Re: [Qemu-devel] [PATCH] Introduce "xen-load-devices-state"

[Changlong Xie]

On 03/11/2016 04:31 AM, Eric Blake wrote:
> On 03/10/2016 03:23 AM, Changlong Xie wrote:
> > From: Wen Congyang <address@hidden>
> >
> > Introduce a "xen-load-devices-state" QAPI command that can be used to load
> > the state of all devices, but not the RAM or the block devices of the
> > VM.
> >
> > We only have hmp commands savevm/loadvm, and qmp commands
> > xen-save-devices-state.
> >
> > We use this new command for COLO:
> > 1. suspend both primay vm and secondary vm
>
> s/primay/primary/

Hi Eric

Will fix in next version.

> > 2. sync the state
> > 3. resume both primary vm and secondary vm
> >
> > In such case, we need to update all devices's state in any time.
>
> s/devices's/devices/'

Ditto.

> > Signed-off-by: Wen Congyang <address@hidden>
> > Signed-off-by: Changlong Xie <address@hidden>
> > ---
>
> > +++ b/qapi-schema.json
> > @@ -4122,3 +4122,21 @@
> >   ##
> >   { 'enum': 'ReplayMode',
> >     'data': [ 'none', 'record', 'play' ] }
> > +
> > +##
> > +# @xen-load-devices-state:
> > +#
> > +# Load the state of all devices from file. The RAM and the block devices
> > +# of the VM are not loaded by this command.
> > +#
> > +# @filename: the file to load the state of the devices from as binary
> > +# data. See xen-save-devices-state.txt for a description of the binary
> > +# format.
> > +#
> > +# Returns: Nothing on success
> > +#          If @filename cannot be opened, OpenFileFailed
> > +#          If an I/O error occurs while reading the file, IOError
>
> Drop the whole Returns: paragraph.  We have very few distinguished error
> categories, and you are not using anything other than a generic error
> category here (that is, OpenFileFailed and IOError are NOT valid QMP
> error categories).

Ditto.

> > +#
> > +# Since: 2.6
>
> You missed soft freeze; is this still 2.6 material?

"Since: 2.7" should be fine.

> > +++ b/qmp-commands.hx
> > @@ -587,6 +587,33 @@ Example:
> >   EQMP
> >
> >       {
> > +        .name       = "xen-load-devices-state",
> > +        .args_type  = "filename:F",
> > +        .mhandler.cmd_new = qmp_marshal_xen_load_devices_state,
> > +    },
> > +
> > +SQMP
> > +xen-load-devices-state
> > +-------
>
> Make the ---- separator line the same length as the text it is underlining.

Surely.

Thanks
        -Xie