Re: [Qemu-devel] [PATCHv2] virtio-net: remove mq feature flag

[Blue Swirl]

On Mon, Feb 4, 2013 at 7:41 AM, Michael S. Tsirkin <address@hidden> wrote:
> mq flag is not needed: we can look at the number of queues and set
> the flag accordingly.
> Removing this feature removes ambiguity (what does it mean to have
> queues=2 with mq=off?), and simplifies compatibility hacks.
> work-around for buggy windows
> guests.
>
> Signed-off-by: Michael S. Tsirkin <address@hidden>
> ---
>  hw/pc_piix.c    |  4 ----
>  hw/virtio-net.c |  8 +++++++-
>  hw/virtio-net.h | 15 ++++++++++++---
>  3 files changed, 19 insertions(+), 8 deletions(-)
>
> diff --git a/hw/pc_piix.c b/hw/pc_piix.c
> index 0af436c..ba09714 100644
> --- a/hw/pc_piix.c
> +++ b/hw/pc_piix.c
> @@ -313,10 +313,6 @@ static QEMUMachine pc_i440fx_machine_v1_4 = {
>              .driver   = "virtio-net-pci",\
>              .property = "ctrl_mac_addr",\
>              .value    = "off",      \
> -        },{ \
> -            .driver   = "virtio-net-pci", \
> -            .property = "mq", \
> -            .value    = "off", \
>          }
>
>  static QEMUMachine pc_machine_v1_3 = {
> diff --git a/hw/virtio-net.c b/hw/virtio-net.c
> index e37358a..8db1787 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);
> @@ -1285,7 +1289,9 @@ 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 f5fea6e..b1f7647 100644
> --- a/hw/virtio-net.h
> +++ b/hw/virtio-net.h
> @@ -69,6 +69,17 @@ 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))
>
> +/*
> + * Windows drivers from 22 Jan 2013 and older fail when config size != 32.
> + */
> +struct virtio_net_config_compat

VirtioNetConfigCompat, don't forget the typedef.

> +{
> +    /* 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) */
> @@ -190,7 +201,5 @@ struct virtio_net_ctrl_mq {
>          DEFINE_PROP_BIT("ctrl_rx", _state, _field, VIRTIO_NET_F_CTRL_RX, 
> true), \
>          DEFINE_PROP_BIT("ctrl_vlan", _state, _field, VIRTIO_NET_F_CTRL_VLAN, 
> true), \
>          DEFINE_PROP_BIT("ctrl_rx_extra", _state, _field, 
> VIRTIO_NET_F_CTRL_RX_EXTRA, true), \
> -        DEFINE_PROP_BIT("ctrl_mac_addr", _state, _field, 
> VIRTIO_NET_F_CTRL_MAC_ADDR, true), \
> -        DEFINE_PROP_BIT("mq", _state, _field, VIRTIO_NET_F_MQ, true)
> -
> +        DEFINE_PROP_BIT("ctrl_mac_addr", _state, _field, 
> VIRTIO_NET_F_CTRL_MAC_ADDR, true)
>  #endif
> --
> MST
>