On Thu, Aug 29, 2019 at 09:59:55AM +0200, Maxime Coquelin wrote:
> 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.coque...@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;
> + }
This will allow guest to access the cq.mz and cq.virtio_net_hdr_mz
via the device which may have potential risks.
Regards,
Tiwei
> +
> + 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
>
