Jason Wang
2021-Jan-27 03:51 UTC
[RFC v3 06/11] vhost-vdpa: Add an opaque pointer for vhost IOTLB
On 2021/1/20 ??3:52, Yongji Xie wrote:> On Wed, Jan 20, 2021 at 2:24 PM Jason Wang <jasowang at redhat.com> wrote: >> >> 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 >> > OK. > >>> 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. >> > If so, we need export both vhost_iotlb_add_range() and > vhost_iotlb_add_range_ctx() which will be used in VDUSE driver. Is it > a bit redundant?Probably not, we do something similar in virtio core: void *virtqueue_get_buf_ctx(struct virtqueue *_vq, unsigned int *len, ??? ??? ??? ??? void **ctx) { ??? struct vring_virtqueue *vq = to_vvq(_vq); ??? return vq->packed_ring ? virtqueue_get_buf_ctx_packed(_vq, len, ctx) : ??? ??? ??? ??? ?virtqueue_get_buf_ctx_split(_vq, len, ctx); } EXPORT_SYMBOL_GPL(virtqueue_get_buf_ctx); void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len) { ??? return virtqueue_get_buf_ctx(_vq, len, NULL); } EXPORT_SYMBOL_GPL(virtqueue_get_buf);> >>> 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(). >> > Good catch! Will fix it. > >>> + >>> + 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? >> > Do you mean we need to check VM_MIXEDMAP | VM_PFNMAP here?I meant do we need to allow VM_IO here? (We don't allow such case in vhost-vdpa now).> > It makes sense to me. > >> >>> + 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. >> > Looks fine to me. > >> Or we can simply fail the map without a file as backend. >> > Actually there will be some vma without vm_file during vm booting.Yes, e.g bios or other rom. Vhost-user has the similar issue and they filter the out them in qemu. For vhost-vDPA, consider it can supports various difference backends, we can't do that.> >>> + 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. >> > OK, so the order of the patches is: > 1) opaque pointer > 2) va support + vma stuffs? > > Is it OK?Fine with me.> >>> /* 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) >> > I agree. So we need to introduce struct vdpa_iotlb_file in > include/linux/vdpa.h, right?Yes.> >> And if we do this, the modification of vdpa_config_ops deserves a >> separate patch. >> > Sorry, I didn't get you here. What do you mean by the modification of > vdpa_config_ops? Do you mean adding an opaque pointer to ops.dma_map?Yes. Thanks> > Thanks, > Yongji >