From: "H. Peter Anvin" <hpa@zytor.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>,
Ingo Molnar <mingo@elte.hu>,
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>,
Thomas Gleixner <tglx@linutronix.de>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [GIT PULL] xen /proc/mtrr implementation
Date: Wed, 20 May 2009 16:03:23 -0700 [thread overview]
Message-ID: <4A148C3B.5050100@zytor.com> (raw)
In-Reply-To: <20090520225235.GJ8684@one.firstfloor.org>
Andi Kleen wrote:
>>> Is this new interface only defined for swiotlb or MMIO mappings?
>>> If yes did you check the drivers only actually set it on
>>> swiotlb or MMIO (that seems dubious to me)?
>> Really? Do we ever set unusual memory types on normal system memory?
>
> There were drivers at some point that set WC MTRRs on their
> transfer rings, not mmio.
>
> Maybe these all switched to PAT now, maybe not
Most of those that I've heard of use WB memory and CLFLUSH.
The ones I know of which marked descriptor rings WB were ones which had
descriptor rings in MMIO space (which makes sense: MMIO reads are fully
synchronizing, but writes can be posted and write combined.)
-hpa
WARNING: multiple messages have this Message-ID (diff)
From: "H. Peter Anvin" <hpa@zytor.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: 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>,
Ingo Molnar <mingo@elte.hu>,
Linus Torvalds <torvalds@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [GIT PULL] xen /proc/mtrr implementation
Date: Wed, 20 May 2009 16:03:23 -0700 [thread overview]
Message-ID: <4A148C3B.5050100@zytor.com> (raw)
In-Reply-To: <20090520225235.GJ8684@one.firstfloor.org>
Andi Kleen wrote:
>>> Is this new interface only defined for swiotlb or MMIO mappings?
>>> If yes did you check the drivers only actually set it on
>>> swiotlb or MMIO (that seems dubious to me)?
>> Really? Do we ever set unusual memory types on normal system memory?
>
> There were drivers at some point that set WC MTRRs on their
> transfer rings, not mmio.
>
> Maybe these all switched to PAT now, maybe not
Most of those that I've heard of use WB memory and CLFLUSH.
The ones I know of which marked descriptor rings WB were ones which had
descriptor rings in MMIO space (which makes sense: MMIO reads are fully
synchronizing, but writes can be posted and write combined.)
-hpa
next prev parent reply other threads:[~2009-05-20 23:05 UTC|newest]
Thread overview: 73+ 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 13:30 ` Ingo Molnar
2009-05-13 14:39 ` Jeremy Fitzhardinge
2009-05-13 14:39 ` Jeremy Fitzhardinge
2009-05-15 18:27 ` Ingo Molnar
2009-05-15 18:27 ` Ingo Molnar
2009-05-15 20:09 ` Jeremy Fitzhardinge
2009-05-15 20:09 ` Jeremy Fitzhardinge
2009-05-15 23:26 ` Eric W. Biederman
2009-05-15 23:49 ` Jeremy Fitzhardinge
2009-05-15 23:49 ` Jeremy Fitzhardinge
2009-05-16 3:22 ` Jesse Barnes
2009-05-16 3:22 ` Jesse Barnes
2009-05-16 4:26 ` Eric W. Biederman
2009-05-16 18:22 ` Jesse Barnes
2009-05-16 18:22 ` Jesse Barnes
2009-05-18 5:02 ` Jeremy Fitzhardinge
2009-05-18 5:02 ` Jeremy Fitzhardinge
2009-05-18 4:57 ` Jeremy Fitzhardinge
2009-05-18 4:57 ` Jeremy Fitzhardinge
2009-05-18 8:59 ` Ingo Molnar
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
2009-05-18 18:07 ` Jeremy Fitzhardinge
2009-05-19 9:59 ` Ingo Molnar
2009-05-19 9:59 ` Ingo Molnar
2009-05-19 10:22 ` [Xen-devel] " Jan Beulich
2009-05-19 10:22 ` Jan Beulich
2009-05-19 11:08 ` [Xen-devel] " Ingo Molnar
2009-05-19 11:08 ` Ingo Molnar
2009-05-19 12:04 ` [Xen-devel] " Gerd Hoffmann
2009-05-19 12:04 ` Gerd Hoffmann
2009-05-19 12:26 ` [Xen-devel] " Ingo Molnar
2009-05-19 12:26 ` Ingo Molnar
2009-05-19 12:32 ` [Xen-devel] " Alan Cox
2009-05-19 12:32 ` Alan Cox
2009-05-19 12:37 ` [Xen-devel] " Ingo Molnar
2009-05-19 12:37 ` Ingo Molnar
2009-05-19 13:21 ` [Xen-devel] " Gerd Hoffmann
2009-05-19 13:21 ` Gerd Hoffmann
2009-05-19 13:31 ` [Xen-devel] " Ingo Molnar
2009-05-19 13:31 ` Ingo Molnar
2009-05-19 13:51 ` [Xen-devel] " Gerd Hoffmann
2009-05-19 13:51 ` Gerd Hoffmann
2009-05-19 14:17 ` [Xen-devel] " Ingo Molnar
2009-05-19 14:17 ` Ingo Molnar
2009-05-19 14:55 ` [Xen-devel] " Gerd Hoffmann
2009-05-19 14:55 ` Gerd Hoffmann
2009-05-19 15:24 ` [Xen-devel] " Ingo Molnar
2009-05-19 15:24 ` Ingo Molnar
2009-05-20 8:01 ` [Xen-devel] " Gerd Hoffmann
2009-05-20 8:01 ` Gerd Hoffmann
2009-05-20 16:35 ` [Xen-devel] " Jeremy Fitzhardinge
2009-05-20 16:35 ` Jeremy Fitzhardinge
2009-05-20 16:12 ` 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 16:39 ` Jeremy Fitzhardinge
2009-05-20 22:52 ` Andi Kleen
2009-05-20 22:49 ` Jeremy Fitzhardinge
2009-05-20 22:49 ` Jeremy Fitzhardinge
2009-05-20 23:03 ` H. Peter Anvin [this message]
2009-05-20 23:03 ` H. Peter Anvin
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