linux-kernel - Re: [RFC PATCH v2 11/34] x86/msr: Remove calling native_{read,write}_msr{,_safe}() in pmu_msr

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Message-ID: <2ce9ab5c-89a5-4504-91d2-fbc12c68117a@zytor.com>
Date: Thu, 24 Apr 2025 00:16:06 -0700
From: Xin Li <xin@...or.com>
To: "Mi, Dapeng" <dapeng1.mi@...ux.intel.com>, linux-kernel@...r.kernel.org,
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Subject: Re: [RFC PATCH v2 11/34] x86/msr: Remove calling
 native_{read,write}_msr{,_safe}() in pmu_msr_{read,write}()

On 4/23/2025 11:25 PM, Mi, Dapeng wrote:

>> -bool pmu_msr_read(unsigned int msr, uint64_t *val, int *err)
>> +bool pmu_msr_read(u32 msr, u64 *val)
> 
> The function name is some kind of misleading right now. With the change,
> this function only read PMU MSR's value if it's emulated, otherwise it
> won't really read PMU MSR. How about changing the name to
> "pmu_emulated_msr_read" or something similar?

This makes sense!

>> -bool pmu_msr_read(unsigned int msr, uint64_t *val, int *err);
>> -bool pmu_msr_write(unsigned int msr, uint32_t low, uint32_t high, int *err);
>> +bool pmu_msr_read(u32 msr, u64 *val);
> 
> The prototype of pmu_msr_read() has been changed, but why there is no
> corresponding change in its caller (xen_do_read_msr())?

Good catch.  I didn't compile one by one thus missed it.