Re: [PATCH] migration: Provide a test for migratability

[Eric Blake <eblake@redhat.com>]

On 1/21/21 12:51 PM, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> 
> Provide a simple way to see if there's currently a migration blocker in
> operation:
> 
> $ ./x86_64-softmmu/qemu-system-x86_64 -nographic -M pc,usb=on -chardev null,id=n -device usb-serial,chardev=n
> 
> (qemu) info migratable
> Error: State blocked by non-migratable device '0000:00:01.2/1/usb-serial'
> 
> $ ./x86_64-softmmu/qemu-system-x86_64 -nographic
> 
> (qemu) info migratable
> Migratable
> 
> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---


> +++ b/qapi/migration.json
> @@ -366,6 +366,20 @@
>  ##
>  { 'command': 'query-migrate', 'returns': 'MigrationInfo' }
>  
> +##
> +# @query-migratable:
> +# Tests whether it will be possible to migrate the VM in the current state.
> +#
> +# Returns: nothing on success (i.e. if the VM is migratable)

Do we really need a new command?  Or can we get away with enhancing the
existing 'query-migrate' to add another bool field to 'MigrationInfo'?

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org