KVM: MMU: handle large host sptes on invlpg/resync

The invlpg and sync walkers lack knowledge of large host sptes,
descending to non-existant pagetable level.

Stop at directory level in such case.

Fixes SMP Windows XP with hugepages.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

2 files changed, 8 insertions, 3 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index d50ebac6a07f..83f11c7474a1 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1007,7 +1007,7 @@ static int __mmu_unsync_walk(struct kvm_mmu_page *sp,
         for_each_unsync_children(sp->unsync_child_bitmap, i) {
                 u64 ent = sp->spt[i];
 
-                if (is_shadow_present_pte(ent)) {
+                if (is_shadow_present_pte(ent) && !is_large_pte(ent)) {
                         struct kvm_mmu_page *child;
                         child = page_header(ent & PT64_BASE_ADDR_MASK);
 
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index d20640154216..9fd78b6e17ad 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -472,14 +472,19 @@ static int FNAME(shadow_invlpg_entry)(struct kvm_shadow_walk *_sw,
         struct shadow_walker *sw =
                 container_of(_sw, struct shadow_walker, walker);
 
-        if (level == PT_PAGE_TABLE_LEVEL) {
+        /* FIXME: properly handle invlpg on large guest pages */
+        if (level == PT_PAGE_TABLE_LEVEL ||
+            ((level == PT_DIRECTORY_LEVEL) && is_large_pte(*sptep))) {
                 struct kvm_mmu_page *sp = page_header(__pa(sptep));
 
                 sw->pte_gpa = (sp->gfn << PAGE_SHIFT);
                 sw->pte_gpa += (sptep - sp->spt) * sizeof(pt_element_t);
 
-                if (is_shadow_present_pte(*sptep))
+                if (is_shadow_present_pte(*sptep)) {
                         rmap_remove(vcpu->kvm, sptep);
+                        if (is_large_pte(*sptep))
+                                --vcpu->kvm->stat.lpages;
+                }
                 set_shadow_pte(sptep, shadow_trap_nonpresent_pte);
                 return 1;
         }