Re: [Qemu-devel] [QEMU PATCH v2] virtio-net: introduce a new macaddr control

[Michael S. Tsirkin]

On Wed, Jan 16, 2013 at 02:37:34PM +0800, Jason Wang wrote:
> On Wednesday, January 16, 2013 02:16:47 PM address@hidden wrote:
> > From: Amos Kong <address@hidden>
> > 
> > In virtio-net guest driver, currently we write MAC address to
> > pci config space byte by byte, this means that we have an
> > intermediate step where mac is wrong. This patch introduced
> > a new control command to set MAC address in one time.
> > 
> > VIRTIO_NET_F_CTRL_MAC_ADDR is a new feature bit for compatibility.
> > 
> > Signed-off-by: Amos Kong <address@hidden>
> > ---
> > V2: check guest's iov_len before memcpy
> > ---
> >  hw/virtio-net.c | 10 ++++++++++
> >  hw/virtio-net.h |  9 ++++++++-
> >  2 files changed, 18 insertions(+), 1 deletion(-)
> > 
> > diff --git a/hw/virtio-net.c b/hw/virtio-net.c
> > index dc7c6d6..d05f98f 100644
> > --- a/hw/virtio-net.c
> > +++ b/hw/virtio-net.c
> > @@ -247,6 +247,7 @@ static uint32_t virtio_net_get_features(VirtIODevice
> > *vdev, uint32_t features) VirtIONet *n = to_virtio_net(vdev);
> > 
> >      features |= (1 << VIRTIO_NET_F_MAC);
> > +    features |= (1 << VIRTIO_NET_F_CTRL_MAC_ADDR);
> > 
> >      if (!peer_has_vnet_hdr(n)) {
> >          features &= ~(0x1 << VIRTIO_NET_F_CSUM);
> > @@ -282,6 +283,7 @@ static uint32_t virtio_net_bad_features(VirtIODevice
> > *vdev) /* Linux kernel 2.6.25.  It understood MAC (as everyone must), * but
> > also these: */
> >      features |= (1 << VIRTIO_NET_F_MAC);
> > +    features |= (1 << VIRTIO_NET_F_CTRL_MAC_ADDR);
> >      features |= (1 << VIRTIO_NET_F_CSUM);
> >      features |= (1 << VIRTIO_NET_F_HOST_TSO4);
> >      features |= (1 << VIRTIO_NET_F_HOST_TSO6);
> > @@ -349,6 +351,14 @@ static int virtio_net_handle_mac(VirtIONet *n, uint8_t
> > cmd, {
> >      struct virtio_net_ctrl_mac mac_data;
> > 
> > +    if (cmd == VIRTIO_NET_CTRL_MAC_ADDR_SET && elem->out_num == 2 &&
> > +        elem->out_sg[1].iov_len == ETH_ALEN) {
> > +        /* Set MAC address */
> > +        memcpy(n->mac, elem->out_sg[1].iov_base, elem->out_sg[1].iov_len);
> > +        qemu_format_nic_info_str(&n->nic->nc, n->mac);
> > +        return VIRTIO_NET_OK;
> > +    }
> > +
> >      if (cmd != VIRTIO_NET_CTRL_MAC_TABLE_SET || elem->out_num != 3 ||
> >          elem->out_sg[1].iov_len < sizeof(mac_data) ||
> >          elem->out_sg[2].iov_len < sizeof(mac_data))
> > diff --git a/hw/virtio-net.h b/hw/virtio-net.h
> > index d46fb98..9394cc0 100644
> > --- a/hw/virtio-net.h
> > +++ b/hw/virtio-net.h
> > @@ -44,6 +44,8 @@
> >  #define VIRTIO_NET_F_CTRL_VLAN  19      /* Control channel VLAN filtering
> > */ #define VIRTIO_NET_F_CTRL_RX_EXTRA 20   /* Extra RX mode control support
> > */
> > 
> > +#define VIRTIO_NET_F_CTRL_MAC_ADDR   23 /* Set MAC address */
> > +
> 
> I wonder whether we need a DEFINE_PROP_BIT to disable and compat this 
> feature. 
> Consider we may migrate from a new version to an old version.

Yes I think we do.

> >  #define VIRTIO_NET_S_LINK_UP    1       /* Link is up */
> > 
> >  #define TX_TIMER_INTERVAL 150000 /* 150 us */
> > @@ -106,7 +108,7 @@ typedef uint8_t virtio_net_ctrl_ack;
> >   #define VIRTIO_NET_CTRL_RX_MODE_NOBCAST      5
> > 
> >  /*
> > - * Control the MAC filter table.
> > + * Control the MAC
> >   *
> >   * The MAC filter table is managed by the hypervisor, the guest should
> >   * assume the size is infinite.  Filtering should be considered
> > @@ -119,6 +121,10 @@ typedef uint8_t virtio_net_ctrl_ack;
> >   * first sg list contains unicast addresses, the second is for multicast.
> >   * This functionality is present if the VIRTIO_NET_F_CTRL_RX feature
> >   * is available.
> > + *
> > + * The ADDR_SET command requests one out scatterlist, it contains a
> > + * 6 bytes MAC address. This functionality is present if the
> > + * VIRTIO_NET_F_CTRL_MAC_ADDR feature is available.
> >   */
> >  struct virtio_net_ctrl_mac {
> >      uint32_t entries;
> > @@ -126,6 +132,7 @@ struct virtio_net_ctrl_mac {
> >  };
> >  #define VIRTIO_NET_CTRL_MAC    1
> >   #define VIRTIO_NET_CTRL_MAC_TABLE_SET        0
> > + #define VIRTIO_NET_CTRL_MAC_ADDR_SET         1
> > 
> >  /*
> >   * Control VLAN filtering