On Fri, Nov 30, 2018 at 12:50:26PM -0500, Jason Baron wrote:
> Guest network devices can set 'overflow' when there are a number of multicast
> ips configured. For virtio_net, the limit is only 64. In this case, the list
> of mac addresses is empty and the 'overflow' condition is set. Thus, the guest
> will currently receive no multicast traffic in this state.
>
> When 'overflow' is set in the guest, let's turn this into ALLMULTI on the host.
>
> Signed-off-by: Jason Baron <jbaron@xxxxxxxxxx>
Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> ---
> v1->v2:
> 1. check for < 0 in virNetDevSetRcvAllMulti() (Michal Privoznik)
> 2. restrict overflow check to VIR_NETDEV_RX_FILTER_MODE_NORMAL mode as to
> avoid unnecessarily calling rx filter updates for other modes
> 3. update virNetDevSetRcvAllMulti() call to use guestFilter->multicast.overflow
> directly (Michal Privoznik)
>
> src/qemu/qemu_driver.c | 22 +++++++++++++++-------
> 1 file changed, 15 insertions(+), 7 deletions(-)
>
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index 7fb9102..f4bbfea 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -4443,11 +4443,12 @@ static void
> syncNicRxFilterMultiMode(char *ifname, virNetDevRxFilterPtr guestFilter,
> virNetDevRxFilterPtr hostFilter)
> {
> - if (hostFilter->multicast.mode != guestFilter->multicast.mode) {
> + if (hostFilter->multicast.mode != guestFilter->multicast.mode ||
> + (guestFilter->multicast.overflow &&
> + guestFilter->multicast.mode == VIR_NETDEV_RX_FILTER_MODE_NORMAL)) {
> switch (guestFilter->multicast.mode) {
> case VIR_NETDEV_RX_FILTER_MODE_ALL:
> if (virNetDevSetRcvAllMulti(ifname, true)) {
> -
> VIR_WARN("Couldn't set allmulticast flag to 'on' for "
> "device %s while responding to "
> "NIC_RX_FILTER_CHANGED", ifname);
> @@ -4455,17 +4456,24 @@ syncNicRxFilterMultiMode(char *ifname, virNetDevRxFilterPtr guestFilter,
> break;
>
> case VIR_NETDEV_RX_FILTER_MODE_NORMAL:
> - if (virNetDevSetRcvMulti(ifname, true)) {
> + if (guestFilter->multicast.overflow &&
> + (hostFilter->multicast.mode == VIR_NETDEV_RX_FILTER_MODE_ALL)) {
> + break;
> + }
>
> + if (virNetDevSetRcvMulti(ifname, true)) {
> VIR_WARN("Couldn't set multicast flag to 'on' for "
> "device %s while responding to "
> "NIC_RX_FILTER_CHANGED", ifname);
> }
>
> - if (virNetDevSetRcvAllMulti(ifname, false)) {
> - VIR_WARN("Couldn't set allmulticast flag to 'off' for "
> - "device %s while responding to "
> - "NIC_RX_FILTER_CHANGED", ifname);
> + if (virNetDevSetRcvAllMulti(ifname,
> + guestFilter->multicast.overflow) < 0) {
> + VIR_WARN("Couldn't set allmulticast flag to '%s' for "
> + "device %s while responding to "
> + "NIC_RX_FILTER_CHANGED",
> + virTristateSwitchTypeToString(virTristateSwitchFromBool(guestFilter->multicast.overflow)),
> + ifname);
> }
> break;
>
> --
> 2.7.4
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