| Message ID | 1465231508-30183-4-git-send-email-marcandre.lureau@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Jun 06, 2016 at 06:45:01PM +0200, marcandre.lureau@redhat.com wrote: > From: Marc-André Lureau <marcandre.lureau@redhat.com> > > This patch is a similar solution to what Yuanhan Liu/Huawei Xie have > suggested for DPDK. When vubr quits (killed or crashed), a restart of > vubr would get stale vring base from QEMU. That would break the kernel > virtio net completely, making it non-work any more, unless a driver > reset is done. > > So, instead of getting the stale vring base from QEMU, Huawei suggested > we could get a proper one from used->idx. This works because the queues > packets are processed in order. > > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> > Tested-by: Yuanhan Liu <yuanhan.liu@linux.intel.com> > Reviewed-by: Yuanhan Liu <yuanhan.liu@linux.intel.com> > --- > tests/vhost-user-bridge.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/tests/vhost-user-bridge.c b/tests/vhost-user-bridge.c > index f907ce7..38963e4 100644 > --- a/tests/vhost-user-bridge.c > +++ b/tests/vhost-user-bridge.c > @@ -946,6 +946,13 @@ vubr_set_vring_addr_exec(VubrDev *dev, VhostUserMsg *vmsg) > DPRINT(" vring_avail at %p\n", vq->avail); > > vq->last_used_index = vq->used->idx; > + > + if (vq->last_avail_index != vq->used->idx) { > + DPRINT("Last avail index != used index: %d != %d, resuming", > + vq->last_avail_index, vq->used->idx); > + vq->last_avail_index = vq->used->idx; > + } > + What if set_vring_base is called after set_vring_addr? Maybe it is worth to add the fixup to the set_vring_base as well? > return 0; > } > > -- > 2.7.4 > >
Hi On Thu, Jun 9, 2016 at 12:07 PM, Victor Kaplansky <victork@redhat.com> wrote: > What if set_vring_base is called after set_vring_addr? > Maybe it is worth to add the fixup to the set_vring_base as well? It would need to handle conditions like set_vring_base() being called while set_vring_addr() is not yet, and thus vq->used isn't set. Imho it's not necessary, since order is currently fixed in vhost_virtqueue_start(), but we could specify this in the protocol to avoid too much possible states.
On Thu, Jun 09, 2016 at 12:25:54PM +0200, Marc-André Lureau wrote: > Hi > > On Thu, Jun 9, 2016 at 12:07 PM, Victor Kaplansky <victork@redhat.com> wrote: > > What if set_vring_base is called after set_vring_addr? > > Maybe it is worth to add the fixup to the set_vring_base as well? > > It would need to handle conditions like set_vring_base() being called > while set_vring_addr() is not yet, and thus vq->used isn't set. > > Imho it's not necessary, since order is currently fixed in > vhost_virtqueue_start(), but we could specify this in the protocol to > avoid too much possible states. I personally think it's better to just get the used idx from memory before reconnecting. Will fix old clients automatically. Whoever wants to support old QEMU, can do this by a work-around similar to the supplied one. Maybe add code here to make sure everything is setup - if not it's a new QEMU so it does not need the work-around. I think there was a patch like this suggested at some point - mind digging it up? > -- > Marc-André Lureau
diff --git a/tests/vhost-user-bridge.c b/tests/vhost-user-bridge.c index f907ce7..38963e4 100644 --- a/tests/vhost-user-bridge.c +++ b/tests/vhost-user-bridge.c @@ -946,6 +946,13 @@ vubr_set_vring_addr_exec(VubrDev *dev, VhostUserMsg *vmsg) DPRINT(" vring_avail at %p\n", vq->avail); vq->last_used_index = vq->used->idx; + + if (vq->last_avail_index != vq->used->idx) { + DPRINT("Last avail index != used index: %d != %d, resuming", + vq->last_avail_index, vq->used->idx); + vq->last_avail_index = vq->used->idx; + } + return 0; }