On Wed, Dec 12, 2012 at 07:10:50PM +0200, Gleb Natapov wrote: > rmode_segment_valid() checks if segment descriptor can be used to enter > vm86 mode. VMX spec mandates that in vm86 mode CS register will be of > type data, not code. Lets allow guest entry with vm86 mode if the only > problem with CS register is incorrect type. Otherwise entire real mode > will be emulated. > > Signed-off-by: Gleb Natapov <g...@redhat.com> > --- > arch/x86/kvm/vmx.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 4df3991..acbe86f 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -3383,6 +3383,8 @@ static bool rmode_segment_valid(struct kvm_vcpu *vcpu, > int seg) > var.dpl = 0x3; > var.g = 0; > var.db = 0; > + if (seg == VCPU_SREG_CS) > + var.type = 0x3; > ar = vmx_segment_access_rights(&var); > > if (var.base != (var.selector << 4)) > -- > 1.7.10.4
But with emulate_invalid_guest_state=1, segments are not fixed on transition to real mode. So this patch can result in invalid guest state entry failure. Does this defeat the purpose of emulate_invalid_guest_state=1? -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
