From 8d87a03aea43535a92efbb180e0ceac94d4bb5db Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Sun, 9 Dec 2007 16:37:36 +0200 Subject: [PATCH] KVM: MMU: Set nx bit correctly on shadow ptes While the page table walker correctly generates a guest page fault if a guest tries to execute a non-executable page, the shadow code does not mark it non-executable. This means that if a guest accesses an nx page first with a read access, then subsequent code fetch accesses will succeed. Fix by setting the nx bit on shadow ptes. Signed-off-by: Avi Kivity --- drivers/kvm/paging_tmpl.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/kvm/paging_tmpl.h b/drivers/kvm/paging_tmpl.h index 7688cbf..59ba752 100644 --- a/drivers/kvm/paging_tmpl.h +++ b/drivers/kvm/paging_tmpl.h @@ -255,6 +255,8 @@ static void FNAME(set_pte)(struct kvm_vcpu *vcpu, pt_element_t gpte, spte |= gpte & PT64_NX_MASK; if (!dirty) pte_access &= ~ACC_WRITE_MASK; + if (!(pte_access & ACC_EXEC_MASK)) + spte |= PT64_NX_MASK; page = gfn_to_page(vcpu->kvm, gfn); -- 2.7.4