Re: [RFC v5 1/6] qmp: add QMP command x-debug-query-virtio

[Eric Blake]

On 3/18/21 11:29 AM, Jonah Palmer wrote:
> From: Laurent Vivier <lvivier@redhat.com>
> 
> This new command lists all the instances of VirtIODevice with
> their path and virtio type
> 
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>
> Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com>
> ---

We've missed soft freeze for 6.0, and this feels like a new feature;
therefore...

> +++ b/hw/virtio/virtio.c

>  
> +VirtioInfoList *qmp_x_debug_query_virtio(Error **errp)
> +{
> +    VirtioInfoList *list = NULL;
> +    VirtioInfoList *node;
> +    VirtIODevice *vdev;
> +
> +    QTAILQ_FOREACH(vdev, &virtio_list, next) {
> +        DeviceState *dev = DEVICE(vdev);
> +        node = g_new0(VirtioInfoList, 1);
> +        node->value = g_new(VirtioInfo, 1);
> +        node->value->path = g_strdup(dev->canonical_path);
> +        node->value->type = qapi_enum_parse(&VirtioType_lookup, vdev->name,
> +                                            VIRTIO_TYPE_UNKNOWN, NULL);
> +        node->next = list;
> +        list = node;

This should be updated to use QAPI_LIST_PREPEND rather than open coding.

> +    }
> +
> +    return list;
> +}
> +
>  static const TypeInfo virtio_device_info = {
>      .name = TYPE_VIRTIO_DEVICE,
>      .parent = TYPE_DEVICE,
> diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
> index b7ece7a..2470e09 100644
> --- a/include/hw/virtio/virtio.h

> +++ b/qapi/virtio.json
> @@ -0,0 +1,68 @@
> +##
> +# = Virtio devices
> +##
> +
> +##
> +# @VirtioType:
> +#
> +# An enumeration of Virtio device types.
> +#
> +# Since: 6.0

...this now needs to reference 6.1.

> +##
> +{ 'enum': 'VirtioType',
> +  'data': [ 'unknown', 'virtio-9p', 'virtio-blk', 'virtio-serial',
> +            'virtio-gpu', 'virtio-input', 'virtio-net', 'virtio-scsi',
> +            'vhost-user-fs', 'vhost-vsock', 'virtio-balloon', 
> 'virtio-crypto',
> +            'virtio-iommu', 'virtio-pmem', 'virtio-rng' ]
> +}
> +
> +##
> +# @VirtioInfo:
> +#
> +# Information about a given VirtIODevice
> +#
> +# @path: VirtIO device canonical path.
> +#
> +# @type: VirtIO device type.
> +#
> +# Since: 6.0

and throughout the series (I'll quit pointing it out)

> +##
> +# @x-debug-query-virtio:
> +#
> +# Return the list of all VirtIO devices
> +#
> +# Returns: list of @VirtioInfo
> +#
> +# Since: 6.0
> +#
> +# Example:
> +#
> +# -> { "execute": "x-debug-query-virtio" }

That said, adding an 'x-' experimental feature is NOT locking us down,
so if some maintainer still wants to include this in -rc1 on the grounds
that it will help debugging other things, rather than pushing it out to
6.1 as a new feature, then keeping things as 6.0 is tolerable in that
border-line case.  (If it misses -rc1, then I will become more adamant
that it does not belong in 6.0)

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