Jeremy Fitzhardinge wrote:
> H. Peter Anvin wrote:
>> Yes, pretty much. There are enough evidence that you can't trust CPU
>> architecture to stay sane. Inside Transmeta it was a constant battle,
>> and we were a small company.
>>
>
> Is there any indication that the msr or cpuid instructions will change
> in this way? rd/wrmsr is pretty explicitly documented as taking the msr
> in %ecx, and the value in %edx:eax; do you think that will change? And
> likewise cpuid?
CPUID already has changed: some CPUID levels are sensitive to %ecx event
though CPUID was originally documented as being sensitive only to %eax,
and I know from personal experience that there are undocumented CPUID
levels in the wild which are sensitive to %ebx. I can't say for sure
(at least on the record) if there are MSRs with nonarchitectural
sensitivities in the wild, but if there aren't, I can guarantee that it
will happen sooner or later, if only because some junior microcode
designer thought it was a great idea.
-hpa
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linux-foundation.org/mailman/listinfo/virtualization
