KVM: SVM: set accessed bit for VMCB segment selectors
In the segment descriptor _cache_ the accessed bit is always set (although it can be cleared in the descriptor itself). Since Intel checks for this condition on a VMENTRY, set this bit in the AMD path to enable cross vendor migration. Cc: stable@kernel.org Signed-off-by: Andre Przywara <andre.przywara@amd.com> Acked-By: Amit Shah <amit.shah@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
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@ -796,20 +796,37 @@ static void svm_get_segment(struct kvm_vcpu *vcpu,
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var->db = (s->attrib >> SVM_SELECTOR_DB_SHIFT) & 1;
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var->g = (s->attrib >> SVM_SELECTOR_G_SHIFT) & 1;
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/*
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* SVM always stores 0 for the 'G' bit in the CS selector in
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* the VMCB on a VMEXIT. This hurts cross-vendor migration:
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* Intel's VMENTRY has a check on the 'G' bit.
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*/
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if (seg == VCPU_SREG_CS)
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switch (seg) {
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case VCPU_SREG_CS:
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/*
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* SVM always stores 0 for the 'G' bit in the CS selector in
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* the VMCB on a VMEXIT. This hurts cross-vendor migration:
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* Intel's VMENTRY has a check on the 'G' bit.
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*/
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var->g = s->limit > 0xfffff;
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/*
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* Work around a bug where the busy flag in the tr selector
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* isn't exposed
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*/
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if (seg == VCPU_SREG_TR)
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break;
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case VCPU_SREG_TR:
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/*
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* Work around a bug where the busy flag in the tr selector
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* isn't exposed
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*/
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var->type |= 0x2;
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break;
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case VCPU_SREG_DS:
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case VCPU_SREG_ES:
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case VCPU_SREG_FS:
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case VCPU_SREG_GS:
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/*
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* The accessed bit must always be set in the segment
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* descriptor cache, although it can be cleared in the
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* descriptor, the cached bit always remains at 1. Since
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* Intel has a check on this, set it here to support
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* cross-vendor migration.
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*/
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if (!var->unusable)
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var->type |= 0x1;
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break;
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}
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var->unusable = !var->present;
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}
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