Commit edc2ae84 authored Sep 12, 2012 by Avi Kivity

KVM: MMU: Optimize gpte_access() slightly



If nx is disabled, then is gpte[63] is set we will hit a reserved
bit set fault before checking permissions; so we can ignore the
setting of efer.nxe.

Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

parent 8ea667f2

arch/x86/kvm/paging_tmpl.h

+1 −3

Original line number	Diff line number	Diff line
		@@ -106,9 +106,7 @@ static unsigned FNAME(gpte_access)(struct kvm_vcpu *vcpu, pt_element_t gpte)
		unsigned access;

		access = (gpte & (PT_WRITABLE_MASK \| PT_USER_MASK)) \| ACC_EXEC_MASK;

		#if PTTYPE == 64
		if (vcpu->arch.mmu.nx)
		access &= ~(gpte >> PT64_NX_SHIFT);
		#endif
		return access;