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From: Jamie Lokier <jamie@shareable.org>
To: Glauber Costa <glommer@redhat.com>
Cc: kvm-devel <kvm@vger.kernel.org>,
	Anthony Liguori <aliguori@us.ibm.com>,
	Avi Kivity <avi@redhat.com>, Gleb Natapov <gleb@redhat.com>,
	qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] Re: [PATCH v2 3/9] provide in-kernel ioapic
Date: Fri, 9 Oct 2009 17:49:55 +0100	[thread overview]
Message-ID: <20091009164955.GC7393@shareable.org> (raw)
In-Reply-To: <20091009143225.GV8092@mothafucka.localdomain>

Glauber Costa wrote:
> On Thu, Oct 08, 2009 at 06:22:48PM +0200, Gleb Natapov wrote:
> > On Thu, Oct 08, 2009 at 06:17:57PM +0200, Avi Kivity wrote:
> > > On 10/08/2009 06:07 PM, Jamie Lokier wrote:
> > > >Haven't we already confirmed that it *isn't* just an ioapic accelerator
> > > >because you can't migrate between in-kernel iopic and qemu's ioapic?
> > > 
> > > We haven't confirmed it.  Both implement the same spec, and if you
> > > can't migrate between them, one of them has a bug (for example, qemu
> > > ioapic doesn't implement polarity - but it's still just a bug).
> > > 
> > Are you saying that HW spec (that only describes software visible behavior)
> > completely defines implementation? No other internal state is needed
> > that may be done differently by different implementations?
> Most specifications leaves a lot as implementation specific.
> 
> It's not hard to imagine a case in which both devices will follow
> the spec correctly, (no bugs involved), and yet differ in the
> implementation.

Avi's not saying the implementations won't differ.  I believe he's
saying that implementation-specific states don't need to be saved if
they have no effect on guest visible behaviour.

-- Jamie

  reply	other threads:[~2009-10-09 16:50 UTC|newest]

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-10-07 22:08 [Qemu-devel] [PATCH v2] Add in-kernel irqchip Glauber Costa
2009-10-07 22:08 ` [Qemu-devel] [PATCH v2 1/9] add base-addr field to io apic state Glauber Costa
2009-10-07 22:08   ` [Qemu-devel] [PATCH v2 2/9] Save missing fields in VMState Glauber Costa
2009-10-07 22:08     ` [Qemu-devel] [PATCH v2 3/9] provide in-kernel ioapic Glauber Costa
2009-10-07 22:08       ` [Qemu-devel] [PATCH v2 4/9] provide in-kernel apic Glauber Costa
2009-10-07 22:08         ` [Qemu-devel] [PATCH v2 5/9] provide apic_set_irq_delivered Glauber Costa
2009-10-07 22:08           ` [Qemu-devel] [PATCH v2 6/9] provide in-kernel i8259 chip Glauber Costa
2009-10-07 22:08             ` [Qemu-devel] [PATCH v2 7/9] initialize " Glauber Costa
2009-10-07 22:08               ` [Qemu-devel] [PATCH v2 8/9] Initialize in-kernel irqchip Glauber Costa
2009-10-07 22:08                 ` [Qemu-devel] [PATCH v2 9/9] Add -kvm option Glauber Costa
2009-10-07 23:00                   ` [Qemu-devel] " Anthony Liguori
2009-10-07 23:14                     ` Glauber Costa
2009-10-07 23:28                       ` Anthony Liguori
2009-10-12 11:58                         ` Gerd Hoffmann
2009-10-12 14:04                           ` Anthony Liguori
2009-10-12 15:34                             ` Gerd Hoffmann
2009-10-12 16:31                               ` Anthony Liguori
2009-10-13  8:05                                 ` Gerd Hoffmann
2009-10-13 15:33                                   ` Anthony Liguori
2009-10-13 19:26                                     ` Markus Armbruster
2009-10-13 20:43                                       ` Anthony Liguori
2009-10-14  8:08                                         ` Gerd Hoffmann
2009-10-13 15:36                                   ` Anthony Liguori
2009-10-13 22:57                                     ` Jamie Lokier
2009-10-08 14:07                     ` Avi Kivity
2009-10-08 14:23                       ` Anthony Liguori
2009-10-08 14:30                         ` Avi Kivity
2009-10-08 14:33                           ` Anthony Liguori
2009-10-08 14:41                             ` Avi Kivity
2009-10-08 14:56                               ` Anthony Liguori
2009-10-08 15:05                                 ` Avi Kivity
2009-10-08 15:14                                   ` Anthony Liguori
2009-10-12 11:15                                     ` Gerd Hoffmann
2009-10-08 14:34                           ` Gleb Natapov
2009-10-08 12:02               ` [Qemu-devel] Re: [PATCH v2 7/9] initialize i8259 chip Jan Kiszka
2009-10-08 13:55         ` [Qemu-devel] Re: [PATCH v2 4/9] provide in-kernel apic Anthony Liguori
2009-10-08 14:09           ` Avi Kivity
2009-10-08 14:22             ` Glauber Costa
2009-10-09 10:06               ` Jamie Lokier
2009-10-09 14:30                 ` Glauber Costa
2009-10-09 16:48                   ` Jamie Lokier
2009-10-09 18:06                     ` Glauber Costa
2009-10-09 19:49                     ` Anthony Liguori
2009-10-11  9:10                       ` Avi Kivity
2009-10-12 13:41                         ` Anthony Liguori
2009-10-08 14:26             ` Anthony Liguori
2009-10-08 14:31               ` Avi Kivity
2009-10-08 14:39                 ` Anthony Liguori
2009-10-08 14:46                   ` Glauber Costa
2009-10-08 14:44                 ` Glauber Costa
2009-10-08 11:46       ` [Qemu-devel] Re: [PATCH v2 3/9] provide in-kernel ioapic Jan Kiszka
2009-10-08 13:49       ` Anthony Liguori
2009-10-08 13:54         ` Avi Kivity
2009-10-08 15:53           ` Jan Kiszka
2009-10-08 16:07           ` Jamie Lokier
2009-10-08 16:12             ` Anthony Liguori
2009-10-08 16:17             ` Avi Kivity
2009-10-08 16:22               ` Gleb Natapov
2009-10-08 16:29                 ` Avi Kivity
2009-10-08 16:34                   ` Gleb Natapov
2009-10-08 16:42                     ` Avi Kivity
2009-10-08 17:11                       ` Gleb Natapov
2009-10-09 10:02                         ` Jamie Lokier
2009-10-09 12:02                           ` Gleb Natapov
2009-10-09 14:32                 ` Glauber Costa
2009-10-09 16:49                   ` Jamie Lokier [this message]
     [not found]                     ` <m31vlctk9q.fsf@neno.mitica>
2009-10-09 21:34                       ` Glauber Costa
2009-10-12 13:20                       ` Anthony Liguori
2009-10-12 14:18                         ` Jamie Lokier
2009-10-12 14:49                           ` Anthony Liguori

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