[PATCH v2 0/3] net/virtio: support IOVA as PA mode for vDPA backend

[PATCH v2 0/3] net/virtio: support IOVA as PA mode for vDPA backend

[Srujana Challa]

This patch series makes Virtio-user works in IOVA as PA mode
for vDPA backend.

First patch fixes the issue when having buffer IOVA address in
control queue descriptors.
Second and third patches helps to share descriptor IOVA address,
to the vhost backend. And also disables the use_va flag for VDPA
backend type.

v1->v2:
- Split single patch into three patches.

Srujana Challa (3):
  net/virtio_user: avoid cq descriptor buffer address accessing
  net/virtio: store desc IOVA address in vring data structure
  net/virtio_user: support sharing vq descriptor IOVA to the backend

 drivers/net/virtio/virtio_ring.h              | 12 ++-
 .../net/virtio/virtio_user/virtio_user_dev.c  | 94 ++++++++++---------
 drivers/net/virtio/virtio_user_ethdev.c       | 10 +-
 drivers/net/virtio/virtqueue.c                |  4 +-
 4 files changed, 69 insertions(+), 51 deletions(-)

-- 
2.25.1

[PATCH v2 1/3] net/virtio_user: avoid cq descriptor buffer address accessing

[Srujana Challa]

This patch makes changes to avoid descriptor buffer address
accessing while processing shadow control queue.
So that Virtio-user can work with having IOVA as descriptor
buffer address.

Signed-off-by: Srujana Challa <schalla@marvell.com>
---
 .../net/virtio/virtio_user/virtio_user_dev.c  | 68 +++++++++----------
 1 file changed, 33 insertions(+), 35 deletions(-)

diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c
index d395fc1676..bf3da4340f 100644
--- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
+++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
@@ -885,11 +885,11 @@ static uint32_t
 virtio_user_handle_ctrl_msg_split(struct virtio_user_dev *dev, struct vring *vring,
 			    uint16_t idx_hdr)
 {
-	struct virtio_net_ctrl_hdr *hdr;
 	virtio_net_ctrl_ack status = ~0;
-	uint16_t i, idx_data, idx_status;
+	uint16_t i, idx_data;
 	uint32_t n_descs = 0;
 	int dlen[CVQ_MAX_DATA_DESCS], nb_dlen = 0;
+	struct virtio_pmd_ctrl *ctrl;
 
 	/* locate desc for header, data, and status */
 	idx_data = vring->desc[idx_hdr].next;
@@ -902,34 +902,33 @@ virtio_user_handle_ctrl_msg_split(struct virtio_user_dev *dev, struct vring *vri
 		n_descs++;
 	}
 
-	/* locate desc for status */
-	idx_status = i;
 	n_descs++;
 
-	hdr = (void *)(uintptr_t)vring->desc[idx_hdr].addr;
-	if (hdr->class == VIRTIO_NET_CTRL_MQ &&
-	    hdr->cmd == VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET) {
-		uint16_t queues;
+	/* Access control command via VA from CVQ */
+	ctrl = (struct virtio_pmd_ctrl *)dev->hw.cvq->hdr_mz->addr;
+	if (ctrl->hdr.class == VIRTIO_NET_CTRL_MQ &&
+	    ctrl->hdr.cmd == VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET) {
+		uint16_t *queues;
 
-		queues = *(uint16_t *)(uintptr_t)vring->desc[idx_data].addr;
-		status = virtio_user_handle_mq(dev, queues);
-	} else if (hdr->class == VIRTIO_NET_CTRL_MQ && hdr->cmd == VIRTIO_NET_CTRL_MQ_RSS_CONFIG) {
+		queues = (uint16_t *)ctrl->data;
+		status = virtio_user_handle_mq(dev, *queues);
+	} else if (ctrl->hdr.class == VIRTIO_NET_CTRL_MQ &&
+		   ctrl->hdr.cmd == VIRTIO_NET_CTRL_MQ_RSS_CONFIG) {
 		struct virtio_net_ctrl_rss *rss;
 
-		rss = (struct virtio_net_ctrl_rss *)(uintptr_t)vring->desc[idx_data].addr;
+		rss = (struct virtio_net_ctrl_rss *)ctrl->data;
 		status = virtio_user_handle_mq(dev, rss->max_tx_vq);
-	} else if (hdr->class == VIRTIO_NET_CTRL_RX  ||
-		   hdr->class == VIRTIO_NET_CTRL_MAC ||
-		   hdr->class == VIRTIO_NET_CTRL_VLAN) {
+	} else if (ctrl->hdr.class == VIRTIO_NET_CTRL_RX  ||
+		   ctrl->hdr.class == VIRTIO_NET_CTRL_MAC ||
+		   ctrl->hdr.class == VIRTIO_NET_CTRL_VLAN) {
 		status = 0;
 	}
 
 	if (!status && dev->scvq)
-		status = virtio_send_command(&dev->scvq->cq,
-				(struct virtio_pmd_ctrl *)hdr, dlen, nb_dlen);
+		status = virtio_send_command(&dev->scvq->cq, ctrl, dlen, nb_dlen);
 
 	/* Update status */
-	*(virtio_net_ctrl_ack *)(uintptr_t)vring->desc[idx_status].addr = status;
+	ctrl->status = status;
 
 	return n_descs;
 }
@@ -948,7 +947,7 @@ virtio_user_handle_ctrl_msg_packed(struct virtio_user_dev *dev,
 				   struct vring_packed *vring,
 				   uint16_t idx_hdr)
 {
-	struct virtio_net_ctrl_hdr *hdr;
+	struct virtio_pmd_ctrl *ctrl;
 	virtio_net_ctrl_ack status = ~0;
 	uint16_t idx_data, idx_status;
 	/* initialize to one, header is first */
@@ -971,32 +970,31 @@ virtio_user_handle_ctrl_msg_packed(struct virtio_user_dev *dev,
 		n_descs++;
 	}
 
-	hdr = (void *)(uintptr_t)vring->desc[idx_hdr].addr;
-	if (hdr->class == VIRTIO_NET_CTRL_MQ &&
-	    hdr->cmd == VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET) {
-		uint16_t queues;
+	/* Access control command via VA from CVQ */
+	ctrl = (struct virtio_pmd_ctrl *)dev->hw.cvq->hdr_mz->addr;
+	if (ctrl->hdr.class == VIRTIO_NET_CTRL_MQ &&
+	    ctrl->hdr.cmd == VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET) {
+		uint16_t *queues;
 
-		queues = *(uint16_t *)(uintptr_t)
-				vring->desc[idx_data].addr;
-		status = virtio_user_handle_mq(dev, queues);
-	} else if (hdr->class == VIRTIO_NET_CTRL_MQ && hdr->cmd == VIRTIO_NET_CTRL_MQ_RSS_CONFIG) {
+		queues = (uint16_t *)ctrl->data;
+		status = virtio_user_handle_mq(dev, *queues);
+	} else if (ctrl->hdr.class == VIRTIO_NET_CTRL_MQ &&
+		   ctrl->hdr.cmd == VIRTIO_NET_CTRL_MQ_RSS_CONFIG) {
 		struct virtio_net_ctrl_rss *rss;
 
-		rss = (struct virtio_net_ctrl_rss *)(uintptr_t)vring->desc[idx_data].addr;
+		rss = (struct virtio_net_ctrl_rss *)ctrl->data;
 		status = virtio_user_handle_mq(dev, rss->max_tx_vq);
-	} else if (hdr->class == VIRTIO_NET_CTRL_RX  ||
-		   hdr->class == VIRTIO_NET_CTRL_MAC ||
-		   hdr->class == VIRTIO_NET_CTRL_VLAN) {
+	} else if (ctrl->hdr.class == VIRTIO_NET_CTRL_RX  ||
+		   ctrl->hdr.class == VIRTIO_NET_CTRL_MAC ||
+		   ctrl->hdr.class == VIRTIO_NET_CTRL_VLAN) {
 		status = 0;
 	}
 
 	if (!status && dev->scvq)
-		status = virtio_send_command(&dev->scvq->cq,
-				(struct virtio_pmd_ctrl *)hdr, dlen, nb_dlen);
+		status = virtio_send_command(&dev->scvq->cq, ctrl, dlen, nb_dlen);
 
 	/* Update status */
-	*(virtio_net_ctrl_ack *)(uintptr_t)
-		vring->desc[idx_status].addr = status;
+	ctrl->status = status;
 
 	/* Update used descriptor */
 	vring->desc[idx_hdr].id = vring->desc[idx_status].id;
-- 
2.25.1

[PATCH v2 2/3] net/virtio: store desc IOVA address in vring data structure

[Srujana Challa]

Stores desc IOVA in the queue's vring data structure,
as preliminary work to provide a way for Virtio-user
to share desc IOVA to the vhost backend.

Signed-off-by: Srujana Challa <schalla@marvell.com>
---
 drivers/net/virtio/virtio_ring.h | 12 ++++++++----
 drivers/net/virtio/virtqueue.c   |  4 ++--
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/net/virtio/virtio_ring.h b/drivers/net/virtio/virtio_ring.h
index e848c0b73b..998605dbb5 100644
--- a/drivers/net/virtio/virtio_ring.h
+++ b/drivers/net/virtio/virtio_ring.h
@@ -83,6 +83,7 @@ struct vring_packed_desc_event {
 
 struct vring_packed {
 	unsigned int num;
+	rte_iova_t desc_iova;
 	struct vring_packed_desc *desc;
 	struct vring_packed_desc_event *driver;
 	struct vring_packed_desc_event *device;
@@ -90,6 +91,7 @@ struct vring_packed {
 
 struct vring {
 	unsigned int num;
+	rte_iova_t desc_iova;
 	struct vring_desc  *desc;
 	struct vring_avail *avail;
 	struct vring_used  *used;
@@ -149,11 +151,12 @@ vring_size(struct virtio_hw *hw, unsigned int num, unsigned long align)
 	return size;
 }
 static inline void
-vring_init_split(struct vring *vr, uint8_t *p, unsigned long align,
-	 unsigned int num)
+vring_init_split(struct vring *vr, uint8_t *p, rte_iova_t iova,
+		 unsigned long align, unsigned int num)
 {
 	vr->num = num;
 	vr->desc = (struct vring_desc *) p;
+	vr->desc_iova = iova;
 	vr->avail = (struct vring_avail *) (p +
 		num * sizeof(struct vring_desc));
 	vr->used = (void *)
@@ -161,11 +164,12 @@ vring_init_split(struct vring *vr, uint8_t *p, unsigned long align,
 }
 
 static inline void
-vring_init_packed(struct vring_packed *vr, uint8_t *p, unsigned long align,
-		 unsigned int num)
+vring_init_packed(struct vring_packed *vr, uint8_t *p, rte_iova_t iova,
+		  unsigned long align, unsigned int num)
 {
 	vr->num = num;
 	vr->desc = (struct vring_packed_desc *)p;
+	vr->desc_iova = iova;
 	vr->driver = (struct vring_packed_desc_event *)(p +
 			vr->num * sizeof(struct vring_packed_desc));
 	vr->device = (struct vring_packed_desc_event *)
diff --git a/drivers/net/virtio/virtqueue.c b/drivers/net/virtio/virtqueue.c
index 6f419665f1..cf46abfd06 100644
--- a/drivers/net/virtio/virtqueue.c
+++ b/drivers/net/virtio/virtqueue.c
@@ -282,13 +282,13 @@ virtio_init_vring(struct virtqueue *vq)
 	vq->vq_free_cnt = vq->vq_nentries;
 	memset(vq->vq_descx, 0, sizeof(struct vq_desc_extra) * vq->vq_nentries);
 	if (virtio_with_packed_queue(vq->hw)) {
-		vring_init_packed(&vq->vq_packed.ring, ring_mem,
+		vring_init_packed(&vq->vq_packed.ring, ring_mem, vq->vq_ring_mem,
 				  VIRTIO_VRING_ALIGN, size);
 		vring_desc_init_packed(vq, size);
 	} else {
 		struct vring *vr = &vq->vq_split.ring;
 
-		vring_init_split(vr, ring_mem, VIRTIO_VRING_ALIGN, size);
+		vring_init_split(vr, ring_mem, vq->vq_ring_mem, VIRTIO_VRING_ALIGN, size);
 		vring_desc_init_split(vr->desc, size);
 	}
 	/*
-- 
2.25.1

[PATCH v2 3/3] net/virtio_user: support sharing vq descriptor IOVA to the backend

[Srujana Challa]

Adds support to share descriptor IOVA to the vhost backend.
This makes virtio_user driver works in IOVA as PA mode when
use_va flag is disabled.
This patch also disables use_va flag for VDPA backend.

Signed-off-by: Srujana Challa <schalla@marvell.com>
---
 .../net/virtio/virtio_user/virtio_user_dev.c  | 26 ++++++++++++-------
 drivers/net/virtio/virtio_user_ethdev.c       | 10 ++++++-
 2 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c
index bf3da4340f..8ad10e6354 100644
--- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
+++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
@@ -62,6 +62,7 @@ virtio_user_kick_queue(struct virtio_user_dev *dev, uint32_t queue_sel)
 	struct vhost_vring_state state;
 	struct vring *vring = &dev->vrings.split[queue_sel];
 	struct vring_packed *pq_vring = &dev->vrings.packed[queue_sel];
+	uint64_t desc_addr, avail_addr, used_addr;
 	struct vhost_vring_addr addr = {
 		.index = queue_sel,
 		.log_guest_addr = 0,
@@ -81,16 +82,23 @@ virtio_user_kick_queue(struct virtio_user_dev *dev, uint32_t queue_sel)
 	}
 
 	if (dev->features & (1ULL << VIRTIO_F_RING_PACKED)) {
-		addr.desc_user_addr =
-			(uint64_t)(uintptr_t)pq_vring->desc;
-		addr.avail_user_addr =
-			(uint64_t)(uintptr_t)pq_vring->driver;
-		addr.used_user_addr =
-			(uint64_t)(uintptr_t)pq_vring->device;
+		desc_addr = pq_vring->desc_iova;
+		avail_addr = desc_addr + pq_vring->num * sizeof(struct vring_packed_desc);
+		used_addr =  RTE_ALIGN_CEIL(avail_addr + sizeof(struct vring_packed_desc_event),
+					    VIRTIO_VRING_ALIGN);
+
+		addr.desc_user_addr = desc_addr;
+		addr.avail_user_addr = avail_addr;
+		addr.used_user_addr = used_addr;
 	} else {
-		addr.desc_user_addr = (uint64_t)(uintptr_t)vring->desc;
-		addr.avail_user_addr = (uint64_t)(uintptr_t)vring->avail;
-		addr.used_user_addr = (uint64_t)(uintptr_t)vring->used;
+		desc_addr = vring->desc_iova;
+		avail_addr = desc_addr + vring->num * sizeof(struct vring_desc);
+		used_addr = RTE_ALIGN_CEIL((uintptr_t)(&vring->avail->ring[vring->num]),
+					   VIRTIO_VRING_ALIGN);
+
+		addr.desc_user_addr = desc_addr;
+		addr.avail_user_addr = avail_addr;
+		addr.used_user_addr = used_addr;
 	}
 
 	state.index = queue_sel;
diff --git a/drivers/net/virtio/virtio_user_ethdev.c b/drivers/net/virtio/virtio_user_ethdev.c
index bf9de36d8f..ae6593ba0b 100644
--- a/drivers/net/virtio/virtio_user_ethdev.c
+++ b/drivers/net/virtio/virtio_user_ethdev.c
@@ -198,6 +198,7 @@ virtio_user_setup_queue_packed(struct virtqueue *vq,
 			   sizeof(struct vring_packed_desc_event),
 			   VIRTIO_VRING_ALIGN);
 	vring->num = vq->vq_nentries;
+	vring->desc_iova = vq->vq_ring_mem;
 	vring->desc = (void *)(uintptr_t)desc_addr;
 	vring->driver = (void *)(uintptr_t)avail_addr;
 	vring->device = (void *)(uintptr_t)used_addr;
@@ -221,6 +222,7 @@ virtio_user_setup_queue_split(struct virtqueue *vq, struct virtio_user_dev *dev)
 				   VIRTIO_VRING_ALIGN);
 
 	dev->vrings.split[queue_idx].num = vq->vq_nentries;
+	dev->vrings.split[queue_idx].desc_iova = vq->vq_ring_mem;
 	dev->vrings.split[queue_idx].desc = (void *)(uintptr_t)desc_addr;
 	dev->vrings.split[queue_idx].avail = (void *)(uintptr_t)avail_addr;
 	dev->vrings.split[queue_idx].used = (void *)(uintptr_t)used_addr;
@@ -689,7 +691,13 @@ virtio_user_pmd_probe(struct rte_vdev_device *vdev)
 	 * Virtio-user requires using virtual addresses for the descriptors
 	 * buffers, whatever other devices require
 	 */
-	hw->use_va = true;
+	if (backend_type == VIRTIO_USER_BACKEND_VHOST_VDPA)
+		/* VDPA backend requires using iova for the buffers to make it
+		 * work in IOVA as PA mode also.
+		 */
+		hw->use_va = false;
+	else
+		hw->use_va = true;
 
 	/* previously called by pci probing for physical dev */
 	if (eth_virtio_dev_init(eth_dev) < 0) {
-- 
2.25.1