linux-kernel - Re: [RFC PATCH v1 02/15] x86/msr: Replace __rdmsr() with native

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Message-ID: <Z-ptzZBePzh05HQI@gmail.com>
Date: Mon, 31 Mar 2025 12:26:21 +0200
From: Ingo Molnar <mingo@...nel.org>
To: "Xin Li (Intel)" <xin@...or.com>
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Subject: Re: [RFC PATCH v1 02/15] x86/msr: Replace __rdmsr() with
 native_rdmsrl()


* Xin Li (Intel) <xin@...or.com> wrote:

> __rdmsr() is the lowest level primitive MSR read API, and its direct 
> use is NOT preferred.  Use its wrapper function native_rdmsrl() 
> instead.

This description is very misleading. As of today, native_rdmsrl() 
doesn't exist in-tree, so it cannot be 'preferred' in any fashion.

We have native_read_msr(), a confusingly similar function name, and 
this changelog doesn't make it clear, at all, why the extra 
native_rdmsrl() indirection is introduced.

Please split this into two changes and explain them properly:

 - x86/msr: Add the native_rdmsrl() helper
 - x86/msr: Convert __rdmsr() uses to native_rdmsrl() uses

For the first patch you should explain why you want an extra layer of 
indirection within these APIs and how it relates to native_read_msr() 
and why there is a _read_msr() and a _rdmsr() variant...

Thanks,

	Ingo