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Commit 8eae9570 authored by Gioh Kim's avatar Gioh Kim Committed by Paolo Bonzini
Browse files

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: default avatarGioh Kim <gi-oh.kim@profitbricks.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent cbf71279

arch/x86/kvm/svm.c

+1 −1
Original line number Original line 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

	 * AMD's VMCB does not have an explicit unusable field, so emulate it

	 * for cross vendor migration purposes by "not present"

	 * for cross vendor migration purposes by "not present"

	 */

	 */

	var->unusable = !var->present || (var->type == 0);

	var->unusable = !var->present;





	switch (seg) {

	switch (seg) {

	case VCPU_SREG_TR:

	case VCPU_SREG_TR: