Date: Tue, 22 Apr 2014 13:23:12 +0200
From: Borislav Petkov <bp@alien8.de>
To: Andrew Lutomirski <amluto@gmail.com>, "H. Peter Anvin" <hpa@zytor.com>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Ingo Molnar <mingo@kernel.org>,
        Alexander van Heukelum <heukelum@fastmail.fm>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Arjan van de Ven <arjan.van.de.ven@intel.com>,
        Brian Gerst <brgerst@gmail.com>,
        Alexandre Julliard <julliard@winehq.com>,
        Andi Kleen <andi@firstfloor.org>, Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH] x86-64: espfix for 64-bit mode *PROTOTYPE*
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On Mon, Apr 21, 2014 at 06:53:36PM -0700, Andrew Lutomirski wrote:
> On Mon, Apr 21, 2014 at 6:47 PM, H. Peter Anvin <hpa@zytor.com> wrote:
> > Race condition (although with x86 being globally ordered, it probably can't actually happen.) The bitmask is probably the way to go.
> 
> Does the race matter?  In the worst case you take the lock
> unnecessarily.  But yes, the bitmask is easy.

I wonder if it would be workable to use a bit in the espfix PGD to
denote that it has been initialized already... I hear, near NX there's
some room :-)

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
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