Commit 8eae9570 authored May 30, 2017 by Gioh Kim Committed by Paolo Bonzini May 30, 2017

KVM: SVM: ignore type when setting segment registers



Commit 19bca6ab ("KVM: SVM: Fix cross vendor migration issue with
unusable bit") added checking type when setting unusable.
So unusable can be set if present is 0 OR type is 0.
According to the AMD processor manual, long mode ignores the type value
in segment descriptor. And type can be 0 if it is read-only data segment.
Therefore type value is not related to unusable flag.

This patch is based on linux-next v4.12.0-rc3.

Signed-off-by: Gioh Kim <gi-oh.kim@profitbricks.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

parent cbf71279

arch/x86/kvm/svm.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1807,7 +1807,7 @@ static void svm_get_segment(struct kvm_vcpu *vcpu,
		* AMD's VMCB does not have an explicit unusable field, so emulate it
		* for cross vendor migration purposes by "not present"
		*/
		var->unusable = !var->present \|\| (var->type == 0);
		var->unusable = !var->present;

		switch (seg) {
		case VCPU_SREG_TR:

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