Re: [PATCH 00/32] x86/msr: Drop 32-bit MSR interfaces
"Arnd Bergmann" <[email protected]>
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On Mon, Jun 29, 2026, at 10:15, Jürgen Groß wrote:
> On 29.06.26 10:06, Arnd Bergmann wrote:
>> On Mon, Jun 29, 2026, at 09:01, Jürgen Groß wrote:
>>> On 29.06.26 08:52, Arnd Bergmann wrote:
>>>> On Mon, Jun 29, 2026, at 08:04, Juergen Gross wrote:
>>>>
>>>> I assume this is fine, but since you don't mention it explicitly here,
>>>> please clarify what this means for 32-bit CPUs without the rdmsrq
>>>> instruction. Those will continue using the same instructions as before
>>>> and just change the calling conventions, right?
>>>
>>> Yes. I thought this would be clear from the following:
>>>
>>> - They are based on primitives using 64-bit sized values anyway.
>>
>> Right, that was my reading of it as well, but it's not entirely
>> clear when the function name is the same as the mnemonic of an
>> instruction that only exists on newer CPUs and the later patch
>
> There is no RDMSRQ instruction on any x86 CPU. Are you mixing this up with
> WRMSRNS/RDMSR using an immediate for addressing the MSR?
Yes, I was just confused about the exact definition here and assumed
the single-register output version was actually called rdmsrq.
Arnd