linux-kernel - Re: [RFC PATCH v1 01/15] x86/msr: Replace __wrmsr() with native

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Message-ID: <580DD4EE-8694-4525-AA73-A6823126FF9F@zytor.com>
Date: Wed, 02 Apr 2025 23:01:27 -0700
From: "H. Peter Anvin" <hpa@...or.com>
To: Xin Li <xin@...or.com>, Ingo Molnar <mingo@...nel.org>
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        Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [RFC PATCH v1 01/15] x86/msr: Replace __wrmsr() with native_wrmsrl()

On April 2, 2025 10:09:21 PM PDT, Xin Li <xin@...or.com> wrote:
>On 4/1/2025 12:52 AM, Ingo Molnar wrote:
>>> Should we rename the *msrl() functions to *msrq() as part of this
>>> overhaul?
>> Yeah, that's a good idea, and because talk is cheap I just implemented
>> this in the tip:WIP.x86/msr branch with a couple of other cleanups in
>> this area (see the shortlog & diffstat below), but the churn is high:
>> 
>>    144 files changed, 1034 insertions(+), 1034 deletions(-)
>
>Hi Ingo,
>
>I noticed that you keep the type of MSR index in these patches as
>"unsigned int".
>
>I'm thinking would it be better to standardize it as "u32"?
>
>Because:
>1) MSR index is placed in ECX to execute MSR instructions, and the
>   high-order 32 bits of RCX are ignored on 64-bit.
>2) MSR index is encoded as a 32-bit immediate in the new immediate form
>   MSR instructions.
>
>Thanks!
>    Xin

"unsigned int" and "u32" are synonymous, but the latter is more explicit and would be better.