Jason Wang
2021-Jan-20 06:24 UTC
[RFC v3 06/11] vhost-vdpa: Add an opaque pointer for vhost IOTLB
On 2021/1/19 ??12:59, Xie Yongji wrote:> Add an opaque pointer for vhost IOTLB to store the > corresponding vma->vm_file and offset on the DMA mapping.Let's split the patch into two. 1) opaque pointer 2) vma stuffs> > It will be used in VDUSE case later. > > Suggested-by: Jason Wang <jasowang at redhat.com> > Signed-off-by: Xie Yongji <xieyongji at bytedance.com> > --- > drivers/vdpa/vdpa_sim/vdpa_sim.c | 11 ++++--- > drivers/vhost/iotlb.c | 5 ++- > drivers/vhost/vdpa.c | 66 +++++++++++++++++++++++++++++++++++----- > drivers/vhost/vhost.c | 4 +-- > include/linux/vdpa.h | 3 +- > include/linux/vhost_iotlb.h | 8 ++++- > 6 files changed, 79 insertions(+), 18 deletions(-) > > diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c > index 03c796873a6b..1ffcef67954f 100644 > --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c > +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c > @@ -279,7 +279,7 @@ static dma_addr_t vdpasim_map_page(struct device *dev, struct page *page, > */ > spin_lock(&vdpasim->iommu_lock); > ret = vhost_iotlb_add_range(iommu, pa, pa + size - 1, > - pa, dir_to_perm(dir)); > + pa, dir_to_perm(dir), NULL);Maybe its better to introduce vhost_iotlb_add_range_ctx() which can accepts the opaque (context). And let vhost_iotlb_add_range() just call that.> spin_unlock(&vdpasim->iommu_lock); > if (ret) > return DMA_MAPPING_ERROR; > @@ -317,7 +317,7 @@ static void *vdpasim_alloc_coherent(struct device *dev, size_t size, > > ret = vhost_iotlb_add_range(iommu, (u64)pa, > (u64)pa + size - 1, > - pa, VHOST_MAP_RW); > + pa, VHOST_MAP_RW, NULL); > if (ret) { > *dma_addr = DMA_MAPPING_ERROR; > kfree(addr); > @@ -625,7 +625,8 @@ static int vdpasim_set_map(struct vdpa_device *vdpa, > for (map = vhost_iotlb_itree_first(iotlb, start, last); map; > map = vhost_iotlb_itree_next(map, start, last)) { > ret = vhost_iotlb_add_range(vdpasim->iommu, map->start, > - map->last, map->addr, map->perm); > + map->last, map->addr, > + map->perm, NULL); > if (ret) > goto err; > } > @@ -639,14 +640,14 @@ static int vdpasim_set_map(struct vdpa_device *vdpa, > } > > static int vdpasim_dma_map(struct vdpa_device *vdpa, u64 iova, u64 size, > - u64 pa, u32 perm) > + u64 pa, u32 perm, void *opaque) > { > struct vdpasim *vdpasim = vdpa_to_sim(vdpa); > int ret; > > spin_lock(&vdpasim->iommu_lock); > ret = vhost_iotlb_add_range(vdpasim->iommu, iova, iova + size - 1, pa, > - perm); > + perm, NULL); > spin_unlock(&vdpasim->iommu_lock); > > return ret; > diff --git a/drivers/vhost/iotlb.c b/drivers/vhost/iotlb.c > index 0fd3f87e913c..3bd5bd06cdbc 100644 > --- a/drivers/vhost/iotlb.c > +++ b/drivers/vhost/iotlb.c > @@ -42,13 +42,15 @@ EXPORT_SYMBOL_GPL(vhost_iotlb_map_free); > * @last: last of IOVA range > * @addr: the address that is mapped to @start > * @perm: access permission of this range > + * @opaque: the opaque pointer for the IOTLB mapping > * > * Returns an error last is smaller than start or memory allocation > * fails > */ > int vhost_iotlb_add_range(struct vhost_iotlb *iotlb, > u64 start, u64 last, > - u64 addr, unsigned int perm) > + u64 addr, unsigned int perm, > + void *opaque) > { > struct vhost_iotlb_map *map; > > @@ -71,6 +73,7 @@ int vhost_iotlb_add_range(struct vhost_iotlb *iotlb, > map->last = last; > map->addr = addr; > map->perm = perm; > + map->opaque = opaque; > > iotlb->nmaps++; > vhost_iotlb_itree_insert(map, &iotlb->root); > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c > index 36b6950ba37f..e83e5be7cec8 100644 > --- a/drivers/vhost/vdpa.c > +++ b/drivers/vhost/vdpa.c > @@ -488,6 +488,7 @@ 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_file *iotlb_file; > struct vhost_iotlb_map *map; > struct page *page; > unsigned long pfn, pinned; > @@ -504,6 +505,10 @@ static void vhost_vdpa_iotlb_unmap(struct vhost_vdpa *v, u64 start, u64 last) > } > atomic64_sub(map->size >> PAGE_SHIFT, > &dev->mm->pinned_vm); > + } else if (map->opaque) { > + iotlb_file = (struct vhost_iotlb_file *)map->opaque; > + fput(iotlb_file->file); > + kfree(iotlb_file); > } > vhost_iotlb_map_free(iotlb, map); > } > @@ -540,8 +545,8 @@ 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; > @@ -549,12 +554,12 @@ static int vhost_vdpa_map(struct vhost_vdpa *v, > int r = 0; > > r = vhost_iotlb_add_range(dev->iotlb, iova, iova + size - 1, > - pa, perm); > + pa, perm, opaque); > if (r) > return r; > > if (ops->dma_map) { > - r = ops->dma_map(vdpa, iova, size, pa, perm); > + 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); > @@ -591,6 +596,51 @@ static void vhost_vdpa_unmap(struct vhost_vdpa *v, u64 iova, u64 size) > } > } > > +static int vhost_vdpa_sva_map(struct vhost_vdpa *v, > + u64 iova, u64 size, u64 uaddr, u32 perm) > +{ > + u64 offset, map_size, map_iova = iova; > + struct vhost_iotlb_file *iotlb_file; > + struct vm_area_struct *vma; > + int ret;Lacking mmap_read_lock().> + > + while (size) { > + vma = find_vma(current->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; > + iotlb_file = NULL; > + if (vma->vm_file && (vma->vm_flags & VM_SHARED)) {I wonder if we need more strict check here. When developing vhost-vdpa, I try hard to make sure the map can only work for user pages. So the question is: do we need to exclude MMIO area or only allow shmem to work here?> + iotlb_file = kmalloc(sizeof(*iotlb_file), GFP_KERNEL); > + if (!iotlb_file) { > + ret = -ENOMEM; > + goto err; > + } > + iotlb_file->file = get_file(vma->vm_file); > + iotlb_file->offset = offset; > + }I wonder if it's better to allocate iotlb_file and make iotlb_file->file = NULL && iotlb_file->offset = 0. This can force a consistent code for the vDPA parents. Or we can simply fail the map without a file as backend.> + ret = vhost_vdpa_map(v, map_iova, map_size, uaddr, > + perm, iotlb_file); > + if (ret) { > + if (iotlb_file) { > + fput(iotlb_file->file); > + kfree(iotlb_file); > + } > + goto err; > + } > + size -= map_size; > + uaddr += map_size; > + map_iova += map_size; > + } > + 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) > { > @@ -615,8 +665,8 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v, > return -EEXIST; > > if (vdpa->sva) > - return vhost_vdpa_map(v, msg->iova, msg->size, > - msg->uaddr, msg->perm); > + return vhost_vdpa_sva_map(v, msg->iova, msg->size, > + msg->uaddr, msg->perm);So I think it's better squash vhost_vdpa_sva_map() and related changes into previous patch.> > /* Limit the use of memory for bookkeeping */ > page_list = (struct page **) __get_free_page(GFP_KERNEL); > @@ -671,7 +721,7 @@ 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 > @@ -700,7 +750,7 @@ 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/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index a262e12c6dc2..120dd5b3c119 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -1104,7 +1104,7 @@ static int vhost_process_iotlb_msg(struct vhost_dev *dev, > vhost_vq_meta_reset(dev); > if (vhost_iotlb_add_range(dev->iotlb, msg->iova, > msg->iova + msg->size - 1, > - msg->uaddr, msg->perm)) { > + msg->uaddr, msg->perm, NULL)) { > ret = -ENOMEM; > break; > } > @@ -1450,7 +1450,7 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) > region->guest_phys_addr + > region->memory_size - 1, > region->userspace_addr, > - VHOST_MAP_RW)) > + VHOST_MAP_RW, NULL)) > goto err; > } > > diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h > index f86869651614..b264c627e94b 100644 > --- a/include/linux/vdpa.h > +++ b/include/linux/vdpa.h > @@ -189,6 +189,7 @@ struct vdpa_iova_range { > * @size: size of the area > * @pa: physical address for the map > * @perm: device access permission (VHOST_MAP_XX) > + * @opaque: the opaque pointer for the mapping > * Returns integer: success (0) or error (< 0) > * @dma_unmap: Unmap an area of IOVA (optional but > * must be implemented with dma_map) > @@ -243,7 +244,7 @@ struct vdpa_config_ops { > /* 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); > + u64 pa, u32 perm, void *opaque); > int (*dma_unmap)(struct vdpa_device *vdev, u64 iova, u64 size); > > /* Free device resources */ > diff --git a/include/linux/vhost_iotlb.h b/include/linux/vhost_iotlb.h > index 6b09b786a762..66a50c11c8ca 100644 > --- a/include/linux/vhost_iotlb.h > +++ b/include/linux/vhost_iotlb.h > @@ -4,6 +4,11 @@ > > #include <linux/interval_tree_generic.h> > > +struct vhost_iotlb_file { > + struct file *file; > + u64 offset; > +};I think we'd better either: 1) simply use struct vhost_iotlb_file * instead of void *opaque for vhost_iotlb_map or 2)rename and move the vhost_iotlb_file to vdpa 2) looks better since we want to let vhost iotlb to carry any type of context (opaque pointer) And if we do this, the modification of vdpa_config_ops deserves a separate patch. Thanks> + > struct vhost_iotlb_map { > struct rb_node rb; > struct list_head link; > @@ -17,6 +22,7 @@ struct vhost_iotlb_map { > u32 perm; > u32 flags_padding; > u64 __subtree_last; > + void *opaque; > }; > > #define VHOST_IOTLB_FLAG_RETIRE 0x1 > @@ -30,7 +36,7 @@ struct vhost_iotlb { > }; > > int vhost_iotlb_add_range(struct vhost_iotlb *iotlb, u64 start, u64 last, > - u64 addr, unsigned int perm); > + u64 addr, unsigned int perm, void *opaque); > void vhost_iotlb_del_range(struct vhost_iotlb *iotlb, u64 start, u64 last); > > struct vhost_iotlb *vhost_iotlb_alloc(unsigned int limit, unsigned int flags);