Re: [RFC v3 06/11] vhost-vdpa: Add an opaque pointer for vhost IOTLB
From: Jason Wang <hidden>
Date: 2021-01-27 05:46:02
Also in:
kvm, linux-fsdevel, virtualization
On 2021/1/20 下午3:52, Yongji Xie wrote:
On Wed, Jan 20, 2021 at 2:24 PM Jason Wang [off-list ref] wrote:quoted
On 2021/1/19 下午12:59, Xie Yongji wrote:quoted
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 stuffsOK.quoted
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It will be used in VDUSE case later. Suggested-by: Jason Wang <redacted> Signed-off-by: Xie Yongji <redacted> --- 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);
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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.quoted
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+ + 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.quoted
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+ 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.quoted
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.
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+ 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.
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/* 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.
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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