Re: Re: [PATCH v5 07/11] vdpa: Support transferring virtual addressing during DMA mapping

On Tue, Mar 23, 2021 at 11:13 AM Jason Wang [off-list ref] wrote:

在 2021/3/15 下午1:37, Xie Yongji 写道:

quoted

This patch introduces an attribute for vDPA device to indicate
whether virtual address can be used. If vDPA device driver set
it, vhost-vdpa bus driver will not pin user page and transfer
userspace virtual address instead of physical address during
DMA mapping. And corresponding vma->vm_file and offset will be
also passed as an opaque pointer.

Suggested-by: Jason Wang <redacted>
Signed-off-by: Xie Yongji <redacted>
---
  drivers/vdpa/ifcvf/ifcvf_main.c   |   2 +-
  drivers/vdpa/mlx5/net/mlx5_vnet.c |   2 +-
  drivers/vdpa/vdpa.c               |   9 +++-
  drivers/vdpa/vdpa_sim/vdpa_sim.c  |   2 +-
  drivers/vdpa/virtio_pci/vp_vdpa.c |   2 +-
  drivers/vhost/vdpa.c              | 104 +++++++++++++++++++++++++++++++-------
  include/linux/vdpa.h              |  19 +++++--
  7 files changed, 113 insertions(+), 27 deletions(-)

diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
index d555a6a5d1ba..aee013f3eb5f 100644
--- a/drivers/vdpa/ifcvf/ifcvf_main.c
+++ b/drivers/vdpa/ifcvf/ifcvf_main.c

@@ -431,7 +431,7 @@ 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, NULL);
+                                 dev, &ifc_vdpa_ops, 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 71397fdafa6a..fb62ebcf464a 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c

@@ -1982,7 +1982,7 @@ 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,
-                              NULL);
+                              NULL, false);
      if (IS_ERR(ndev))
              return PTR_ERR(ndev);

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index 5cffce67cab0..97fbac276c72 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c

@@ -71,6 +71,7 @@ static void vdpa_release_dev(struct device *d)
   * @config: the bus operations that is supported by this device
   * @size: size of the parent structure that contains private data
   * @name: name of the vdpa device; optional.
+ * @use_va: indicate whether virtual address must be used by this device
   *
   * Driver should use vdpa_alloc_device() wrapper macro instead of
   * using this directly.

@@ -80,7 +81,8 @@ static void vdpa_release_dev(struct device *d)
   */
  struct vdpa_device *__vdpa_alloc_device(struct device *parent,
                                      const struct vdpa_config_ops *config,
-                                     size_t size, const char *name)
+                                     size_t size, const char *name,
+                                     bool use_va)
  {
      struct vdpa_device *vdev;
      int err = -EINVAL;

@@ -91,6 +93,10 @@ struct vdpa_device *__vdpa_alloc_device(struct device *parent,
      if (!!config->dma_map != !!config->dma_unmap)
              goto err;

+     /* It should only work for the device that use on-chip IOMMU */
+     if (use_va && !(config->dma_map || config->set_map))
+             goto err;
+
      err = -ENOMEM;
      vdev = kzalloc(size, GFP_KERNEL);
      if (!vdev)

@@ -106,6 +112,7 @@ struct vdpa_device *__vdpa_alloc_device(struct device *parent,
      vdev->index = err;
      vdev->config = config;
      vdev->features_valid = false;
+     vdev->use_va = use_va;

      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 ff331f088baf..d26334e9a412 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c

@@ -235,7 +235,7 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr)
              ops = &vdpasim_config_ops;

      vdpasim = vdpa_alloc_device(struct vdpasim, vdpa, NULL, ops,
-                                 dev_attr->name);
+                                 dev_attr->name, false);
      if (!vdpasim)
              goto err_alloc;

diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
index 1321a2fcd088..03b36aed48d6 100644
--- a/drivers/vdpa/virtio_pci/vp_vdpa.c
+++ b/drivers/vdpa/virtio_pci/vp_vdpa.c

@@ -377,7 +377,7 @@ static int vp_vdpa_probe(struct pci_dev *pdev, const struct pci_device_id *id)
              return ret;

      vp_vdpa = vdpa_alloc_device(struct vp_vdpa, vdpa,
-                                 dev, &vp_vdpa_ops, NULL);
+                                 dev, &vp_vdpa_ops, NULL, false);
      if (vp_vdpa == NULL) {
              dev_err(dev, "vp_vdpa: Failed to allocate vDPA structure\n");
              return -ENOMEM;

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 7c83fbf3edac..b65c21ae98d1 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c

@@ -480,21 +480,30 @@ 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 vdpa_map_file *map_file;
      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->use_va) {
+                     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);
+             } else {
+                     map_file = (struct vdpa_map_file *)map->opaque;
+                     fput(map_file->file);
+                     kfree(map_file);

Let's factor out the logic of pa and va separatedly here.

Will do it.

Thanks,
Yongji