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

drivers/kvm/paging_tmpl.h

+2 −0
Original line number Diff line number Diff line
@@ -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);