Re: [Xen-devel] [PATCH v11 13/23] x86: refactor psr: CDP: implement CPU init flow.

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 06.06.17 at 10:13, <yi.y.sun@xxxxxxxxxxxxxxx> wrote:
> On 17-06-06 01:45:11, Jan Beulich wrote:
>> >>> On 02.06.17 at 09:26, <yi.y.sun@xxxxxxxxxxxxxxx> wrote:
>> > On 17-05-31 03:37:48, Jan Beulich wrote:
>> >> >>> On 03.05.17 at 10:44, <yi.y.sun@xxxxxxxxxxxxxxx> wrote:
>> >> > +        /* Cut half of cos_max when CDP is enabled. */
>> >> > +        feat->cos_max >>= 1;
>> >> > +
>> >> > +        /* We only write mask1 since mask0 is always all ones by 
>> >> > default. */
>> >> 
>> >> Is this, btw, just reset state or even guaranteed after offlining
>> >> and re-onlining a CPU?
>> >> 
>> > Below MSRs are all per socket. So, we just need reset them when socket is
>> > online.
>> 
>> Which I hope you've understood then means the comment and
>> presumably also the code here need further refinement.
>> 
> Spec states it below. So, the mask0 is guranteed.
> "the default mask in IA32_L3_MASK_0 - which is all “1”s (on reset)"

Sigh. I did ask very clearly (and this is still visible above) about
the case where the CPU did _not_ undergo a reset cycle.

Jan

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