KVM: VMX: Relax check on unusable segment (f0495f9b) · Commits · 戴 / test

Some userspace (e.g. QEMU 1.1) munge the d and g bits of segment descriptors, causing us not to recognize them as unusable segments with emulate_invalid_guest_state=1. Relax the check by testing for segment not present (a non-present segment cannot be usable). Signed-off-by:

Avi Kivity <avi@redhat.com>

arch/x86/kvm/vmx.c

+1 −3

Original line number	Diff line number	Diff line
		@@ -3198,7 +3198,7 @@ static u32 vmx_segment_access_rights(struct kvm_segment *var)
		{
		u32 ar;

		if (var->unusable)
		if (var->unusable \|\| !var->present)
		ar = 1 << 16;
		else {
		ar = var->type & 15;
		@@ -3210,8 +3210,6 @@ static u32 vmx_segment_access_rights(struct kvm_segment *var)
		ar \|= (var->db & 1) << 14;
		ar \|= (var->g & 1) << 15;
		}
		if (ar == 0) /* a 0 value means unusable */
		ar = AR_UNUSABLE_MASK;

		return ar;
		}

Admin message