Re: [Xen-devel] [PATCH v2 07/14] x86/cpuid: Handle leaves 0x80000005-7 in guest_cpuid()

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 24.01.17 at 15:48, <andrew.cooper3@xxxxxxxxxx> wrote:
> On 24/01/17 11:59, Jan Beulich wrote:
>>>>> On 23.01.17 at 15:39, <andrew.cooper3@xxxxxxxxxx> wrote:
>>> Intel reserves all of this information other than the L2 cache information,
>>> and the ITSC bit from the power management leaf.
>>>
>>> AMD passes all of the cache/TLB information through to the guest, while most
>>> of of the power management information is explicitly clobbered by the
>>> toolstack.
>> Both of these look to not be fully in line with ...
>>
>>> --- a/xen/arch/x86/cpuid.c
>>> +++ b/xen/arch/x86/cpuid.c
>>> @@ -167,6 +167,9 @@ static void recalculate_misc(struct cpuid_policy *p)
>>>  
>>>      p->extd.e1d &= ~CPUID_COMMON_1D_FEATURES;
>>>  
>>> +    /* Most of Power/RAS hidden from guests. */
>>> +    p->extd.raw[0x7].a = p->extd.raw[0x7].b = p->extd.raw[0x7].c = 0;
>> ... you leaving .d completely untouched. Can you clarify this please?
> 
> e7d is covered by the featureset bitmap, because it contains the ITSC
> feature.
> 
> It is therefore covered by the main body of recalculate_domain_policy().

Oh, of course.

Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>

Jan


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