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Subject[PATCH v2 1/6] KVM: MMU: fix forgot 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>
---
arch/x86/kvm/mmu.c | 9 ++++++++-
arch/x86/kvm/paging_tmpl.h | 5 +++--
2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index d16efbe..1a4b42e 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2693,6 +2693,9 @@ 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);
@@ -2771,6 +2774,7 @@ 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);
@@ -2845,6 +2849,7 @@ 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);
@@ -2892,7 +2897,9 @@ 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 a09e04c..231fce1 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)
--
1.6.1.2


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