[PATCH v5 1/9] KVM: MMU: fix forgot reserved bits check in speculativepath

From: Xiao Guangrong
Date: Tue Jul 06 2010 - 06:48:48 EST


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

Reported-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxx>
---
arch/x86/kvm/mmu.c | 3 +++
arch/x86/kvm/paging_tmpl.h | 3 ++-
2 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 104756b..3dcd55d 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2781,6 +2781,9 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
break;
}

+ if (is_rsvd_bits_set(vcpu, gentry, PT_PAGE_TABLE_LEVEL))
+ gentry = 0;
+
mmu_guess_page_from_pte_write(vcpu, gpa, gentry);
spin_lock(&vcpu->kvm->mmu_lock);
if (atomic_read(&vcpu->kvm->arch.invlpg_counter) != invlpg_counter)
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index dfb2720..19f0077 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -628,7 +628,8 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
pte_gpa = first_pte_gpa + i * sizeof(pt_element_t);

if (kvm_read_guest_atomic(vcpu->kvm, pte_gpa, &gpte,
- sizeof(pt_element_t)))
+ sizeof(pt_element_t)) ||
+ is_rsvd_bits_set(vcpu, gpte, PT_PAGE_TABLE_LEVEL))
return -EINVAL;

gfn = gpte_to_gfn(gpte);
--
1.6.1.2

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