On Mon, 2010-09-27 at 23:52 +0200, Michael S. Tsirkin wrote:
> On Mon, Sep 27, 2010 at 01:43:11PM -0600, Alex Williamson wrote:
> > On Mon, 2010-09-27 at 18:41 +0200, Michael S. Tsirkin wrote:
> > > Move all of vhost-net start/stop logic to a single routine,
> > > and call it from everywhere.
> > >
> > > Additionally, start/stop vhost-net on link up/down:
> > > we should not transmit anything if user asked us to
> > > put the link down.
> > >
> > > Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
> > > ---
> > >
> > > Sent a wrong version, sorry about the noise.
> > >
> > > hw/virtio-net.c | 89
> > > ++++++++++++++++++++++++++----------------------------
> > > 1 files changed, 43 insertions(+), 46 deletions(-)
> > >
> > > diff --git a/hw/virtio-net.c b/hw/virtio-net.c
> > > index 075f72d..f87c219 100644
> > > --- a/hw/virtio-net.c
> > > +++ b/hw/virtio-net.c
> > > @@ -51,6 +51,7 @@ typedef struct VirtIONet
> > > uint8_t nouni;
> > > uint8_t nobcast;
> > > uint8_t vhost_started;
> > > + bool vm_running;
> > > VMChangeStateEntry *vmstate;
> > > struct {
> > > int in_use;
> > > @@ -95,6 +96,38 @@ static void virtio_net_set_config(VirtIODevice *vdev,
> > > const uint8_t *config)
> > > }
> > > }
> > >
> > > +static void virtio_net_set_status(struct VirtIODevice *vdev, uint8_t
> > > status)
> > > +{
> > > + VirtIONet *n = to_virtio_net(vdev);
> > > + if (!n->nic->nc.peer) {
> > > + return;
> > > + }
> > > + if (n->nic->nc.peer->info->type != NET_CLIENT_TYPE_TAP) {
> > > + return;
> > > + }
> > > +
> > > + if (!tap_get_vhost_net(n->nic->nc.peer)) {
> > > + return;
> > > + }
> > > + if (!!n->vhost_started == (status & VIRTIO_CONFIG_S_DRIVER_OK) &&
> > > + (n->status & VIRTIO_NET_S_LINK_UP) &&
> > > + n->vm_running) {
> >
> > I don't think this works...
> >
> > #define VIRTIO_CONFIG_S_DRIVER_OK 4
> >
> > !!(1) == (status & 4)?
>
> The && converts it to a boolean.
Are you missing a set of parens around everything right of the ==? ie:
if (!!n->vhost_started == ((status & VIRTIO_CONFIG_S_DRIVER_OK) &&
(n->status & VIRTIO_NET_S_LINK_UP) &&
n->vm_running)) {...
Has this actually been tested?
Alex
> > > + return;
> > > + }
> > > + if (!n->vhost_started) {
> > > + int r = vhost_net_start(tap_get_vhost_net(n->nic->nc.peer),
> > > &n->vdev);
> > > + if (r < 0) {
> > > + fprintf(stderr, "unable to start vhost net: %d: "
> > > + "falling back on userspace virtio\n", -r);
> >
> > Definitely worth noting if not using vhost, but aren't we potentially
> > going to see this in the log a lot in that case? Thanks,
> >
> > Alex
>
> Not really, we detect failure at start normally, and do
> not proceed.
> This means that somehow the device went dead: should not
> happen really, but since it's easy to recover we do.
>
> > > + } else {
> > > + n->vhost_started = 1;
> > > + }
> > > + } else {
> > > + vhost_net_stop(tap_get_vhost_net(n->nic->nc.peer), &n->vdev);
> > > + n->vhost_started = 0;
> > > + }
> > > +}
> > > +
> > > static void virtio_net_set_link_status(VLANClientState *nc)
> > > {
> > > VirtIONet *n = DO_UPCAST(NICState, nc, nc)->opaque;
> > > @@ -107,6 +140,8 @@ static void
> > > virtio_net_set_link_status(VLANClientState *nc)
> > >
> > > if (n->status != old_status)
> > > virtio_notify_config(&n->vdev);
> > > +
> > > + virtio_net_set_status(&n->vdev, n->vdev.status);
> > > }
> > >
> > > static void virtio_net_reset(VirtIODevice *vdev)
> > > @@ -120,10 +155,6 @@ static void virtio_net_reset(VirtIODevice *vdev)
> > > n->nomulti = 0;
> > > n->nouni = 0;
> > > n->nobcast = 0;
> > > - if (n->vhost_started) {
> > > - vhost_net_stop(tap_get_vhost_net(n->nic->nc.peer), vdev);
> > > - n->vhost_started = 0;
> > > - }
> > >
> > > /* Flush any MAC and VLAN filter table state */
> > > n->mac_table.in_use = 0;
> > > @@ -726,12 +757,9 @@ static void virtio_net_save(QEMUFile *f, void
> > > *opaque)
> > > {
> > > VirtIONet *n = opaque;
> > >
> > > - if (n->vhost_started) {
> > > - /* TODO: should we really stop the backend?
> > > - * If we don't, it might keep writing to memory. */
> > > - vhost_net_stop(tap_get_vhost_net(n->nic->nc.peer), &n->vdev);
> > > - n->vhost_started = 0;
> > > - }
> > > + /* At this point, backend must be stopped, otherwise
> > > + * it might keep writing to memory. */
> > > + assert(!n->vhost_started);
> > > virtio_save(&n->vdev, f);
> > >
> > > qemu_put_buffer(f, n->mac, ETH_ALEN);
> > > @@ -863,44 +891,14 @@ static NetClientInfo net_virtio_info = {
> > > .link_status_changed = virtio_net_set_link_status,
> > > };
> > >
> > > -static void virtio_net_set_status(struct VirtIODevice *vdev, uint8_t
> > > status)
> > > -{
> > > - VirtIONet *n = to_virtio_net(vdev);
> > > - if (!n->nic->nc.peer) {
> > > - return;
> > > - }
> > > - if (n->nic->nc.peer->info->type != NET_CLIENT_TYPE_TAP) {
> > > - return;
> > > - }
> > > -
> > > - if (!tap_get_vhost_net(n->nic->nc.peer)) {
> > > - return;
> > > - }
> > > - if (!!n->vhost_started == !!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
> > > - return;
> > > - }
> > > - if (status & VIRTIO_CONFIG_S_DRIVER_OK) {
> > > - int r = vhost_net_start(tap_get_vhost_net(n->nic->nc.peer),
> > > vdev);
> > > - if (r < 0) {
> > > - fprintf(stderr, "unable to start vhost net: %d: "
> > > - "falling back on userspace virtio\n", -r);
> > > - } else {
> > > - n->vhost_started = 1;
> > > - }
> > > - } else {
> > > - vhost_net_stop(tap_get_vhost_net(n->nic->nc.peer), vdev);
> > > - n->vhost_started = 0;
> > > - }
> > > -}
> > > -
> > > static void virtio_net_vmstate_change(void *opaque, int running, int
> > > reason)
> > > {
> > > VirtIONet *n = opaque;
> > > - uint8_t status = running ? VIRTIO_CONFIG_S_DRIVER_OK : 0;
> > > + n->vm_running = running;
> > > /* This is called when vm is started/stopped,
> > > - * it will start/stop vhost backend if * appropriate
> > > + * it will start/stop vhost backend if appropriate
> > > * e.g. after migration. */
> > > - virtio_net_set_status(&n->vdev, n->vdev.status & status);
> > > + virtio_net_set_status(&n->vdev, n->vdev.status);
> > > }
> > >
> > > VirtIODevice *virtio_net_init(DeviceState *dev, NICConf *conf)
> > > @@ -951,9 +949,8 @@ void virtio_net_exit(VirtIODevice *vdev)
> > > VirtIONet *n = DO_UPCAST(VirtIONet, vdev, vdev);
> > > qemu_del_vm_change_state_handler(n->vmstate);
> > >
> > > - if (n->vhost_started) {
> > > - vhost_net_stop(tap_get_vhost_net(n->nic->nc.peer), vdev);
> > > - }
> > > + /* This will stop vhost backend if appropriate. */
> > > + virtio_net_set_status(vdev, 0);
> > >
> > > qemu_purge_queued_packets(&n->nic->nc);
> > >
> >
> >
