Jason Wang
2021-Mar-04 03:07 UTC
[RFC v4 05/11] vdpa: Support transferring virtual addressing during DMA mapping
On 2021/2/23 7:50 ??, Xie Yongji wrote:> 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 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 | 9 +++- > drivers/vdpa/vdpa_sim/vdpa_sim.c | 2 +- > drivers/vhost/vdpa.c | 104 +++++++++++++++++++++++++++++++------- > include/linux/vdpa.h | 20 ++++++-- > 6 files changed, 113 insertions(+), 26 deletions(-) > > diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c > index 7c8bbfcf6c3e..228b9f920fea 100644 > --- a/drivers/vdpa/ifcvf/ifcvf_main.c > +++ b/drivers/vdpa/ifcvf/ifcvf_main.c > @@ -432,7 +432,7 @@ 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 029822060017..54290438da28 100644 > --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c > +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c > @@ -1964,7 +1964,7 @@ 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 9700a0adcca0..fafc0ee5eb05 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. > + * @use_va: indicate whether virtual address can be used by this deviceI think "use_va" means va must be used instead of "can be" here.> * > * 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 use_va) > { > struct vdpa_device *vdev; > int err = -EINVAL; > @@ -92,6 +94,10 @@ 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) > @@ -108,6 +114,7 @@ struct vdpa_device *__vdpa_alloc_device(struct device *parent, > vdev->config = config; > vdev->features_valid = false; > vdev->nvqs = nvqs; > + 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 5cfc262ce055..3a9a2dd4e987 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->nvqs, dev_attr->name); > + dev_attr->nvqs, dev_attr->name, false); > if (!vdpasim) > goto err_alloc; > > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c > index 70857fe3263c..93769ace34df 100644 > --- a/drivers/vhost/vdpa.c > +++ b/drivers/vhost/vdpa.c > @@ -480,21 +480,31 @@ 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; > + if (map_file->file) > + fput(map_file->file); > + kfree(map_file); > } > - atomic64_sub(map->size >> PAGE_SHIFT, &dev->mm->pinned_vm); > vhost_iotlb_map_free(iotlb, map); > } > } > @@ -530,21 +540,21 @@ 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); > @@ -552,13 +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->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) > @@ -579,10 +591,60 @@ 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; > + goto err; > + } > + map_size = min(size, vma->vm_end - uaddr); > + offset = (vma->vm_pgoff << PAGE_SHIFT) + uaddr - vma->vm_start; > + map_file = kzalloc(sizeof(*map_file), GFP_KERNEL); > + if (!map_file) { > + ret = -ENOMEM; > + goto err; > + } > + if (vma->vm_file && (vma->vm_flags & VM_SHARED) && > + !(vma->vm_flags & (VM_IO | VM_PFNMAP))) { > + map_file->file = get_file(vma->vm_file); > + map_file->offset = offset; > + }I think it's better to do the flag check right after find_vma(), this can avoid things like kfree etc (e.g the code will still call vhost_vdpa_map() even if the flag is not expected now).> + ret = vhost_vdpa_map(v, map_iova, map_size, uaddr, > + perm, map_file); > + if (ret) { > + if (map_file->file) > + fput(map_file->file); > + kfree(map_file); > + goto err; > + } > + size -= map_size; > + uaddr += map_size; > + map_iova += map_size; > + } > + mmap_read_unlock(dev->mm); > + > + return 0; > +err: > + vhost_vdpa_unmap(v, iova, map_iova - iova); > + return ret; > +} > + > 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 *); > @@ -601,6 +663,10 @@ 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);If possible, I would like to factor out the pa map below into a something like vhost_vdpa_pa_map() first with a separated patch. Then introduce vhost_vdpa_va_map(). Thanks> + > /* Limit the use of memory for bookkeeping */ > page_list = (struct page **) __get_free_page(GFP_KERNEL); > if (!page_list) > @@ -654,7 +720,7 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v, > csize = (last_pfn - map_pfn + 1) << PAGE_SHIFT; > ret = vhost_vdpa_map(v, iova, csize, > map_pfn << PAGE_SHIFT, > - msg->perm); > + msg->perm, NULL); > if (ret) { > /* > * Unpin the pages that are left unmapped > @@ -683,7 +749,7 @@ static int vhost_vdpa_process_iotlb_update(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, msg->perm); > + map_pfn << PAGE_SHIFT, msg->perm, NULL); > out: > if (ret) { > if (nchunks) { > diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h > index 93dca2c328ae..bfae6d780c38 100644 > --- a/include/linux/vdpa.h > +++ b/include/linux/vdpa.h > @@ -44,6 +44,7 @@ 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 can 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(). > @@ -54,6 +55,7 @@ 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; > }; > @@ -69,6 +71,16 @@ 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; > +}; > + > +/** > * 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 > @@ -250,14 +262,16 @@ 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 use_va); > > -#define vdpa_alloc_device(dev_struct, member, parent, config, nvqs, name) \ > +#define vdpa_alloc_device(dev_struct, member, parent, config, \ > + nvqs, name, use_va) \ > container_of(__vdpa_alloc_device( \ > parent, config, nvqs, \ > 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);