linux-kernel - Re: [PATCH] kvm: x86: mmu: Add cast to negated bitmasks in update_permission

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Message-ID: <a1c2d331-ea79-b2de-af32-1f914bea2fda@redhat.com>
Date:   Tue, 19 Jun 2018 19:13:41 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Nick Desaulniers <ndesaulniers@...gle.com>
Cc:     joe@...ches.com, Matthias Kaehlcke <mka@...omium.org>,
        rkrcmar@...hat.com, Thomas Gleixner <tglx@...utronix.de>,
        hpa@...or.com, x86@...nel.org, kvm@...r.kernel.org,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] kvm: x86: mmu: Add cast to negated bitmasks in
 update_permission_bitmask()

On 19/06/2018 19:08, Nick Desaulniers wrote:
>> This one really makes the code uglier though, so I'm not really inclined
>> to applying the patch.
> Note that of the three variables (w, u, x), only u is used later on.
> What about declaring them as negated with the cast, that way there's
> no cast in a ternary?

I still find it inferior, but I guess it's at least acceptable.  I
prefer not_{x,w,u} though. :)

Paolo