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Re: [RFC PATCH for-4.22 v2 2/3] x86/platform: Expose DTS sensors MSR


  • To: Teddy Astie <teddy.astie@xxxxxxxxxx>
  • From: Jan Beulich <jbeulich@xxxxxxxx>
  • Date: Thu, 6 Nov 2025 09:14:29 +0100
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  • Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, Roger Pau Monné <roger.pau@xxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxxx
  • Delivery-date: Thu, 06 Nov 2025 08:14:36 +0000
  • List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

On 03.11.2025 15:30, Teddy Astie wrote:
> Le 30/10/2025 à 14:54, Jan Beulich a écrit :
>> On 29.10.2025 16:59, Teddy Astie wrote:
>> I'd also like to note that unlike the two THERM_STATUS, 
>> MSR_TEMPERATURE_TARGET
>> (as per the absence if an IA32 infix in the SDM) isn't an architectural MSR,
>> and hence I'm not entirely convinced we can "blindly" expose it. 
>> (Interestingly
>> in Linux code there is an IA32 infix.)
> 
> We only perform rdmsr_safe on this MSR, so I don't think there is much 
> problem with it as I don't expect Intel to reuse this MSR number for 
> something else (at worst, it is going to not be implemented and would 
> gracefully fail).
> 
> Some parts of this MSR slightly change, but the one (tjmax) that is 
> interesting in here is consistent across the architectures.

Perhaps it's indeed okay here, but the aspect needs calling out / justifying in
the description.

Jan



 


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