KVM: x86: raise TSS exception for NULL CS and SS segments
Windows 2003 uses task switch to triple fault and reboot (the other
exception being reserved pdptrs bits).
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8d860e0..2793186 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4410,6 +4410,15 @@
(kvm_get_rflags(vcpu) & X86_EFLAGS_VM);
}
+static void kvm_check_segment_descriptor(struct kvm_vcpu *vcpu, int seg,
+ u16 selector)
+{
+ /* NULL selector is not valid for CS and SS */
+ if (seg == VCPU_SREG_CS || seg == VCPU_SREG_SS)
+ if (!selector)
+ kvm_queue_exception_e(vcpu, TS_VECTOR, selector >> 3);
+}
+
int kvm_load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector,
int type_bits, int seg)
{
@@ -4419,6 +4428,8 @@
return kvm_load_realmode_segment(vcpu, selector, seg);
if (load_segment_descriptor_to_kvm_desct(vcpu, selector, &kvm_seg))
return 1;
+
+ kvm_check_segment_descriptor(vcpu, seg, selector);
kvm_seg.type |= type_bits;
if (seg != VCPU_SREG_SS && seg != VCPU_SREG_CS &&