From: Paul Brook <paul@codesourcery.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: qemu-devel@nongnu.org, Carsten Otte <cotte@de.ibm.com>,
kvm@vger.kernel.org, Rusty Russell <rusty@rustcorp.com.au>,
virtualization@lists.linux-foundation.org,
Blue Swirl <blauwirbel@gmail.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Avi Kivity <avi@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 05/11] qemu: MSI-X support functions
Date: Wed, 10 Jun 2009 17:46:03 +0100 [thread overview]
Message-ID: <200906101746.06740.paul@codesourcery.com> (raw)
In-Reply-To: <20090610162644.GJ28601@redhat.com>
> > If you can't create an identical machine from scratch then I don't
> > consider snapshot/migration to be a useful feature. i.e. as soon as you
> > shutdown and restart the guest it is liable to break anyway.
>
> Why is liable to break?
A VM booted on an old version of qemu and migrated to a new version will
behave differently to a the same VM booted on a new version of qemu.
I hope I don't need to explain why this is bad.
As previously discussed, any guest visible changes are liable to break a guest
OS, particularly guests like Windows which deliberately break when run on
"different" hardware. Personally I don't particularly care, but if we support
live migration we also need to support "cold" migration - i.e. shutdown and
restart.
>So once you load and image with MSIX capability off,
>it will stay off across guest restarts.
I'm assuming guest restart includes restarting qemu.
Paul
WARNING: multiple messages have this Message-ID (diff)
From: Paul Brook <paul@codesourcery.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Carsten Otte <cotte@de.ibm.com>,
kvm@vger.kernel.org, Rusty Russell <rusty@rustcorp.com.au>,
qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org,
Blue Swirl <blauwirbel@gmail.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Avi Kivity <avi@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 05/11] qemu: MSI-X support functions
Date: Wed, 10 Jun 2009 17:46:03 +0100 [thread overview]
Message-ID: <200906101746.06740.paul@codesourcery.com> (raw)
In-Reply-To: <20090610162644.GJ28601@redhat.com>
> > If you can't create an identical machine from scratch then I don't
> > consider snapshot/migration to be a useful feature. i.e. as soon as you
> > shutdown and restart the guest it is liable to break anyway.
>
> Why is liable to break?
A VM booted on an old version of qemu and migrated to a new version will
behave differently to a the same VM booted on a new version of qemu.
I hope I don't need to explain why this is bad.
As previously discussed, any guest visible changes are liable to break a guest
OS, particularly guests like Windows which deliberately break when run on
"different" hardware. Personally I don't particularly care, but if we support
live migration we also need to support "cold" migration - i.e. shutdown and
restart.
>So once you load and image with MSIX capability off,
>it will stay off across guest restarts.
I'm assuming guest restart includes restarting qemu.
Paul
next prev parent reply other threads:[~2009-06-10 16:46 UTC|newest]
Thread overview: 105+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1243253205.git.mst@redhat.com>
2009-05-25 12:12 ` [PATCHv2] qemu: make default_write_config use mask table Michael S. Tsirkin
2009-05-25 12:12 ` Michael S. Tsirkin
2009-05-25 12:12 ` [Qemu-devel] " Michael S. Tsirkin
2009-05-25 12:24 ` [PATCH 01/11] " Michael S. Tsirkin
2009-05-25 12:24 ` Michael S. Tsirkin
2009-05-25 12:24 ` [Qemu-devel] " Michael S. Tsirkin
2009-05-25 12:25 ` [PATCH 02/11] qemu: capability bits in pci save/restore Michael S. Tsirkin
2009-05-25 12:25 ` Michael S. Tsirkin
2009-05-25 12:25 ` [Qemu-devel] " Michael S. Tsirkin
2009-05-25 12:25 ` [PATCH 03/11] qemu: add routines to manage PCI capabilities Michael S. Tsirkin
2009-05-25 12:25 ` [Qemu-devel] " Michael S. Tsirkin
2009-05-26 8:49 ` Isaku Yamahata
2009-05-26 8:49 ` Isaku Yamahata
2009-05-26 9:22 ` Michael S. Tsirkin
2009-05-26 9:22 ` Michael S. Tsirkin
2009-05-26 9:22 ` Michael S. Tsirkin
2009-05-26 8:49 ` Isaku Yamahata
2009-05-26 9:30 ` [PATCH] qemu: fix pci_find_capability for multiple caps Michael S. Tsirkin
2009-05-26 9:30 ` [Qemu-devel] " Michael S. Tsirkin
2009-05-26 9:30 ` Michael S. Tsirkin
2009-05-25 12:25 ` [PATCH 03/11] qemu: add routines to manage PCI capabilities Michael S. Tsirkin
2009-05-25 12:25 ` [PATCH 04/11] qemu: helper routines for pci access Michael S. Tsirkin
2009-05-25 12:25 ` [Qemu-devel] " Michael S. Tsirkin
2009-05-26 2:33 ` Isaku Yamahata
2009-05-26 2:33 ` Isaku Yamahata
2009-05-26 6:41 ` Michael S. Tsirkin
2009-05-26 6:41 ` Michael S. Tsirkin
2009-05-26 8:07 ` Avi Kivity
2009-05-26 8:07 ` Avi Kivity
2009-05-26 8:49 ` Michael S. Tsirkin
2009-05-26 8:49 ` Michael S. Tsirkin
2009-05-26 8:49 ` Michael S. Tsirkin
2009-05-26 8:07 ` Avi Kivity
2009-05-26 6:41 ` Michael S. Tsirkin
2009-05-26 2:33 ` Isaku Yamahata
2009-05-25 12:25 ` Michael S. Tsirkin
2009-05-25 12:25 ` [PATCH 05/11] qemu: MSI-X support functions Michael S. Tsirkin
2009-05-25 12:25 ` [Qemu-devel] " Michael S. Tsirkin
2009-06-09 23:19 ` Paul Brook
2009-06-09 23:19 ` Paul Brook
2009-06-10 9:46 ` Michael S. Tsirkin
2009-06-10 9:46 ` Michael S. Tsirkin
2009-06-10 14:07 ` Paul Brook
2009-06-10 14:07 ` Paul Brook
2009-06-10 14:25 ` Michael S. Tsirkin
2009-06-10 14:25 ` Michael S. Tsirkin
2009-06-10 14:39 ` Paul Brook
2009-06-10 14:39 ` Paul Brook
2009-06-10 14:39 ` Paul Brook
2009-06-10 14:47 ` Michael S. Tsirkin
2009-06-10 14:47 ` Michael S. Tsirkin
2009-06-10 14:47 ` Michael S. Tsirkin
2009-06-10 15:15 ` Paul Brook
2009-06-10 15:15 ` Paul Brook
2009-06-10 15:52 ` Michael S. Tsirkin
2009-06-10 15:52 ` Michael S. Tsirkin
2009-06-10 16:08 ` Paul Brook
2009-06-10 16:08 ` Paul Brook
2009-06-10 16:26 ` Michael S. Tsirkin
2009-06-10 16:26 ` Michael S. Tsirkin
2009-06-10 16:26 ` Michael S. Tsirkin
2009-06-10 16:46 ` Paul Brook [this message]
2009-06-10 16:46 ` Paul Brook
2009-06-10 17:03 ` Michael S. Tsirkin
2009-06-10 17:03 ` Michael S. Tsirkin
2009-06-10 17:03 ` Michael S. Tsirkin
2009-06-10 17:30 ` Paul Brook
2009-06-10 17:30 ` Paul Brook
2009-06-10 18:07 ` Michael S. Tsirkin
2009-06-10 18:07 ` Michael S. Tsirkin
2009-06-10 19:04 ` Paul Brook
2009-06-10 19:04 ` Paul Brook
2009-06-11 8:29 ` Michael S. Tsirkin
2009-06-11 8:29 ` Michael S. Tsirkin
2009-06-11 8:29 ` Michael S. Tsirkin
2009-06-10 19:04 ` Paul Brook
2009-06-10 18:07 ` Michael S. Tsirkin
2009-06-10 17:30 ` Paul Brook
2009-06-10 16:46 ` Paul Brook
2009-06-10 16:08 ` Paul Brook
2009-06-10 15:52 ` Michael S. Tsirkin
2009-06-10 15:15 ` Paul Brook
2009-06-10 14:25 ` Michael S. Tsirkin
2009-06-10 14:07 ` Paul Brook
2009-06-10 9:46 ` Michael S. Tsirkin
2009-06-09 23:19 ` Paul Brook
2009-05-25 12:25 ` Michael S. Tsirkin
2009-05-25 12:25 ` [PATCH 06/11] qemu: add flag to disable MSI-X by default Michael S. Tsirkin
2009-05-25 12:25 ` Michael S. Tsirkin
2009-05-25 12:25 ` [Qemu-devel] " Michael S. Tsirkin
2009-05-25 12:25 ` [PATCH 07/11] qemu: minimal MSI/MSI-X implementation for PC Michael S. Tsirkin
2009-05-25 12:25 ` [Qemu-devel] " Michael S. Tsirkin
2009-05-25 12:25 ` Michael S. Tsirkin
2009-05-25 12:26 ` [PATCH 08/11] qemu: add support for resizing regions Michael S. Tsirkin
2009-05-25 12:26 ` Michael S. Tsirkin
2009-05-25 12:26 ` [Qemu-devel] " Michael S. Tsirkin
2009-05-25 12:26 ` [PATCH 09/11] qemu: virtio support for many interrupt vectors Michael S. Tsirkin
2009-05-25 12:26 ` [Qemu-devel] " Michael S. Tsirkin
2009-05-25 12:26 ` Michael S. Tsirkin
2009-05-25 12:26 ` [PATCH 10/11] qemu: MSI-X support in virtio PCI Michael S. Tsirkin
2009-05-25 12:26 ` Michael S. Tsirkin
2009-05-25 12:26 ` [Qemu-devel] " Michael S. Tsirkin
2009-05-25 12:26 ` [PATCH 11/11] qemu: request 3 vectors in virtio-net Michael S. Tsirkin
2009-05-25 12:26 ` [Qemu-devel] " Michael S. Tsirkin
2009-05-25 12:26 ` Michael S. Tsirkin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=200906101746.06740.paul@codesourcery.com \
--to=paul@codesourcery.com \
--cc=avi@redhat.com \
--cc=blauwirbel@gmail.com \
--cc=borntraeger@de.ibm.com \
--cc=cotte@de.ibm.com \
--cc=kvm@vger.kernel.org \
--cc=mst@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=rusty@rustcorp.com.au \
--cc=virtualization@lists.linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.