On 01/30/2012 02:04 PM, Gleb Natapov wrote: > On Mon, Jan 30, 2012 at 02:02:14PM +0200, Avi Kivity wrote: > > On 01/30/2012 12:56 PM, Gleb Natapov wrote: > > > On Mon, Jan 30, 2012 at 12:24:11PM +0200, Avi Kivity wrote: > > > > > + > > > > > ctxt->ops->set_segment(ctxt, selector, &desc, base3, seg); > > > > > } > > > > > > > > > > @@ -2273,6 +2281,24 @@ static int load_state_from_tss32(struct > > > > > x86_emulate_ctxt *ctxt, > > > > > return emulate_gp(ctxt, 0); > > > > > ctxt->_eip = tss->eip; > > > > > ctxt->eflags = tss->eflags | 2; > > > > > + > > > > > + /* > > > > > + * If we're switching between Protected Mode and VM86, we need > > > > > to make > > > > > + * sure to update the mode before loading the segment > > > > > descriptors so > > > > > + * that the selectors are interpreted correctly. > > > > > + * > > > > > + * Need to get it to the vcpu struct immediately because it > > > > > influences > > > > > + * the CPL which is checked at least when loading the segment > > > > > + * descriptors and when pushing an error code to the new kernel > > > > > stack. > > > > > + */ > > > > > + if (ctxt->eflags & X86_EFLAGS_VM) > > > > > + ctxt->mode = X86EMUL_MODE_VM86; > > > > > + else > > > > > + ctxt->mode = X86EMUL_MODE_PROT32; > > > > > + > > > > > > > > Shouldn't this be done after the set_segment_selector() block? My > > > > interpretation of the SDM is that if a fault happens while loading > > > > descriptors the fault happens with old segment cache, that is, it needs > > > > to be interpreted according to the old mode. > > > > > > > No, spec says: > > > Any errors associated with this loading and qualification occur in the > > > context of the new task. > > > > There aren't any possible errors until that point. But we don't want > > set_segment_selector() to use the new mode, it just changes the segment > > selectors, nothing else. > > > I agree with that set_segment_selector() part, but > load_segment_descriptor() happens on a new task. >
Yes. What I think is that the mode change should happen on the boundary, after the set_segment_selector() block and before the load_segment_descriptor() block. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
