linux-kernel - Re: [patch V3 4/6] x86/pkru: Make PKRU=0 actually work

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Date:   Tue, 8 Jun 2021 09:06:44 -0700
From:   Dave Hansen <dave.hansen@...el.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        LKML <linux-kernel@...r.kernel.org>
Cc:     x86@...nel.org, Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Fenghua Yu <fenghua.yu@...el.com>,
        Tony Luck <tony.luck@...el.com>,
        Yu-cheng Yu <yu-cheng.yu@...el.com>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Rik van Riel <riel@...riel.com>, Borislav Petkov <bp@...e.de>
Subject: Re: [patch V3 4/6] x86/pkru: Make PKRU=0 actually work

On 6/8/21 7:36 AM, Thomas Gleixner wrote:
> When user space brings PKRU into init state, then the kernel handling is
> broken:

Nit: while setting PKRU=0 _can_ trigger this issue (on AMD), the
underlying problem is truly with the init state and not simply with any
wrpkru(0).  IOW, I like the changelog better than the subject.

Maybe something like this would be more precise:

	x86/pkru: Write hardware init value to PKRU when xstate is init