Re: [PATCH v2 01/15] net: Introduce NetClientInfo.check_peer_type()

Some network backends (vhost-user and vhost-vdpa) work only with specific devices. At startup, they second guess what the command line option handling will do and error out if they think a non-virtio device will attach to them. This second guessing is not only ugly, it can lead to wrong error messages ('-device floppy,netdev=foo' should complain about an unknown property, not about the wrong kind of network device being attached) and completely ignores hotplugging. Add a callback where backends can check compatibility with a device when it actually tries to attach, even on hotplug. Signed-off-by: Kevin Wolf <kwolf(a)redhat.com&gt;

--- include/net/net.h | 2 ++ hw/core/qdev-properties-system.c | 6 ++++++ 2 files changed, 8 insertions(+) diff --git a/include/net/net.h b/include/net/net.h index 5d1508081f..986288eb07 100644 --- a/include/net/net.h +++ b/include/net/net.h @@ -62,6 +62,7 @@ typedef struct SocketReadState SocketReadState; typedef void (SocketReadStateFinalize)(SocketReadState *rs); typedef void (NetAnnounce)(NetClientState *); typedef bool (SetSteeringEBPF)(NetClientState *, int); +typedef bool (NetCheckPeerType)(NetClientState *, ObjectClass *, Error **); typedef struct NetClientInfo { NetClientDriver type; @@ -84,6 +85,7 @@ typedef struct NetClientInfo { SetVnetBE *set_vnet_be; NetAnnounce *announce; SetSteeringEBPF *set_steering_ebpf; + NetCheckPeerType *check_peer_type; } NetClientInfo; struct NetClientState { diff --git a/hw/core/qdev-properties-system.c b/hw/core/qdev-properties-system.c index e71f5d64d1..a91f60567a 100644 --- a/hw/core/qdev-properties-system.c +++ b/hw/core/qdev-properties-system.c @@ -431,6 +431,12 @@ static void set_netdev(Object *obj, Visitor *v, const char *name, goto out; } + if (peers[i]->info->check_peer_type) { + if (!peers[i]->info->check_peer_type(peers[i], obj->class, errp)) { + goto out; + } + } + ncs[i] = peers[i]; ncs[i]->queue_index = i; }