From: "H. Peter Anvin" <hpa@zytor.com>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Andi Kleen <andi@firstfloor.org>,
Andrew Morton <akpm@linux-foundation.org>,
Xen-devel <xen-devel@lists.xensource.com>,
the arch/x86 maintainers <x86@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] xen: core dom0 support
Date: Sun, 01 Mar 2009 15:52:24 -0800 [thread overview]
Message-ID: <49AB1FB8.607@zytor.com> (raw)
In-Reply-To: <49AB1B75.2060200@goop.org>
Jeremy Fitzhardinge wrote:
>
> Unless we're planning on dropping support for processes with no or
> broken PAT support, we're always going to have to deal with the non-PAT
> case. Xen just falls into the "processor with no PAT" case. And
> if/when we work out how to paravirtualize PAT, it will no longer be in
> that case.
>
In this particular case, this is actually false. "No PAT" in the
processor is *not* the same thing as "no cacheability controls in the
page tables". Every processor since the 386 has had UC, WT, and WB
controls in the page tables; PAT only added the ability to do WC (and
WP, which we don't use). Since the number of processors which can do WC
at all but don't have PAT is a small set of increasingly obsolete
processors, we may very well choose to simply ignore the WC capabilities
of these particular processors.
-hpa
next prev parent reply other threads:[~2009-03-01 23:56 UTC|newest]
Thread overview: 123+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-28 1:59 [PATCH] xen: core dom0 support Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen dom0: Make hvc_xen console work for dom0 Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen dom0: Initialize xenbus " Jeremy Fitzhardinge
2009-02-28 1:59 ` Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen dom0: Set up basic IO permissions " Jeremy Fitzhardinge
2009-02-28 1:59 ` Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen-dom0: only selectively disable cpu features Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen dom0: Add support for the platform_ops hypercall Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen mtrr: Add mtrr_ops support for Xen mtrr Jeremy Fitzhardinge
2009-02-28 1:59 ` Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen: disable PAT Jeremy Fitzhardinge
2009-02-28 1:59 ` Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen/dom0: use _PAGE_IOMAP in ioremap to do machine mappings Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] paravirt/xen: add pvop for page_is_ram Jeremy Fitzhardinge
2009-03-10 1:07 ` H. Peter Anvin
2009-03-10 21:19 ` Jeremy Fitzhardinge
2009-03-10 21:19 ` Jeremy Fitzhardinge
2009-03-10 22:21 ` H. Peter Anvin
2009-03-10 22:44 ` Jeremy Fitzhardinge
2009-03-10 22:44 ` Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen/dom0: Use host E820 map Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen: implement XENMEM_machphys_mapping Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen: clear reserved bits in l3 entries given in the initial pagetables Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen/dom0: add XEN_DOM0 config option Jeremy Fitzhardinge
2009-02-28 1:59 ` Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen: allow enable use of VGA console on dom0 Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen mtrr: Use specific cpu_has_foo macros instead of generic cpu_has() Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen mtrr: Kill some unneccessary includes Jeremy Fitzhardinge
2009-02-28 1:59 ` Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen mtrr: Use generic_validate_add_page() Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen mtrr: Implement xen_get_free_region() Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen mtrr: Add xen_{get,set}_mtrr() implementations Jeremy Fitzhardinge
2009-02-28 5:28 ` [PATCH] xen: core dom0 support Andrew Morton
2009-02-28 6:52 ` Jeremy Fitzhardinge
2009-02-28 6:52 ` Jeremy Fitzhardinge
2009-02-28 7:20 ` Ingo Molnar
2009-02-28 7:20 ` Ingo Molnar
2009-02-28 8:05 ` Jeremy Fitzhardinge
2009-02-28 8:05 ` Jeremy Fitzhardinge
2009-02-28 8:36 ` Ingo Molnar
2009-02-28 8:36 ` Ingo Molnar
2009-02-28 9:57 ` Jeremy Fitzhardinge
2009-02-28 9:57 ` Jeremy Fitzhardinge
2009-03-02 9:26 ` Gerd Hoffmann
2009-03-02 9:26 ` Gerd Hoffmann
2009-03-02 12:04 ` Ingo Molnar
2009-03-02 12:04 ` Ingo Molnar
2009-03-02 12:26 ` Gerd Hoffmann
2009-03-02 12:26 ` Gerd Hoffmann
2009-02-28 12:09 ` Nick Piggin
2009-02-28 12:09 ` Nick Piggin
2009-02-28 18:11 ` [Xen-devel] " Jody Belka
2009-02-28 18:11 ` Jody Belka
2009-02-28 18:15 ` Andi Kleen
2009-03-01 23:38 ` Jeremy Fitzhardinge
2009-03-01 23:38 ` Jeremy Fitzhardinge
2009-03-02 0:14 ` Andi Kleen
2009-03-01 23:27 ` Jeremy Fitzhardinge
2009-03-01 23:27 ` Jeremy Fitzhardinge
2009-03-02 6:37 ` Nick Piggin
2009-03-02 6:37 ` Nick Piggin
2009-03-02 8:05 ` Jeremy Fitzhardinge
2009-03-02 8:05 ` Jeremy Fitzhardinge
2009-03-02 8:19 ` Nick Piggin
2009-03-02 8:19 ` Nick Piggin
2009-03-02 9:05 ` Jeremy Fitzhardinge
2009-03-04 17:34 ` Anthony Liguori
2009-03-04 17:34 ` Anthony Liguori
2009-03-04 17:38 ` Jeremy Fitzhardinge
2009-03-04 17:38 ` Jeremy Fitzhardinge
2009-03-05 10:59 ` [Xen-devel] " George Dunlap
2009-03-05 10:59 ` George Dunlap
2009-03-05 14:37 ` [Xen-devel] " Anthony Liguori
2009-03-05 14:37 ` Anthony Liguori
2009-03-04 17:31 ` Anthony Liguori
2009-03-04 17:31 ` Anthony Liguori
2009-03-04 19:03 ` Anthony Liguori
2009-03-04 19:16 ` H. Peter Anvin
2009-03-04 19:33 ` Anthony Liguori
2009-03-04 19:33 ` Anthony Liguori
2009-02-28 16:14 ` Andi Kleen
2009-03-01 23:34 ` Jeremy Fitzhardinge
2009-03-01 23:34 ` Jeremy Fitzhardinge
2009-03-01 23:52 ` H. Peter Anvin [this message]
2009-03-02 0:08 ` Jeremy Fitzhardinge
2009-03-02 0:08 ` Jeremy Fitzhardinge
2009-03-02 0:14 ` H. Peter Anvin
2009-03-02 0:42 ` Jeremy Fitzhardinge
2009-03-02 0:42 ` Jeremy Fitzhardinge
2009-03-02 0:46 ` H. Peter Anvin
2009-03-02 0:10 ` Andi Kleen
2009-02-28 8:42 ` Ingo Molnar
2009-02-28 8:42 ` Ingo Molnar
2009-02-28 9:46 ` Jeremy Fitzhardinge
2009-02-28 9:46 ` Jeremy Fitzhardinge
2009-03-02 12:08 ` Ingo Molnar
2009-03-02 12:08 ` Ingo Molnar
2009-03-07 9:06 ` Jeremy Fitzhardinge
2009-03-07 9:06 ` Jeremy Fitzhardinge
2009-03-08 11:01 ` Ingo Molnar
2009-03-08 11:01 ` Ingo Molnar
2009-03-08 21:56 ` H. Peter Anvin
2009-03-08 22:06 ` Ingo Molnar
2009-03-08 22:06 ` Ingo Molnar
2009-03-08 22:08 ` H. Peter Anvin
2009-03-08 22:12 ` Ingo Molnar
2009-03-08 22:12 ` Ingo Molnar
2009-03-09 18:06 ` Jeremy Fitzhardinge
2009-03-09 18:06 ` Jeremy Fitzhardinge
2009-03-10 12:44 ` Ingo Molnar
2009-03-10 12:44 ` Ingo Molnar
2009-03-10 12:49 ` Nick Piggin
2009-03-10 12:49 ` Nick Piggin
2009-03-05 13:52 ` Morten P.D. Stevens
2009-03-08 14:25 ` Manfred Knick
2009-03-09 19:51 ` Morten P.D. Stevens
2009-03-09 20:00 ` Morten P.D. Stevens
2009-02-28 6:17 ` Boris Derzhavets
2009-02-28 6:23 ` [Xen-devel] " Jeremy Fitzhardinge
2009-02-28 6:23 ` Jeremy Fitzhardinge
2009-02-28 6:28 ` Boris Derzhavets
-- strict thread matches above, loose matches on Subject: below --
2009-03-11 19:58 devzero
2009-03-14 1:08 ` Morten P.D. Stevens
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