[dpdk-dev,13/17] vhost: packed queue enqueue path
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Commit Message
Implement enqueue of packets to the receive virtqueue.
Set descriptor flag VIRTQ_DESC_F_USED and toggle used wrap counter if
last descriptor in ring is used. Perform a write memory barrier before
flags are written to descriptor.
Chained descriptors are not supported with this patch.
Signed-off-by: Jens Freimann <jfreimann@redhat.com>
---
lib/librte_vhost/virtio_net.c | 129 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 129 insertions(+)
Comments
On Fri, Mar 16, 2018 at 04:21:16PM +0100, Jens Freimann wrote:
[...]
> +static inline uint32_t __attribute__((always_inline))
> +vhost_enqueue_burst_packed(struct virtio_net *dev, uint16_t queue_id,
> + struct rte_mbuf **pkts, uint32_t count)
> +{
> + struct vhost_virtqueue *vq;
> + struct vring_desc_packed *descs;
> + uint16_t idx;
> + uint16_t mask;
> + uint16_t i;
> +
> + vq = dev->virtqueue[queue_id];
> +
> + rte_spinlock_lock(&vq->access_lock);
> +
> + if (unlikely(vq->enabled == 0)) {
> + i = 0;
> + goto out_access_unlock;
> + }
> +
> + if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
> + vhost_user_iotlb_rd_lock(vq);
> +
> + descs = vq->desc_packed;
> + mask = vq->size - 1;
Queue size may not be a power of 2 in packed ring.
> +
> + for (i = 0; i < count; i++) {
[...]
> + mbuf_avail = rte_pktmbuf_data_len(m);
> + mbuf_offset = 0;
> + while (mbuf_avail != 0 || m->next != NULL) {
> + /* done with current mbuf, fetch next */
> + if (mbuf_avail == 0) {
> + m = m->next;
> +
> + mbuf_offset = 0;
> + mbuf_avail = rte_pktmbuf_data_len(m);
> + }
> +
> + /* done with current desc buf, fetch next */
> + if (desc_avail == 0) {
> + if ((desc->flags & VRING_DESC_F_NEXT) == 0) {
> + /* Room in vring buffer is not enough */
> + goto out;
> + }
> +
> + idx = (idx + 1);
> + desc = &descs[idx];
Need to check whether idx >= queue size.
Thanks
On Mon, Mar 19, 2018 at 07:02:56PM +0800, Tiwei Bie wrote:
>On Fri, Mar 16, 2018 at 04:21:16PM +0100, Jens Freimann wrote:
>[...]
>> +static inline uint32_t __attribute__((always_inline))
>> +vhost_enqueue_burst_packed(struct virtio_net *dev, uint16_t queue_id,
>> + struct rte_mbuf **pkts, uint32_t count)
>> +{
>> + struct vhost_virtqueue *vq;
>> + struct vring_desc_packed *descs;
>> + uint16_t idx;
>> + uint16_t mask;
>> + uint16_t i;
>> +
>> + vq = dev->virtqueue[queue_id];
>> +
>> + rte_spinlock_lock(&vq->access_lock);
>> +
>> + if (unlikely(vq->enabled == 0)) {
>> + i = 0;
>> + goto out_access_unlock;
>> + }
>> +
>> + if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
>> + vhost_user_iotlb_rd_lock(vq);
>> +
>> + descs = vq->desc_packed;
>> + mask = vq->size - 1;
>
>Queue size may not be a power of 2 in packed ring.
yes, you are right. my patches don't support this yet, but I plan to
add it in the next version.
Thanks for the review!
regards,
Jens
On Wed, Mar 21, 2018 at 09:45:59AM +0100, Jens Freimann wrote:
> On Mon, Mar 19, 2018 at 07:02:56PM +0800, Tiwei Bie wrote:
> > On Fri, Mar 16, 2018 at 04:21:16PM +0100, Jens Freimann wrote:
> > [...]
> > > +static inline uint32_t __attribute__((always_inline))
> > > +vhost_enqueue_burst_packed(struct virtio_net *dev, uint16_t queue_id,
> > > + struct rte_mbuf **pkts, uint32_t count)
> > > +{
> > > + struct vhost_virtqueue *vq;
> > > + struct vring_desc_packed *descs;
> > > + uint16_t idx;
> > > + uint16_t mask;
> > > + uint16_t i;
> > > +
> > > + vq = dev->virtqueue[queue_id];
> > > +
> > > + rte_spinlock_lock(&vq->access_lock);
> > > +
> > > + if (unlikely(vq->enabled == 0)) {
> > > + i = 0;
> > > + goto out_access_unlock;
> > > + }
> > > +
> > > + if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
> > > + vhost_user_iotlb_rd_lock(vq);
> > > +
> > > + descs = vq->desc_packed;
> > > + mask = vq->size - 1;
> >
> > Queue size may not be a power of 2 in packed ring.
>
> yes, you are right. my patches don't support this yet, but I plan to
> add it in the next version.
Yeah, thanks. Otherwise, because this is vhost code, and
the vq->size is set by virtio driver. So when above code
works with a virtio driver which uses a ring size that's
not a power of 2, such assumption will cause problems.
Thanks
>
> Thanks for the review!
>
> regards,
> Jens
@@ -695,6 +695,135 @@
return pkt_idx;
}
+static inline uint32_t __attribute__((always_inline))
+vhost_enqueue_burst_packed(struct virtio_net *dev, uint16_t queue_id,
+ struct rte_mbuf **pkts, uint32_t count)
+{
+ struct vhost_virtqueue *vq;
+ struct vring_desc_packed *descs;
+ uint16_t idx;
+ uint16_t mask;
+ uint16_t i;
+
+ vq = dev->virtqueue[queue_id];
+
+ rte_spinlock_lock(&vq->access_lock);
+
+ if (unlikely(vq->enabled == 0)) {
+ i = 0;
+ goto out_access_unlock;
+ }
+
+ if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
+ vhost_user_iotlb_rd_lock(vq);
+
+ descs = vq->desc_packed;
+ mask = vq->size - 1;
+
+ for (i = 0; i < count; i++) {
+ uint32_t desc_avail, desc_offset;
+ uint32_t mbuf_avail, mbuf_offset;
+ uint32_t cpy_len;
+ struct vring_desc_packed *desc;
+ uint64_t desc_addr;
+ struct virtio_net_hdr_mrg_rxbuf *hdr;
+ struct rte_mbuf *m = pkts[i];
+
+ /* XXX: there is an assumption that no desc will be chained */
+ idx = vq->last_used_idx & mask;
+ desc = &descs[idx];
+
+ if (!desc_is_avail(vq, desc))
+ break;
+ rte_smp_rmb();
+
+ desc_addr = vhost_iova_to_vva(dev, vq, desc->addr,
+ sizeof(*desc), VHOST_ACCESS_RW);
+ /*
+ * Checking of 'desc_addr' placed outside of 'unlikely' macro
+ * to avoid performance issue with some versions of gcc (4.8.4
+ * and 5.3.0) which otherwise stores offset on the stack instead
+ * of in a register.
+ */
+ if (unlikely(desc->len < dev->vhost_hlen) || !desc_addr)
+ break;
+
+ hdr = (struct virtio_net_hdr_mrg_rxbuf *)(uintptr_t)desc_addr;
+ virtio_enqueue_offload(m, &hdr->hdr);
+ vhost_log_write(dev, desc->addr, dev->vhost_hlen);
+ PRINT_PACKET(dev, (uintptr_t)desc_addr, dev->vhost_hlen, 0);
+
+ desc_offset = dev->vhost_hlen;
+ desc_avail = desc->len - dev->vhost_hlen;
+
+ mbuf_avail = rte_pktmbuf_data_len(m);
+ mbuf_offset = 0;
+ while (mbuf_avail != 0 || m->next != NULL) {
+ /* done with current mbuf, fetch next */
+ if (mbuf_avail == 0) {
+ m = m->next;
+
+ mbuf_offset = 0;
+ mbuf_avail = rte_pktmbuf_data_len(m);
+ }
+
+ /* done with current desc buf, fetch next */
+ if (desc_avail == 0) {
+ if ((desc->flags & VRING_DESC_F_NEXT) == 0) {
+ /* Room in vring buffer is not enough */
+ goto out;
+ }
+
+ idx = (idx + 1);
+ desc = &descs[idx];
+ if (unlikely(!desc_is_avail(vq, desc)))
+ goto out ;
+
+ desc_addr = vhost_iova_to_vva(dev, vq, desc->addr,
+ sizeof(*desc),
+ VHOST_ACCESS_RW);
+ if (unlikely(!desc_addr))
+ goto out;
+
+ desc_offset = 0;
+ desc_avail = desc->len;
+ }
+
+ cpy_len = RTE_MIN(desc_avail, mbuf_avail);
+ rte_memcpy((void *)((uintptr_t)(desc_addr + desc_offset)),
+ rte_pktmbuf_mtod_offset(m, void *, mbuf_offset),
+ cpy_len);
+ vhost_log_write(dev, desc->addr + desc_offset, cpy_len);
+ PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset),
+ cpy_len, 0);
+
+ mbuf_avail -= cpy_len;
+ mbuf_offset += cpy_len;
+ desc_avail -= cpy_len;
+ desc_offset += cpy_len;
+ }
+
+ descs[idx].len = pkts[i]->pkt_len + dev->vhost_hlen;
+ rte_smp_wmb();
+ set_desc_used(vq, desc);
+
+ vq->last_used_idx++;
+ if ((vq->last_used_idx & (vq->size - 1)) == 0)
+ toggle_wrap_counter(vq);
+ }
+
+out:
+ if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
+ vhost_user_iotlb_rd_unlock(vq);
+
+out_access_unlock:
+ rte_spinlock_unlock(&vq->access_lock);
+
+ count = i;
+
+ return count;
+}
+
uint16_t
rte_vhost_enqueue_burst(int vid, uint16_t queue_id,
struct rte_mbuf **pkts, uint16_t count)