Re: [RFC PATCH 09/24] vdpa: multiple address spaces support

From: Eli Cohen
Date: Thu Oct 01 2020 - 09:24:04 EST

On Thu, Sep 24, 2020 at 11:21:10AM +0800, Jason Wang wrote:
> This patches introduces the multiple address spaces support for vDPA
> device. This idea is to identify a specific address space via an
> dedicated identifier - ASID.
>
> During vDPA device allocation, vDPA device driver needs to report the
> number of address spaces supported by the device then the DMA mapping
> ops of the vDPA device needs to be extended to support ASID.
>
> This helps to isolate the DMA among the virtqueues. E.g in the case of
> virtio-net, the control virtqueue will not be assigned directly to
> guest.
>
> This RFC patch only converts for the device that wants its own
> IOMMU/DMA translation logic. So it will rejects the device with more
> that 1 address space that depends on platform IOMMU. The plan to
> moving all the DMA mapping logic to the vDPA device driver instead of
> doing it in vhost-vDPA (otherwise it could result a very complicated
> APIs and actually vhost-vDPA doesn't care about how the actual
> composition/emulation were done in the device driver).
>
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> ---
> drivers/vdpa/ifcvf/ifcvf_main.c | 2 +-
> drivers/vdpa/mlx5/net/mlx5_vnet.c | 5 +++--
> drivers/vdpa/vdpa.c | 4 +++-
> drivers/vdpa/vdpa_sim/vdpa_sim.c | 10 ++++++----
> drivers/vhost/vdpa.c | 14 +++++++++-----
> include/linux/vdpa.h | 23 ++++++++++++++++-------
> 6 files changed, 38 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
> index e6a0be374e51..86cdf5f8bcae 100644
> --- a/drivers/vdpa/ifcvf/ifcvf_main.c
> +++ b/drivers/vdpa/ifcvf/ifcvf_main.c
> @@ -440,7 +440,7 @@ static int ifcvf_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>
> adapter = vdpa_alloc_device(struct ifcvf_adapter, vdpa,
> dev, &ifc_vdpa_ops,
> - IFCVF_MAX_QUEUE_PAIRS * 2, 1);
> + IFCVF_MAX_QUEUE_PAIRS * 2, 1, 1);
>
> if (adapter == NULL) {
> IFCVF_ERR(pdev, "Failed to allocate vDPA structure");
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 4e480f4f754e..db7404e121bf 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -1788,7 +1788,8 @@ static u32 mlx5_vdpa_get_generation(struct vdpa_device *vdev)
> return mvdev->generation;
> }
>
> -static int mlx5_vdpa_set_map(struct vdpa_device *vdev, struct vhost_iotlb *iotlb)
> +static int mlx5_vdpa_set_map(struct vdpa_device *vdev, unsigned int asid,
> + struct vhost_iotlb *iotlb)
> {
> struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
> struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
> @@ -1931,7 +1932,7 @@ void *mlx5_vdpa_add_dev(struct mlx5_core_dev *mdev)
> max_vqs = min_t(u32, max_vqs, MLX5_MAX_SUPPORTED_VQS);
>
> ndev = vdpa_alloc_device(struct mlx5_vdpa_net, mvdev.vdev, mdev->device, &mlx5_vdpa_ops,
> - 2 * mlx5_vdpa_max_qps(max_vqs), 1);
> + 2 * mlx5_vdpa_max_qps(max_vqs), 1, 1);
> if (IS_ERR(ndev))
> return ndev;
>
> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
> index 46399746ec7c..05195fa7865d 100644
> --- a/drivers/vdpa/vdpa.c
> +++ b/drivers/vdpa/vdpa.c
> @@ -63,6 +63,7 @@ static void vdpa_release_dev(struct device *d)
> * @config: the bus operations that is supported by this device
> * @nvqs: number of virtqueues supported by this device
> * @ngroups: number of groups supported by this device
> + * @nas: number of address spaces supported by this device
> * @size: size of the parent structure that contains private data
> *
> * Driver should use vdpa_alloc_device() wrapper macro instead of
> @@ -74,7 +75,7 @@ static void vdpa_release_dev(struct device *d)
> struct vdpa_device *__vdpa_alloc_device(struct device *parent,
> const struct vdpa_config_ops *config,
> int nvqs, unsigned int ngroups,
> - size_t size)
> + unsigned int nas, size_t size)
> {
> struct vdpa_device *vdev;
> int err = -EINVAL;
> @@ -102,6 +103,7 @@ struct vdpa_device *__vdpa_alloc_device(struct device *parent,
> vdev->features_valid = false;
> vdev->nvqs = nvqs;
> vdev->ngroups = ngroups;
> + vdev->nas = nas;
>
> err = dev_set_name(&vdev->dev, "vdpa%u", vdev->index);
> if (err)
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> index 6669c561bc6e..5dc04ec271bb 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> @@ -354,7 +354,7 @@ static struct vdpasim *vdpasim_create(void)
> ops = &vdpasim_net_config_ops;
>
> vdpasim = vdpa_alloc_device(struct vdpasim, vdpa, NULL, ops,
> - VDPASIM_VQ_NUM, 1);
> + VDPASIM_VQ_NUM, 1, 1);
> if (!vdpasim)
> goto err_alloc;
>
> @@ -581,7 +581,7 @@ static u32 vdpasim_get_generation(struct vdpa_device *vdpa)
> return vdpasim->generation;
> }
>
> -static int vdpasim_set_map(struct vdpa_device *vdpa,
> +static int vdpasim_set_map(struct vdpa_device *vdpa, unsigned int asid,
> struct vhost_iotlb *iotlb)
> {
> struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
> @@ -608,7 +608,8 @@ static int vdpasim_set_map(struct vdpa_device *vdpa,
> return ret;
> }
>
> -static int vdpasim_dma_map(struct vdpa_device *vdpa, u64 iova, u64 size,
> +static int vdpasim_dma_map(struct vdpa_device *vdpa, unsigned int asid,
> + u64 iova, u64 size,
> u64 pa, u32 perm)
> {
> struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
> @@ -622,7 +623,8 @@ static int vdpasim_dma_map(struct vdpa_device *vdpa, u64 iova, u64 size,
> return ret;
> }
>
> -static int vdpasim_dma_unmap(struct vdpa_device *vdpa, u64 iova, u64 size)
> +static int vdpasim_dma_unmap(struct vdpa_device *vdpa, unsigned int asid,
> + u64 iova, u64 size)
> {
> struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
>
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index ec3c94f706c1..eeefcd971e3f 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -557,10 +557,10 @@ static int vhost_vdpa_map(struct vhost_vdpa *v, struct vhost_iotlb *iotlb,
> return r;
>
> if (ops->dma_map) {
> - r = ops->dma_map(vdpa, iova, size, pa, perm);
> + r = ops->dma_map(vdpa, 0, iova, size, pa, perm);
> } else if (ops->set_map) {
> if (!v->in_batch)
> - r = ops->set_map(vdpa, iotlb);
> + r = ops->set_map(vdpa, 0, iotlb);
> } else {
> r = iommu_map(v->domain, iova, pa, size,
> perm_to_iommu_flags(perm));
> @@ -579,10 +579,10 @@ static void vhost_vdpa_unmap(struct vhost_vdpa *v,
> vhost_vdpa_iotlb_unmap(v, iotlb, iova, iova + size - 1);
>
> if (ops->dma_map) {
> - ops->dma_unmap(vdpa, iova, size);
> + ops->dma_unmap(vdpa, 0, iova, size);
> } else if (ops->set_map) {
> if (!v->in_batch)
> - ops->set_map(vdpa, iotlb);
> + ops->set_map(vdpa, 0, iotlb);
> } else {
> iommu_unmap(v->domain, iova, size);
> }
> @@ -700,7 +700,7 @@ static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev,
> break;
> case VHOST_IOTLB_BATCH_END:
> if (v->in_batch && ops->set_map)
> - ops->set_map(vdpa, iotlb);
> + ops->set_map(vdpa, 0, iotlb);
> v->in_batch = false;
> break;
> default:
> @@ -949,6 +949,10 @@ static int vhost_vdpa_probe(struct vdpa_device *vdpa)
> int minor;
> int r;
>
> + /* Only support 1 address space */
> + if (vdpa->ngroups != 1)
> + return -ENOTSUPP;

Checkpatch warning: prefer EOPNOTSUPP

> +
> /* Currently, we only accept the network devices. */
> if (ops->get_device_id(vdpa) != VIRTIO_ID_NET)
> return -ENOTSUPP;
> diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> index d829512efd27..1e1163daa352 100644
> --- a/include/linux/vdpa.h
> +++ b/include/linux/vdpa.h
> @@ -43,6 +43,8 @@ struct vdpa_vq_state {
> * @index: device index
> * @features_valid: were features initialized? for legacy guests
> * @nvqs: the number of virtqueues
> + * @ngroups: the number of virtqueue groups
> + * @nas: the number of address spaces
> */
> struct vdpa_device {
> struct device dev;
> @@ -52,6 +54,7 @@ struct vdpa_device {
> bool features_valid;
> int nvqs;
> unsigned int ngroups;
> + unsigned int nas;
> };
>
> /**
> @@ -161,6 +164,7 @@ struct vdpa_device {
> * Needed for device that using device
> * specific DMA translation (on-chip IOMMU)
> * @vdev: vdpa device
> + * @asid: address space identifier
> * @iotlb: vhost memory mapping to be
> * used by the vDPA
> * Returns integer: success (0) or error (< 0)
> @@ -169,6 +173,7 @@ struct vdpa_device {
> * specific DMA translation (on-chip IOMMU)
> * and preferring incremental map.
> * @vdev: vdpa device
> + * @asid: address space identifier
> * @iova: iova to be mapped
> * @size: size of the area
> * @pa: physical address for the map
> @@ -180,6 +185,7 @@ struct vdpa_device {
> * specific DMA translation (on-chip IOMMU)
> * and preferring incremental unmap.
> * @vdev: vdpa device
> + * @asid: address space identifier
> * @iova: iova to be unmapped
> * @size: size of the area
> * Returns integer: success (0) or error (< 0)
> @@ -225,10 +231,12 @@ struct vdpa_config_ops {
> u32 (*get_generation)(struct vdpa_device *vdev);
>
> /* DMA ops */
> - int (*set_map)(struct vdpa_device *vdev, struct vhost_iotlb *iotlb);
> - int (*dma_map)(struct vdpa_device *vdev, u64 iova, u64 size,
> - u64 pa, u32 perm);
> - int (*dma_unmap)(struct vdpa_device *vdev, u64 iova, u64 size);
> + int (*set_map)(struct vdpa_device *vdev, unsigned int asid,
> + struct vhost_iotlb *iotlb);
> + int (*dma_map)(struct vdpa_device *vdev, unsigned int asid,
> + u64 iova, u64 size, u64 pa, u32 perm);
> + int (*dma_unmap)(struct vdpa_device *vdev, unsigned int asid,
> + u64 iova, u64 size);
>
> /* Free device resources */
> void (*free)(struct vdpa_device *vdev);
> @@ -237,11 +245,12 @@ struct vdpa_config_ops {
> struct vdpa_device *__vdpa_alloc_device(struct device *parent,
> const struct vdpa_config_ops *config,
> int nvqs, unsigned int ngroups,
> - size_t size);
> + unsigned int nas, size_t size);
>
> -#define vdpa_alloc_device(dev_struct, member, parent, config, nvqs, ngroups) \
> +#define vdpa_alloc_device(dev_struct, member, parent, config, nvqs, \
> + ngroups, nas) \
> container_of(__vdpa_alloc_device( \
> - parent, config, nvqs, ngroups, \
> + parent, config, nvqs, ngroups, nas, \
> sizeof(dev_struct) + \
> BUILD_BUG_ON_ZERO(offsetof( \
> dev_struct, member))), \
> --
> 2.20.1
>