Re: [PATCH] x86/amd: fix crash as Xen Dom0 on AMD Trinity systems

From: H. Peter Anvin
Date: Wed May 30 2012 - 10:58:54 EST


On 05/30/2012 07:55 AM, Borislav Petkov wrote:
> On Wed, May 30, 2012 at 07:42:27AM -0700, H. Peter Anvin wrote:
>> On 05/30/2012 06:10 AM, Andre Przywara wrote:
>>> Because we are behind a family check before tweaking the topology
>>> bit, we can use the standard rd/wrmsr variants for the CPUID feature
>>> register.
>>
>> That is not what the *msr*_amd*() functions do.
>>
>> NAK. This is a totally bogus patch.
>
> The *msr*_amd*() variants were used instead of the normal *msrl_safe
> variants although the AMD variants weren't needed there at all.
>
> This has no issue on baremetal but breaks xen and this is how we caught
> this.
>
> So the patch corrects the original patch so that xen is happy too.
>

If so, then fix the description to match reality and we can take the patch.

-hpa

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