Commit 8d87a03a authored by Avi Kivity's avatar Avi Kivity

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: default avatarAvi Kivity <avi@qumranet.com>
parent fe135d2c
...@@ -255,6 +255,8 @@ static void FNAME(set_pte)(struct kvm_vcpu *vcpu, pt_element_t gpte, ...@@ -255,6 +255,8 @@ static void FNAME(set_pte)(struct kvm_vcpu *vcpu, pt_element_t gpte,
spte |= gpte & PT64_NX_MASK; spte |= gpte & PT64_NX_MASK;
if (!dirty) if (!dirty)
pte_access &= ~ACC_WRITE_MASK; pte_access &= ~ACC_WRITE_MASK;
if (!(pte_access & ACC_EXEC_MASK))
spte |= PT64_NX_MASK;
page = gfn_to_page(vcpu->kvm, gfn); page = gfn_to_page(vcpu->kvm, gfn);
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment