From: Gerd Hoffmann <kraxel@redhat.com>
To: George Dunlap <George.Dunlap@eu.citrix.com>
Cc: Ingo Molnar <mingo@elte.hu>,
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>,
Avi Kivity <avi@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Keir Fraser <keir.fraser@eu.citrix.com>
Subject: Re: [Xen-devel] Re: [GIT PULL] Xen APIC hooks (with io_apic_ops)
Date: Tue, 26 May 2009 23:19:44 +0200 [thread overview]
Message-ID: <4A1C5CF0.3090107@redhat.com> (raw)
In-Reply-To: <de76405a0905260546k56bc866bx1658ec13f65e3eec@mail.gmail.com>
On 05/26/09 14:46, George Dunlap wrote:
> On Mon, May 25, 2009 at 5:10 AM, Ingo Molnar<mingo@elte.hu> wrote:
>> Note that this design problem has been created by Xen,
>> intentionally, and Xen is now suffering under those bad technical
>> choices made years ago. It's not Linux's problem.
>
> I'd like to respecfully disagree with this.
Well. Xen *does* suffer from bad technical choices made years ago. I'm
pretty sure Xen would look radically different when being rewritten from
scratch today.
One reason is that Xen predates vt and svm. With that in mind some of
the xen interface bits don't look *that* odd any more. Back then it did
made sense to handle things that way. The ioapic hypercalls discussed
in this thread belong into that group IMHO.
Another reason is that Xen wasn't "designed". Xen was "hacked up". As
far I know there is no document which describes the overall design of
the guest/xen ABI. Also there is no documentation (other than code)
which describes all details of the guest/xen ABI. Simple reason: The
ABI wasn't designed. It was hammered into shape until it worked. On
x86. The guys who attempted (and failed) to port xen to ppc had alot of
*ahem* fun with that stuff. For example: Passing guest virtual
addresses in (some) hypercalls. Also direct paging mode is a very
x86-ish and is the reason for a number of ia64-ifdefs in places where
you don't expect them ...
cheers,
Gerd
next prev parent reply other threads:[~2009-05-26 21:21 UTC|newest]
Thread overview: 104+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-12 23:25 [GIT PULL] Xen APIC hooks (with io_apic_ops) Jeremy Fitzhardinge
2009-05-12 23:25 ` [PATCH 01/17] xen/dom0: handle acpi lapic parsing in Xen dom0 Jeremy Fitzhardinge
2009-05-12 23:25 ` [PATCH 02/17] x86: add io_apic_ops to allow interception Jeremy Fitzhardinge
2009-05-25 3:54 ` Ingo Molnar
2009-05-27 7:17 ` Jeremy Fitzhardinge
2009-05-12 23:25 ` [PATCH 03/17] xen: implement io_apic_ops Jeremy Fitzhardinge
2009-05-12 23:25 ` [PATCH 04/17] xen: create dummy ioapic mapping Jeremy Fitzhardinge
2009-05-12 23:25 ` [PATCH 05/17] xen: implement pirq type event channels Jeremy Fitzhardinge
2009-05-12 23:25 ` [PATCH 06/17] x86/io_apic: add get_nr_irqs_gsi() Jeremy Fitzhardinge
2009-05-12 23:25 ` [PATCH 07/17] xen/apic: identity map gsi->irqs Jeremy Fitzhardinge
2009-05-12 23:25 ` [PATCH 08/17] xen: direct irq registration to pirq event channels Jeremy Fitzhardinge
2009-05-12 23:25 ` [PATCH 09/17] xen: bind pirq to vector and event channel Jeremy Fitzhardinge
2009-05-12 23:25 ` [PATCH 10/17] xen: pre-initialize legacy irqs early Jeremy Fitzhardinge
2009-05-12 23:25 ` [PATCH 11/17] xen: don't setup acpi interrupt unless there is one Jeremy Fitzhardinge
2009-05-12 23:25 ` [PATCH 12/17] xen: use acpi_get_override_irq() to get triggering for legacy irqs Jeremy Fitzhardinge
2009-05-12 23:25 ` [PATCH 13/17] xen: initialize irq 0 too Jeremy Fitzhardinge
2009-05-12 23:25 ` [PATCH 14/17] xen: dynamically allocate irq & event structures Jeremy Fitzhardinge
2009-05-12 23:25 ` [PATCH 15/17] xen: set pirq name to something useful Jeremy Fitzhardinge
2009-05-12 23:25 ` [PATCH 16/17] xen: fix legacy irq setup, make ioapic-less machines work Jeremy Fitzhardinge
2009-05-12 23:25 ` [PATCH 17/17] xen: disable MSI Jeremy Fitzhardinge
2009-05-19 12:35 ` [GIT PULL] Xen APIC hooks (with io_apic_ops) Ingo Molnar
2009-05-20 17:57 ` Jeremy Fitzhardinge
2009-05-25 4:10 ` Ingo Molnar
2009-05-26 12:46 ` [Xen-devel] " George Dunlap
2009-05-26 18:26 ` Avi Kivity
2009-05-26 19:18 ` Dan Magenheimer
2009-05-26 19:41 ` Avi Kivity
2009-05-28 0:13 ` Ingo Molnar
2009-05-28 0:49 ` Jeremy Fitzhardinge
2009-05-28 3:47 ` Dan Magenheimer
2009-05-28 14:26 ` George Dunlap
2009-05-29 0:45 ` Xen is a feature Jeremy Fitzhardinge
2009-05-29 1:27 ` Greg KH
2009-05-29 4:05 ` David Miller
2009-05-29 6:37 ` Jaswinder Singh Rajput
2009-05-29 6:51 ` David Miller
2009-05-29 12:01 ` George Dunlap
2009-05-29 14:14 ` Pasi Kärkkäinen
2009-05-29 21:29 ` David Miller
[not found] ` <87tz33ep1b.fsf@basil.nowhere.org>
2009-05-29 21:31 ` [Xen-devel] " Jeremy Fitzhardinge
2009-05-29 23:09 ` Nakajima, Jun
2009-05-29 23:26 ` Jeremy Fitzhardinge
2009-06-02 15:23 ` Thomas Gleixner
2009-06-02 16:41 ` George Dunlap
2009-06-02 17:28 ` Chris Friesen
2009-06-02 17:46 ` Linus Torvalds
2009-06-02 18:02 ` Linus Torvalds
2009-06-02 18:59 ` Avi Kivity
2009-06-07 9:13 ` Ingo Molnar
2009-06-07 10:01 ` Avi Kivity
2009-06-07 10:35 ` Ingo Molnar
2009-06-07 12:46 ` Avi Kivity
2009-06-07 13:02 ` Jaswinder Singh Rajput
2009-06-04 14:02 ` [Xen-users] " Thomas Goirand
2009-06-02 18:59 ` Thomas Gleixner
2009-06-03 19:49 ` Bill Davidsen
2009-06-03 20:20 ` Thomas Gleixner
2009-06-03 22:37 ` Bill Davidsen
2009-06-03 23:29 ` Frans Pop
2009-06-04 13:21 ` George Dunlap
2009-06-04 15:10 ` Theodore Tso
2009-06-04 15:31 ` Chris Friesen
2009-06-05 4:14 ` Bill Davidsen
2009-06-05 4:55 ` Chris Friesen
2009-06-02 22:40 ` Steven Rostedt
2009-06-02 23:28 ` Merge Xen (the hypervisor) into Linux Ingo Molnar
2009-06-03 0:00 ` Dan Magenheimer
2009-06-03 0:32 ` Thomas Gleixner
2009-06-03 2:43 ` Theodore Tso
2009-06-03 3:42 ` Steven Rostedt
2009-06-03 4:49 ` Dan Magenheimer
2009-06-03 4:58 ` David Miller
2009-06-03 5:07 ` Steven Rostedt
2009-06-03 5:22 ` Steven Rostedt
2009-06-03 12:03 ` George Dunlap
2009-06-03 19:05 ` Theodore Tso
[not found] ` <4A27CF94.1050903@gmx.de>
2009-06-04 14:03 ` [Xen-users] " Steven Rostedt
2009-06-03 7:28 ` Gerd Hoffmann
2009-06-03 8:47 ` Alan Cox
2009-06-03 9:09 ` Gerd Hoffmann
2009-06-03 9:20 ` Keir Fraser
2009-06-03 11:15 ` Theodore Tso
2009-06-03 11:39 ` Keir Fraser
2009-06-03 11:41 ` Gerd Hoffmann
2009-06-03 1:00 ` Joel Becker
2009-06-03 2:00 ` david
2009-06-03 7:59 ` Alan Cox
2009-06-03 8:07 ` Christian Tramnitz
2009-06-04 18:53 ` Linus Torvalds
2009-06-05 0:09 ` Samuel Thibault
2009-06-05 0:18 ` David Miller
2009-06-05 0:54 ` Linus Torvalds
2009-06-03 17:31 ` Chris Friesen
2009-06-03 17:36 ` Alan Cox
2009-06-02 23:41 ` Xen is a feature Thomas Gleixner
2009-05-30 2:19 ` [Xen-devel] " Andy Burns
2009-05-26 21:19 ` Gerd Hoffmann [this message]
2009-05-27 10:14 ` [Xen-devel] Re: [GIT PULL] Xen APIC hooks (with io_apic_ops) George Dunlap
2009-05-24 20:10 ` Avi Kivity
2009-05-25 3:51 ` Ingo Molnar
2009-05-25 4:55 ` Avi Kivity
2009-05-25 5:06 ` Ingo Molnar
2009-05-25 5:12 ` Avi Kivity
2009-05-25 5:19 ` Ingo Molnar
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