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From: "H. Peter Anvin" <hpa@zytor.com>
To: Juergen Gross <jgross@suse.com>,
	x86@kernel.org, tglx@linutronix.de, mingo@redhat.com,
	linux-kernel@vger.kernel.org, akataria@vmware.com,
	jongman.heo@samsung.com
Subject: Re: [PATCH] x86: don't rely on VMWare emulating PAT MSR correctly
Date: Tue, 16 Dec 2014 08:47:14 -0800	[thread overview]
Message-ID: <54906212.2010102@zytor.com> (raw)
In-Reply-To: <1418723914-9736-1-git-send-email-jgross@suse.com>

On 12/16/2014 01:58 AM, Juergen Gross wrote:
> VMWare seems not to emulate the PAT MSR correctly: reaeding
> MSR_IA32_CR_PAT returns 0 even after writing another value to it.
> 
> Detect this bug and don't use the read value if it is 0.
> 
> Commit bd809af16e3ab1f8d55b3e2928c47c67e2a865d2 ("x86: Enable PAT to
> use cache mode translation tables") triggers this VMWare bug when the
> kernel is booted as a VMWare guest.
> 
> Reported-by: Jongman Heo <jongman.heo@samsung.com>
> Signed-off-by: Juergen Gross <jgross@suse.com>
> Tested-by: Jongman Heo <jongman.heo@samsung.com>

I presume cachability control is irrelevant for a VMware guest?  I'm
wondering if it would be better to just plain ignore the failure rather
than disabling PAT.

	-hpa



  reply	other threads:[~2014-12-16 16:47 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-16  9:58 [PATCH] x86: don't rely on VMWare emulating PAT MSR correctly Juergen Gross
2014-12-16 16:47 ` H. Peter Anvin [this message]
2014-12-17  4:52   ` Juergen Gross
2014-12-17  4:57 ` Alok Kataria
2015-01-07  4:58   ` Juergen Gross

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