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Re: [Qemu-devel] [RFC] qmp interface for save vmstate to image
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [RFC] qmp interface for save vmstate to image |
Date: |
Thu, 21 Mar 2013 15:56:30 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Thu, Mar 21, 2013 at 02:42:23PM +0100, Paolo Bonzini wrote:
> Il 21/03/2013 14:38, Stefan Hajnoczi ha scritto:
> > There already is a guest RAM cloning mechanism: fork the QEMU process.
> > Then you have a copy-on-write guest RAM.
> >
> > In a little more detail:
> >
> > 1. save non-RAM device state
> > 2. quiesce QEMU to a state that is safe for forking
> > 3. create an EventNotifier for live savevm completion signal
> > 4. fork and pass completion EventNotifier to child
> > 5. parent continues running VM
> > 6. child performs vmsave of copy-on-write guest RAM
> > 7. child signals completion EventNotifier and terminates
> > 8. parent raises live savevm completion QMP event
>
> Forking a threaded program is not so easy, but it could be done if the
> child is very simple and only uses syscalls to communicate back with the
> parent:
On Linux you should be able to use clone(2) to spawn a thread with
copy-on-write memory. Too bad it's not portable because it gets around
the messy fork issues.
Stefan
Re: [Qemu-devel] [RFC] qmp interface for save vmstate to image, Pavel Hrdina, 2013/03/18
- Re: [Qemu-devel] [RFC] qmp interface for save vmstate to image, Wenchao Xia, 2013/03/21
- Re: [Qemu-devel] [RFC] qmp interface for save vmstate to image, Pavel Hrdina, 2013/03/21
- Re: [Qemu-devel] [RFC] qmp interface for save vmstate to image, Stefan Hajnoczi, 2013/03/21
- Re: [Qemu-devel] [RFC] qmp interface for save vmstate to image, Paolo Bonzini, 2013/03/21
- Re: [Qemu-devel] [RFC] qmp interface for save vmstate to image, Pavel Hrdina, 2013/03/21
- Re: [Qemu-devel] [RFC] qmp interface for save vmstate to image,
Stefan Hajnoczi <=
- Re: [Qemu-devel] [RFC] qmp interface for save vmstate to image, Eric Blake, 2013/03/21
- Re: [Qemu-devel] [RFC] qmp interface for save vmstate to image, Wenchao Xia, 2013/03/23
- Re: [Qemu-devel] [RFC] qmp interface for save vmstate to image, Wenchao Xia, 2013/03/26
Re: [Qemu-devel] [RFC] qmp interface for save vmstate to image, Pavel Hrdina, 2013/03/21