linux-kernel - Re: [PATCH RFC v2a 5/9] x86/cpufeatures: Add X86_FEATURE

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Message-ID: <a218888a-fe10-48c4-a61d-6f1a93da5a06@intel.com>
Date: Mon, 14 Apr 2025 11:02:51 -0700
From: "Chang S. Bae" <chang.seok.bae@...el.com>
To: Sohil Mehta <sohil.mehta@...el.com>, Dave Hansen <dave.hansen@...el.com>,
	Ingo Molnar <mingo@...nel.org>
CC: <linux-kernel@...r.kernel.org>, <x86@...nel.org>, <tglx@...utronix.de>,
	<mingo@...hat.com>, <bp@...en8.de>, <dave.hansen@...ux.intel.com>
Subject: Re: [PATCH RFC v2a 5/9] x86/cpufeatures: Add X86_FEATURE_APX

On 4/14/2025 10:45 AM, Sohil Mehta wrote:
> 
> That way my initial inclination as well. My suggestion was mainly to
> keep it consistent. But looking more closely, there is mismatch already.
> So either of the options work for me.
> 
> "x86/fpu: FP/SSE not present amongst the CPU's xstate features: 0x%llx."
> 
> "x86/fpu: init_fpstate buffer too small (%zu < %d), disabling XSAVE"
> 
> "x86/fpu: xfeatures modified from 0x%016llx to 0x%016llx during init,
> disabling XSAVE"


And you also left this comment in patch 7:

 > It might be useful to add a "disabling XSAVE" print at the end of this
 > statement, like the other error messages in the same function.

So it sounds like you were suggesting something along the lines of:
   "x86/fpu: Both APX/MPX present in the CPU's xstate features: 0x%llx,
    disabling XSAVE"

If so, I see that as an improvement to the error message rather than a 
functional change. But I agree it reads better and more in line with the 
other cases.

Thanks,
Chang