Re: [PATCH v2 6/6] qapi: introduce CONFIG_READ event

[Markus Armbruster <armbru@redhat.com>]

Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> writes:

> Send a new event when guest reads virtio-pci config after
> virtio_notify_config() call.
>
> That's useful to check that guest fetched modified config, for example
> after resizing disk backend.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>

[...]

> diff --git a/qapi/qdev.json b/qapi/qdev.json
> index 6ece164172..ffc5e3be18 100644
> --- a/qapi/qdev.json
> +++ b/qapi/qdev.json
> @@ -179,3 +179,29 @@
>  { 'command': 'device-sync-config',
>    'features': [ 'unstable' ],
>    'data': {'id': 'str'} }
> +
> +##
> +# @VIRTIO_CONFIG_READ:
> +#
> +# Emitted whenever guest reads virtio device config after config change.

Let's not abbreviate "configuration" to "config".

> +#
> +# @device: device name
> +#
> +# @path: device path
> +#
> +# Features:
> +#
> +# @unstable: The event is experimental.
> +#
> +# Since: 9.0
> +#
> +# Example:
> +#
> +#     <- { "event": "VIRTIO_CONFIG_READ",
> +#          "data": { "device": "virtio-net-pci-0",
> +#                    "path": "/machine/peripheral/virtio-net-pci-0" },
> +#          "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }
> +##

As for PATCH 4, I'd like to see some guidance on intended use.

> +{ 'event': 'VIRTIO_CONFIG_READ',
> +  'features': [ 'unstable' ],
> +  'data': { '*device': 'str', 'path': 'str' } }

[...]