From: Paolo Bonzini <pbonzini@redhat.com>
To: Avi Kivity <avi@redhat.com>
Cc: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
"Jan Kiszka" <jan.kiszka@siemens.com>,
"Matthew Ogilvie" <mmogilvi_qemu@miniinfo.net>,
"Andreas Färber" <afaerber@suse.de>,
"quintela@redhat.com" <quintela@redhat.com>
Subject: Re: [Qemu-devel] [PATCH v4 5/5] i8259: fix dynamically masking slave IRQs with IMR register
Date: Tue, 04 Sep 2012 11:15:43 +0200 [thread overview]
Message-ID: <5045C6BF.3040207@redhat.com> (raw)
In-Reply-To: <5045B8E3.9070305@redhat.com>
Il 04/09/2012 10:16, Avi Kivity ha scritto:
>> > But the point of subsections is to succeed migration in the common case,
>> > assuming there is more than one case that doesn't affect guest operation.
> According to the patch, if icw3 == 4 && !(eclr & 4), then behaviour will
> change. With the standard configuration, if two pci interrupts hit at
> once, then before the patch irr.2 will be clear, and afterwards set.
>
> So we do have a behavioural change. Is the rest of the code masking
> this change under the standard configuration?
No, it is not masking the change. The assumption is that nothing should
care about irr.2 or isr.2, because nothing attaches an handler to the
cascade interrupt.
You have to choose between assuming this, and breaking backwards
migration. I would rather break backwards migration, but others disagree...
Paolo
next prev parent reply other threads:[~2012-09-04 9:16 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-03 2:56 [Qemu-devel] [PATCH v4 0/5] Running Microport UNIX (ca 1987) Matthew Ogilvie
2012-09-03 2:56 ` [Qemu-devel] [PATCH v4 1/5] fix some debug printf format strings Matthew Ogilvie
2012-09-03 2:56 ` [Qemu-devel] [PATCH v4 2/5] vl: fix -hdachs/-hda argument order parsing issues Matthew Ogilvie
2012-09-03 2:56 ` [Qemu-devel] [PATCH v4 3/5] qemu-options.hx: mention retrace= VGA option Matthew Ogilvie
2012-09-03 2:56 ` [Qemu-devel] [PATCH v4 4/5] vga: add some optional CGA compatibility hacks Matthew Ogilvie
2012-09-03 2:56 ` [Qemu-devel] [PATCH v4 5/5] i8259: fix dynamically masking slave IRQs with IMR register Matthew Ogilvie
2012-09-03 7:08 ` Paolo Bonzini
2012-09-03 8:40 ` Andreas Färber
2012-09-03 14:39 ` Avi Kivity
2012-09-03 15:42 ` Juan Quintela
2012-09-03 15:45 ` Jan Kiszka
2012-09-03 15:52 ` Avi Kivity
2012-09-03 15:54 ` Jan Kiszka
2012-09-03 15:57 ` Avi Kivity
2012-09-03 16:02 ` Jan Kiszka
2012-09-03 16:15 ` Avi Kivity
2012-09-03 16:23 ` Paolo Bonzini
2012-09-03 16:30 ` Avi Kivity
2012-09-03 16:33 ` Paolo Bonzini
2012-09-03 16:40 ` Jan Kiszka
2012-09-03 16:56 ` Paolo Bonzini
2012-09-04 8:16 ` Avi Kivity
2012-09-04 9:15 ` Paolo Bonzini [this message]
2012-09-04 9:20 ` Avi Kivity
2012-09-04 9:29 ` BALATON Zoltan
2012-09-04 9:37 ` Avi Kivity
2012-09-04 9:51 ` Jan Kiszka
2012-09-04 10:06 ` Paolo Bonzini
2012-09-04 10:44 ` Avi Kivity
2012-09-03 16:30 ` Jan Kiszka
2012-09-03 8:51 ` Jan Kiszka
2012-09-03 8:53 ` Jan Kiszka
2012-09-03 9:34 ` Paolo Bonzini
2012-09-03 10:34 ` Jan Kiszka
2012-09-03 11:11 ` Paolo Bonzini
2012-09-03 11:26 ` Jan Kiszka
2012-09-04 14:29 ` Maciej W. Rozycki
2012-09-04 14:42 ` Paolo Bonzini
2012-09-04 16:01 ` Jan Kiszka
2012-09-04 17:41 ` Maciej W. Rozycki
2012-09-04 17:55 ` Jan Kiszka
2012-09-04 18:27 ` Maciej W. Rozycki
2012-09-04 18:39 ` Jan Kiszka
2012-09-05 4:33 ` Matthew Ogilvie
2012-09-05 15:43 ` Jan Kiszka
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