RE: [Xen-devel] [PATCH] X86: cpuid faulting feature enable

["Liu, Jinsong" <jinsong.liu@xxxxxxxxx>]

Liu, Jinsong wrote:
> Keir Fraser wrote:
>> On 01/07/2011 18:48, "Liu, Jinsong" <jinsong.liu@xxxxxxxxx> wrote:
>> 
>>>> Down to a particular stepping? That surely doesn't make sense for
>>>> anything but your own experimenting.
>>> 
>>> Yes, it's some ugly.
>>> Currently cpuid faulting is not a architecturally commited feature,
>>> and, some other Intel processors (which do not has cpuid faulting
>>> feature) also has 0xceh MSR. Hence I use current way for safe.
>>> However, I marked it as FIXME to update in the future accordingly.
>> 
>> But Intel's own supporting document states that bit 31 of the
>> PLATFORM_INFO MSR should be sufficient to identify the cpuid faulting
>> feature. Do you really need the stepping check as well? Could you
>> just do a rdmsr_safe read-and-check of PLATFORM_INFO_MSR[31] instead?
>> 
>> It would be okay for other Intel CPUs to have MSR 0xce, so long as
>> they don't set bit 31... 
>> 
>>  -- Keir
> 
> That's good. It does formally state.
> We can move family/model/stepping now.

sorry, remove. my poor english :(

> 
> Thanks,
> Jinsong


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