From cb84b55f6cde26c7c17beaf87da08645ae6ccbf9 Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Wed, 11 Nov 2009 17:29:49 -0200 Subject: [PATCH] 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 --- arch/x86/kvm/x86.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 8d860e0301a0..279318677911 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4410,6 +4410,15 @@ static int is_vm86_segment(struct kvm_vcpu *vcpu, int seg) (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 @@ int kvm_load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector, 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 && -- 2.20.1