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Re: [Qemu-devel] [PATCH 02/18] Introduce read() to FdMigrationState.
From: |
Daniel P. Berrange |
Subject: |
Re: [Qemu-devel] [PATCH 02/18] Introduce read() to FdMigrationState. |
Date: |
Thu, 10 Feb 2011 10:44:45 +0000 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Thu, Feb 10, 2011 at 07:23:33PM +0900, Yoshiaki Tamura wrote:
> 2011/2/10 Daniel P. Berrange <address@hidden>:
> > On Thu, Feb 10, 2011 at 10:54:01AM +0100, Anthony Liguori wrote:
> >> On 02/10/2011 10:30 AM, Yoshiaki Tamura wrote:
> >> >Currently FdMigrationState doesn't support read(), and this patch
> >> >introduces it to get response from the other side.
> >> >
> >> >Signed-off-by: Yoshiaki Tamura<address@hidden>
> >>
> >> Migration is unidirectional. Changing this is fundamental and not
> >> something to be done lightly.
> >
> > Making it bi-directional might break libvirt's save/restore
> > to file support which uses migration, passing a unidirectional
> > FD for the file. It could also break libvirt's secure tunnelled
> > migration support which is currently only expecting to have
> > data sent in one direction on the socket.
>
> Hi Daniel,
>
> IIUC, this patch isn't something to make existing live migration
> bi-directional. Just opens up a way for Kemari to use it. Do
> you think it's dangerous for libvirt still?
The key is for it to be a no-op for any usage of the existing
'migrate' command. I had thought this was wiring up read into
the event loop too, so it would be poll()ing for reads, but
after re-reading I see this isn't the case here.
Regards,
Daniel
--
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- [Qemu-devel] [PATCH 12/18] Insert event_tap_mmio() to cpu_physical_memory_rw() in exec.c., (continued)
- [Qemu-devel] [PATCH 12/18] Insert event_tap_mmio() to cpu_physical_memory_rw() in exec.c., Yoshiaki Tamura, 2011/02/10
- [Qemu-devel] [PATCH 13/18] net: insert event-tap to qemu_send_packet() and qemu_sendv_packet_async()., Yoshiaki Tamura, 2011/02/10
- [Qemu-devel] [PATCH 01/18] Make QEMUFile buf expandable, and introduce qemu_realloc_buffer() and qemu_clear_buffer()., Yoshiaki Tamura, 2011/02/10
- [Qemu-devel] [PATCH 18/18] Introduce "kemari:" to enable FT migration mode (Kemari)., Yoshiaki Tamura, 2011/02/10
- [Qemu-devel] [PATCH 02/18] Introduce read() to FdMigrationState., Yoshiaki Tamura, 2011/02/10
- [Qemu-devel] [PATCH 08/18] savevm: introduce util functions to control ft_trans_file from savevm layer., Yoshiaki Tamura, 2011/02/10
- [Qemu-devel] [PATCH 03/18] Introduce skip_header parameter to qemu_loadvm_state()., Yoshiaki Tamura, 2011/02/10
- [Qemu-devel] [PATCH 16/18] migration: introduce migrate_ft_trans_{put, get}_ready(), and modify migrate_fd_put_ready() when ft_mode is on., Yoshiaki Tamura, 2011/02/10
- [Qemu-devel] [PATCH 17/18] migration-tcp: modify tcp_accept_incoming_migration() to handle ft_mode, and add a hack not to close fd when ft_mode is enabled., Yoshiaki Tamura, 2011/02/10
- [Qemu-devel] [PATCH 11/18] ioport: insert event_tap_ioport() to ioport_write()., Yoshiaki Tamura, 2011/02/10
- [Qemu-devel] [PATCH 07/18] Introduce fault tolerant VM transaction QEMUFile and ft_mode., Yoshiaki Tamura, 2011/02/10