KVM: MMU: add missing reserved bits check in speculative path

In the speculative path, we should check guest pte's reserved bits just as
the real processor does

Reported-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

2 files changed, 11 insertions, 3 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 812770cddc8d..d2ea9cabc066 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2697,6 +2697,9 @@ static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
                 return;
         }
 
+        if (is_rsvd_bits_set(vcpu, *(u64 *)new, PT_PAGE_TABLE_LEVEL))
+                return;
+
         ++vcpu->kvm->stat.mmu_pte_updated;
         if (!sp->role.cr4_pae)
                 paging32_update_pte(vcpu, sp, spte, new);
@@ -2775,6 +2778,7 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
                        bool guest_initiated)
 {
         gfn_t gfn = gpa >> PAGE_SHIFT;
+        union kvm_mmu_page_role mask = { .word = 0 };
         struct kvm_mmu_page *sp;
         struct hlist_node *node;
         LIST_HEAD(invalid_list);
@@ -2849,6 +2853,7 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
                 }
         }
 
+        mask.cr0_wp = mask.cr4_pae = mask.nxe = 1;
         for_each_gfn_indirect_valid_sp(vcpu->kvm, sp, gfn, node) {
                 pte_size = sp->role.cr4_pae ? 8 : 4;
                 misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
@@ -2896,7 +2901,9 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
                 while (npte--) {
                         entry = *spte;
                         mmu_pte_write_zap_pte(vcpu, sp, spte);
-                        if (gentry)
+                        if (gentry &&
+                              !((sp->role.word ^ vcpu->arch.mmu.base_role.word)
+                              & mask.word))
                                 mmu_pte_write_new_pte(vcpu, sp, spte, &gentry);
                         if (!remote_flush && need_remote_flush(entry, *spte))
                                 remote_flush = true;
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index d9a2742014e3..51ef9097960d 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -638,8 +638,9 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
                         return -EINVAL;
 
                 gfn = gpte_to_gfn(gpte);
-                if (gfn != sp->gfns[i] ||
-                      !is_present_gpte(gpte) || !(gpte & PT_ACCESSED_MASK)) {
+                if (is_rsvd_bits_set(vcpu, gpte, PT_PAGE_TABLE_LEVEL)
+                      || gfn != sp->gfns[i] || !is_present_gpte(gpte)
+                      || !(gpte & PT_ACCESSED_MASK)) {
                         u64 nonpresent;
 
                         if (is_present_gpte(gpte) || !clear_unsync)