Re: [Xen-devel] Re: [PATCH] libxc: remove CPUID core information mangling

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

Ah yes, I agree.


On 25/08/2010 16:53, "Huang2, Wei" <Wei.Huang2@xxxxxxx> wrote:

> OK. BTW, the old way seems wrong. The correct implementation should be
> (((regs[2] & 0xf000u) >> 12) + 1) << 12.
> 
> -----Original Message-----
> From: Keir Fraser [mailto:keir.fraser@xxxxxxxxxxxxx]
> Sent: Wednesday, August 25, 2010 10:39 AM
> To: Huang2, Wei; Przywara, Andre; Nitin Kamble
> Cc: xen-devel
> Subject: Re: [Xen-devel] Re: [PATCH] libxc: remove CPUID core information
> mangling
> 
> I meant it should remain the old way, since HVM virtual APIC IDs are
> vcpu_id*2.
> 
>  -- Keir
> 
> On 25/08/2010 16:28, "Huang2, Wei" <Wei.Huang2@xxxxxxx> wrote:
> 
>> Hi Keir,
>> 
>> Do you mean that we should leave 80000008:ECX[15:12] as zero or in old way
>> (i.e. (regs[2] & 0xf000u) + 1))? These bits can't be zero, unless we want to
>> use legacy method in multi-core calculation.
>> 
>> -Wei
>> 
>> ========
>> I think you shouldn't change handling of 80000008:ECX[15:12] since that does
>> explicitly refer to APIC ID arrangement. The rest of your changes could be
>> correct as far as I can tell from the reference manuals.
>> 
>> _______________________________________________
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>> http://lists.xensource.com/xen-devel
>> 
>> 
> 
> 
> 
> 



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