On 11/03/2016 05:09 PM, Yuanhan Liu wrote: > Queue allocation should be done once, since the queue related info (such > as vring addreess) will only be informed to the vhost-user backend once > without virtio device reset. > > That means, if you allocate queues again after the vhost-user negotiation, > the vhost-user backend will not be informed any more. Leading to a state > that the vring info mismatches between virtio PMD driver and vhost-backend: > the driver switches to the new address has just been allocated, while the > vhost-backend still sticks to the old address has been assigned in the init > stage. > > Unfortunately, that is exactly how the virtio driver is coded so far: queue > allocation is done at queue_setup stage (when rte_eth_tx/rx_queue_setup is > invoked). This is wrong, because queue_setup can be invoked several times. > For example, > > $ start_testpmd.sh ... --txq=1 --rxq=1 ... > > port stop 0 > > port config all txq 1 # just trigger the queue_setup callback again > > port config all rxq 1 > > port start 0 > > The right way to do is allocate the queues in the init stage, so that the > vring info could be persistent with the vhost-user backend. > > Besides that, we should allocate max_queue pairs the device supports, but > not nr queue pairs firstly configured, to make following case work. > > $ start_testpmd.sh ... --txq=1 --rxq=1 ... > > port stop 0 > > port config all txq 2 > > port config all rxq 2 > > port start 0 > > Signed-off-by: Yuanhan Liu <yuanhan.liu at linux.intel.com> > --- > drivers/net/virtio/virtio_ethdev.c | 105 > +++++++++++++++++++++++-------------- > drivers/net/virtio/virtio_ethdev.h | 8 --- > drivers/net/virtio/virtio_pci.h | 2 + > drivers/net/virtio/virtio_rxtx.c | 38 +++++++------- > 4 files changed, 85 insertions(+), 68 deletions(-) >
Reviewed-by: Maxime Coquelin <maxime.coquelin at redhat.com> Thanks, Maxime
