From: Ingo Molnar <mingo@elte.hu>
To: Gerd Hoffmann <kraxel@redhat.com>
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 14:26:23 +0200 [thread overview]
Message-ID: <20090519122623.GD14305@elte.hu> (raw)
In-Reply-To: <4A12A05C.6050004@redhat.com>
* Gerd Hoffmann <kraxel@redhat.com> wrote:
> On 05/19/09 13:08, Ingo Molnar wrote:
>> Or, alternatively, the hypervisor can expose its own administrative
>> interface to manage MTRRs.
>
> Guess what? Xen does exactly that. And the xen mtrr_ops
> implementation uses that interface ...
No, that is not an 'administrative interface' - that is a guest
kernel level hack that complicates Linux, extends its effective ABI
dependencies and which has to be maintained there from that point
on.
There's really just three proper technical solutions here:
- either catch the lowlevel CPU hw ops (the MSR modifications, which
isnt really all that different from the mtrr_ops approach so it
shouldnt pose undue difficulties to the Xen hypervisor). That will
be maximally transparent and compatible, with zero changes needed
to the Linux kernel.
- or introduce its own hypercall API based administration API,
without bothering the guest kernel with crap. Trivially patch Xorg
to make use of it and that's it.
There is absolutely no reason to introduce some intermediate crap
into Linux.
Ingo
next prev parent reply other threads:[~2009-05-19 12:27 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 [this message]
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
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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