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KVM: SVM: Fix cross vendor migration issue with unusable bit
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AMDs VMCB does not have an explicit unusable segment descriptor field,
so we emulate it by using "not present". This has to be setup before
the fixups, because this field is used there.

Signed-off-by: Andre Przywara <andre.przywara@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Andre Przywara authored and Avi Kivity committed May 11, 2009
1 parent a4d7749 commit 19bca6a
Showing 1 changed file with 5 additions and 2 deletions.
7 changes: 5 additions & 2 deletions arch/x86/kvm/svm.c
Original file line number Diff line number Diff line change
Expand Up @@ -796,6 +796,11 @@ static void svm_get_segment(struct kvm_vcpu *vcpu,
var->db = (s->attrib >> SVM_SELECTOR_DB_SHIFT) & 1;
var->g = (s->attrib >> SVM_SELECTOR_G_SHIFT) & 1;

/* 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);

switch (seg) {
case VCPU_SREG_CS:
/*
Expand Down Expand Up @@ -827,8 +832,6 @@ static void svm_get_segment(struct kvm_vcpu *vcpu,
var->type |= 0x1;
break;
}

var->unusable = !var->present;
}

static int svm_get_cpl(struct kvm_vcpu *vcpu)
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