[dpdk-dev] [PATCH 10/15] net/virtio: add vDPA op to configure and start the device

Maxime Coquelin maxime.coquelin at redhat.com
Thu Aug 29 09:59:55 CEST 2019


In order to support multi-queue, we need to implement the control
path. The problem is that both the Vhost-user master and slave use
VAs in their processes address spaces as IOVAs, which creates
collusions between the data rings IOVAs managed the master, and
the Control ring IOVAs. The trick here is to remmap the Control
ring memory to another range, after the slave is aware of master's
ranges.

Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
---
 drivers/net/virtio/virtio_vdpa.c | 255 +++++++++++++++++++++++++++++++
 1 file changed, 255 insertions(+)

diff --git a/drivers/net/virtio/virtio_vdpa.c b/drivers/net/virtio/virtio_vdpa.c
index fc52a8e92..13b4dd07d 100644
--- a/drivers/net/virtio/virtio_vdpa.c
+++ b/drivers/net/virtio/virtio_vdpa.c
@@ -106,6 +106,127 @@ find_internal_resource_by_dev(struct rte_pci_device *pdev)
 	return list;
 }
 
+static int
+virtio_vdpa_dma_map_ctrl_queue(struct virtio_vdpa_device *dev, int do_map,
+		uint64_t iova)
+{
+	const struct rte_memzone *mz;
+	int ret;
+
+	/*
+	 * IOVAs are processes VAs. We cannot use them as the Data and Control
+	 * paths are run in different processes, which may (does) lead to
+	 * collusions. The trick here is to fixup Ctrl path IOVAs so that they
+	 * start after the Data path ranges.
+	 */
+	if (do_map) {
+		mz = dev->cvq->cq.mz;
+		ret = rte_vfio_container_dma_map(dev->vfio_container_fd,
+				(uint64_t)(uintptr_t)mz->addr,
+				iova, mz->len);
+		if (ret < 0) {
+			DRV_LOG(ERR, "Failed to map ctrl ring (%d)", ret);
+			return ret;
+		}
+
+		dev->cvq->vq_ring_mem = iova;
+		iova += mz->len;
+
+		mz = dev->cvq->cq.virtio_net_hdr_mz;
+		ret = rte_vfio_container_dma_map(dev->vfio_container_fd,
+				(uint64_t)(uintptr_t)mz->addr,
+				iova, mz->len);
+		if (ret < 0) {
+			DRV_LOG(ERR, "Failed to map ctrl headers (%d)", ret);
+			return ret;
+		}
+
+		dev->cvq->cq.virtio_net_hdr_mem = iova;
+	} else {
+		mz = dev->cvq->cq.mz;
+		ret = rte_vfio_container_dma_unmap(dev->vfio_container_fd,
+				(uint64_t)(uintptr_t)mz->addr,
+				iova, mz->len);
+		if (ret < 0) {
+			DRV_LOG(ERR, "Failed to unmap ctrl ring (%d)", ret);
+			return ret;
+		}
+
+		dev->cvq->vq_ring_mem = 0;
+		iova += mz->len;
+
+		mz = dev->cvq->cq.virtio_net_hdr_mz;
+		ret = rte_vfio_container_dma_unmap(dev->vfio_container_fd,
+				(uint64_t)(uintptr_t)mz->addr,
+				iova, mz->len);
+		if (ret < 0) {
+			DRV_LOG(ERR, "Failed to unmap ctrl headers (%d)", ret);
+			return ret;
+		}
+
+		dev->cvq->cq.virtio_net_hdr_mem = 0;
+	}
+
+	return 0;
+}
+
+static int
+virtio_vdpa_dma_map(struct virtio_vdpa_device *dev, int do_map)
+{
+	uint32_t i;
+	int ret;
+	struct rte_vhost_memory *mem = NULL;
+	int vfio_container_fd;
+	uint64_t avail_iova = 0;
+
+	ret = rte_vhost_get_mem_table(dev->vid, &mem);
+	if (ret < 0 || !mem) {
+		DRV_LOG(ERR, "failed to get VM memory layout.");
+		return ret;
+	}
+
+	vfio_container_fd = dev->vfio_container_fd;
+
+	for (i = 0; i < mem->nregions; i++) {
+		struct rte_vhost_mem_region *reg;
+
+		reg = &mem->regions[i];
+		DRV_LOG(INFO, "%s, region %u: HVA 0x%" PRIx64 ", "
+			"GPA 0x%" PRIx64 ", size 0x%" PRIx64 ".",
+			do_map ? "DMA map" : "DMA unmap", i,
+			reg->host_user_addr, reg->guest_phys_addr, reg->size);
+
+		if (reg->guest_phys_addr + reg->size > avail_iova)
+			avail_iova = reg->guest_phys_addr + reg->size;
+
+		if (do_map) {
+			ret = rte_vfio_container_dma_map(vfio_container_fd,
+				reg->host_user_addr, reg->guest_phys_addr,
+				reg->size);
+			if (ret < 0) {
+				DRV_LOG(ERR, "DMA map failed.");
+				goto exit;
+			}
+		} else {
+			ret = rte_vfio_container_dma_unmap(vfio_container_fd,
+				reg->host_user_addr, reg->guest_phys_addr,
+				reg->size);
+			if (ret < 0) {
+				DRV_LOG(ERR, "DMA unmap failed.");
+				goto exit;
+			}
+		}
+	}
+
+	if (dev->cvq)
+		ret = virtio_vdpa_dma_map_ctrl_queue(dev, do_map, avail_iova);
+
+exit:
+	free(mem);
+
+	return ret;
+}
+
 static int
 virtio_vdpa_vfio_setup(struct virtio_vdpa_device *dev)
 {
@@ -216,10 +337,144 @@ virtio_vdpa_get_protocol_features(int did __rte_unused, uint64_t *features)
 	return 0;
 }
 
+static uint64_t
+hva_to_gpa(int vid, uint64_t hva)
+{
+	struct rte_vhost_memory *mem = NULL;
+	struct rte_vhost_mem_region *reg;
+	uint32_t i;
+	uint64_t gpa = 0;
+
+	if (rte_vhost_get_mem_table(vid, &mem) < 0)
+		goto exit;
+
+	for (i = 0; i < mem->nregions; i++) {
+		reg = &mem->regions[i];
+
+		if (hva >= reg->host_user_addr &&
+				hva < reg->host_user_addr + reg->size) {
+			gpa = hva - reg->host_user_addr + reg->guest_phys_addr;
+			break;
+		}
+	}
+
+exit:
+	if (mem)
+		free(mem);
+	return gpa;
+}
+
+static int
+virtio_vdpa_start(struct virtio_vdpa_device *dev)
+{
+	struct virtio_hw *hw = &dev->hw;
+	int i, vid, nr_vring, ret;
+	struct rte_vhost_vring vr;
+	struct virtio_pmd_ctrl ctrl;
+	int dlen[1];
+
+	vid = dev->vid;
+	nr_vring = rte_vhost_get_vring_num(vid);
+
+	if (dev->vqs)
+		rte_free(dev->vqs);
+
+	dev->vqs = rte_zmalloc("virtio_vdpa", sizeof(*dev->vqs) * nr_vring, 0);
+
+	for (i = 0; i < nr_vring; i++) {
+		struct virtqueue *vq = &dev->vqs[i];
+
+		rte_vhost_get_vhost_vring(vid, i, &vr);
+
+		vq->vq_queue_index = i;
+		vq->vq_nentries = vr.size;
+		vq->vq_ring_mem = hva_to_gpa(vid, (uint64_t)(uintptr_t)vr.desc);
+		if (vq->vq_ring_mem  == 0) {
+			DRV_LOG(ERR, "Fail to get GPA for descriptor ring.");
+			ret = -1;
+			goto out_free_vqs;
+		}
+
+		ret = VTPCI_OPS(hw)->setup_queue(hw, vq);
+		if (ret) {
+			DRV_LOG(ERR, "Fail to setup queue.");
+			goto out_free_vqs;
+		}
+	}
+
+	if (dev->cvq) {
+		ret = VTPCI_OPS(hw)->setup_queue(hw, dev->cvq);
+		if (ret) {
+			DRV_LOG(ERR, "Fail to setup ctrl queue.");
+			goto out_free_vqs;
+		}
+	}
+
+	vtpci_set_status(hw, VIRTIO_CONFIG_STATUS_DRIVER_OK);
+
+	if (!dev->cvq)
+		return 0;
+
+	ctrl.hdr.class = VIRTIO_NET_CTRL_MQ;
+	ctrl.hdr.cmd = VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET;
+	memcpy(ctrl.data, &dev->max_queue_pairs, sizeof(uint16_t));
+
+	dlen[0] = sizeof(uint16_t);
+
+	ret = virtio_send_command(hw->cvq, &ctrl, dlen, 1);
+	if (ret) {
+		DRV_LOG(ERR, "Multiqueue configured but send command "
+			  "failed, this is too late now...");
+		ret = -EINVAL;
+		goto out_free_vqs;
+	}
+
+	return 0;
+out_free_vqs:
+	rte_free(dev->vqs);
+
+	return ret;
+}
+
+static int
+virtio_vdpa_dev_config(int vid)
+{
+	int did, ret;
+	struct internal_list *list;
+	struct virtio_vdpa_device *dev;
+
+	did = rte_vhost_get_vdpa_device_id(vid);
+	list = find_internal_resource_by_did(did);
+	if (list == NULL) {
+		DRV_LOG(ERR, "Invalid device id: %d", did);
+		return -1;
+	}
+
+	dev = list->dev;
+	dev->vid = vid;
+
+	rte_spinlock_lock(&dev->lock);
+
+	ret = virtio_vdpa_dma_map(dev, 1);
+	if (ret)
+		goto out_unlock;
+
+	ret = virtio_vdpa_start(dev);
+
+	if (rte_vhost_host_notifier_ctrl(vid, true) != 0)
+		DRV_LOG(NOTICE, "vDPA (%d): software relay is used.", did);
+
+out_unlock:
+	rte_spinlock_unlock(&dev->lock);
+
+	return ret;
+}
+
 static struct rte_vdpa_dev_ops virtio_vdpa_ops = {
 	.get_queue_num = virtio_vdpa_get_queue_num,
 	.get_features = virtio_vdpa_get_features,
 	.get_protocol_features = virtio_vdpa_get_protocol_features,
+	.dev_conf = virtio_vdpa_dev_config,
 };
 
 static inline int
-- 
2.21.0



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