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KVM: Load real mode segments correctly

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Real mode segments to not reference the GDT or LDT; they simply compute
base = selector * 16.

Signed-off-by: Avi Kivity <avi@qumranet.com>
This commit is contained in:
Avi Kivity
2008-08-20 15:51:42 +03:00
parent a16b20da87
commit f4bbd9aaaa
1 changed files with 22 additions and 0 deletions
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22
arch/x86/kvm/x86.c
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@@ -3588,11 +3588,33 @@ static int load_segment_descriptor_to_kvm_desct(struct kvm_vcpu *vcpu,
return 0; return 0;
} }
int kvm_load_realmode_segment(struct kvm_vcpu *vcpu, u16 selector, int seg)
{
struct kvm_segment segvar = {
.base = selector << 4,
.limit = 0xffff,
.selector = selector,
.type = 3,
.present = 1,
.dpl = 3,
.db = 0,
.s = 1,
.l = 0,
.g = 0,
.avl = 0,
.unusable = 0,
};
kvm_x86_ops->set_segment(vcpu, &segvar, seg);
return 0;
}
int kvm_load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector, int kvm_load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector,
int type_bits, int seg) int type_bits, int seg)
{ {
struct kvm_segment kvm_seg; struct kvm_segment kvm_seg;
if (!(vcpu->arch.cr0 & X86_CR0_PE))
return kvm_load_realmode_segment(vcpu, selector, seg);
if (load_segment_descriptor_to_kvm_desct(vcpu, selector, &kvm_seg)) if (load_segment_descriptor_to_kvm_desct(vcpu, selector, &kvm_seg))
return 1; return 1;
kvm_seg.type |= type_bits; kvm_seg.type |= type_bits;