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From: Gerd Hoffmann <kraxel@redhat.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Jan Beulich <JBeulich@novell.com>,
	Jeremy Fitzhardinge <jeremy@goop.org>,
	Xen-devel <xen-devel@lists.xensource.com>,
	the arch/x86 maintainers <x86@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Jesse Barnes <jbarnes@virtuousgeek.org>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [Xen-devel] Re: [GIT PULL] xen /proc/mtrr implementation
Date: Tue, 19 May 2009 16:55:06 +0200	[thread overview]
Message-ID: <4A12C84A.5070100@redhat.com> (raw)
In-Reply-To: <20090519141708.GA6008@elte.hu>

>>>> No, the linux kernel probably should do the wrmsr on one cpu only then.
>>> Why?

> | The change of MTRR's on _any_ of the guest CPUs in a dom0 context
> | should immediately be refected on all CPUs. Assymetric MTRR
> | settings are madness.

Exactly.  And thats why it is pointless to let the dom0 kernel write the 
mtrr msrs on more than one cpu.

>>>> Oops, the third "proper technical solutions" is missing.
>>> Yeah, the third one is to not touch MTRRs after bootup and use PAT.
>> Works only in case the CPU has PAT support.
>
> Which specific CPU without PAT support do you worry about?

For example:  I have a Notebook here, with MTRR and without PAT 
according to the boot log.  "Pentium III (Coppermine)" says /proc/cpuinfo.

cheers,
   Gerd

  reply	other threads:[~2009-05-19 14:57 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-12 23:27 [GIT PULL] xen /proc/mtrr implementation Jeremy Fitzhardinge
2009-05-12 23:27 ` [PATCH 1/6] xen: set cpu_callout_mask to make mtrr work Jeremy Fitzhardinge
2009-05-12 23:27 ` [PATCH 2/6] xen mtrr: Use specific cpu_has_foo macros instead of generic cpu_has() Jeremy Fitzhardinge
2009-05-12 23:27 ` [PATCH 3/6] xen mtrr: Use generic_validate_add_page() Jeremy Fitzhardinge
2009-05-12 23:27 ` [PATCH 4/6] xen mtrr: Implement xen_get_free_region() Jeremy Fitzhardinge
2009-05-12 23:27 ` [PATCH 5/6] xen mtrr: Add xen_{get,set}_mtrr() implementations Jeremy Fitzhardinge
2009-05-12 23:27 ` [PATCH 6/6] xen mtrr: Kill some unnecessary includes Jeremy Fitzhardinge
2009-05-13 13:30 ` [GIT PULL] xen /proc/mtrr implementation Ingo Molnar
2009-05-13 14:39   ` Jeremy Fitzhardinge
2009-05-15 18:27     ` Ingo Molnar
2009-05-15 20:09       ` Jeremy Fitzhardinge
2009-05-15 23:26         ` Eric W. Biederman
2009-05-15 23:49           ` Jeremy Fitzhardinge
2009-05-16  3:22             ` Jesse Barnes
2009-05-16  4:26               ` Eric W. Biederman
2009-05-16 18:22                 ` Jesse Barnes
2009-05-18  5:02                   ` Jeremy Fitzhardinge
2009-05-18  4:57                 ` Jeremy Fitzhardinge
2009-05-18  8:59                   ` Ingo Molnar
2009-05-18 13:17                     ` [Xen-devel] " Jan Beulich
2009-05-18 17:51                     ` Chris Wright
2009-05-18 18:07                     ` Jeremy Fitzhardinge
2009-05-19  9:59                       ` Ingo Molnar
2009-05-19 10:22                         ` [Xen-devel] " Jan Beulich
2009-05-19 11:08                           ` Ingo Molnar
2009-05-19 12:04                             ` Gerd Hoffmann
2009-05-19 12:26                               ` Ingo Molnar
2009-05-19 12:32                                 ` Alan Cox
2009-05-19 12:37                                   ` Ingo Molnar
2009-05-19 13:21                                 ` Gerd Hoffmann
2009-05-19 13:31                                   ` Ingo Molnar
2009-05-19 13:51                                     ` Gerd Hoffmann
2009-05-19 14:17                                       ` Ingo Molnar
2009-05-19 14:55                                         ` Gerd Hoffmann [this message]
2009-05-19 15:24                                           ` Ingo Molnar
2009-05-20  8:01                                             ` Gerd Hoffmann
2009-05-20 16:35                             ` Jeremy Fitzhardinge
2009-05-20 16:12                         ` Jeremy Fitzhardinge
2009-05-20  8:16                       ` Andi Kleen
2009-05-20 16:39                         ` Jeremy Fitzhardinge
2009-05-20 22:52                           ` Andi Kleen
2009-05-20 22:49                             ` Jeremy Fitzhardinge
2009-05-20 23:03                             ` H. Peter Anvin
  -- strict thread matches above, loose matches on Subject: below --
2009-05-25  8:42 [Xen-devel] " Tomasz Chmielewski
2009-05-25  9:15 ` Andi Kleen
2009-05-25  9:31   ` Jan Beulich
2009-05-25  9:47     ` Andi Kleen
2009-05-25 16:05   ` H. Peter Anvin

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