[dpdk-dev] [PATCH v3 14/21] vhost: dequeue for packed queues
Jens Freimann
jfreimann at redhat.com
Fri Apr 6 12:07:26 CEST 2018
On Fri, Apr 06, 2018 at 11:30:10AM +0200, Maxime Coquelin wrote:
>
>
>On 04/05/2018 12:10 PM, Jens Freimann wrote:
>>Implement code to dequeue and process descriptors from
>>the vring if VIRTIO_F_RING_PACKED is enabled.
>>
>>Check if descriptor was made available by driver by looking at
>>VIRTIO_F_DESC_AVAIL flag in descriptor. If so dequeue and set
>>the used flag VIRTIO_F_DESC_USED to the current value of the
>>used wrap counter.
>>
>>Used ring wrap counter needs to be toggled when last descriptor is
>>written out. This allows the host/guest to detect new descriptors even
>>after the ring has wrapped.
>>
>>Signed-off-by: Jens Freimann <jfreimann at redhat.com>
>>---
>> lib/librte_vhost/vhost.c | 1 +
>> lib/librte_vhost/vhost.h | 1 +
>> lib/librte_vhost/virtio_net.c | 228 ++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 230 insertions(+)
>>
>>diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
>>index 1f17cdd75..eb5a98875 100644
>>--- a/lib/librte_vhost/vhost.c
>>+++ b/lib/librte_vhost/vhost.c
>>@@ -185,6 +185,7 @@ init_vring_queue(struct virtio_net *dev, uint32_t vring_idx)
>> vq->kickfd = VIRTIO_UNINITIALIZED_EVENTFD;
>> vq->callfd = VIRTIO_UNINITIALIZED_EVENTFD;
>>+ vq->used_wrap_counter = 1;
>> vhost_user_iotlb_init(dev, vring_idx);
>> /* Backends are set to -1 indicating an inactive device. */
>>diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
>>index 20d78f883..c8aa946fd 100644
>>--- a/lib/librte_vhost/vhost.h
>>+++ b/lib/librte_vhost/vhost.h
>>@@ -112,6 +112,7 @@ struct vhost_virtqueue {
>> struct batch_copy_elem *batch_copy_elems;
>> uint16_t batch_copy_nb_elems;
>>+ uint16_t used_wrap_counter;
>> rte_rwlock_t iotlb_lock;
>> rte_rwlock_t iotlb_pending_lock;
>>diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
>>index ed7198dbb..7eea1da04 100644
>>--- a/lib/librte_vhost/virtio_net.c
>>+++ b/lib/librte_vhost/virtio_net.c
>>@@ -19,6 +19,7 @@
>> #include "iotlb.h"
>> #include "vhost.h"
>>+#include "virtio-1.1.h"
>> #define MAX_PKT_BURST 32
>>@@ -1118,6 +1119,233 @@ restore_mbuf(struct rte_mbuf *m)
>> }
>> }
>>+static inline uint16_t
>>+dequeue_desc_packed(struct virtio_net *dev, struct vhost_virtqueue *vq,
>>+ struct rte_mempool *mbuf_pool, struct rte_mbuf *m,
>>+ struct vring_desc_packed *descs)
>>+{
>>+ struct vring_desc_packed *desc;
>>+ uint64_t desc_addr;
>>+ uint32_t desc_avail, desc_offset;
>>+ uint32_t mbuf_avail, mbuf_offset;
>>+ uint32_t cpy_len;
>>+ struct rte_mbuf *cur = m, *prev = m;
>>+ struct virtio_net_hdr *hdr = NULL;
>>+ uint16_t head_idx = vq->last_used_idx & (vq->size - 1);
>>+ int wrap_counter = vq->used_wrap_counter;
>>+ int rc = 0;
>>+
>>+ rte_spinlock_lock(&vq->access_lock);
>>+
>>+ if (unlikely(vq->enabled == 0))
>>+ goto out;
>
>It is unbalanced as it would unlock iotlb_rd_lock that isn't locked yet.
yes, will fix
>
>>+ if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
>>+ vhost_user_iotlb_rd_lock(vq);
>>+
>>+ desc = &descs[vq->last_used_idx & (vq->size - 1)];
>>+ if (unlikely((desc->len < dev->vhost_hlen)) ||
>>+ (desc->flags & VRING_DESC_F_INDIRECT)) {
>>+ RTE_LOG(ERR, VHOST_DATA,
>>+ "INDIRECT not supported yet\n");
>>+ rc = -1;
>>+ goto out;
>>+ }
>>+
>>+ desc_addr = vhost_iova_to_vva(dev, vq, desc->addr,
>>+ sizeof(*desc), VHOST_ACCESS_RO);
>>+
>>+ if (unlikely(!desc_addr)) {
>>+ rc = -1;
>>+ goto out;
>>+ }
>>+
>>+ if (virtio_net_with_host_offload(dev)) {
>>+ hdr = (struct virtio_net_hdr *)((uintptr_t)desc_addr);
>>+ rte_prefetch0(hdr);
>>+ }
>>+
>>+ /*
>>+ * A virtio driver normally uses at least 2 desc buffers
>>+ * for Tx: the first for storing the header, and others
>>+ * for storing the data.
>>+ */
>>+ if (likely((desc->len == dev->vhost_hlen) &&
>>+ (desc->flags & VRING_DESC_F_NEXT) != 0)) {
>>+ if ((++vq->last_used_idx & (vq->size - 1)) == 0)
>>+ toggle_wrap_counter(vq);
>>+
>>+ desc = &descs[vq->last_used_idx & (vq->size - 1)];
>>+
>>+ if (unlikely(desc->flags & VRING_DESC_F_INDIRECT)) {
>>+ RTE_LOG(ERR, VHOST_DATA,
>>+ "INDIRECT not supported yet\n");
>>+ rc = -1;
>>+ goto out;
>>+ }
>>+
>>+ desc_addr = vhost_iova_to_vva(dev, vq, desc->addr,
>>+ sizeof(*desc), VHOST_ACCESS_RO);
>>+ if (unlikely(!desc_addr)) {
>>+ rc = -1;
>>+ goto out;
>>+ }
>>+
>>+ desc_offset = 0;
>>+ desc_avail = desc->len;
>>+ } else {
>>+ desc_avail = desc->len - dev->vhost_hlen;
>>+ desc_offset = dev->vhost_hlen;
>>+ }
>>+
>>+ rte_prefetch0((void *)(uintptr_t)(desc_addr + desc_offset));
>>+
>>+ PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset), desc_avail, 0);
>>+
>>+ mbuf_offset = 0;
>>+ mbuf_avail = m->buf_len - RTE_PKTMBUF_HEADROOM;
>>+ while (1) {
>>+ uint64_t hpa;
>>+
>>+ cpy_len = RTE_MIN(desc_avail, mbuf_avail);
>>+
>>+ /*
>>+ * A desc buf might across two host physical pages that are
>>+ * not continuous. In such case (gpa_to_hpa returns 0), data
>>+ * will be copied even though zero copy is enabled.
>>+ */
>>+ if (unlikely(dev->dequeue_zero_copy && (hpa = gpa_to_hpa(dev,
>>+ desc->addr + desc_offset, cpy_len)))) {
>>+ cur->data_len = cpy_len;
>>+ cur->data_off = 0;
>>+ cur->buf_addr = (void *)(uintptr_t)desc_addr;
>>+ cur->buf_physaddr = hpa;
>>+
>>+ /*
>>+ * In zero copy mode, one mbuf can only reference data
>>+ * for one or partial of one desc buff.
>>+ */
>>+ mbuf_avail = cpy_len;
>>+ } else {
>>+ rte_memcpy(rte_pktmbuf_mtod_offset(cur, void *,
>>+ mbuf_offset),
>>+ (void *)((uintptr_t)(desc_addr + desc_offset)),
>>+ cpy_len);
>>+ }
>>+
>>+ mbuf_avail -= cpy_len;
>>+ mbuf_offset += cpy_len;
>>+ desc_avail -= cpy_len;
>>+ desc_offset += cpy_len;
>>+
>>+ /* This desc reaches to its end, get the next one */
>>+ if (desc_avail == 0) {
>>+ if ((desc->flags & VRING_DESC_F_NEXT) == 0)
>>+ break;
>>+
>>+ if ((++vq->last_used_idx & (vq->size - 1)) == 0)
>>+ toggle_wrap_counter(vq);
>>+
>>+ desc = &descs[vq->last_used_idx & (vq->size - 1)];
>>+ if (unlikely(desc->flags & VRING_DESC_F_INDIRECT)) {
>>+ RTE_LOG(ERR, VHOST_DATA, "INDIRECT not supported yet");
>>+ }
>>+
>>+ desc_addr = vhost_iova_to_vva(dev, vq, desc->addr,
>>+ sizeof(*desc), VHOST_ACCESS_RO);
>>+ if (unlikely(!desc_addr)) {
>>+ rc = -1;
>>+ goto out;
>Not sure, but, shouldn't you break here instead so rings gets updated if
>some of the descs have been processed?
It should break here and in other places in this loop as well. will
fix it.
>>+ }
>>+
>>+ rte_prefetch0((void *)(uintptr_t)desc_addr);
>>+
>>+ desc_offset = 0;
>>+ desc_avail = desc->len;
>>+
>>+ PRINT_PACKET(dev, (uintptr_t)desc_addr, desc->len, 0);
>>+ }
>>+
>>+ /*
>>+ * This mbuf reaches to its end, get a new one
>>+ * to hold more data.
>>+ */
>>+ if (mbuf_avail == 0) {
>>+ cur = rte_pktmbuf_alloc(mbuf_pool);
>>+ if (unlikely(cur == NULL)) {
>>+ RTE_LOG(ERR, VHOST_DATA, "Failed to "
>>+ "allocate memory for mbuf.\n");
>>+ rc = -1;
>>+ goto out;
>>+ }
>>+
>>+ prev->next = cur;
>>+ prev->data_len = mbuf_offset;
>>+ m->nb_segs += 1;
>>+ m->pkt_len += mbuf_offset;
>>+ prev = cur;
>>+
>>+ mbuf_offset = 0;
>>+ mbuf_avail = cur->buf_len - RTE_PKTMBUF_HEADROOM;
>>+ }
>>+ }
>>+
>>+ if (hdr)
>>+ vhost_dequeue_offload(hdr, m);
>>+
>>+ if ((++vq->last_used_idx & (vq->size - 1)) == 0)
>>+ toggle_wrap_counter(vq);
>>+
>>+ rte_smp_wmb();
>>+ _set_desc_used(&descs[head_idx], wrap_counter);
>>+
>>+ prev->data_len = mbuf_offset;
>>+ m->pkt_len += mbuf_offset;
>>+
>>+out:
>>+ if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
>>+ vhost_user_iotlb_rd_unlock(vq);
>>+ rte_spinlock_unlock(&vq->access_lock);
>>+
>>+ return rc;
>>+}
>>+
>>+static inline uint16_t
>>+vhost_dequeue_burst_packed(struct virtio_net *dev, struct vhost_virtqueue *vq,
>>+ struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts,
>>+ uint16_t count)
>>+{
>>+ uint16_t i;
>>+ uint16_t idx;
>>+ struct vring_desc_packed *desc = vq->desc_packed;
>>+ int err;
>>+
>>+ count = RTE_MIN(MAX_PKT_BURST, count);
>>+ for (i = 0; i < count; i++) {
>>+ idx = vq->last_used_idx & (vq->size - 1);
>>+ if (!desc_is_avail(vq, &desc[idx]))
>>+ break;
>>+ rte_smp_rmb();
>>+
>>+ pkts[i] = rte_pktmbuf_alloc(mbuf_pool);
>>+ if (unlikely(pkts[i] == NULL)) {
>>+ RTE_LOG(ERR, VHOST_DATA,
>>+ "Failed to allocate memory for mbuf.\n");
>>+ break;
>>+ }
>>+
>>+ err = dequeue_desc_packed(dev, vq, mbuf_pool, pkts[i], desc);
>>+ if (unlikely(err)) {
>>+ rte_pktmbuf_free(pkts[i]);
>>+ break;
>>+ }
>>+ }
>>+
>>+ rte_spinlock_unlock(&vq->access_lock);
>I think you forgot to remove this line.
yes
Thanks!
regards,
Jens
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