linux-kernel - Re: [patch 16/31] x86/fpu: Replace KVMs homebrewn FPU copy to user

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Message-ID: <cc8893f1-df60-2155-d3b6-f889bc1c2201@redhat.com>
Date:   Wed, 13 Oct 2021 07:34:43 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        LKML <linux-kernel@...r.kernel.org>
Cc:     x86@...nel.org, "Chang S. Bae" <chang.seok.bae@...el.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Arjan van de Ven <arjan@...ux.intel.com>,
        kvm@...r.kernel.org
Subject: Re: [patch 16/31] x86/fpu: Replace KVMs homebrewn FPU copy to user

On 12/10/21 19:47, Thomas Gleixner wrote:
>> The memset(guest_xsave, 0, sizeof(struct kvm_xsave)) also is not
>> reproduced, you can make it unconditional for simplicity; this is not a
>> fast path.
> Duh, I should have mentioned that in the changelog. The buffer is
> allocated with kzalloc() soe the memset is redundant, right?

Yes, I always confuse the __user pointers with the temporary ones that 
are allocated in the callers.

Paolo