linux-kernel - Re: [PATCH v3 08/21] x86/fpu/xstate: Define the scope of the initial xstate data

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Message-ID: <C97BCE05-8033-4605-8699-8558BB7D905B@intel.com>
Date:   Tue, 9 Feb 2021 15:38:58 +0000
From:   "Bae, Chang Seok" <chang.seok.bae@...el.com>
To:     Borislav Petkov <bp@...e.de>
CC:     Andy Lutomirski <luto@...nel.org>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "mingo@...nel.org" <mingo@...nel.org>,
        "x86@...nel.org" <x86@...nel.org>,
        "Brown, Len" <len.brown@...el.com>,
        "Hansen, Dave" <dave.hansen@...el.com>,
        "Liu, Jing2" <jing2.liu@...el.com>,
        "Shankar, Ravi V" <ravi.v.shankar@...el.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 08/21] x86/fpu/xstate: Define the scope of the initial
 xstate data

On Feb 9, 2021, at 04:49, Borislav Petkov <bp@...e.de> wrote:
> On Mon, Feb 08, 2021 at 06:53:23PM +0000, Bae, Chang Seok wrote:
> Yours does. So drop it from this one and from all the other patches as
> it is causing more confusion than it is trying to dispel.

Okay.

>> I think they are in a different context.
>> 
>> The helper indicates the mask for the ‘init_fpstate’ buffer. The rest is the
>> initial mask value for the per-task xstate buffer.
> 
> Wait, what?
> 
> Are you trying to tell me that that helper will return different masks
> depending on xfeatures_mask_user_dynamic, which changes in its lifetime?

At least in this series, no. But I thought it is possible in the future.

> Then drop that helper altogether - that is more confusion and the xstate
> code is already confusing enough.

Okay.

>> Since you suggested to introduce get_xstate_buffer_attr(), how about replacing
>> what you found with something like:
>> 
>> get_xstate_buffer_attr(XSTATE_INIT_MASK)
> 
> I'd prefer no helper at all but only comments above the usage site.

Yes, I will do that.

Thanks,
Chang