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KVM: x86: Fix TSS size check for 16-bit tasks
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A 16-bit TSS is only 44 bytes long. So make sure to test for the correct
size on task switch.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Jan Kiszka authored and Avi Kivity committed Apr 21, 2010
1 parent eda2bed commit e8861cf
Showing 1 changed file with 5 additions and 1 deletion.
6 changes: 5 additions & 1 deletion arch/x86/kvm/x86.c
Original file line number Diff line number Diff line change
Expand Up @@ -5126,6 +5126,7 @@ int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason)
int ret = 0;
u32 old_tss_base = get_segment_base(vcpu, VCPU_SREG_TR);
u16 old_tss_sel = get_segment_selector(vcpu, VCPU_SREG_TR);
u32 desc_limit;

old_tss_base = kvm_mmu_gva_to_gpa_write(vcpu, old_tss_base, NULL);

Expand All @@ -5148,7 +5149,10 @@ int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason)
}
}

if (!nseg_desc.p || get_desc_limit(&nseg_desc) < 0x67) {
desc_limit = get_desc_limit(&nseg_desc);
if (!nseg_desc.p ||
((desc_limit < 0x67 && (nseg_desc.type & 8)) ||
desc_limit < 0x2b)) {
kvm_queue_exception_e(vcpu, TS_VECTOR, tss_selector & 0xfffc);
return 1;
}
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