linux-kernel - Re: [patch V3 54/66] x86/fpu: Mask PKRU from kernel XRSTOR[S] operations

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Date:   Tue, 22 Jun 2021 19:07:20 +0200
From:   Borislav Petkov <bp@...e.de>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     LKML <linux-kernel@...r.kernel.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>,
        Peter Zijlstra <peterz@...radead.org>,
        Kan Liang <kan.liang@...ux.intel.com>
Subject: Re: [patch V3 54/66] x86/fpu: Mask PKRU from kernel XRSTOR[S]
 operations

On Fri, Jun 18, 2021 at 04:19:17PM +0200, Thomas Gleixner wrote:
> As the PKRU state is managed seperately restoring it from the xstate buffer

separately

> would be counterproductive as it might either restore a stale value or
> reinit the PKRU state to 0.
> 
> Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
> ---
>  arch/x86/include/asm/fpu/internal.h |    4 ++--
>  arch/x86/include/asm/fpu/xstate.h   |   10 ++++++++++
>  arch/x86/kernel/fpu/xstate.c        |    1 +
>  arch/x86/mm/extable.c               |    2 +-
>  4 files changed, 14 insertions(+), 3 deletions(-)

Reviewed-by: Borislav Petkov <bp@...e.de>

-- 
Regards/Gruss,
    Boris.

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