> > +
> > + if (!eax_0 ||
> > + ((ebx_0 & INTEL_PT_MINIMAL_EBX) != INTEL_PT_MINIMAL_EBX) ||
> > + ((ecx_0 & INTEL_PT_MINIMAL_ECX) != INTEL_PT_MINIMAL_ECX) ||
> > + ((eax_1 & INTEL_PT_MTC_BITMAP) != INTEL_PT_MTC_BITMAP) ||
> > + ((eax_1 & INTEL_PT_ADDR_RANGES_NUM_MASK) <
> > + INTEL_PT_ADDR_RANGES_NUM) ||
> > + ((ebx_1 & (INTEL_PT_PSB_BITMAP | INTEL_PT_CYCLE_BITMAP)) !=
> > + (INTEL_PT_PSB_BITMAP | INTEL_PT_CYCLE_BITMAP))) {
>
> I still don't see a check to ensure the host has bit 31 on ecx_0 set to 0, as I mentioned when reviewing v3.
Hi Eduardo,
Thanks for the code review. I don't quite understand here why bit31 must same with host (meaning we must reject a host
where ecx_0 & (1 << 31) is set).
Do you mean PT must be disabled in guest when host bit31 is set?
Bit 31: If 1, generated packets which contain IP payloads have LIP values, which include the CS base component.
I can't find any special on this bit. Could you help clarify?
Thanks,
Luwei Kang
>
> The rest of the patch looks good.
>
> > + /*
> > + * Processor Trace capabilities aren't configurable, so if the
> > + * host can't emulate the capabilities we report on
> > + * cpu_x86_cpuid(), intel-pt can't be enabled on the current host.
> > + */
> > + env->features[FEAT_7_0_EBX] &= ~CPUID_7_0_EBX_INTEL_PT;
> > + cpu->filtered_features[FEAT_7_0_EBX] |= CPUID_7_0_EBX_INTEL_PT;
> > + rv = 1;
> > + }
> > + }
> > +
> > return rv;
> > }
> >
> [...]
>
> --
> Eduardo
