On 2021/1/19 ??12:59, Xie Yongji wrote:> This patches introduces SVA (Shared Virtual Addressing)
> support for vDPA device. During vDPA device allocation,
> vDPA device driver needs to indicate whether SVA is
> supported by the device. Then vhost-vdpa bus driver
> will not pin user page and transfer userspace virtual
> address instead of physical address during DMA mapping.
>
> Suggested-by: Jason Wang <jasowang at redhat.com>
> Signed-off-by: Xie Yongji <xieyongji at bytedance.com>
> ---
> drivers/vdpa/ifcvf/ifcvf_main.c | 2 +-
> drivers/vdpa/mlx5/net/mlx5_vnet.c | 2 +-
> drivers/vdpa/vdpa.c | 5 ++++-
> drivers/vdpa/vdpa_sim/vdpa_sim.c | 3 ++-
> drivers/vhost/vdpa.c | 35
+++++++++++++++++++++++------------
> include/linux/vdpa.h | 10 +++++++---
> 6 files changed, 38 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c
b/drivers/vdpa/ifcvf/ifcvf_main.c
> index 23474af7da40..95c4601f82f5 100644
> --- a/drivers/vdpa/ifcvf/ifcvf_main.c
> +++ b/drivers/vdpa/ifcvf/ifcvf_main.c
> @@ -439,7 +439,7 @@ 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, NULL);
> + IFCVF_MAX_QUEUE_PAIRS * 2, NULL, false);
> if (adapter == NULL) {
> IFCVF_ERR(pdev, "Failed to allocate vDPA structure");
> return -ENOMEM;
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c
b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 77595c81488d..05988d6907f2 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -1959,7 +1959,7 @@ static int mlx5v_probe(struct auxiliary_device *adev,
> 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), NULL);
> + 2 * mlx5_vdpa_max_qps(max_vqs), NULL, false);
> if (IS_ERR(ndev))
> return PTR_ERR(ndev);
>
> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
> index 32bd48baffab..50cab930b2e5 100644
> --- a/drivers/vdpa/vdpa.c
> +++ b/drivers/vdpa/vdpa.c
> @@ -72,6 +72,7 @@ static void vdpa_release_dev(struct device *d)
> * @nvqs: number of virtqueues supported by this device
> * @size: size of the parent structure that contains private data
> * @name: name of the vdpa device; optional.
> + * @sva: indicate whether SVA (Shared Virtual Addressing) is supported
> *
> * Driver should use vdpa_alloc_device() wrapper macro instead of
> * using this directly.
> @@ -81,7 +82,8 @@ 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, size_t size, const char *name)
> + int nvqs, size_t size, const char *name,
> + bool sva)
> {
> struct vdpa_device *vdev;
> int err = -EINVAL;
> @@ -108,6 +110,7 @@ struct vdpa_device *__vdpa_alloc_device(struct device
*parent,
> vdev->config = config;
> vdev->features_valid = false;
> vdev->nvqs = nvqs;
> + vdev->sva = sva;
>
> if (name)
> err = dev_set_name(&vdev->dev, "%s", name);
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c
b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> index 85776e4e6749..03c796873a6b 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> @@ -367,7 +367,8 @@ static struct vdpasim *vdpasim_create(const char *name)
> else
> ops = &vdpasim_net_config_ops;
>
> - vdpasim = vdpa_alloc_device(struct vdpasim, vdpa, NULL, ops,
VDPASIM_VQ_NUM, name);
> + vdpasim = vdpa_alloc_device(struct vdpasim, vdpa, NULL, ops,
> + VDPASIM_VQ_NUM, name, false);
> if (!vdpasim)
> goto err_alloc;
>
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index 4a241d380c40..36b6950ba37f 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -486,21 +486,25 @@ static long vhost_vdpa_unlocked_ioctl(struct file
*filep,
> static void vhost_vdpa_iotlb_unmap(struct vhost_vdpa *v, u64 start, u64
last)
> {
> struct vhost_dev *dev = &v->vdev;
> + struct vdpa_device *vdpa = v->vdpa;
> struct vhost_iotlb *iotlb = dev->iotlb;
> struct vhost_iotlb_map *map;
> struct page *page;
> unsigned long pfn, pinned;
>
> while ((map = vhost_iotlb_itree_first(iotlb, start, last)) != NULL) {
> - pinned = map->size >> PAGE_SHIFT;
> - for (pfn = map->addr >> PAGE_SHIFT;
> - pinned > 0; pfn++, pinned--) {
> - page = pfn_to_page(pfn);
> - if (map->perm & VHOST_ACCESS_WO)
> - set_page_dirty_lock(page);
> - unpin_user_page(page);
> + if (!vdpa->sva) {
> + pinned = map->size >> PAGE_SHIFT;
> + for (pfn = map->addr >> PAGE_SHIFT;
> + pinned > 0; pfn++, pinned--) {
> + page = pfn_to_page(pfn);
> + if (map->perm & VHOST_ACCESS_WO)
> + set_page_dirty_lock(page);
> + unpin_user_page(page);
> + }
> + atomic64_sub(map->size >> PAGE_SHIFT,
> + &dev->mm->pinned_vm);
> }
> - atomic64_sub(map->size >> PAGE_SHIFT,
&dev->mm->pinned_vm);
> vhost_iotlb_map_free(iotlb, map);
> }
> }
> @@ -558,13 +562,15 @@ static int vhost_vdpa_map(struct vhost_vdpa *v,
> r = iommu_map(v->domain, iova, pa, size,
> perm_to_iommu_flags(perm));
> }
> -
> - if (r)
> + if (r) {
> vhost_iotlb_del_range(dev->iotlb, iova, iova + size - 1);
> - else
> + return r;
> + }
> +
> + if (!vdpa->sva)
> atomic64_add(size >> PAGE_SHIFT, &dev->mm->pinned_vm);
>
> - return r;
> + return 0;
> }
>
> static void vhost_vdpa_unmap(struct vhost_vdpa *v, u64 iova, u64 size)
> @@ -589,6 +595,7 @@ static int vhost_vdpa_process_iotlb_update(struct
vhost_vdpa *v,
> struct vhost_iotlb_msg *msg)
> {
> struct vhost_dev *dev = &v->vdev;
> + struct vdpa_device *vdpa = v->vdpa;
> struct vhost_iotlb *iotlb = dev->iotlb;
> struct page **page_list;
> unsigned long list_size = PAGE_SIZE / sizeof(struct page *);
> @@ -607,6 +614,10 @@ static int vhost_vdpa_process_iotlb_update(struct
vhost_vdpa *v,
> msg->iova + msg->size - 1))
> return -EEXIST;
>
> + if (vdpa->sva)
> + return vhost_vdpa_map(v, msg->iova, msg->size,
> + msg->uaddr, msg->perm);
> +
> /* Limit the use of memory for bookkeeping */
> page_list = (struct page **) __get_free_page(GFP_KERNEL);
> if (!page_list)
> diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> index cb5a3d847af3..f86869651614 100644
> --- a/include/linux/vdpa.h
> +++ b/include/linux/vdpa.h
> @@ -44,6 +44,7 @@ struct vdpa_parent_dev;
> * @config: the configuration ops for this device.
> * @index: device index
> * @features_valid: were features initialized? for legacy guests
> + * @sva: indicate whether SVA (Shared Virtual Addressing) is supported
Rethink about this. I think we probably need a better name other than
"sva" since kernel already use that for shared virtual address space.
But actually we don't the whole virtual address space.
And I guess this can not work for the device that use platform IOMMU, so
we should check and fail if sva && !(dma_map || set_map).
Thanks
> * @nvqs: maximum number of supported virtqueues
> * @pdev: parent device pointer; caller must setup when registering
device as part
> * of dev_add() parentdev ops callback before invoking
_vdpa_register_device().
> @@ -54,6 +55,7 @@ struct vdpa_device {
> const struct vdpa_config_ops *config;
> unsigned int index;
> bool features_valid;
> + bool sva;
> int nvqs;
> struct vdpa_parent_dev *pdev;
> };
> @@ -250,14 +252,16 @@ struct vdpa_config_ops {
>
> struct vdpa_device *__vdpa_alloc_device(struct device *parent,
> const struct vdpa_config_ops *config,
> - int nvqs, size_t size, const char *name);
> + int nvqs, size_t size,
> + const char *name, bool sva);
>
> -#define vdpa_alloc_device(dev_struct, member, parent, config, nvqs, name)
\
> +#define vdpa_alloc_device(dev_struct, member, parent, config, \
> + nvqs, name, sva) \
> container_of(__vdpa_alloc_device( \
> parent, config, nvqs, \
> sizeof(dev_struct) + \
> BUILD_BUG_ON_ZERO(offsetof( \
> - dev_struct, member)), name), \
> + dev_struct, member)), name, sva), \
> dev_struct, member)
>
> int vdpa_register_device(struct vdpa_device *vdev);