes));
curr_pte = gw->prefetch_ptes[index];
} else
r = kvm_read_guest_atomic(vcpu->kvm, pte_gpa,
&curr_pte, sizeof(curr_pte));
return r || curr_pte != gw->ptes[level - 1];
}
static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, struct guest_walker *gw,
u64 *sptep)
{
struct kvm_mmu_page *sp;
pt_element_t *gptep = gw->prefetch_ptes;
u64 *spte;
int i;
sp = page_header(__pa(sptep));
if (sp->role.level > PT_PAGE_TABLE_LEVEL)
return;
if (sp->role.direct)
return __direct_pte_prefetch(vcpu, sp, sptep);
i = (sptep - sp->spt) & ~(PTE_PREFETCH_NUM - 1);
spte = sp->spt + i;
for (i = 0; i < PTE_PREFETCH_NUM; i++, spte++) {
pt_element_t gpte;
unsigned pte_access;
gfn_t gfn;
pfn_t pfn;
if (spte == sptep)
continue;
if (is_shadow_present_pte(*spte))
continue;
gpte = gptep[i];
if (FNAME(prefetch_invalid_gpte)(vcpu, sp, spte, gpte))
continue;
pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte,
true);
gfn = gpte_to_gfn(gpte);
pfn = pte_prefetch_gfn_to_pfn(vcpu, gfn,
pte_access & ACC_WRITE_MASK);
if (mmu_invalid_pfn(pfn)) {
kvm_release_pfn_clean(pfn);
break;
}
mmu_set_spte(vcpu, spte, sp->role.access, pte_access, 0, 0,
NULL, PT_PAGE_TABLE_LEVEL, gfn,
pfn, true, true);
}
}
/*
* Fetch a shadow pte for a specific level in the paging hierarchy.
*/
static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
struct guest_walker *gw,
int user_fault, int write_fault, int hlevel,
int *emulate, pfn_t pfn, bool map_writable,
bool prefault)
{
unsigned access = gw->pt_access;
struct kvm_mmu_page *sp = NULL;
int top_level;
unsigned direct_access;
struct kvm_shadow_walk_iterator it;
if (!is_present_gpte(gw->ptes[gw->level - 1]))
return NULL;
direct_access = gw->pte_access;
top_level = vcpu->arch.mmu.root_level;
if (top_level == PT32E_ROOT_LEVEL)
top_level = PT32_ROOT_LEVEL;
/*
* Verify that the top-level gpte is still there. Since the page
* is a root page, it is either write protected (and cannot be
* changed from now on) or it is invalid (in which case, we don't
* really care if it changes underneath us after this point).
*/
if (FNAME(gpte_changed)(vcpu, gw, top_level))
goto out_gpte_changed;
for (shadow_walk_init(&it, vcpu, addr);
shadow_walk_okay(&it) && it.level > gw->level;
shadow_walk_next(&it)) {
gfn_t table_gfn;
clear_sp_write_flooding_count(it.sptep);
drop_large_spte(vcpu, it.sptep);
sp = NULL;
if (!is_shadow_present_pte(*it.sptep)) {
table_gfn = gw->table_gfn[it.level - 2];
sp = kvm_mmu_get_page(vcpu, table_gfn, addr, it.level-1,
false, access, it.sptep);
}
/*
* Verify that the gpte in the page we've just write
* protected is still there.
*/
if (FNAME(gpte_changed)(vcpu, gw, it.level - 1))
goto out_gpte_changed;
if (sp)
link_shadow_page(it.sptep, sp);
}
for (;
shadow_walk_okay(&it) && it.level > hlevel;
shadow_walk_next(&it)) {
gfn_t direct_gfn;
clear_sp_write_flooding_count(it.sptep);
validate_direct_spte(vcpu, it.sptep, direct_access);
drop_large_spte(vcpu, it.sptep);
if (is_shadow_present_pte(*it.sptep))
continue;
direct_gfn = gw->gfn & ~(KVM_PAGES_PER_HPAGE(it.level) - 1);
sp = kvm_mmu_get_page(vcpu, direct_gfn, addr, it.level-1,
true, direct_access, it.sptep);
link_shadow_page(it.sptep, sp);
}
clear_sp_write_flooding_count(it.sptep);
mmu_set_spte(vcpu, it.sptep, access, gw->pte_access,
user_fault, write_fault, emulate, it.level,
gw->gfn, pfn, prefault, map_writable);
FNAME(pte_prefetch)(vcpu, gw, it.sptep);
return it.sptep;
out_gpte_changed:
if (sp)
kvm_mmu_put_page(sp, it.sptep);
kvm_release_pfn_clean(pfn);
return NULL;
}
/*
* Page fault handler. There are several causes for a page fault:
* - there is no shadow pte for the guest pte
* - write access through a shadow pte marked read only so that we can set
* the dirty bit
* - write access to a shadow pte marked read only so we can update the page
* dirty bitmap, when userspace requests it
* - mmio access; in this case we will never install a present shadow pte
* - normal guest page fault due to the guest pte marked not present, not
* writable, or not executable
*
* Returns: 1 if we need to emulate the instruction, 0 otherwise, or
* a negative value on error.
*/
static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
bool prefault)
{
int write_fault = error_code & PFERR_WRITE_MASK;
int user_fault = error_code & PFERR_USER_MASK;
struct guest_walker walker;
u64 *sptep;
int emulate = 0;
int r;
pfn_t pfn;
int level = PT_PAGE_TABLE_LEVEL;
int force_pt_level;
unsigned long mmu_seq;
bool map_writable;
pgprintk("%s: addr %lx err %x\n", __func__, addr, error_code);
if (unlikely(error_code & PFERR_RSVD_MASK))
return handle_mmio_page_fault(vcpu, addr, error_code,
mmu_is_nested(vcpu));
r = mmu_topup_memory_caches(vcpu);
if (r)
return r;
/*
* Look up the guest pte for the faulting address.
*/
r = FNAME(walk_addr)(&walker, vcpu, addr, error_code);
/*
* The page is not mapped by the guest. Let the guest handle it.
*/
if (!r) {
pgprintk("%s: guest page fault\n", __func__);
if (!prefault)
inject_page_fault(vcpu, &walker.fault);
return 0;
}
if (walker.level >= PT_DIRECTORY_LEVEL)
force_pt_level = mapping_level_dirty_bitmap(vcpu, walker.gfn);
else
force_pt_level = 1;
if (!force_pt_level) {
level = min(walker.level, mapping_level(vcpu, walker.gfn));
walker.gfn = walker.gfn & ~(KVM_PAGES_PER_HPAGE(level) - 1);
}
mmu_seq = vcpu->kvm->mmu_notifier_seq;
smp_rmb();
if (try_async_pf(vcpu, prefault, walker.gfn, addr, &pfn, write_fault,
&map_writable))
return 0;
if (handle_abnormal_pfn(vcpu, mmu_is_nested(vcpu) ? 0 : addr,
walker.gfn, pfn, walker.pte_access, &r))
return r;
spin_lock(&vcpu->kvm->mmu_lock);
if (mmu_notifier_retry(vcpu, mmu_seq))
goto out_unlock;
kvm_mmu_audit(vcpu, AUDIT_PRE_PAGE_FAULT);
kvm_mmu_free_some_pages(vcpu);
if (!force_pt_level)
transparent_hugepage_adjust(vcpu, &walker.gfn, &pfn, &level);
sptep = FNAME(fetch)(vcpu, addr, &walker, user_fault, write_fault,
level, &emulate, pfn, map_writable, prefault);
(void)sptep;
pgprintk("%s: shadow pte %p %llx emulate %d\n", __func__,
sptep, *sptep, emulate);
++vcpu->stat.pf_fixed;
kvm_mmu_audit(vcpu, AUDIT_POST_PAGE_FAULT);
spin_unlock(&vcpu->kvm->mmu_lock);
return emulate;
out_unlock:
spin_unlock(&vcpu->kvm->mmu_lock);
kvm_release_pfn_clean(pfn);
return 0;
}
static gpa_t FNAME(get_level1_sp_gpa)(struct kvm_mmu_page *sp)
{
int offset = 0;
WARN_ON(sp->role.level != 1);
if (PTTYPE == 32)
offset = sp->role.quadrant << PT64_LEVEL_BITS;
return gfn_to_gpa(sp->gfn) + offset * sizeof(pt_element_t);
}
static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva)
{
struct kvm_shadow_walk_iterator iterator;
struct kvm_mmu_page *sp;
int level;
u64 *sptep;
vcpu_clear_mmio_info(vcpu, gva);
/*
* No need to check return value here, rmap_can_add() can
* help us to skip pte prefetch later.
*/
mmu_topup_memory_caches(vcpu);
spin_lock(&vcpu->kvm->mmu_lock);
for_each_shadow_entry(vcpu, gva, iterator) {
level = iterator.level;
sptep = iterator.sptep;
sp = page_header(__pa(sptep));
if (is_last_spte(*sptep, level)) {
pt_element_t gpte;
gpa_t pte_gpa;
if (!sp->unsync)
break;
pte_gpa = FNAME(get_level1_sp_gpa)(sp);
pte_gpa += (sptep - sp->spt) * sizeof(pt_element_t);
if (mmu_page_zap_pte(vcpu->kvm, sp, sptep))
kvm_flush_remote_tlbs(vcpu->kvm);
if (!rmap_can_add(vcpu))
break;
if (kvm_read_guest_atomic(vcpu->kvm, pte_gpa, &gpte,
sizeof(pt_element_t)))
break;
FNAME(update_pte)(vcpu, sp, sptep, &gpte);
}
if (!is_shadow_present_pte(*sptep) || !sp->unsync_children)
break;
}
spin_unlock(&vcpu->kvm->mmu_lock);
}
static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t vaddr, u32 access,
struct x86_exception *exception)
{
struct guest_walker walker;
gpa_t gpa = UNMAPPED_GVA;
int r;
r = FNAME(walk_addr)(&walker, vcpu, vaddr, access);
if (r) {
gpa = gfn_to_gpa(walker.gfn);
gpa |= vaddr & ~PAGE_MASK;
} else if (exception)
*exception = walker.fault;
return gpa;
}
static gpa_t FNAME(gva_to_gpa_nested)(struct kvm_vcpu *vcpu, gva_t vaddr,
u32 access,
struct x86_exception *exception)
{
struct guest_walker walker;
gpa_t gpa = UNMAPPED_GVA;
int r;
r = FNAME(walk_addr_nested)(&walker, vcpu, vaddr, access);
if (r) {
gpa = gfn_to_gpa(walker.gfn);
gpa |= vaddr & ~PAGE_MASK;
} else if (exception)
*exception = walker.fault;
return gpa;
}
/*
* Using the cached information from sp->gfns is safe because:
* - The spte has a reference to the struct page, so the pfn for a given gfn
* can't change unless all sptes pointing to it are nuked first.
*
* Note:
* We should flush all tlbs if spte is dropped even though guest is
* responsible for it. Since if we don't, kvm_mmu_notifier_invalidate_page
* and kvm_mmu_notifier_invalidate_range_start detect the mapping page isn't
* used by guest then tlbs are not flushed, so guest is allowed to access the
* freed pages.
* And we increase kvm->tlbs_dirty to delay tlbs flush in this case.
*/
static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
{
int i, nr_present = 0;
bool host_writable;
gpa_t first_pte_gpa;
/* direct kvm_mmu_page can not be unsync. */
BUG_ON(sp->role.direct);
first_pte_gpa = FNAME(get_level1_sp_gpa)(sp);
for (i = 0; i < PT64_ENT_PER_PAGE; i++) {
unsigned pte_access;
pt_element_t gpte;
gpa_t pte_gpa;
gfn_t gfn;
if (!sp->spt[i])
continue;
pte_gpa = first_pte_gpa + i * sizeof(pt_element_t);
if (kvm_read_guest_atomic(vcpu->kvm, pte_gpa, &gpte,
sizeof(pt_element_t)))
return -EINVAL;
if (FNAME(prefetch_invalid_gpte)(vcpu, sp, &sp->spt[i], gpte)) {
vcpu->kvm->tlbs_dirty++;
continue;
}
gfn = gpte_to_gfn(gpte);
pte_access = sp->role.access;
pte_access &= FNAME(gpte_access)(vcpu, gpte, true);
if (sync_mmio_spte(&sp->spt[i], gfn, pte_access, &nr_present))
continue;
if (gfn != sp->gfns[i]) {
drop_spte(vcpu->kvm, &sp->spt[i]);
vcpu->kvm->tlbs_dirty++;
continue;
}
nr_present++;
host_writable = sp->spt[i] & SPTE_HOST_WRITEABLE;
set_spte(vcpu, &sp->spt[i], pte_access, 0, 0,
PT_PAGE_TABLE_LEVEL, gfn,
spte_to_pfn(sp->spt[i]), true, false,
host_writable);
}
return !nr_present;
}
#undef pt_element_t
#undef guest_walker
#undef FNAME
#undef PT_BASE_ADDR_MASK
#undef PT_INDEX
#undef PT_LVL_ADDR_MASK
#undef PT_LVL_OFFSET_MASK
#undef PT_LEVEL_BITS
#undef PT_MAX_FULL_LEVELS
#undef gpte_to_gfn
#undef gpte_to_gfn_lvl
#undef CMPXCHG