KVM: MMU: shadow support for 1gb pages
This patch adds support for shadow paging to the 1gb page table code in KVM.
With this code the guest can use 1gb pages even if the host does not support
them.
[ Marcelo: fix shadow page collision on pmd level if a guest 1gb page is mapped
with 4kb ptes on host level ]
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index e09dc26..c9fb2bc 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -315,7 +315,6 @@
struct {
gfn_t gfn; /* presumed gfn during guest pte update */
pfn_t pfn; /* pfn corresponding to that gfn */
- int level;
unsigned long mmu_seq;
} update_pte;
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 09ab643..1249c12 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2478,11 +2478,8 @@
const void *new)
{
if (sp->role.level != PT_PAGE_TABLE_LEVEL) {
- if (vcpu->arch.update_pte.level == PT_PAGE_TABLE_LEVEL ||
- sp->role.glevels == PT32_ROOT_LEVEL) {
- ++vcpu->kvm->stat.mmu_pde_zapped;
- return;
- }
+ ++vcpu->kvm->stat.mmu_pde_zapped;
+ return;
}
++vcpu->kvm->stat.mmu_pte_updated;
@@ -2528,8 +2525,6 @@
u64 gpte = 0;
pfn_t pfn;
- vcpu->arch.update_pte.level = PT_PAGE_TABLE_LEVEL;
-
if (bytes != 4 && bytes != 8)
return;
@@ -2557,11 +2552,6 @@
return;
gfn = (gpte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
- if (is_large_pte(gpte) &&
- (mapping_level(vcpu, gfn) == PT_DIRECTORY_LEVEL)) {
- gfn &= ~(KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL) - 1);
- vcpu->arch.update_pte.level = PT_DIRECTORY_LEVEL;
- }
vcpu->arch.update_pte.mmu_seq = vcpu->kvm->mmu_notifier_seq;
smp_rmb();
pfn = gfn_to_pfn(vcpu->kvm, gfn);
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 578276e..d2fec9c 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -256,7 +256,6 @@
pt_element_t gpte;
unsigned pte_access;
pfn_t pfn;
- int level = vcpu->arch.update_pte.level;
gpte = *(const pt_element_t *)pte;
if (~gpte & (PT_PRESENT_MASK | PT_ACCESSED_MASK)) {
@@ -275,7 +274,7 @@
return;
kvm_get_pfn(pfn);
mmu_set_spte(vcpu, spte, page->role.access, pte_access, 0, 0,
- gpte & PT_DIRTY_MASK, NULL, level,
+ gpte & PT_DIRTY_MASK, NULL, PT_PAGE_TABLE_LEVEL,
gpte_to_gfn(gpte), pfn, true);
}
@@ -284,7 +283,7 @@
*/
static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
struct guest_walker *gw,
- int user_fault, int write_fault, int largepage,
+ int user_fault, int write_fault, int hlevel,
int *ptwrite, pfn_t pfn)
{
unsigned access = gw->pt_access;
@@ -303,8 +302,7 @@
for_each_shadow_entry(vcpu, addr, iterator) {
level = iterator.level;
sptep = iterator.sptep;
- if (level == PT_PAGE_TABLE_LEVEL
- || (largepage && level == PT_DIRECTORY_LEVEL)) {
+ if (iterator.level == hlevel) {
mmu_set_spte(vcpu, sptep, access,
gw->pte_access & access,
user_fault, write_fault,
@@ -323,12 +321,15 @@
kvm_flush_remote_tlbs(vcpu->kvm);
}
- if (level == PT_DIRECTORY_LEVEL
- && gw->level == PT_DIRECTORY_LEVEL) {
+ if (level <= gw->level) {
+ int delta = level - gw->level + 1;
direct = 1;
- if (!is_dirty_gpte(gw->ptes[level - 1]))
+ if (!is_dirty_gpte(gw->ptes[level - delta]))
access &= ~ACC_WRITE_MASK;
- table_gfn = gpte_to_gfn(gw->ptes[level - 1]);
+ table_gfn = gpte_to_gfn(gw->ptes[level - delta]);
+ /* advance table_gfn when emulating 1gb pages with 4k */
+ if (delta == 0)
+ table_gfn += PT_INDEX(addr, level);
} else {
direct = 0;
table_gfn = gw->table_gfn[level - 2];
@@ -381,7 +382,7 @@
int write_pt = 0;
int r;
pfn_t pfn;
- int largepage = 0;
+ int level = PT_PAGE_TABLE_LEVEL;
unsigned long mmu_seq;
pgprintk("%s: addr %lx err %x\n", __func__, addr, error_code);
@@ -407,15 +408,11 @@
return 0;
}
- if (walker.level == PT_DIRECTORY_LEVEL) {
- gfn_t large_gfn;
- large_gfn = walker.gfn &
- ~(KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL) - 1);
- if (mapping_level(vcpu, large_gfn) == PT_DIRECTORY_LEVEL) {
- walker.gfn = large_gfn;
- largepage = 1;
- }
+ if (walker.level >= PT_DIRECTORY_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();
pfn = gfn_to_pfn(vcpu->kvm, walker.gfn);
@@ -432,8 +429,7 @@
goto out_unlock;
kvm_mmu_free_some_pages(vcpu);
sptep = FNAME(fetch)(vcpu, addr, &walker, user_fault, write_fault,
- largepage, &write_pt, pfn);
-
+ level, &write_pt, pfn);
pgprintk("%s: shadow pte %p %llx ptwrite %d\n", __func__,
sptep, *sptep, write_pt);
@@ -468,8 +464,9 @@
sptep = iterator.sptep;
/* FIXME: properly handle invlpg on large guest pages */
- if (level == PT_PAGE_TABLE_LEVEL ||
- ((level == PT_DIRECTORY_LEVEL) && is_large_pte(*sptep))) {
+ if (level == PT_PAGE_TABLE_LEVEL ||
+ ((level == PT_DIRECTORY_LEVEL && is_large_pte(*sptep))) ||
+ ((level == PT_PDPE_LEVEL && is_large_pte(*sptep)))) {
struct kvm_mmu_page *sp = page_header(__pa(sptep));
pte_gpa = (sp->gfn << PAGE_SHIFT);
@@ -599,7 +596,7 @@
nr_present++;
pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte);
set_spte(vcpu, &sp->spt[i], pte_access, 0, 0,
- is_dirty_gpte(gpte), 0, gfn,
+ is_dirty_gpte(gpte), PT_PAGE_TABLE_LEVEL, gfn,
spte_to_pfn(sp->spt[i]), true, false);
}