[RFC net-next 00/13] virtio-net: support AF_XDP zero copy (tx)

[RFC net-next 00/13] virtio-net: support AF_XDP zero copy (tx)

[Xuan Zhuo]

## AF_XDP

XDP socket(AF_XDP) is an excellent bypass kernel network framework. The zero
copy feature of xsk (XDP socket) needs to be supported by the driver. The
performance of zero copy is very good. mlx5 and intel ixgbe already support
this feature, This patch set allows virtio-net to support xsk's zerocopy xmit
feature.

At present, we have completed some preparation:

1. vq-reset (virtio spec and kernel code)
2. virtio-core premapped dma
3. virtio-net xdp refactor

So it is time for Virtio-Net to complete the support for the XDP Socket
Zerocopy.

Virtio-net can not increase the queue num at will, so xsk shares the queue with
kernel.

This patch set includes some refactor to the virtio-net to let that to support
AF_XDP.

## About virtio premapped mode

The current configuration sets the virtqueue (vq) to premapped mode,
implying that all buffers submitted to this queue must be mapped ahead
of time. This presents a challenge for the virtnet send queue (sq): the
virtnet driver would be required to keep track of dma information for vq
size * 17, which can be substantial. However, if the premapped mode were
applied on a per-buffer basis, the complexity would be greatly reduced.
With AF_XDP enabled, AF_XDP buffers would become premapped, while kernel
skb buffers could remain unmapped.

We can distinguish them by sg_page(sg), When sg_page(sg) is NULL, this
indicates that the driver has performed DMA mapping in advance, allowing
the Virtio core to directly utilize sg_dma_address(sg) without
conducting any internal DMA mapping. Additionally, DMA unmap operations
for this buffer will be bypassed.

## performance

ENV: Qemu with vhost-user(polling mode).
Host CPU: Intel(R) Xeon(R) Platinum 8163 CPU @ 2.50GHz

### virtio PMD in guest with testpmd

testpmd> show port stats all

 ######################## NIC statistics for port 0 ########################
 RX-packets: 19531092064 RX-missed: 0     RX-bytes: 1093741155584
 RX-errors: 0
 RX-nombuf: 0
 TX-packets: 5959955552 TX-errors: 0     TX-bytes: 371030645664


 Throughput (since last show)
 Rx-pps:   8861574     Rx-bps:  3969985208
 Tx-pps:   8861493     Tx-bps:  3969962736
 ############################################################################

### AF_XDP PMD in guest with testpmd

testpmd> show port stats all

  ######################## NIC statistics for port 0  ########################
  RX-packets: 68152727   RX-missed: 0          RX-bytes:  3816552712
  RX-errors: 0
  RX-nombuf:  0
  TX-packets: 68114967   TX-errors: 33216      TX-bytes:  3814438152

  Throughput (since last show)
  Rx-pps:      6333196          Rx-bps:   2837272088
  Tx-pps:      6333227          Tx-bps:   2837285936
  ############################################################################

But AF_XDP consumes more CPU for tx and rx napi(100% and 86%).

Please review.

Thanks.

Xuan Zhuo (13):
  virtio_ring: introduce vring_need_unmap_buffer
  virtio_ring: split: harden dma unmap for indirect
  virtio_ring: packed: harden dma unmap for indirect
  virtio_ring: perform premapped operations based on per-buffer
  virtio-net: rq submits premapped buffer per buffer
  virtio_ring: remove API virtqueue_set_dma_premapped
  virtio_net: refactor the xmit type
  virtio_net: xsk: bind/unbind xsk for tx
  virtio_net: xsk: prevent disable tx napi
  virtio_net: xsk: tx: support xmit xsk buffer
  virtio_net: xsk: tx: handle the transmitted xsk buffer
  virtio_net: update tx timeout record
  virtio_net: xdp_features add NETDEV_XDP_ACT_XSK_ZEROCOPY

 drivers/net/virtio_net.c     | 363 ++++++++++++++++++++++++++++-------
 drivers/virtio/virtio_ring.c | 302 ++++++++++++-----------------
 include/linux/virtio.h       |   2 -
 3 files changed, 421 insertions(+), 246 deletions(-)

--
2.32.0.3.g01195cf9f

[RFC net-next 01/13] virtio_ring: introduce vring_need_unmap_buffer

[Xuan Zhuo]

To make the code readable, introduce vring_need_unmap_buffer() to
replace do_unmap.

   use_dma_api premapped -> vring_need_unmap_buffer()
1. false       false        false
2. true        false        true
3. true        true         false

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
 drivers/virtio/virtio_ring.c | 27 ++++++++++++---------------
 1 file changed, 12 insertions(+), 15 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 2a972752ff1b..df8eb0521aa0 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -175,11 +175,6 @@ struct vring_virtqueue {
 	/* Do DMA mapping by driver */
 	bool premapped;
 
-	/* Do unmap or not for desc. Just when premapped is False and
-	 * use_dma_api is true, this is true.
-	 */
-	bool do_unmap;
-
 	/* Head of free buffer list. */
 	unsigned int free_head;
 	/* Number we've added since last sync. */
@@ -297,6 +292,11 @@ static bool vring_use_dma_api(const struct virtio_device *vdev)
 	return false;
 }
 
+static bool vring_need_unmap_buffer(const struct vring_virtqueue *vring)
+{
+	return vring->use_dma_api && !vring->premapped;
+}
+
 size_t virtio_max_dma_size(const struct virtio_device *vdev)
 {
 	size_t max_segment_size = SIZE_MAX;
@@ -445,7 +445,7 @@ static void vring_unmap_one_split_indirect(const struct vring_virtqueue *vq,
 {
 	u16 flags;
 
-	if (!vq->do_unmap)
+	if (!vring_need_unmap_buffer(vq))
 		return;
 
 	flags = virtio16_to_cpu(vq->vq.vdev, desc->flags);
@@ -475,7 +475,7 @@ static unsigned int vring_unmap_one_split(const struct vring_virtqueue *vq,
 				 (flags & VRING_DESC_F_WRITE) ?
 				 DMA_FROM_DEVICE : DMA_TO_DEVICE);
 	} else {
-		if (!vq->do_unmap)
+		if (!vring_need_unmap_buffer(vq))
 			goto out;
 
 		dma_unmap_page(vring_dma_dev(vq),
@@ -643,7 +643,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
 	}
 	/* Last one doesn't continue. */
 	desc[prev].flags &= cpu_to_virtio16(_vq->vdev, ~VRING_DESC_F_NEXT);
-	if (!indirect && vq->do_unmap)
+	if (!indirect && vring_need_unmap_buffer(vq))
 		vq->split.desc_extra[prev & (vq->split.vring.num - 1)].flags &=
 			~VRING_DESC_F_NEXT;
 
@@ -802,7 +802,7 @@ static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head,
 				VRING_DESC_F_INDIRECT));
 		BUG_ON(len == 0 || len % sizeof(struct vring_desc));
 
-		if (vq->do_unmap) {
+		if (vring_need_unmap_buffer(vq)) {
 			for (j = 0; j < len / sizeof(struct vring_desc); j++)
 				vring_unmap_one_split_indirect(vq, &indir_desc[j]);
 		}
@@ -1236,7 +1236,7 @@ static void vring_unmap_extra_packed(const struct vring_virtqueue *vq,
 				 (flags & VRING_DESC_F_WRITE) ?
 				 DMA_FROM_DEVICE : DMA_TO_DEVICE);
 	} else {
-		if (!vq->do_unmap)
+		if (!vring_need_unmap_buffer(vq))
 			return;
 
 		dma_unmap_page(vring_dma_dev(vq),
@@ -1251,7 +1251,7 @@ static void vring_unmap_desc_packed(const struct vring_virtqueue *vq,
 {
 	u16 flags;
 
-	if (!vq->do_unmap)
+	if (!vring_need_unmap_buffer(vq))
 		return;
 
 	flags = le16_to_cpu(desc->flags);
@@ -1632,7 +1632,7 @@ static void detach_buf_packed(struct vring_virtqueue *vq,
 		if (!desc)
 			return;
 
-		if (vq->do_unmap) {
+		if (vring_need_unmap_buffer(vq)) {
 			len = vq->packed.desc_extra[id].len;
 			for (i = 0; i < len / sizeof(struct vring_packed_desc);
 					i++)
@@ -2091,7 +2091,6 @@ static struct virtqueue *vring_create_virtqueue_packed(
 	vq->dma_dev = dma_dev;
 	vq->use_dma_api = vring_use_dma_api(vdev);
 	vq->premapped = false;
-	vq->do_unmap = vq->use_dma_api;
 
 	vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) &&
 		!context;
@@ -2636,7 +2635,6 @@ static struct virtqueue *__vring_new_virtqueue(unsigned int index,
 	vq->dma_dev = dma_dev;
 	vq->use_dma_api = vring_use_dma_api(vdev);
 	vq->premapped = false;
-	vq->do_unmap = vq->use_dma_api;
 
 	vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) &&
 		!context;
@@ -2799,7 +2797,6 @@ int virtqueue_set_dma_premapped(struct virtqueue *_vq)
 	}
 
 	vq->premapped = true;
-	vq->do_unmap = false;
 
 	END_USE(vq);
 
-- 
2.32.0.3.g01195cf9f

[RFC net-next 02/13] virtio_ring: split: harden dma unmap for indirect

[Xuan Zhuo]

1. this commit hardens dma unmap for indirect
2. the subsequent commit uses the struct extra to record whether the
   buffers need to be unmapped or not. So we need a struct extra for
   every desc, whatever it is indirect or not.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 122 ++++++++++++++++-------------------
 1 file changed, 57 insertions(+), 65 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index df8eb0521aa0..1e037da542b9 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -67,9 +67,16 @@
 #define LAST_ADD_TIME_INVALID(vq)
 #endif
 
+struct vring_desc_extra {
+	dma_addr_t addr;		/* Descriptor DMA addr. */
+	u32 len;			/* Descriptor length. */
+	u16 flags;			/* Descriptor flags. */
+	u16 next;			/* The next desc state in a list. */
+};
+
 struct vring_desc_state_split {
 	void *data;			/* Data for callback. */
-	struct vring_desc *indir_desc;	/* Indirect descriptor, if any. */
+	struct vring_desc_extra *indir;	/* Indirect descriptor, if any. */
 };
 
 struct vring_desc_state_packed {
@@ -79,13 +86,6 @@ struct vring_desc_state_packed {
 	u16 last;			/* The last desc state in a list. */
 };
 
-struct vring_desc_extra {
-	dma_addr_t addr;		/* Descriptor DMA addr. */
-	u32 len;			/* Descriptor length. */
-	u16 flags;			/* Descriptor flags. */
-	u16 next;			/* The next desc state in a list. */
-};
-
 struct vring_virtqueue_split {
 	/* Actual memory layout for this queue. */
 	struct vring vring;
@@ -440,38 +440,20 @@ static void virtqueue_init(struct vring_virtqueue *vq, u32 num)
  * Split ring specific functions - *_split().
  */
 
-static void vring_unmap_one_split_indirect(const struct vring_virtqueue *vq,
-					   const struct vring_desc *desc)
-{
-	u16 flags;
-
-	if (!vring_need_unmap_buffer(vq))
-		return;
-
-	flags = virtio16_to_cpu(vq->vq.vdev, desc->flags);
-
-	dma_unmap_page(vring_dma_dev(vq),
-		       virtio64_to_cpu(vq->vq.vdev, desc->addr),
-		       virtio32_to_cpu(vq->vq.vdev, desc->len),
-		       (flags & VRING_DESC_F_WRITE) ?
-		       DMA_FROM_DEVICE : DMA_TO_DEVICE);
-}
-
 static unsigned int vring_unmap_one_split(const struct vring_virtqueue *vq,
-					  unsigned int i)
+					  struct vring_desc_extra *extra)
 {
-	struct vring_desc_extra *extra = vq->split.desc_extra;
 	u16 flags;
 
-	flags = extra[i].flags;
+	flags = extra->flags;
 
 	if (flags & VRING_DESC_F_INDIRECT) {
 		if (!vq->use_dma_api)
 			goto out;
 
 		dma_unmap_single(vring_dma_dev(vq),
-				 extra[i].addr,
-				 extra[i].len,
+				 extra->addr,
+				 extra->len,
 				 (flags & VRING_DESC_F_WRITE) ?
 				 DMA_FROM_DEVICE : DMA_TO_DEVICE);
 	} else {
@@ -479,20 +461,22 @@ static unsigned int vring_unmap_one_split(const struct vring_virtqueue *vq,
 			goto out;
 
 		dma_unmap_page(vring_dma_dev(vq),
-			       extra[i].addr,
-			       extra[i].len,
+			       extra->addr,
+			       extra->len,
 			       (flags & VRING_DESC_F_WRITE) ?
 			       DMA_FROM_DEVICE : DMA_TO_DEVICE);
 	}
 
 out:
-	return extra[i].next;
+	return extra->next;
 }
 
 static struct vring_desc *alloc_indirect_split(struct virtqueue *_vq,
 					       unsigned int total_sg,
+					       struct vring_desc_extra **pextra,
 					       gfp_t gfp)
 {
+	struct vring_desc_extra *extra;
 	struct vring_desc *desc;
 	unsigned int i;
 
@@ -503,40 +487,45 @@ static struct vring_desc *alloc_indirect_split(struct virtqueue *_vq,
 	 */
 	gfp &= ~__GFP_HIGHMEM;
 
-	desc = kmalloc_array(total_sg, sizeof(struct vring_desc), gfp);
-	if (!desc)
+	extra = kmalloc_array(total_sg, sizeof(*desc) + sizeof(*extra), gfp);
+	if (!extra)
 		return NULL;
 
-	for (i = 0; i < total_sg; i++)
+	desc = (struct vring_desc *)&extra[total_sg];
+
+	for (i = 0; i < total_sg; i++) {
 		desc[i].next = cpu_to_virtio16(_vq->vdev, i + 1);
+		extra[i].next = i + 1;
+	}
+
+	*pextra = extra;
+
 	return desc;
 }
 
 static inline unsigned int virtqueue_add_desc_split(struct virtqueue *vq,
 						    struct vring_desc *desc,
+						    struct vring_desc_extra *extra,
 						    unsigned int i,
 						    dma_addr_t addr,
 						    unsigned int len,
 						    u16 flags,
 						    bool indirect)
 {
-	struct vring_virtqueue *vring = to_vvq(vq);
-	struct vring_desc_extra *extra = vring->split.desc_extra;
 	u16 next;
 
 	desc[i].flags = cpu_to_virtio16(vq->vdev, flags);
 	desc[i].addr = cpu_to_virtio64(vq->vdev, addr);
 	desc[i].len = cpu_to_virtio32(vq->vdev, len);
 
-	if (!indirect) {
-		next = extra[i].next;
-		desc[i].next = cpu_to_virtio16(vq->vdev, next);
+	extra[i].addr = addr;
+	extra[i].len = len;
+	extra[i].flags = flags;
 
-		extra[i].addr = addr;
-		extra[i].len = len;
-		extra[i].flags = flags;
-	} else
-		next = virtio16_to_cpu(vq->vdev, desc[i].next);
+	next = extra[i].next;
+
+	if (!indirect)
+		desc[i].next = cpu_to_virtio16(vq->vdev, next);
 
 	return next;
 }
@@ -551,6 +540,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
 				      gfp_t gfp)
 {
 	struct vring_virtqueue *vq = to_vvq(_vq);
+	struct vring_desc_extra *extra;
 	struct scatterlist *sg;
 	struct vring_desc *desc;
 	unsigned int i, n, avail, descs_used, prev, err_idx;
@@ -574,7 +564,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
 	head = vq->free_head;
 
 	if (virtqueue_use_indirect(vq, total_sg))
-		desc = alloc_indirect_split(_vq, total_sg, gfp);
+		desc = alloc_indirect_split(_vq, total_sg, &extra, gfp);
 	else {
 		desc = NULL;
 		WARN_ON_ONCE(total_sg > vq->split.vring.num && !vq->indirect);
@@ -589,6 +579,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
 	} else {
 		indirect = false;
 		desc = vq->split.vring.desc;
+		extra = vq->split.desc_extra;
 		i = head;
 		descs_used = total_sg;
 	}
@@ -618,7 +609,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
 			/* Note that we trust indirect descriptor
 			 * table since it use stream DMA mapping.
 			 */
-			i = virtqueue_add_desc_split(_vq, desc, i, addr, sg->length,
+			i = virtqueue_add_desc_split(_vq, desc, extra, i, addr, sg->length,
 						     VRING_DESC_F_NEXT,
 						     indirect);
 		}
@@ -634,7 +625,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
 			/* Note that we trust indirect descriptor
 			 * table since it use stream DMA mapping.
 			 */
-			i = virtqueue_add_desc_split(_vq, desc, i, addr,
+			i = virtqueue_add_desc_split(_vq, desc, extra, i, addr,
 						     sg->length,
 						     VRING_DESC_F_NEXT |
 						     VRING_DESC_F_WRITE,
@@ -660,6 +651,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
 		}
 
 		virtqueue_add_desc_split(_vq, vq->split.vring.desc,
+					 vq->split.desc_extra,
 					 head, addr,
 					 total_sg * sizeof(struct vring_desc),
 					 VRING_DESC_F_INDIRECT,
@@ -678,9 +670,9 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
 	/* Store token and indirect buffer state. */
 	vq->split.desc_state[head].data = data;
 	if (indirect)
-		vq->split.desc_state[head].indir_desc = desc;
+		vq->split.desc_state[head].indir = extra;
 	else
-		vq->split.desc_state[head].indir_desc = ctx;
+		vq->split.desc_state[head].indir = ctx;
 
 	/* Put entry in available array (but don't update avail->idx until they
 	 * do sync). */
@@ -716,11 +708,8 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
 	for (n = 0; n < total_sg; n++) {
 		if (i == err_idx)
 			break;
-		if (indirect) {
-			vring_unmap_one_split_indirect(vq, &desc[i]);
-			i = virtio16_to_cpu(_vq->vdev, desc[i].next);
-		} else
-			i = vring_unmap_one_split(vq, i);
+
+		i = vring_unmap_one_split(vq, &extra[i]);
 	}
 
 free_indirect:
@@ -765,22 +754,25 @@ static bool virtqueue_kick_prepare_split(struct virtqueue *_vq)
 static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head,
 			     void **ctx)
 {
+	struct vring_desc_extra *extra;
 	unsigned int i, j;
 	__virtio16 nextflag = cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT);
 
 	/* Clear data ptr. */
 	vq->split.desc_state[head].data = NULL;
 
+	extra = vq->split.desc_extra;
+
 	/* Put back on free list: unmap first-level descriptors and find end */
 	i = head;
 
 	while (vq->split.vring.desc[i].flags & nextflag) {
-		vring_unmap_one_split(vq, i);
+		vring_unmap_one_split(vq, &extra[i]);
 		i = vq->split.desc_extra[i].next;
 		vq->vq.num_free++;
 	}
 
-	vring_unmap_one_split(vq, i);
+	vring_unmap_one_split(vq, &extra[i]);
 	vq->split.desc_extra[i].next = vq->free_head;
 	vq->free_head = head;
 
@@ -788,12 +780,12 @@ static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head,
 	vq->vq.num_free++;
 
 	if (vq->indirect) {
-		struct vring_desc *indir_desc =
-				vq->split.desc_state[head].indir_desc;
 		u32 len;
 
+		extra = vq->split.desc_state[head].indir;
+
 		/* Free the indirect table, if any, now that it's unmapped. */
-		if (!indir_desc)
+		if (!extra)
 			return;
 
 		len = vq->split.desc_extra[head].len;
@@ -804,13 +796,13 @@ static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head,
 
 		if (vring_need_unmap_buffer(vq)) {
 			for (j = 0; j < len / sizeof(struct vring_desc); j++)
-				vring_unmap_one_split_indirect(vq, &indir_desc[j]);
+				vring_unmap_one_split(vq, &extra[j]);
 		}
 
-		kfree(indir_desc);
-		vq->split.desc_state[head].indir_desc = NULL;
+		kfree(extra);
+		vq->split.desc_state[head].indir = NULL;
 	} else if (ctx) {
-		*ctx = vq->split.desc_state[head].indir_desc;
+		*ctx = vq->split.desc_state[head].indir;
 	}
 }
 
-- 
2.32.0.3.g01195cf9f

[RFC net-next 03/13] virtio_ring: packed: harden dma unmap for indirect

[Xuan Zhuo]

1. this commit hardens dma unmap for indirect
2. the subsequent commit uses the struct extra to record whether the
   buffers need to be unmapped or not. So we need a struct extra for
   every desc, whatever it is indirect or not.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 57 ++++++++++++++++++------------------
 1 file changed, 29 insertions(+), 28 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 1e037da542b9..5fb94f735edb 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -81,7 +81,7 @@ struct vring_desc_state_split {
 
 struct vring_desc_state_packed {
 	void *data;			/* Data for callback. */
-	struct vring_packed_desc *indir_desc; /* Indirect descriptor, if any. */
+	struct vring_desc_extra *indir; /* Indirect descriptor, if any. */
 	u16 num;			/* Descriptor list length. */
 	u16 last;			/* The last desc state in a list. */
 };
@@ -1238,27 +1238,13 @@ static void vring_unmap_extra_packed(const struct vring_virtqueue *vq,
 	}
 }
 
-static void vring_unmap_desc_packed(const struct vring_virtqueue *vq,
-				    const struct vring_packed_desc *desc)
-{
-	u16 flags;
-
-	if (!vring_need_unmap_buffer(vq))
-		return;
-
-	flags = le16_to_cpu(desc->flags);
-
-	dma_unmap_page(vring_dma_dev(vq),
-		       le64_to_cpu(desc->addr),
-		       le32_to_cpu(desc->len),
-		       (flags & VRING_DESC_F_WRITE) ?
-		       DMA_FROM_DEVICE : DMA_TO_DEVICE);
-}
-
 static struct vring_packed_desc *alloc_indirect_packed(unsigned int total_sg,
+						       struct vring_desc_extra **pextra,
 						       gfp_t gfp)
 {
+	struct vring_desc_extra *extra;
 	struct vring_packed_desc *desc;
+	int i;
 
 	/*
 	 * We require lowmem mappings for the descriptors because
@@ -1267,7 +1253,14 @@ static struct vring_packed_desc *alloc_indirect_packed(unsigned int total_sg,
 	 */
 	gfp &= ~__GFP_HIGHMEM;
 
-	desc = kmalloc_array(total_sg, sizeof(struct vring_packed_desc), gfp);
+	extra = kmalloc_array(total_sg, sizeof(*desc) + sizeof(*extra), gfp);
+
+	desc = (struct vring_packed_desc *)&extra[total_sg];
+
+	for (i = 0; i < total_sg; i++)
+		extra[i].next = i + 1;
+
+	*pextra = extra;
 
 	return desc;
 }
@@ -1280,6 +1273,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
 					 void *data,
 					 gfp_t gfp)
 {
+	struct vring_desc_extra *extra;
 	struct vring_packed_desc *desc;
 	struct scatterlist *sg;
 	unsigned int i, n, err_idx;
@@ -1287,7 +1281,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
 	dma_addr_t addr;
 
 	head = vq->packed.next_avail_idx;
-	desc = alloc_indirect_packed(total_sg, gfp);
+	desc = alloc_indirect_packed(total_sg, &extra, gfp);
 	if (!desc)
 		return -ENOMEM;
 
@@ -1313,6 +1307,12 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
 			desc[i].addr = cpu_to_le64(addr);
 			desc[i].len = cpu_to_le32(sg->length);
 			i++;
+
+			if (unlikely(vq->use_dma_api)) {
+				extra[i].addr = addr;
+				extra[i].len = sg->length;
+				extra[i].flags = n < out_sgs ?  0 : VRING_DESC_F_WRITE;
+			}
 		}
 	}
 
@@ -1367,7 +1367,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
 	/* Store token and indirect buffer state. */
 	vq->packed.desc_state[id].num = 1;
 	vq->packed.desc_state[id].data = data;
-	vq->packed.desc_state[id].indir_desc = desc;
+	vq->packed.desc_state[id].indir = extra;
 	vq->packed.desc_state[id].last = id;
 
 	vq->num_added += 1;
@@ -1381,7 +1381,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
 	err_idx = i;
 
 	for (i = 0; i < err_idx; i++)
-		vring_unmap_desc_packed(vq, &desc[i]);
+		vring_unmap_extra_packed(vq, &extra[i]);
 
 free_desc:
 	kfree(desc);
@@ -1504,7 +1504,7 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq,
 	/* Store token. */
 	vq->packed.desc_state[id].num = descs_used;
 	vq->packed.desc_state[id].data = data;
-	vq->packed.desc_state[id].indir_desc = ctx;
+	vq->packed.desc_state[id].indir = ctx;
 	vq->packed.desc_state[id].last = prev;
 
 	/*
@@ -1617,23 +1617,24 @@ static void detach_buf_packed(struct vring_virtqueue *vq,
 	}
 
 	if (vq->indirect) {
+		struct vring_desc_extra *extra;
 		u32 len;
 
 		/* Free the indirect table, if any, now that it's unmapped. */
-		desc = state->indir_desc;
-		if (!desc)
+		extra = state->indir;
+		if (!extra)
 			return;
 
 		if (vring_need_unmap_buffer(vq)) {
 			len = vq->packed.desc_extra[id].len;
 			for (i = 0; i < len / sizeof(struct vring_packed_desc);
 					i++)
-				vring_unmap_desc_packed(vq, &desc[i]);
+				vring_unmap_extra_packed(vq, &extra[i]);
 		}
 		kfree(desc);
-		state->indir_desc = NULL;
+		state->indir = NULL;
 	} else if (ctx) {
-		*ctx = state->indir_desc;
+		*ctx = state->indir;
 	}
 }
 
-- 
2.32.0.3.g01195cf9f

[RFC net-next 04/13] virtio_ring: perform premapped operations based on per-buffer

[Xuan Zhuo]

The current configuration sets the virtqueue (vq) to premapped mode,
implying that all buffers submitted to this queue must be mapped ahead
of time. This presents a challenge for the virtnet send queue (sq): the
virtnet driver would be required to keep track of dma information for vq
size * 17, which can be substantial. However, if the premapped mode were
applied on a per-buffer basis, the complexity would be greatly reduced.
With AF_XDP enabled, AF_XDP buffers would become premapped, while kernel
skb buffers could remain unmapped.

We can distinguish them by sg_page(sg), When sg_page(sg) is NULL, this
indicates that the driver has performed DMA mapping in advance, allowing
the Virtio core to directly utilize sg_dma_address(sg) without
conducting any internal DMA mapping. Additionally, DMA unmap operations
for this buffer will be bypassed.

Suggested-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 70 +++++++++++++++++++++---------------
 1 file changed, 41 insertions(+), 29 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 5fb94f735edb..d357f1b219d1 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -235,6 +235,7 @@ static void vring_free(struct virtqueue *_vq);
  */
 
 #define to_vvq(_vq) container_of_const(_vq, struct vring_virtqueue, vq)
+#define sg_is_premapped(sg) (!sg_page(sg))
 
 static bool virtqueue_use_indirect(const struct vring_virtqueue *vq,
 				   unsigned int total_sg)
@@ -292,9 +293,10 @@ static bool vring_use_dma_api(const struct virtio_device *vdev)
 	return false;
 }
 
-static bool vring_need_unmap_buffer(const struct vring_virtqueue *vring)
+static bool vring_need_unmap_buffer(const struct vring_virtqueue *vring,
+				    const struct vring_desc_extra *extra)
 {
-	return vring->use_dma_api && !vring->premapped;
+	return vring->use_dma_api && (extra->addr != DMA_MAPPING_ERROR);
 }
 
 size_t virtio_max_dma_size(const struct virtio_device *vdev)
@@ -366,7 +368,7 @@ static struct device *vring_dma_dev(const struct vring_virtqueue *vq)
 static int vring_map_one_sg(const struct vring_virtqueue *vq, struct scatterlist *sg,
 			    enum dma_data_direction direction, dma_addr_t *addr)
 {
-	if (vq->premapped) {
+	if (sg_is_premapped(sg)) {
 		*addr = sg_dma_address(sg);
 		return 0;
 	}
@@ -457,7 +459,7 @@ static unsigned int vring_unmap_one_split(const struct vring_virtqueue *vq,
 				 (flags & VRING_DESC_F_WRITE) ?
 				 DMA_FROM_DEVICE : DMA_TO_DEVICE);
 	} else {
-		if (!vring_need_unmap_buffer(vq))
+		if (!vring_need_unmap_buffer(vq, extra))
 			goto out;
 
 		dma_unmap_page(vring_dma_dev(vq),
@@ -510,7 +512,7 @@ static inline unsigned int virtqueue_add_desc_split(struct virtqueue *vq,
 						    dma_addr_t addr,
 						    unsigned int len,
 						    u16 flags,
-						    bool indirect)
+						    bool indirect, bool premapped)
 {
 	u16 next;
 
@@ -518,7 +520,7 @@ static inline unsigned int virtqueue_add_desc_split(struct virtqueue *vq,
 	desc[i].addr = cpu_to_virtio64(vq->vdev, addr);
 	desc[i].len = cpu_to_virtio32(vq->vdev, len);
 
-	extra[i].addr = addr;
+	extra[i].addr = premapped ? DMA_MAPPING_ERROR : addr;
 	extra[i].len = len;
 	extra[i].flags = flags;
 
@@ -611,7 +613,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
 			 */
 			i = virtqueue_add_desc_split(_vq, desc, extra, i, addr, sg->length,
 						     VRING_DESC_F_NEXT,
-						     indirect);
+						     indirect, sg_is_premapped(sg));
 		}
 	}
 	for (; n < (out_sgs + in_sgs); n++) {
@@ -629,12 +631,12 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
 						     sg->length,
 						     VRING_DESC_F_NEXT |
 						     VRING_DESC_F_WRITE,
-						     indirect);
+						     indirect, sg_is_premapped(sg));
 		}
 	}
 	/* Last one doesn't continue. */
 	desc[prev].flags &= cpu_to_virtio16(_vq->vdev, ~VRING_DESC_F_NEXT);
-	if (!indirect && vring_need_unmap_buffer(vq))
+	if (!indirect && vring_need_unmap_buffer(vq, &extra[prev]))
 		vq->split.desc_extra[prev & (vq->split.vring.num - 1)].flags &=
 			~VRING_DESC_F_NEXT;
 
@@ -643,19 +645,15 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
 		dma_addr_t addr = vring_map_single(
 			vq, desc, total_sg * sizeof(struct vring_desc),
 			DMA_TO_DEVICE);
-		if (vring_mapping_error(vq, addr)) {
-			if (vq->premapped)
-				goto free_indirect;
-
+		if (vring_mapping_error(vq, addr))
 			goto unmap_release;
-		}
 
 		virtqueue_add_desc_split(_vq, vq->split.vring.desc,
 					 vq->split.desc_extra,
 					 head, addr,
 					 total_sg * sizeof(struct vring_desc),
 					 VRING_DESC_F_INDIRECT,
-					 false);
+					 false, false);
 	}
 
 	/* We're using some buffers from the free list. */
@@ -712,7 +710,6 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
 		i = vring_unmap_one_split(vq, &extra[i]);
 	}
 
-free_indirect:
 	if (indirect)
 		kfree(desc);
 
@@ -794,7 +791,7 @@ static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head,
 				VRING_DESC_F_INDIRECT));
 		BUG_ON(len == 0 || len % sizeof(struct vring_desc));
 
-		if (vring_need_unmap_buffer(vq)) {
+		if (vq->use_dma_api) {
 			for (j = 0; j < len / sizeof(struct vring_desc); j++)
 				vring_unmap_one_split(vq, &extra[j]);
 		}
@@ -1228,7 +1225,7 @@ static void vring_unmap_extra_packed(const struct vring_virtqueue *vq,
 				 (flags & VRING_DESC_F_WRITE) ?
 				 DMA_FROM_DEVICE : DMA_TO_DEVICE);
 	} else {
-		if (!vring_need_unmap_buffer(vq))
+		if (!vring_need_unmap_buffer(vq, extra))
 			return;
 
 		dma_unmap_page(vring_dma_dev(vq),
@@ -1309,7 +1306,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
 			i++;
 
 			if (unlikely(vq->use_dma_api)) {
-				extra[i].addr = addr;
+				extra[i].addr = sg_is_premapped(sg) ? DMA_MAPPING_ERROR : addr;
 				extra[i].len = sg->length;
 				extra[i].flags = n < out_sgs ?  0 : VRING_DESC_F_WRITE;
 			}
@@ -1320,12 +1317,8 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
 	addr = vring_map_single(vq, desc,
 			total_sg * sizeof(struct vring_packed_desc),
 			DMA_TO_DEVICE);
-	if (vring_mapping_error(vq, addr)) {
-		if (vq->premapped)
-			goto free_desc;
-
+	if (vring_mapping_error(vq, addr))
 		goto unmap_release;
-	}
 
 	vq->packed.vring.desc[head].addr = cpu_to_le64(addr);
 	vq->packed.vring.desc[head].len = cpu_to_le32(total_sg *
@@ -1383,7 +1376,6 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
 	for (i = 0; i < err_idx; i++)
 		vring_unmap_extra_packed(vq, &extra[i]);
 
-free_desc:
 	kfree(desc);
 
 	END_USE(vq);
@@ -1474,7 +1466,8 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq,
 			desc[i].id = cpu_to_le16(id);
 
 			if (unlikely(vq->use_dma_api)) {
-				vq->packed.desc_extra[curr].addr = addr;
+				vq->packed.desc_extra[curr].addr = sg_is_premapped(sg) ?
+					DMA_MAPPING_ERROR : addr;
 				vq->packed.desc_extra[curr].len = sg->length;
 				vq->packed.desc_extra[curr].flags =
 					le16_to_cpu(flags);
@@ -1625,10 +1618,9 @@ static void detach_buf_packed(struct vring_virtqueue *vq,
 		if (!extra)
 			return;
 
-		if (vring_need_unmap_buffer(vq)) {
+		if (vq->use_dma_api) {
 			len = vq->packed.desc_extra[id].len;
-			for (i = 0; i < len / sizeof(struct vring_packed_desc);
-					i++)
+			for (i = 0; i < len / sizeof(struct vring_packed_desc); i++)
 				vring_unmap_extra_packed(vq, &extra[i]);
 		}
 		kfree(desc);
@@ -2212,6 +2204,11 @@ static inline int virtqueue_add(struct virtqueue *_vq,
  * @data: the token identifying the buffer.
  * @gfp: how to do memory allocations (if necessary).
  *
+ * When sg_page(sg) is NULL, this indicates that the driver has performed DMA
+ * mapping in advance, allowing the virtio core to directly utilize
+ * sg_dma_address(sg) without conducting any internal DMA mapping. Additionally,
+ * DMA unmap operations for this buffer will be bypassed.
+ *
  * Caller must ensure we don't call this with other virtqueue operations
  * at the same time (except where noted).
  *
@@ -2246,6 +2243,11 @@ EXPORT_SYMBOL_GPL(virtqueue_add_sgs);
  * @data: the token identifying the buffer.
  * @gfp: how to do memory allocations (if necessary).
  *
+ * When sg_page(sg) is NULL, this indicates that the driver has performed DMA
+ * mapping in advance, allowing the virtio core to directly utilize
+ * sg_dma_address(sg) without conducting any internal DMA mapping. Additionally,
+ * DMA unmap operations for this buffer will be bypassed.
+ *
  * Caller must ensure we don't call this with other virtqueue operations
  * at the same time (except where noted).
  *
@@ -2268,6 +2270,11 @@ EXPORT_SYMBOL_GPL(virtqueue_add_outbuf);
  * @data: the token identifying the buffer.
  * @gfp: how to do memory allocations (if necessary).
  *
+ * When sg_page(sg) is NULL, this indicates that the driver has performed DMA
+ * mapping in advance, allowing the virtio core to directly utilize
+ * sg_dma_address(sg) without conducting any internal DMA mapping. Additionally,
+ * DMA unmap operations for this buffer will be bypassed.
+ *
  * Caller must ensure we don't call this with other virtqueue operations
  * at the same time (except where noted).
  *
@@ -2291,6 +2298,11 @@ EXPORT_SYMBOL_GPL(virtqueue_add_inbuf);
  * @ctx: extra context for the token
  * @gfp: how to do memory allocations (if necessary).
  *
+ * When sg_page(sg) is NULL, this indicates that the driver has performed DMA
+ * mapping in advance, allowing the virtio core to directly utilize
+ * sg_dma_address(sg) without conducting any internal DMA mapping. Additionally,
+ * DMA unmap operations for this buffer will be bypassed.
+ *
  * Caller must ensure we don't call this with other virtqueue operations
  * at the same time (except where noted).
  *
-- 
2.32.0.3.g01195cf9f

[RFC net-next 05/13] virtio-net: rq submits premapped buffer per buffer

[Xuan Zhuo]

virtio-net rq submits premapped buffer per buffer.
And removes the call of the virtnet_rq_set_premapped().

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 drivers/net/virtio_net.c | 31 ++++++++-----------------------
 1 file changed, 8 insertions(+), 23 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index af474cc191d0..ce83826df90f 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -539,6 +539,13 @@ static struct sk_buff *ptr_to_skb(void *ptr)
 	return (struct sk_buff *)((unsigned long)ptr & ~VIRTIO_ORPHAN_FLAG);
 }
 
+static void sg_fill_dma(struct scatterlist *sg, dma_addr_t addr, u32 len)
+{
+	sg_assign_page(sg, NULL);
+	sg->dma_address = addr;
+	sg->length = len;
+}
+
 static void __free_old_xmit(struct send_queue *sq, struct netdev_queue *txq,
 			    bool in_napi, struct virtnet_sq_free_stats *stats)
 {
@@ -907,8 +914,7 @@ static void virtnet_rq_init_one_sg(struct receive_queue *rq, void *buf, u32 len)
 	addr = dma->addr - sizeof(*dma) + offset;
 
 	sg_init_table(rq->sg, 1);
-	rq->sg[0].dma_address = addr;
-	rq->sg[0].length = len;
+	sg_fill_dma(&rq->sg[0], addr, len);
 }
 
 static void *virtnet_rq_alloc(struct receive_queue *rq, u32 size, gfp_t gfp)
@@ -967,19 +973,6 @@ static void *virtnet_rq_alloc(struct receive_queue *rq, u32 size, gfp_t gfp)
 	return buf;
 }
 
-static void virtnet_rq_set_premapped(struct virtnet_info *vi)
-{
-	int i;
-
-	/* disable for big mode */
-	if (!vi->mergeable_rx_bufs && vi->big_packets)
-		return;
-
-	for (i = 0; i < vi->max_queue_pairs; i++)
-		/* error should never happen */
-		BUG_ON(virtqueue_set_dma_premapped(vi->rq[i].vq));
-}
-
 static void virtnet_rq_unmap_free_buf(struct virtqueue *vq, void *buf)
 {
 	struct virtnet_info *vi = vq->vdev->priv;
@@ -1071,12 +1064,6 @@ static void check_sq_full_and_disable(struct virtnet_info *vi,
 	}
 }
 
-static void sg_fill_dma(struct scatterlist *sg, dma_addr_t addr, u32 len)
-{
-	sg->dma_address = addr;
-	sg->length = len;
-}
-
 static struct xdp_buff *buf_to_xdp(struct virtnet_info *vi,
 				   struct receive_queue *rq, void *buf, u32 len)
 {
@@ -6088,8 +6075,6 @@ static int init_vqs(struct virtnet_info *vi)
 	if (ret)
 		goto err_free;
 
-	virtnet_rq_set_premapped(vi);
-
 	cpus_read_lock();
 	virtnet_set_affinity(vi);
 	cpus_read_unlock();
-- 
2.32.0.3.g01195cf9f

[RFC net-next 06/13] virtio_ring: remove API virtqueue_set_dma_premapped

[Xuan Zhuo]

Now, this API is useless. remove it.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 48 ------------------------------------
 include/linux/virtio.h       |  2 --
 2 files changed, 50 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index d357f1b219d1..950c65b49288 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -172,9 +172,6 @@ struct vring_virtqueue {
 	/* Host publishes avail event idx */
 	bool event;
 
-	/* Do DMA mapping by driver */
-	bool premapped;
-
 	/* Head of free buffer list. */
 	unsigned int free_head;
 	/* Number we've added since last sync. */
@@ -2075,7 +2072,6 @@ static struct virtqueue *vring_create_virtqueue_packed(
 	vq->packed_ring = true;
 	vq->dma_dev = dma_dev;
 	vq->use_dma_api = vring_use_dma_api(vdev);
-	vq->premapped = false;
 
 	vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) &&
 		!context;
@@ -2639,7 +2635,6 @@ static struct virtqueue *__vring_new_virtqueue(unsigned int index,
 #endif
 	vq->dma_dev = dma_dev;
 	vq->use_dma_api = vring_use_dma_api(vdev);
-	vq->premapped = false;
 
 	vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) &&
 		!context;
@@ -2766,49 +2761,6 @@ int virtqueue_resize(struct virtqueue *_vq, u32 num,
 }
 EXPORT_SYMBOL_GPL(virtqueue_resize);
 
-/**
- * virtqueue_set_dma_premapped - set the vring premapped mode
- * @_vq: the struct virtqueue we're talking about.
- *
- * Enable the premapped mode of the vq.
- *
- * The vring in premapped mode does not do dma internally, so the driver must
- * do dma mapping in advance. The driver must pass the dma_address through
- * dma_address of scatterlist. When the driver got a used buffer from
- * the vring, it has to unmap the dma address.
- *
- * This function must be called immediately after creating the vq, or after vq
- * reset, and before adding any buffers to it.
- *
- * 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.
- * 0: success.
- * -EINVAL: too late to enable premapped mode, the vq already contains buffers.
- */
-int virtqueue_set_dma_premapped(struct virtqueue *_vq)
-{
-	struct vring_virtqueue *vq = to_vvq(_vq);
-	u32 num;
-
-	START_USE(vq);
-
-	num = vq->packed_ring ? vq->packed.vring.num : vq->split.vring.num;
-
-	if (num != vq->vq.num_free) {
-		END_USE(vq);
-		return -EINVAL;
-	}
-
-	vq->premapped = true;
-
-	END_USE(vq);
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(virtqueue_set_dma_premapped);
-
 /**
  * virtqueue_reset - detach and recycle all unused buffers
  * @_vq: the struct virtqueue we're talking about.
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 96fea920873b..1300359e5154 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -81,8 +81,6 @@ bool virtqueue_enable_cb(struct virtqueue *vq);
 
 unsigned virtqueue_enable_cb_prepare(struct virtqueue *vq);
 
-int virtqueue_set_dma_premapped(struct virtqueue *_vq);
-
 bool virtqueue_poll(struct virtqueue *vq, unsigned);
 
 bool virtqueue_enable_cb_delayed(struct virtqueue *vq);
-- 
2.32.0.3.g01195cf9f

[RFC net-next 07/13] virtio_net: refactor the xmit type

[Xuan Zhuo]

Because the af-xdp will introduce a new xmit type, so I refactor the
xmit type mechanism first.

We use the last two bits of the pointer to distinguish the xmit type,
so we can distinguish four xmit types. Now we have three types: skb,
orphan and xdp.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 drivers/net/virtio_net.c | 90 +++++++++++++++++++++++-----------------
 1 file changed, 51 insertions(+), 39 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index ce83826df90f..f5edd8be4668 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -45,9 +45,6 @@ module_param(napi_tx, bool, 0644);
 #define VIRTIO_XDP_TX		BIT(0)
 #define VIRTIO_XDP_REDIR	BIT(1)
 
-#define VIRTIO_XDP_FLAG		BIT(0)
-#define VIRTIO_ORPHAN_FLAG	BIT(1)
-
 /* RX packet size EWMA. The average packet size is used to determine the packet
  * buffer size when refilling RX rings. As the entire RX ring may be refilled
  * at once, the weight is chosen so that the EWMA will be insensitive to short-
@@ -509,34 +506,35 @@ static struct sk_buff *virtnet_skb_append_frag(struct sk_buff *head_skb,
 					       struct page *page, void *buf,
 					       int len, int truesize);
 
-static bool is_xdp_frame(void *ptr)
-{
-	return (unsigned long)ptr & VIRTIO_XDP_FLAG;
-}
+enum virtnet_xmit_type {
+	VIRTNET_XMIT_TYPE_SKB,
+	VIRTNET_XMIT_TYPE_ORPHAN,
+	VIRTNET_XMIT_TYPE_XDP,
+};
 
-static void *xdp_to_ptr(struct xdp_frame *ptr)
-{
-	return (void *)((unsigned long)ptr | VIRTIO_XDP_FLAG);
-}
+#define VIRTNET_XMIT_TYPE_MASK (VIRTNET_XMIT_TYPE_SKB | VIRTNET_XMIT_TYPE_ORPHAN \
+				| VIRTNET_XMIT_TYPE_XDP)
 
-static struct xdp_frame *ptr_to_xdp(void *ptr)
+static enum virtnet_xmit_type virtnet_xmit_ptr_strip(void **ptr)
 {
-	return (struct xdp_frame *)((unsigned long)ptr & ~VIRTIO_XDP_FLAG);
-}
+	unsigned long p = (unsigned long)*ptr;
 
-static bool is_orphan_skb(void *ptr)
-{
-	return (unsigned long)ptr & VIRTIO_ORPHAN_FLAG;
+	*ptr = (void *)(p & ~VIRTNET_XMIT_TYPE_MASK);
+
+	return p & VIRTNET_XMIT_TYPE_MASK;
 }
 
-static void *skb_to_ptr(struct sk_buff *skb, bool orphan)
+static void *virtnet_xmit_ptr_mix(void *ptr, enum virtnet_xmit_type type)
 {
-	return (void *)((unsigned long)skb | (orphan ? VIRTIO_ORPHAN_FLAG : 0));
+	return (void *)((unsigned long)ptr | type);
 }
 
-static struct sk_buff *ptr_to_skb(void *ptr)
+static int virtnet_add_outbuf(struct send_queue *sq, int num, void *data,
+			      enum virtnet_xmit_type type)
 {
-	return (struct sk_buff *)((unsigned long)ptr & ~VIRTIO_ORPHAN_FLAG);
+	return virtqueue_add_outbuf(sq->vq, sq->sg, num,
+				    virtnet_xmit_ptr_mix(data, type),
+				    GFP_ATOMIC);
 }
 
 static void sg_fill_dma(struct scatterlist *sg, dma_addr_t addr, u32 len)
@@ -549,29 +547,37 @@ static void sg_fill_dma(struct scatterlist *sg, dma_addr_t addr, u32 len)
 static void __free_old_xmit(struct send_queue *sq, struct netdev_queue *txq,
 			    bool in_napi, struct virtnet_sq_free_stats *stats)
 {
+	struct xdp_frame *frame;
+	struct sk_buff *skb;
 	unsigned int len;
 	void *ptr;
 
 	while ((ptr = virtqueue_get_buf(sq->vq, &len)) != NULL) {
-		if (!is_xdp_frame(ptr)) {
-			struct sk_buff *skb = ptr_to_skb(ptr);
+		switch (virtnet_xmit_ptr_strip(&ptr)) {
+		case VIRTNET_XMIT_TYPE_SKB:
+			skb = ptr;
 
 			pr_debug("Sent skb %p\n", skb);
+			stats->napi_packets++;
+			stats->napi_bytes += skb->len;
+			napi_consume_skb(skb, in_napi);
+			break;
 
-			if (is_orphan_skb(ptr)) {
-				stats->packets++;
-				stats->bytes += skb->len;
-			} else {
-				stats->napi_packets++;
-				stats->napi_bytes += skb->len;
-			}
+		case VIRTNET_XMIT_TYPE_ORPHAN:
+			skb = ptr;
+
+			stats->packets++;
+			stats->bytes += skb->len;
 			napi_consume_skb(skb, in_napi);
-		} else {
-			struct xdp_frame *frame = ptr_to_xdp(ptr);
+			break;
+
+		case VIRTNET_XMIT_TYPE_XDP:
+			frame = ptr;
 
 			stats->packets++;
 			stats->bytes += xdp_get_frame_len(frame);
 			xdp_return_frame(frame);
+			break;
 		}
 	}
 	netdev_tx_completed_queue(txq, stats->napi_packets, stats->napi_bytes);
@@ -1421,8 +1427,7 @@ static int __virtnet_xdp_xmit_one(struct virtnet_info *vi,
 			    skb_frag_size(frag), skb_frag_off(frag));
 	}
 
-	err = virtqueue_add_outbuf(sq->vq, sq->sg, nr_frags + 1,
-				   xdp_to_ptr(xdpf), GFP_ATOMIC);
+	err = virtnet_add_outbuf(sq, nr_frags + 1, xdpf, VIRTNET_XMIT_TYPE_XDP);
 	if (unlikely(err))
 		return -ENOSPC; /* Caller handle free/refcnt */
 
@@ -3000,8 +3005,9 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb, bool orphan)
 			return num_sg;
 		num_sg++;
 	}
-	return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg,
-				    skb_to_ptr(skb, orphan), GFP_ATOMIC);
+
+	return virtnet_add_outbuf(sq, num_sg, skb,
+				  orphan ? VIRTNET_XMIT_TYPE_ORPHAN : VIRTNET_XMIT_TYPE_SKB);
 }
 
 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
@@ -5877,10 +5883,16 @@ static void free_receive_page_frags(struct virtnet_info *vi)
 
 static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf)
 {
-	if (!is_xdp_frame(buf))
+	switch (virtnet_xmit_ptr_strip(&buf)) {
+	case VIRTNET_XMIT_TYPE_SKB:
+	case VIRTNET_XMIT_TYPE_ORPHAN:
 		dev_kfree_skb(buf);
-	else
-		xdp_return_frame(ptr_to_xdp(buf));
+		break;
+
+	case VIRTNET_XMIT_TYPE_XDP:
+		xdp_return_frame(buf);
+		break;
+	}
 }
 
 static void free_unused_bufs(struct virtnet_info *vi)
-- 
2.32.0.3.g01195cf9f

[RFC net-next 08/13] virtio_net: xsk: bind/unbind xsk for tx

[Xuan Zhuo]

This patch implement the logic of bind/unbind xsk pool to sq and rq.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 drivers/net/virtio_net.c | 54 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index f5edd8be4668..c0aba5d4aa48 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -54,6 +54,8 @@ DECLARE_EWMA(pkt_len, 0, 64)
 
 #define VIRTNET_DRIVER_VERSION "1.0.0"
 
+static struct virtio_net_common_hdr xsk_hdr;
+
 static const unsigned long guest_offloads[] = {
 	VIRTIO_NET_F_GUEST_TSO4,
 	VIRTIO_NET_F_GUEST_TSO6,
@@ -295,6 +297,10 @@ struct send_queue {
 
 	/* Record whether sq is in reset state. */
 	bool reset;
+
+	struct xsk_buff_pool *xsk_pool;
+
+	dma_addr_t xsk_hdr_dma_addr;
 };
 
 /* Internal representation of a receive virtqueue */
@@ -5447,6 +5453,29 @@ static int virtnet_rq_bind_xsk_pool(struct virtnet_info *vi, struct receive_queu
 	return err;
 }
 
+static int virtnet_sq_bind_xsk_pool(struct virtnet_info *vi,
+				    struct send_queue *sq,
+				    struct xsk_buff_pool *pool)
+{
+	int err, qindex;
+
+	qindex = sq - vi->sq;
+
+	virtnet_tx_pause(vi, sq);
+
+	err = virtqueue_reset(sq->vq, virtnet_sq_free_unused_buf);
+	if (err) {
+		netdev_err(vi->dev, "reset tx fail: tx queue index: %d err: %d\n", qindex, err);
+		pool = NULL;
+	}
+
+	sq->xsk_pool = pool;
+
+	virtnet_tx_resume(vi, sq);
+
+	return err;
+}
+
 static int virtnet_xsk_pool_enable(struct net_device *dev,
 				   struct xsk_buff_pool *pool,
 				   u16 qid)
@@ -5455,6 +5484,7 @@ static int virtnet_xsk_pool_enable(struct net_device *dev,
 	struct receive_queue *rq;
 	struct device *dma_dev;
 	struct send_queue *sq;
+	dma_addr_t hdr_dma;
 	int err, size;
 
 	if (vi->hdr_len > xsk_pool_get_headroom(pool))
@@ -5492,6 +5522,10 @@ static int virtnet_xsk_pool_enable(struct net_device *dev,
 	if (!rq->xsk_buffs)
 		return -ENOMEM;
 
+	hdr_dma = dma_map_single(dma_dev, &xsk_hdr, vi->hdr_len, DMA_TO_DEVICE);
+	if (dma_mapping_error(dma_dev, hdr_dma))
+		return -ENOMEM;
+
 	err = xsk_pool_dma_map(pool, dma_dev, 0);
 	if (err)
 		goto err_xsk_map;
@@ -5500,11 +5534,23 @@ static int virtnet_xsk_pool_enable(struct net_device *dev,
 	if (err)
 		goto err_rq;
 
+	err = virtnet_sq_bind_xsk_pool(vi, sq, pool);
+	if (err)
+		goto err_sq;
+
+	/* Now, we do not support tx offset, so all the tx virtnet hdr is zero.
+	 * So all the tx packets can share a single hdr.
+	 */
+	sq->xsk_hdr_dma_addr = hdr_dma;
+
 	return 0;
 
+err_sq:
+	virtnet_rq_bind_xsk_pool(vi, rq, NULL);
 err_rq:
 	xsk_pool_dma_unmap(pool, 0);
 err_xsk_map:
+	dma_unmap_single(dma_dev, hdr_dma, vi->hdr_len, DMA_TO_DEVICE);
 	return err;
 }
 
@@ -5513,19 +5559,27 @@ static int virtnet_xsk_pool_disable(struct net_device *dev, u16 qid)
 	struct virtnet_info *vi = netdev_priv(dev);
 	struct xsk_buff_pool *pool;
 	struct receive_queue *rq;
+	struct device *dma_dev;
+	struct send_queue *sq;
 	int err;
 
 	if (qid >= vi->curr_queue_pairs)
 		return -EINVAL;
 
+	sq = &vi->sq[qid];
 	rq = &vi->rq[qid];
 
 	pool = rq->xsk_pool;
 
 	err = virtnet_rq_bind_xsk_pool(vi, rq, NULL);
+	err |= virtnet_sq_bind_xsk_pool(vi, sq, NULL);
 
 	xsk_pool_dma_unmap(pool, 0);
 
+	dma_dev = virtqueue_dma_dev(sq->vq);
+
+	dma_unmap_single(dma_dev, sq->xsk_hdr_dma_addr, vi->hdr_len, DMA_TO_DEVICE);
+
 	kvfree(rq->xsk_buffs);
 
 	return err;
-- 
2.32.0.3.g01195cf9f

[RFC net-next 09/13] virtio_net: xsk: prevent disable tx napi

[Xuan Zhuo]

Since xsk's TX queue is consumed by TX NAPI, if sq is bound to xsk, then
we must stop tx napi from being disabled.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
 drivers/net/virtio_net.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index c0aba5d4aa48..b02fc118b0b8 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -4957,7 +4957,7 @@ static int virtnet_set_coalesce(struct net_device *dev,
 				struct netlink_ext_ack *extack)
 {
 	struct virtnet_info *vi = netdev_priv(dev);
-	int ret, queue_number, napi_weight;
+	int ret, queue_number, napi_weight, i;
 	bool update_napi = false;
 
 	/* Can't change NAPI weight if the link is up */
@@ -4986,6 +4986,14 @@ static int virtnet_set_coalesce(struct net_device *dev,
 		return ret;
 
 	if (update_napi) {
+		/* xsk xmit depends on the tx napi. So if xsk is active,
+		 * prevent modifications to tx napi.
+		 */
+		for (i = queue_number; i < vi->max_queue_pairs; i++) {
+			if (vi->sq[i].xsk_pool)
+				return -EBUSY;
+		}
+
 		for (; queue_number < vi->max_queue_pairs; queue_number++)
 			vi->sq[queue_number].napi.weight = napi_weight;
 	}
-- 
2.32.0.3.g01195cf9f

[RFC net-next 10/13] virtio_net: xsk: tx: support xmit xsk buffer

[Xuan Zhuo]

The driver's tx napi is very important for XSK. It is responsible for
obtaining data from the XSK queue and sending it out.

At the beginning, we need to trigger tx napi.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 drivers/net/virtio_net.c | 127 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 125 insertions(+), 2 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index b02fc118b0b8..ce8ac9239158 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -516,10 +516,13 @@ enum virtnet_xmit_type {
 	VIRTNET_XMIT_TYPE_SKB,
 	VIRTNET_XMIT_TYPE_ORPHAN,
 	VIRTNET_XMIT_TYPE_XDP,
+	VIRTNET_XMIT_TYPE_XSK,
 };
 
 #define VIRTNET_XMIT_TYPE_MASK (VIRTNET_XMIT_TYPE_SKB | VIRTNET_XMIT_TYPE_ORPHAN \
-				| VIRTNET_XMIT_TYPE_XDP)
+				| VIRTNET_XMIT_TYPE_XDP | VIRTNET_XMIT_TYPE_XSK)
+
+#define VIRTIO_XSK_FLAG_OFFSET 4
 
 static enum virtnet_xmit_type virtnet_xmit_ptr_strip(void **ptr)
 {
@@ -543,6 +546,11 @@ static int virtnet_add_outbuf(struct send_queue *sq, int num, void *data,
 				    GFP_ATOMIC);
 }
 
+static u32 virtnet_ptr_to_xsk(void *ptr)
+{
+	return ((unsigned long)ptr) >> VIRTIO_XSK_FLAG_OFFSET;
+}
+
 static void sg_fill_dma(struct scatterlist *sg, dma_addr_t addr, u32 len)
 {
 	sg_assign_page(sg, NULL);
@@ -584,6 +592,10 @@ static void __free_old_xmit(struct send_queue *sq, struct netdev_queue *txq,
 			stats->bytes += xdp_get_frame_len(frame);
 			xdp_return_frame(frame);
 			break;
+
+		case VIRTNET_XMIT_TYPE_XSK:
+			stats->bytes += virtnet_ptr_to_xsk(ptr);
+			break;
 		}
 	}
 	netdev_tx_completed_queue(txq, stats->napi_packets, stats->napi_bytes);
@@ -1393,6 +1405,97 @@ static int virtnet_xsk_wakeup(struct net_device *dev, u32 qid, u32 flag)
 	return 0;
 }
 
+static void *virtnet_xsk_to_ptr(u32 len)
+{
+	unsigned long p;
+
+	p = len << VIRTIO_XSK_FLAG_OFFSET;
+
+	return virtnet_xmit_ptr_mix((void *)p, VIRTNET_XMIT_TYPE_XSK);
+}
+
+static int virtnet_xsk_xmit_one(struct send_queue *sq,
+				struct xsk_buff_pool *pool,
+				struct xdp_desc *desc)
+{
+	struct virtnet_info *vi;
+	dma_addr_t addr;
+
+	vi = sq->vq->vdev->priv;
+
+	addr = xsk_buff_raw_get_dma(pool, desc->addr);
+	xsk_buff_raw_dma_sync_for_device(pool, addr, desc->len);
+
+	sg_init_table(sq->sg, 2);
+
+	sg_fill_dma(sq->sg, sq->xsk_hdr_dma_addr, vi->hdr_len);
+	sg_fill_dma(sq->sg + 1, addr, desc->len);
+
+	return virtqueue_add_outbuf(sq->vq, sq->sg, 2,
+				    virtnet_xsk_to_ptr(desc->len), GFP_ATOMIC);
+}
+
+static int virtnet_xsk_xmit_batch(struct send_queue *sq,
+				  struct xsk_buff_pool *pool,
+				  unsigned int budget,
+				  u64 *kicks)
+{
+	struct xdp_desc *descs = pool->tx_descs;
+	bool kick = false;
+	u32 nb_pkts, i;
+	int err;
+
+	budget = min_t(u32, budget, sq->vq->num_free);
+
+	nb_pkts = xsk_tx_peek_release_desc_batch(pool, budget);
+	if (!nb_pkts)
+		return 0;
+
+	for (i = 0; i < nb_pkts; i++) {
+		err = virtnet_xsk_xmit_one(sq, pool, &descs[i]);
+		if (unlikely(err)) {
+			xsk_tx_completed(sq->xsk_pool, nb_pkts - i);
+			break;
+		}
+
+		kick = true;
+	}
+
+	if (kick && virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq))
+		(*kicks)++;
+
+	return i;
+}
+
+static bool virtnet_xsk_xmit(struct send_queue *sq, struct xsk_buff_pool *pool,
+			     int budget)
+{
+	struct virtnet_info *vi = sq->vq->vdev->priv;
+	struct virtnet_sq_free_stats stats = {};
+	struct net_device *dev = vi->dev;
+	u64 kicks = 0;
+	int sent;
+
+	__free_old_xmit(sq, netdev_get_tx_queue(dev, sq - vi->sq), true, &stats);
+
+	sent = virtnet_xsk_xmit_batch(sq, pool, budget, &kicks);
+
+	if (!is_xdp_raw_buffer_queue(vi, sq - vi->sq))
+		check_sq_full_and_disable(vi, vi->dev, sq);
+
+	u64_stats_update_begin(&sq->stats.syncp);
+	u64_stats_add(&sq->stats.packets, stats.packets);
+	u64_stats_add(&sq->stats.bytes,   stats.bytes);
+	u64_stats_add(&sq->stats.kicks,   kicks);
+	u64_stats_add(&sq->stats.xdp_tx,  sent);
+	u64_stats_update_end(&sq->stats.syncp);
+
+	if (xsk_uses_need_wakeup(pool))
+		xsk_set_tx_need_wakeup(pool);
+
+	return sent == budget;
+}
+
 static int __virtnet_xdp_xmit_one(struct virtnet_info *vi,
 				   struct send_queue *sq,
 				   struct xdp_frame *xdpf)
@@ -2921,6 +3024,7 @@ static int virtnet_poll_tx(struct napi_struct *napi, int budget)
 	struct virtnet_info *vi = sq->vq->vdev->priv;
 	unsigned int index = vq2txq(sq->vq);
 	struct netdev_queue *txq;
+	bool xsk_busy = false;
 	int opaque;
 	bool done;
 
@@ -2933,7 +3037,11 @@ static int virtnet_poll_tx(struct napi_struct *napi, int budget)
 	txq = netdev_get_tx_queue(vi->dev, index);
 	__netif_tx_lock(txq, raw_smp_processor_id());
 	virtqueue_disable_cb(sq->vq);
-	free_old_xmit(sq, txq, !!budget);
+
+	if (sq->xsk_pool)
+		xsk_busy = virtnet_xsk_xmit(sq, sq->xsk_pool, budget);
+	else
+		free_old_xmit(sq, txq, !!budget);
 
 	if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS) {
 		if (netif_tx_queue_stopped(txq)) {
@@ -2944,6 +3052,11 @@ static int virtnet_poll_tx(struct napi_struct *napi, int budget)
 		netif_tx_wake_queue(txq);
 	}
 
+	if (xsk_busy) {
+		__netif_tx_unlock(txq);
+		return budget;
+	}
+
 	opaque = virtqueue_enable_cb_prepare(sq->vq);
 
 	done = napi_complete_done(napi, 0);
@@ -5945,6 +6058,12 @@ static void free_receive_page_frags(struct virtnet_info *vi)
 
 static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf)
 {
+	struct virtnet_info *vi = vq->vdev->priv;
+	struct send_queue *sq;
+	int i = vq2rxq(vq);
+
+	sq = &vi->sq[i];
+
 	switch (virtnet_xmit_ptr_strip(&buf)) {
 	case VIRTNET_XMIT_TYPE_SKB:
 	case VIRTNET_XMIT_TYPE_ORPHAN:
@@ -5954,6 +6073,10 @@ static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf)
 	case VIRTNET_XMIT_TYPE_XDP:
 		xdp_return_frame(buf);
 		break;
+
+	case VIRTNET_XMIT_TYPE_XSK:
+		xsk_tx_completed(sq->xsk_pool, 1);
+		break;
 	}
 }
 
-- 
2.32.0.3.g01195cf9f

[RFC net-next 11/13] virtio_net: xsk: tx: handle the transmitted xsk buffer

[Xuan Zhuo]

virtnet_free_old_xmit distinguishes three type ptr(skb, xdp frame, xsk
buffer) by the last bits of the pointer.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 drivers/net/virtio_net.c | 85 ++++++++++++++++++++++++++++------------
 1 file changed, 59 insertions(+), 26 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index ce8ac9239158..700d080d8c5b 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -85,6 +85,7 @@ struct virtnet_sq_free_stats {
 	u64 bytes;
 	u64 napi_packets;
 	u64 napi_bytes;
+	u64 xsk;
 };
 
 struct virtnet_sq_stats {
@@ -511,6 +512,7 @@ static struct sk_buff *virtnet_skb_append_frag(struct sk_buff *head_skb,
 					       struct sk_buff *curr_skb,
 					       struct page *page, void *buf,
 					       int len, int truesize);
+static void virtnet_xsk_completed(struct send_queue *sq, int num);
 
 enum virtnet_xmit_type {
 	VIRTNET_XMIT_TYPE_SKB,
@@ -595,12 +597,24 @@ static void __free_old_xmit(struct send_queue *sq, struct netdev_queue *txq,
 
 		case VIRTNET_XMIT_TYPE_XSK:
 			stats->bytes += virtnet_ptr_to_xsk(ptr);
+			stats->xsk++;
 			break;
 		}
 	}
 	netdev_tx_completed_queue(txq, stats->napi_packets, stats->napi_bytes);
 }
 
+static void virtnet_free_old_xmit(struct send_queue *sq,
+				  struct netdev_queue *txq,
+				  bool in_napi,
+				  struct virtnet_sq_free_stats *stats)
+{
+	__free_old_xmit(sq, txq, in_napi, stats);
+
+	if (stats->xsk)
+		virtnet_xsk_completed(sq, stats->xsk);
+}
+
 /* Converting between virtqueue no. and kernel tx/rx queue no.
  * 0:rx0 1:tx0 2:rx1 3:tx1 ... 2N:rxN 2N+1:txN 2N+2:cvq
  */
@@ -1021,7 +1035,7 @@ static void free_old_xmit(struct send_queue *sq, struct netdev_queue *txq,
 {
 	struct virtnet_sq_free_stats stats = {0};
 
-	__free_old_xmit(sq, txq, in_napi, &stats);
+	virtnet_free_old_xmit(sq, txq, in_napi, &stats);
 
 	/* Avoid overhead when no packets have been processed
 	 * happens when called speculatively from start_xmit.
@@ -1382,29 +1396,6 @@ static int virtnet_add_recvbuf_xsk(struct virtnet_info *vi, struct receive_queue
 	return err;
 }
 
-static int virtnet_xsk_wakeup(struct net_device *dev, u32 qid, u32 flag)
-{
-	struct virtnet_info *vi = netdev_priv(dev);
-	struct send_queue *sq;
-
-	if (!netif_running(dev))
-		return -ENETDOWN;
-
-	if (qid >= vi->curr_queue_pairs)
-		return -EINVAL;
-
-	sq = &vi->sq[qid];
-
-	if (napi_if_scheduled_mark_missed(&sq->napi))
-		return 0;
-
-	local_bh_disable();
-	virtqueue_napi_schedule(&sq->napi, sq->vq);
-	local_bh_enable();
-
-	return 0;
-}
-
 static void *virtnet_xsk_to_ptr(u32 len)
 {
 	unsigned long p;
@@ -1476,8 +1467,12 @@ static bool virtnet_xsk_xmit(struct send_queue *sq, struct xsk_buff_pool *pool,
 	u64 kicks = 0;
 	int sent;
 
+	/* Avoid to wakeup napi meanless, so call __free_old_xmit. */
 	__free_old_xmit(sq, netdev_get_tx_queue(dev, sq - vi->sq), true, &stats);
 
+	if (stats.xsk)
+		xsk_tx_completed(sq->xsk_pool, stats.xsk);
+
 	sent = virtnet_xsk_xmit_batch(sq, pool, budget, &kicks);
 
 	if (!is_xdp_raw_buffer_queue(vi, sq - vi->sq))
@@ -1496,6 +1491,44 @@ static bool virtnet_xsk_xmit(struct send_queue *sq, struct xsk_buff_pool *pool,
 	return sent == budget;
 }
 
+static void xsk_wakeup(struct send_queue *sq)
+{
+	if (napi_if_scheduled_mark_missed(&sq->napi))
+		return;
+
+	local_bh_disable();
+	virtqueue_napi_schedule(&sq->napi, sq->vq);
+	local_bh_enable();
+}
+
+static int virtnet_xsk_wakeup(struct net_device *dev, u32 qid, u32 flag)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	struct send_queue *sq;
+
+	if (!netif_running(dev))
+		return -ENETDOWN;
+
+	if (qid >= vi->curr_queue_pairs)
+		return -EINVAL;
+
+	sq = &vi->sq[qid];
+
+	xsk_wakeup(sq);
+	return 0;
+}
+
+static void virtnet_xsk_completed(struct send_queue *sq, int num)
+{
+	xsk_tx_completed(sq->xsk_pool, num);
+
+	/* If this is called by rx poll, start_xmit and xdp xmit we should
+	 * wakeup the tx napi to consume the xsk tx queue, because the tx
+	 * interrupt may not be triggered.
+	 */
+	xsk_wakeup(sq);
+}
+
 static int __virtnet_xdp_xmit_one(struct virtnet_info *vi,
 				   struct send_queue *sq,
 				   struct xdp_frame *xdpf)
@@ -1609,8 +1642,8 @@ static int virtnet_xdp_xmit(struct net_device *dev,
 	}
 
 	/* Free up any pending old buffers before queueing new ones. */
-	__free_old_xmit(sq, netdev_get_tx_queue(dev, sq - vi->sq),
-			false, &stats);
+	virtnet_free_old_xmit(sq, netdev_get_tx_queue(dev, sq - vi->sq),
+			      false, &stats);
 
 	for (i = 0; i < n; i++) {
 		struct xdp_frame *xdpf = frames[i];
-- 
2.32.0.3.g01195cf9f

[RFC net-next 12/13] virtio_net: update tx timeout record

[Xuan Zhuo]

If send queue sent some packets, we update the tx timeout
record to prevent the tx timeout.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
 drivers/net/virtio_net.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 700d080d8c5b..38af9f0b632e 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1478,6 +1478,13 @@ static bool virtnet_xsk_xmit(struct send_queue *sq, struct xsk_buff_pool *pool,
 	if (!is_xdp_raw_buffer_queue(vi, sq - vi->sq))
 		check_sq_full_and_disable(vi, vi->dev, sq);
 
+	if (stats.packets) {
+		struct netdev_queue *txq;
+
+		txq = netdev_get_tx_queue(vi->dev, sq - vi->sq);
+		txq_trans_cond_update(txq);
+	}
+
 	u64_stats_update_begin(&sq->stats.syncp);
 	u64_stats_add(&sq->stats.packets, stats.packets);
 	u64_stats_add(&sq->stats.bytes,   stats.bytes);
-- 
2.32.0.3.g01195cf9f

[RFC net-next 13/13] virtio_net: xdp_features add NETDEV_XDP_ACT_XSK_ZEROCOPY

[Xuan Zhuo]

Now, we supported AF_XDP(xsk). Add NETDEV_XDP_ACT_XSK_ZEROCOPY to
xdp_features.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 drivers/net/virtio_net.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 38af9f0b632e..79bfc5231426 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -6573,7 +6573,8 @@ static int virtnet_probe(struct virtio_device *vdev)
 		dev->hw_features |= NETIF_F_GRO_HW;
 
 	dev->vlan_features = dev->features;
-	dev->xdp_features = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT;
+	dev->xdp_features = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
+		NETDEV_XDP_ACT_XSK_ZEROCOPY;
 
 	/* MTU range: 68 - 65535 */
 	dev->min_mtu = MIN_MTU;
-- 
2.32.0.3.g01195cf9f

Re: [RFC net-next 00/13] virtio-net: support AF_XDP zero copy (tx)

[Jason Wang]

On Tue, Jul 16, 2024 at 2:46 PM Xuan Zhuo <xuanzhuo@linux.alibaba.com> wrote:
>
> ## AF_XDP
>
> XDP socket(AF_XDP) is an excellent bypass kernel network framework. The zero
> copy feature of xsk (XDP socket) needs to be supported by the driver. The
> performance of zero copy is very good. mlx5 and intel ixgbe already support
> this feature, This patch set allows virtio-net to support xsk's zerocopy xmit
> feature.
>
> At present, we have completed some preparation:
>
> 1. vq-reset (virtio spec and kernel code)
> 2. virtio-core premapped dma
> 3. virtio-net xdp refactor
>
> So it is time for Virtio-Net to complete the support for the XDP Socket
> Zerocopy.
>
> Virtio-net can not increase the queue num at will, so xsk shares the queue with
> kernel.
>
> This patch set includes some refactor to the virtio-net to let that to support
> AF_XDP.
>
> ## About virtio premapped mode
>
> The current configuration sets the virtqueue (vq) to premapped mode,
> implying that all buffers submitted to this queue must be mapped ahead
> of time. This presents a challenge for the virtnet send queue (sq): the
> virtnet driver would be required to keep track of dma information for vq
> size * 17, which can be substantial. However, if the premapped mode were
> applied on a per-buffer basis, the complexity would be greatly reduced.
> With AF_XDP enabled, AF_XDP buffers would become premapped, while kernel
> skb buffers could remain unmapped.
>
> We can distinguish them by sg_page(sg), When sg_page(sg) is NULL, this
> indicates that the driver has performed DMA mapping in advance, allowing
> the Virtio core to directly utilize sg_dma_address(sg) without
> conducting any internal DMA mapping. Additionally, DMA unmap operations
> for this buffer will be bypassed.
>
> ## performance
>
> ENV: Qemu with vhost-user(polling mode).
> Host CPU: Intel(R) Xeon(R) Platinum 8163 CPU @ 2.50GHz
>
> ### virtio PMD in guest with testpmd
>
> testpmd> show port stats all
>
>  ######################## NIC statistics for port 0 ########################
>  RX-packets: 19531092064 RX-missed: 0     RX-bytes: 1093741155584
>  RX-errors: 0
>  RX-nombuf: 0
>  TX-packets: 5959955552 TX-errors: 0     TX-bytes: 371030645664
>
>
>  Throughput (since last show)
>  Rx-pps:   8861574     Rx-bps:  3969985208
>  Tx-pps:   8861493     Tx-bps:  3969962736
>  ############################################################################
>
> ### AF_XDP PMD in guest with testpmd
>
> testpmd> show port stats all
>
>   ######################## NIC statistics for port 0  ########################
>   RX-packets: 68152727   RX-missed: 0          RX-bytes:  3816552712
>   RX-errors: 0
>   RX-nombuf:  0
>   TX-packets: 68114967   TX-errors: 33216      TX-bytes:  3814438152
>
>   Throughput (since last show)
>   Rx-pps:      6333196          Rx-bps:   2837272088
>   Tx-pps:      6333227          Tx-bps:   2837285936
>   ############################################################################
>
> But AF_XDP consumes more CPU for tx and rx napi(100% and 86%).
>
> Please review.
>
> Thanks.
>
> Xuan Zhuo (13):
>   virtio_ring: introduce vring_need_unmap_buffer
>   virtio_ring: split: harden dma unmap for indirect
>   virtio_ring: packed: harden dma unmap for indirect
>   virtio_ring: perform premapped operations based on per-buffer
>   virtio-net: rq submits premapped buffer per buffer
>   virtio_ring: remove API virtqueue_set_dma_premapped
>   virtio_net: refactor the xmit type
>   virtio_net: xsk: bind/unbind xsk for tx
>   virtio_net: xsk: prevent disable tx napi
>   virtio_net: xsk: tx: support xmit xsk buffer
>   virtio_net: xsk: tx: handle the transmitted xsk buffer
>   virtio_net: update tx timeout record
>   virtio_net: xdp_features add NETDEV_XDP_ACT_XSK_ZEROCOPY
>
>  drivers/net/virtio_net.c     | 363 ++++++++++++++++++++++++++++-------
>  drivers/virtio/virtio_ring.c | 302 ++++++++++++-----------------
>  include/linux/virtio.h       |   2 -
>  3 files changed, 421 insertions(+), 246 deletions(-)
>
> --
> 2.32.0.3.g01195cf9f
>

Hi Xuan:

I wonder why this series is tagged as "RFC"?

Thanks

Re: [RFC net-next 00/13] virtio-net: support AF_XDP zero copy (tx)

[Jakub Kicinski]

On Mon, 22 Jul 2024 15:27:42 +0800 Jason Wang wrote:
> I wonder why this series is tagged as "RFC"?

I guess it's because net-next is closed during merge window.
I understand that the situation is somewhat special 
because we got Rx merged but not Tx.
Do you think this is ready for v6.11 with high confidence?

Re: [RFC net-next 00/13] virtio-net: support AF_XDP zero copy (tx)

[Xuan Zhuo]

On Mon, 22 Jul 2024 17:42:04 -0700, Jakub Kicinski <kuba@kernel.org> wrote:
> On Mon, 22 Jul 2024 15:27:42 +0800 Jason Wang wrote:
> > I wonder why this series is tagged as "RFC"?
>
> I guess it's because net-next is closed during merge window.


YES. As I know, we can not post "PATCH" during merge window.
So, I post "RFC".

Thanks.


> I understand that the situation is somewhat special
> because we got Rx merged but not Tx.
> Do you think this is ready for v6.11 with high confidence?