[Qemu-devel] Re: [PATCH v4] savevm: Fix no_migrate

["Daniel P. Berrange" <berrange@redhat.com>]

On Fri, Jan 07, 2011 at 03:13:25PM -0700, Alex Williamson wrote:
> The no_migrate save state flag is currently only checked in the
> last phase of migration.  This means that we potentially waste
> a lot of time and bandwidth with the live state handlers before
> we ever check the no_migrate flags.  The error message printed
> when we catch a non-migratable device doesn't get printed for
> a detached migration.  And, no_migrate does nothing to prevent
> an incoming migration to a target that includes a non-migratable
> device.  This attempts to fix all of these.
> 
> One notable difference in behavior is that an outgoing migration
> now checks for non-migratable devices before ever connecting to
> the target system.  This means the target will remain listening
> rather than exit from failure.
> 
> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> ---
> 
> v4:
>   - fix braces noted by Jan
>   - return error from qemu_savevm_state_blocked rather than fixed EINVAL
>     at qemu_loadvm_state(), since it'a already using errno values
> 
> v3:
> 
> Daniel, adding you to see if libvirt cares about the difference in
> whether the target exits on migration failure as noted above.

If the 'migrate' command on the source QEMU returns an error,
then libvirt will teardown the target QEMU automatically, so
that's not a problem.

Regards,
Daniel