On 22.01.2019 20:01, Tiwei Bie wrote:
This patch mainly fixed below issues in the packed ring based
control vq support in virtio driver:
1. When parsing the used descriptors, we have to track the
number of descs that we need to skip;
2. vq->vq_free_cnt was decreased twice for a same desc;
Meanwhile, make the function name consistent with other parts.
Fixes: ec194c2f1895 ("net/virtio: support packed queue in send command")
Fixes: a4270ea4ff79 ("net/virtio: check head desc with correct wrap counter")
Signed-off-by: Tiwei Bie <tiwei....@intel.com>
---
drivers/net/virtio/virtio_ethdev.c | 62 ++++++++++++++----------------
drivers/net/virtio/virtqueue.h | 12 +-----
2 files changed, 31 insertions(+), 43 deletions(-)
diff --git a/drivers/net/virtio/virtio_ethdev.c
b/drivers/net/virtio/virtio_ethdev.c
index ee5a98b7c..a3fe65599 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -142,16 +142,17 @@ static const struct rte_virtio_xstats_name_off
rte_virtio_txq_stat_strings[] = {
struct virtio_hw_internal virtio_hw_internal[RTE_MAX_ETHPORTS];
static struct virtio_pmd_ctrl *
-virtio_pq_send_command(struct virtnet_ctl *cvq, struct virtio_pmd_ctrl *ctrl,
- int *dlen, int pkt_num)
+virtio_send_command_packed(struct virtnet_ctl *cvq,
+ struct virtio_pmd_ctrl *ctrl,
+ int *dlen, int pkt_num)
{
struct virtqueue *vq = cvq->vq;
int head;
struct vring_packed_desc *desc = vq->ring_packed.desc_packed;
struct virtio_pmd_ctrl *result;
- bool avail_wrap_counter, used_wrap_counter;
- uint16_t flags;
+ bool avail_wrap_counter;
int sum = 0;
+ int nb_descs = 0;
int k;
/*
@@ -162,11 +163,10 @@ virtio_pq_send_command(struct virtnet_ctl *cvq, struct
virtio_pmd_ctrl *ctrl,
*/
head = vq->vq_avail_idx;
avail_wrap_counter = vq->avail_wrap_counter;
- used_wrap_counter = vq->used_wrap_counter;
- desc[head].flags = VRING_DESC_F_NEXT;
desc[head].addr = cvq->virtio_net_hdr_mem;
desc[head].len = sizeof(struct virtio_net_ctrl_hdr);
vq->vq_free_cnt--;
+ nb_descs++;
if (++vq->vq_avail_idx >= vq->vq_nentries) {
vq->vq_avail_idx -= vq->vq_nentries;
vq->avail_wrap_counter ^= 1;
@@ -177,55 +177,51 @@ virtio_pq_send_command(struct virtnet_ctl *cvq, struct
virtio_pmd_ctrl *ctrl,
+ sizeof(struct virtio_net_ctrl_hdr)
+ sizeof(ctrl->status) + sizeof(uint8_t) * sum;
desc[vq->vq_avail_idx].len = dlen[k];
- flags = VRING_DESC_F_NEXT;
Looks like barriers was badly placed here before this patch.
Anyway, you need a write barrier here between {addr, len} and flags updates.
+ desc[vq->vq_avail_idx].flags = VRING_DESC_F_NEXT |
+ VRING_DESC_F_AVAIL(vq->avail_wrap_counter) |
+ VRING_DESC_F_USED(!vq->avail_wrap_counter);
sum += dlen[k];
vq->vq_free_cnt--;
- flags |= VRING_DESC_F_AVAIL(vq->avail_wrap_counter) |
- VRING_DESC_F_USED(!vq->avail_wrap_counter);
- desc[vq->vq_avail_idx].flags = flags;
- rte_smp_wmb();
- vq->vq_free_cnt--;
+ nb_descs++;
if (++vq->vq_avail_idx >= vq->vq_nentries) {
vq->vq_avail_idx -= vq->vq_nentries;
vq->avail_wrap_counter ^= 1;
}
}
-
desc[vq->vq_avail_idx].addr = cvq->virtio_net_hdr_mem
+ sizeof(struct virtio_net_ctrl_hdr);
desc[vq->vq_avail_idx].len = sizeof(ctrl->status);
- flags = VRING_DESC_F_WRITE;
- flags |= VRING_DESC_F_AVAIL(vq->avail_wrap_counter) |
- VRING_DESC_F_USED(!vq->avail_wrap_counter);
- desc[vq->vq_avail_idx].flags = flags;
- flags = VRING_DESC_F_NEXT;
- flags |= VRING_DESC_F_AVAIL(avail_wrap_counter) |
- VRING_DESC_F_USED(!avail_wrap_counter);
- desc[head].flags = flags;
- rte_smp_wmb();
-
Same here. We need a write barrier to be sure that {addr, len} written
before updating flags.
Another way to avoid most of barriers is to work similar to
'flush_shadow_used_ring_packed',
i.e. update all the data in a loop - write barrier - update all the flags.
+ desc[vq->vq_avail_idx].flags = VRING_DESC_F_WRITE |
+ VRING_DESC_F_AVAIL(vq->avail_wrap_counter) |
+ VRING_DESC_F_USED(!vq->avail_wrap_counter);
vq->vq_free_cnt--;
+ nb_descs++;
if (++vq->vq_avail_idx >= vq->vq_nentries) {
vq->vq_avail_idx -= vq->vq_nentries;
vq->avail_wrap_counter ^= 1;
}
+ virtio_wmb(vq->hw->weak_barriers);
+ desc[head].flags = VRING_DESC_F_NEXT |
+ VRING_DESC_F_AVAIL(avail_wrap_counter) |
+ VRING_DESC_F_USED(!avail_wrap_counter);
+
+ virtio_wmb(vq->hw->weak_barriers);
virtqueue_notify(vq);
/* wait for used descriptors in virtqueue */
- do {
- rte_rmb();
+ while (!desc_is_used(&desc[head], vq))
usleep(100);
- } while (!__desc_is_used(&desc[head], used_wrap_counter));
+
+ virtio_rmb(vq->hw->weak_barriers);
/* now get used descriptors */
- while (desc_is_used(&desc[vq->vq_used_cons_idx], vq)) {
- vq->vq_free_cnt++;
- if (++vq->vq_used_cons_idx >= vq->vq_nentries) {
- vq->vq_used_cons_idx -= vq->vq_nentries;
- vq->used_wrap_counter ^= 1;
- }
+ vq->vq_free_cnt += nb_descs;
+ vq->vq_used_cons_idx += nb_descs;
+ if (vq->vq_used_cons_idx >= vq->vq_nentries) {
+ vq->vq_used_cons_idx -= vq->vq_nentries;
+ vq->used_wrap_counter ^= 1;
}
result = cvq->virtio_net_hdr_mz->addr;
@@ -266,7 +262,7 @@ virtio_send_command(struct virtnet_ctl *cvq, struct
virtio_pmd_ctrl *ctrl,
sizeof(struct virtio_pmd_ctrl));
if (vtpci_packed_queue(vq->hw)) {
- result = virtio_pq_send_command(cvq, ctrl, dlen, pkt_num);
+ result = virtio_send_command_packed(cvq, ctrl, dlen, pkt_num);
goto out_unlock;
}
diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
index 7fcde5643..ca9d8e6e3 100644
--- a/drivers/net/virtio/virtqueue.h
+++ b/drivers/net/virtio/virtqueue.h
@@ -281,7 +281,7 @@ struct virtio_tx_region {
};
static inline int
-__desc_is_used(struct vring_packed_desc *desc, bool wrap_counter)
+desc_is_used(struct vring_packed_desc *desc, struct virtqueue *vq)
{
uint16_t used, avail, flags;
@@ -289,16 +289,9 @@ __desc_is_used(struct vring_packed_desc *desc, bool wrap_counter)
used = !!(flags & VRING_DESC_F_USED(1));
avail = !!(flags & VRING_DESC_F_AVAIL(1));
- return avail == used && used == wrap_counter;
+ return avail == used && used == vq->used_wrap_counter;
}
-static inline int
-desc_is_used(struct vring_packed_desc *desc, struct virtqueue *vq)
-{
- return __desc_is_used(desc, vq->used_wrap_counter);
-}
-
-
static inline void
vring_desc_init_packed(struct virtqueue *vq, int n)
{
@@ -354,7 +347,6 @@ virtqueue_enable_intr_packed(struct virtqueue *vq)
{
uint16_t *event_flags = &vq->ring_packed.driver_event->desc_event_flags;
-
if (vq->event_flags_shadow == RING_EVENT_FLAGS_DISABLE) {
virtio_wmb(vq->hw->weak_barriers);
vq->event_flags_shadow = RING_EVENT_FLAGS_ENABLE;
