[PATCH v13 10/13] vdpa: Support transferring virtual addressing during DMA mapping

Xie Yongji
2021-08-31T10:37:52Z

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 <jasowang@redhat.com>
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
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 | 99 ++++++++++++++++++++++++++++++++++-----
include/linux/vdpa.h | 20 ++++++--
7 files changed, 117 insertions(+), 19 deletions(-)

diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
index 4293481ce910..dcd648e1f7e7 100644
--- a/drivers/vdpa/ifcvf/ifcvf_main.c
+++ b/drivers/vdpa/ifcvf/ifcvf_main.c
@@ -515,7 +515,7 @@ static int ifcvf_vdpa_dev_add(struct vdpa_mgmt_dev *mdev, const char *name)
pdev = ifcvf_mgmt_dev->pdev;
dev = &pdev->dev;
adapter = vdpa_alloc_device(struct ifcvf_adapter, vdpa,
- dev, &ifc_vdpa_ops, name);
+ dev, &ifc_vdpa_ops, name, false);
if (IS_ERR(adapter)) {
IFCVF_ERR(pdev, "Failed to allocate vDPA structure");
return PTR_ERR(adapter);
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 608f6b900cd9..08f39952fa6a 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -2425,7 +2425,7 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name)
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,
- name);
+ name, false);
if (IS_ERR(ndev))
return PTR_ERR(ndev);

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index bb3f1d1f0422..8f01d6a7ecc5 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 a70fd2a08ff1..5f484fff8dbe 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -251,7 +251,7 @@ 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 (IS_ERR(vdpasim)) {
ret = PTR_ERR(vdpasim);
goto err_alloc;
diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
index cd7718b43a6e..5bcd00246d2e 100644
--- a/drivers/vdpa/virtio_pci/vp_vdpa.c
+++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
@@ -446,7 +446,7 @@ 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 (IS_ERR(vp_vdpa)) {
dev_err(dev, "vp_vdpa: Failed to allocate vDPA structure\n");
return PTR_ERR(vp_vdpa);
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 49a1f45ccef8..e7b75f49f668 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -526,8 +526,28 @@ static void vhost_vdpa_pa_unmap(struct vhost_vdpa *v, u64 start, u64 last)
}
}

+static void vhost_vdpa_va_unmap(struct vhost_vdpa *v, u64 start, u64 last)
+{
+ struct vhost_dev *dev = &v->vdev;
+ struct vhost_iotlb *iotlb = dev->iotlb;
+ struct vhost_iotlb_map *map;
+ struct vdpa_map_file *map_file;
+
+ while ((map = vhost_iotlb_itree_first(iotlb, start, last)) != NULL) {
+ map_file = (struct vdpa_map_file *)map->opaque;
+ fput(map_file->file);
+ kfree(map_file);
+ vhost_iotlb_map_free(iotlb, map);
+ }
+}
+
static void vhost_vdpa_iotlb_unmap(struct vhost_vdpa *v, u64 start, u64 last)
{
+ struct vdpa_device *vdpa = v->vdpa;
+
+ if (vdpa->use_va)
+ return vhost_vdpa_va_unmap(v, start, last);
+
return vhost_vdpa_pa_unmap(v, start, last);
}

@@ -562,21 +582,21 @@ static int perm_to_iommu_flags(u32 perm)
return flags | IOMMU_CACHE;
}

-static int vhost_vdpa_map(struct vhost_vdpa *v,
- u64 iova, u64 size, u64 pa, u32 perm)
+static int vhost_vdpa_map(struct vhost_vdpa *v, u64 iova,
+ u64 size, u64 pa, u32 perm, void *opaque)
{
struct vhost_dev *dev = &v->vdev;
struct vdpa_device *vdpa = v->vdpa;
const struct vdpa_config_ops *ops = vdpa->config;
int r = 0;

- r = vhost_iotlb_add_range(dev->iotlb, iova, iova + size - 1,
- pa, perm);
+ r = vhost_iotlb_add_range_ctx(dev->iotlb, iova, iova + size - 1,
+ pa, perm, opaque);
if (r)
return r;

if (ops->dma_map) {
- r = ops->dma_map(vdpa, iova, size, pa, perm, NULL);
+ r = ops->dma_map(vdpa, iova, size, pa, perm, opaque);
} else if (ops->set_map) {
if (!v->in_batch)
r = ops->set_map(vdpa, dev->iotlb);
@@ -584,13 +604,15 @@ 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->use_va)
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)
@@ -611,6 +633,56 @@ static void vhost_vdpa_unmap(struct vhost_vdpa *v, u64 iova, u64 size)
}
}

+static int vhost_vdpa_va_map(struct vhost_vdpa *v,
+ u64 iova, u64 size, u64 uaddr, u32 perm)
+{
+ struct vhost_dev *dev = &v->vdev;
+ u64 offset, map_size, map_iova = iova;
+ struct vdpa_map_file *map_file;
+ struct vm_area_struct *vma;
+ int ret;
+
+ mmap_read_lock(dev->mm);
+
+ while (size) {
+ vma = find_vma(dev->mm, uaddr);
+ if (!vma) {
+ ret = -EINVAL;
+ break;
+ }
+ map_size = min(size, vma->vm_end - uaddr);
+ if (!(vma->vm_file && (vma->vm_flags & VM_SHARED) &&
+ !(vma->vm_flags & (VM_IO | VM_PFNMAP))))
+ goto next;
+
+ map_file = kzalloc(sizeof(*map_file), GFP_KERNEL);
+ if (!map_file) {
+ ret = -ENOMEM;
+ break;
+ }
+ offset = (vma->vm_pgoff << PAGE_SHIFT) + uaddr - vma->vm_start;
+ map_file->offset = offset;
+ map_file->file = get_file(vma->vm_file);
+ ret = vhost_vdpa_map(v, map_iova, map_size, uaddr,
+ perm, map_file);
+ if (ret) {
+ fput(map_file->file);
+ kfree(map_file);
+ break;
+ }
+next:
+ size -= map_size;
+ uaddr += map_size;
+ map_iova += map_size;
+ }
+ if (ret)
+ vhost_vdpa_unmap(v, iova, map_iova - iova);
+
+ mmap_read_unlock(dev->mm);
+
+ return ret;
+}
+
static int vhost_vdpa_pa_map(struct vhost_vdpa *v,
u64 iova, u64 size, u64 uaddr, u32 perm)
{
@@ -677,7 +749,7 @@ static int vhost_vdpa_pa_map(struct vhost_vdpa *v,
csize = (last_pfn - map_pfn + 1) << PAGE_SHIFT;
ret = vhost_vdpa_map(v, iova, csize,
map_pfn << PAGE_SHIFT,
- perm);
+ perm, NULL);
if (ret) {
/*
* Unpin the pages that are left unmapped
@@ -706,7 +778,7 @@ static int vhost_vdpa_pa_map(struct vhost_vdpa *v,

/* Pin the rest chunk */
ret = vhost_vdpa_map(v, iova, (last_pfn - map_pfn + 1) << PAGE_SHIFT,
- map_pfn << PAGE_SHIFT, perm);
+ map_pfn << PAGE_SHIFT, perm, NULL);
out:
if (ret) {
if (nchunks) {
@@ -739,6 +811,7 @@ 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;

if (msg->iova < v->range.first || !msg->size ||
@@ -750,6 +823,10 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
msg->iova + msg->size - 1))
return -EEXIST;

+ if (vdpa->use_va)
+ return vhost_vdpa_va_map(v, msg->iova, msg->size,
+ msg->uaddr, msg->perm);
+
return vhost_vdpa_pa_map(v, msg->iova, msg->size, msg->uaddr,
msg->perm);
}
diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
index f3014aaca47e..3972ab765de1 100644
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h
@@ -65,6 +65,7 @@ struct vdpa_mgmt_dev;
* @config: the configuration ops for this device.
* @index: device index
* @features_valid: were features initialized? for legacy guests
+ * @use_va: indicate whether virtual address must be used by this device
* @nvqs: maximum number of supported virtqueues
* @mdev: management device pointer; caller must setup when registering device as part
* of dev_add() mgmtdev ops callback before invoking _vdpa_register_device().
@@ -75,6 +76,7 @@ struct vdpa_device {
const struct vdpa_config_ops *config;
unsigned int index;
bool features_valid;
+ bool use_va;
int nvqs;
struct vdpa_mgmt_dev *mdev;
};
@@ -90,6 +92,16 @@ struct vdpa_iova_range {
};

/**
+ * Corresponding file area for device memory mapping
+ * @file: vma->vm_file for the mapping
+ * @offset: mapping offset in the vm_file
+ */
+struct vdpa_map_file {
+ struct file *file;
+ u64 offset;
+};
+
+/**
* struct vdpa_config_ops - operations for configuring a vDPA device.
* Note: vDPA device drivers are required to implement all of the
* operations unless it is mentioned to be optional in the following
@@ -279,7 +291,8 @@ struct vdpa_config_ops {

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);

/**
* vdpa_alloc_device - allocate and initilaize a vDPA device
@@ -289,15 +302,16 @@ struct vdpa_device *__vdpa_alloc_device(struct device *parent,
* @parent: the parent device
* @config: the bus operations that is supported by this device
* @name: name of the vdpa device
+ * @use_va: indicate whether virtual address must be used by this device
*
* Return allocated data structure or ERR_PTR upon error
*/
-#define vdpa_alloc_device(dev_struct, member, parent, config, name) \
+#define vdpa_alloc_device(dev_struct, member, parent, config, name, use_va) \
container_of(__vdpa_alloc_device( \
parent, config, \
sizeof(dev_struct) + \
BUILD_BUG_ON_ZERO(offsetof( \
- dev_struct, member)), name), \
+ dev_struct, member)), name, use_va), \
dev_struct, member)

int vdpa_register_device(struct vdpa_device *vdev, int nvqs);
--
2.11.0