linux-kernel - Re: [patch V3 49/66] x86/fpu: Move FXSAVE_LEAK quirk info __copy_kernel_to

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Message-ID: <YNIIsWcv6vM1gnp+@zn.tnic>
Date:   Tue, 22 Jun 2021 17:58:41 +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 49/66] x86/fpu: Move FXSAVE_LEAK quirk info
 __copy_kernel_to_fpregs()

On Fri, Jun 18, 2021 at 04:19:12PM +0200, Thomas Gleixner wrote:
> copy_kernel_to_fpregs() restores all xfeatures but it is also the place
> where the AMD FXSAVE_LEAK bug is handled.
> 
> That prevents fpregs_restore_userregs() to limit the restored features,
> which is required to distangle PKRU and XSTATE handling and also for the

"untangle"

> upcoming supervisor state management.
> 
> Move the FXSAVE_LEAK quirk into __copy_kernel_to_fpregs() and deinline that
> function which has become rather fat.
> 
> Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
> ---
>  arch/x86/include/asm/fpu/internal.h |   25 +------------------------
>  arch/x86/kernel/fpu/core.c          |   27 +++++++++++++++++++++++++++
>  2 files changed, 28 insertions(+), 24 deletions(-)

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

-- 
Regards/Gruss,
    Boris.

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