Xen devel - Sep 2013 - probe_intel_cpuid_faulting() behavior

Jinsong,

somehow it escaped my attention so far that this probing, on a CPU
not supporting the respective MSR, necessarily produces a GPF log
message. Since such instances are generally a reason to worry,
would it be possible to at least avoid this for all CPU families/models
below a certain level (the system I''m seeing this on is family 0xf
model 6)? If so, could you provide precise cut-off values (I can of
course easily enough create a patch myself once I have the
numbers)?

Jan

Jan Beulich wrote:
> Jinsong,
> 
> somehow it escaped my attention so far that this probing, on a CPU
> not supporting the respective MSR, necessarily produces a GPF log
> message. Since such instances are generally a reason to worry,
> would it be possible to at least avoid this for all CPU
> families/models below a certain level (the system I''m seeing this
on
> is family 0xf model 6)? If so, could you provide precise cut-off
> values (I can of course easily enough create a patch myself once I
> have the 
> numbers)?
> 
> Jan
Sorry, no. It''s non-architectural but no official/precise
family/model/stepping provided, so enumeration has to tolerate GPF log on legacy
processors. What is more, no guarantee for future processors also support it.

Thanks,
Jinsong