On Sun, Feb 03, 2013 at 03:09:39PM -0600, Anthony Liguori wrote: > Michael Tokarev <m...@tls.msk.ru> writes: > > > 03.02.2013 17:23, Yan Vugenfirer wrote: > > > >>> If it helps, mq changes the config size from 8 to 16 bytes. If the > >>> driver was making an assumption about an 8-byte config size, that's > >>> likely what the problem is. > >>> > >> That's exactly the problem. > > > > So what do we do? It isn't nice to break existing setups. > > Maybe mq can be disabled by default (together with Antony's > > patch) until fixed drivers will be more widely available? > > I've got a patch that does exactly like this. It's pretty ugly though > because of the relationship between virtio-pci and virtio-net. I'm > going to try to see if I can find a cleaner way to do it on Monday. > > I'm also contemplating just disabling mq by default. Since a special > command line is needed to enable it anyway (on the backend), having to > specify mq=on for the device doesn't seem so bad.
It's after midnight here so didn't test yet, but wouldn't the following achieve this in a way that is a bit cleaner? Signed-off-by: Michael S. Tsirkin <m...@redhat.com> diff --git a/hw/virtio-net.c b/hw/virtio-net.c index 5699f5e..3342a76 100644 --- a/hw/virtio-net.c +++ b/hw/virtio-net.c @@ -346,6 +346,10 @@ static uint32_t virtio_net_get_features(VirtIODevice *vdev, uint32_t features) features |= (1 << VIRTIO_NET_F_MAC); + if (n->max_queues <= 1) { + features &= ~(0x1 << VIRTIO_NET_F_MQ); + } + if (!peer_has_vnet_hdr(n)) { features &= ~(0x1 << VIRTIO_NET_F_CSUM); features &= ~(0x1 << VIRTIO_NET_F_HOST_TSO4); @@ -1284,7 +1288,9 @@ VirtIODevice *virtio_net_init(DeviceState *dev, NICConf *conf, int i; n = (VirtIONet *)virtio_common_init("virtio-net", VIRTIO_ID_NET, - sizeof(struct virtio_net_config), + conf->queues > 1 ? + sizeof(struct virtio_net_config) : + sizeof(struct virtio_net_config_compat), sizeof(VirtIONet)); n->vdev.get_config = virtio_net_get_config; diff --git a/hw/virtio-net.h b/hw/virtio-net.h index 1d5c721..95ad54f 100644 --- a/hw/virtio-net.h +++ b/hw/virtio-net.h @@ -69,6 +69,15 @@ typedef struct virtio_net_conf /* Maximum packet size we can receive from tap device: header + 64k */ #define VIRTIO_NET_MAX_BUFSIZE (sizeof(struct virtio_net_hdr) + (64 << 10)) + +struct virtio_net_config_compat +{ + /* The config defining mac address ($ETH_ALEN bytes) */ + uint8_t mac[ETH_ALEN]; + /* See VIRTIO_NET_F_STATUS and VIRTIO_NET_S_* above */ + uint16_t status; +} QEMU_PACKED; + struct virtio_net_config { /* The config defining mac address ($ETH_ALEN bytes) */