On Thu, Feb 02, 2017 at 07:14:05PM -0800, John Fastabend wrote:
> This series adds adjust head support for virtio. The following is my
> test setup. I use qemu + virtio as follows,
>
> ./x86_64-softmmu/qemu-system-x86_64 \
> -hda /var/lib/libvirt/images/Fedora-test0.img \
> -m 4096 -enable-kvm -smp 2 -netdev tap,id=hn0,queues=4,vhost=on \
> -device
> virtio-net-pci,netdev=hn0,mq=on,guest_tso4=off,guest_tso6=off,guest_ecn=off,guest_ufo=off,vectors=9
>
> In order to use XDP with virtio until LRO is supported TSO must be
> turned off in the host. The important fields in the above command line
> are the following,
>
> guest_tso4=off,guest_tso6=off,guest_ecn=off,guest_ufo=off
>
> Also note it is possible to conusme more queues than can be supported
> because when XDP is enabled for retransmit XDP attempts to use a queue
> per cpu. My standard queue count is 'queues=4'.
>
> After loading the VM I run the relevant XDP test programs in,
>
> ./sammples/bpf
>
> For this series I tested xdp1, xdp2, and xdp_tx_iptunnel. I usually test
> with iperf (-d option to get bidirectional traffic), ping, and pktgen.
> I also have a modified xdp1 that returns XDP_PASS on any packet to ensure
> the normal traffic path to the stack continues to work with XDP loaded.
>
> It would be great to automate this soon. At the moment I do it by hand
> which is starting to get tedious.
>
> v2: original series dropped trace points after merge.
So I'd say ok, let's go ahead and merge this for now.
However, I came up with a new idea for the future and I'd like to show
where I'm going. The idea is that we don't use s/g buffers on RX, so we
have a pointer per descriptor untapped. So we can allow users to stick
their own pointer in there, if they promise not to use s/g on this vq.
With a full extra pointer to play with, we can go wild.
Take a look but it doesn't even build yet.
Need to roll it out to all devices etc.
--->
Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
--
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 409aeaa..b59e95e 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -263,6 +263,7 @@ static inline int virtqueue_add(struct virtqueue *_vq,
unsigned int out_sgs,
unsigned int in_sgs,
void *data,
+ void *ctx,
gfp_t gfp)
{
struct vring_virtqueue *vq = to_vvq(_vq);
@@ -275,6 +276,7 @@ static inline int virtqueue_add(struct virtqueue *_vq,
START_USE(vq);
BUG_ON(data == NULL);
+ BUG_ON(ctx && vq->indirect);
if (unlikely(vq->broken)) {
END_USE(vq);
@@ -389,6 +391,8 @@ static inline int virtqueue_add(struct virtqueue *_vq,
vq->desc_state[head].data = data;
if (indirect)
vq->desc_state[head].indir_desc = desc;
+ if (ctx)
+ vq->desc_state[head].indir_desc = ctx;
/* Put entry in available array (but don't update avail->idx until they
* do sync). */
@@ -461,7 +465,8 @@ int virtqueue_add_sgs(struct virtqueue *_vq,
for (sg = sgs[i]; sg; sg = sg_next(sg))
total_sg++;
}
- return virtqueue_add(_vq, sgs, total_sg, out_sgs, in_sgs, data, gfp);
+ return virtqueue_add(_vq, sgs, total_sg, out_sgs, in_sgs,
+ data, NULL, gfp);
}
EXPORT_SYMBOL_GPL(virtqueue_add_sgs);
@@ -483,7 +488,7 @@ int virtqueue_add_outbuf(struct virtqueue *vq,
void *data,
gfp_t gfp)
{
- return virtqueue_add(vq, &sg, num, 1, 0, data, gfp);
+ return virtqueue_add(vq, &sg, num, 1, 0, data, NULL, gfp);
}
EXPORT_SYMBOL_GPL(virtqueue_add_outbuf);
@@ -505,7 +510,31 @@ int virtqueue_add_inbuf(struct virtqueue *vq,
void *data,
gfp_t gfp)
{
- return virtqueue_add(vq, &sg, num, 0, 1, data, gfp);
+ return virtqueue_add(vq, &sg, num, 0, 1, data, NULL, gfp);
+}
+EXPORT_SYMBOL_GPL(virtqueue_add_inbuf);
+
+/**
+ * virtqueue_add_inbuf_ctx - expose input buffers to other end
+ * @vq: the struct virtqueue we're talking about.
+ * @sg: scatterlist (must be well-formed and terminated!)
+ * @num: the number of entries in @sg writable by other side
+ * @data: the token identifying the buffer.
+ * @ctx: extra context for the token
+ * @gfp: how to do memory allocations (if necessary).
+ *
+ * Caller must ensure we don't call this with other virtqueue operations
+ * at the same time (except where noted).
+ *
+ * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
+ */
+int virtqueue_add_inbuf_ctx(struct virtqueue *vq,
+ struct scatterlist *sg, unsigned int num,
+ void *data,
+ void *ctx,
+ gfp_t gfp)
+{
+ return virtqueue_add(vq, &sg, num, 0, 1, data, ctx, gfp);
}
EXPORT_SYMBOL_GPL(virtqueue_add_inbuf);
@@ -598,7 +627,8 @@ bool virtqueue_kick(struct virtqueue *vq)
}
EXPORT_SYMBOL_GPL(virtqueue_kick);
-static void detach_buf(struct vring_virtqueue *vq, unsigned int head)
+static void detach_buf(struct vring_virtqueue *vq, unsigned int head,
+ void **ctx)
{
unsigned int i, j;
__virtio16 nextflag = cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT);
@@ -623,7 +653,10 @@ static void detach_buf(struct vring_virtqueue *vq,
unsigned int head)
vq->vq.num_free++;
/* Free the indirect table, if any, now that it's unmapped. */
- if (vq->desc_state[head].indir_desc) {
+ if (!vq->desc_state[head].indir_desc)
+ return;
+
+ if (vq->indirect) {
struct vring_desc *indir_desc = vq->desc_state[head].indir_desc;
u32 len = virtio32_to_cpu(vq->vq.vdev,
vq->vring.desc[head].len);
@@ -635,8 +668,10 @@ static void detach_buf(struct vring_virtqueue *vq,
unsigned int head)
vring_unmap_one(vq, &indir_desc[j]);
kfree(vq->desc_state[head].indir_desc);
- vq->desc_state[head].indir_desc = NULL;
+ } else if (ctx) {
+ *ctx = vq->desc_state[head].indir_desc;
}
+ vq->desc_state[head].indir_desc = NULL;
}
static inline bool more_used(const struct vring_virtqueue *vq)
@@ -660,7 +695,8 @@ static inline bool more_used(const struct vring_virtqueue
*vq)
* Returns NULL if there are no used buffers, or the "data" token
* handed to virtqueue_add_*().
*/
-void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len)
+void *virtqueue_get_buf_ctx(struct virtqueue *_vq, unsigned int *len,
+ void **ctx)
{
struct vring_virtqueue *vq = to_vvq(_vq);
void *ret;
@@ -698,7 +734,7 @@ void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int
*len)
/* detach_buf clears data, so grab it now. */
ret = vq->desc_state[i].data;
- detach_buf(vq, i);
+ detach_buf(vq, i, ctx);
vq->last_used_idx++;
/* If we expect an interrupt for the next entry, tell host
* by writing event index and flush out the write before
@@ -715,8 +751,13 @@ void *virtqueue_get_buf(struct virtqueue *_vq, unsigned
int *len)
END_USE(vq);
return ret;
}
-EXPORT_SYMBOL_GPL(virtqueue_get_buf);
+EXPORT_SYMBOL_GPL(virtqueue_get_buf_ctx);
+void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len)
+{
+ return virtqueue_get_buf_ctx(_vq, len, NULL);
+}
+EXPORT_SYMBOL_GPL(virtqueue_get_buf);
/**
* virtqueue_disable_cb - disable callbacks
* @vq: the struct virtqueue we're talking about.
@@ -870,6 +911,7 @@ void *virtqueue_detach_unused_buf(struct virtqueue *_vq)
struct vring_virtqueue *vq = to_vvq(_vq);
unsigned int i;
void *buf;
+ void *ctx;
START_USE(vq);
@@ -878,7 +920,7 @@ void *virtqueue_detach_unused_buf(struct virtqueue *_vq)
continue;
/* detach_buf clears data, so grab it now. */
buf = vq->desc_state[i].data;
- detach_buf(vq, i);
+ detach_buf(vq, i, NULL);
vq->avail_idx_shadow--;
vq->vring.avail->idx = cpu_to_virtio16(_vq->vdev,
vq->avail_idx_shadow);
END_USE(vq);
@@ -916,6 +958,7 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index,
struct vring vring,
struct virtio_device *vdev,
bool weak_barriers,
+ bool context,
bool (*notify)(struct virtqueue *),
void (*callback)(struct virtqueue *),
const char *name)
@@ -950,7 +993,8 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index,
vq->last_add_time_valid = false;
#endif
- vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC);
+ vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) &&
+ !context;
vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
/* No callback? Tell other side not to bother us. */
@@ -1019,6 +1063,7 @@ struct virtqueue *vring_create_virtqueue(
struct virtio_device *vdev,
bool weak_barriers,
bool may_reduce_num,
+ bool context,
bool (*notify)(struct virtqueue *),
void (*callback)(struct virtqueue *),
const char *name)
@@ -1058,7 +1103,7 @@ struct virtqueue *vring_create_virtqueue(
queue_size_in_bytes = vring_size(num, vring_align);
vring_init(&vring, num, queue, vring_align);
- vq = __vring_new_virtqueue(index, vring, vdev, weak_barriers,
+ vq = __vring_new_virtqueue(index, vring, vdev, weak_barriers, context,
notify, callback, name);
if (!vq) {
vring_free_queue(vdev, queue_size_in_bytes, queue,
@@ -1079,6 +1124,7 @@ struct virtqueue *vring_new_virtqueue(unsigned int index,
unsigned int vring_align,
struct virtio_device *vdev,
bool weak_barriers,
+ bool context,
void *pages,
bool (*notify)(struct virtqueue *vq),
void (*callback)(struct virtqueue *vq),
@@ -1086,7 +1132,7 @@ struct virtqueue *vring_new_virtqueue(unsigned int index,
{
struct vring vring;
vring_init(&vring, num, pages, vring_align);
- return __vring_new_virtqueue(index, vring, vdev, weak_barriers,
+ return __vring_new_virtqueue(index, vring, vdev, weak_barriers, context,
notify, callback, name);
}
EXPORT_SYMBOL_GPL(vring_new_virtqueue);
--
MST
