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Date: Wed, 10 Sep 2014 13:14:02 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Toshi Kani <toshi.kani@hp.com>, Andy Lutomirski <luto@amacapital.net>
CC: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Arnd Bergmann <arnd@arndb.de>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Juergen Gross <jgross@suse.com>,
        Stefan Bader <stefan.bader@canonical.com>,
        Henrique de Moraes Holschuh <hmh@hmh.eng.br>,
        Yigal Korman <yigal@plexistor.com>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: [PATCH v2 2/6] x86, mm, pat: Change reserve_memtype() to handle
 WT
References: <1410367910-6026-1-git-send-email-toshi.kani@hp.com>	 <1410367910-6026-3-git-send-email-toshi.kani@hp.com>	 <CALCETrXRjU3HvHogpm5eKB3Cogr5QHUvE67JOFGbOmygKYEGyA@mail.gmail.com> <1410377428.28990.260.camel@misato.fc.hp.com>
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On 09/10/2014 12:30 PM, Toshi Kani wrote:
> 
> When WT is unavailable due to the PAT errata, it does not fail but gets
> redirected to UC-.  Similarly, when PAT is disabled, WT gets redirected
> to UC- as well.
> 

But on pre-PAT hardware you can still do WT.

	-hpa