| Message ID | 1573578220-7530-5-git-send-email-kwankhede@nvidia.com |
|---|---|
| State | New |
| Headers | show |
| Series | Add KABIs to support migration for VFIO devices | expand |
On Tue, 12 Nov 2019 22:33:39 +0530 Kirti Wankhede <kwankhede@nvidia.com> wrote: > IOMMU container maintains list of external pinned pages. Bitmap of pinned > pages for input IO virtual address range is created and returned. > IO virtual address range should be from a single mapping created by > map request. Input bitmap_size is validated by calculating the size of > requested range. > This ioctl returns bitmap of dirty pages, its user space application > responsibility to copy content of dirty pages from source to destination > during migration. > > Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> > Reviewed-by: Neo Jia <cjia@nvidia.com> > --- > drivers/vfio/vfio_iommu_type1.c | 92 +++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 92 insertions(+) > > diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > index 2ada8e6cdb88..ac176e672857 100644 > --- a/drivers/vfio/vfio_iommu_type1.c > +++ b/drivers/vfio/vfio_iommu_type1.c > @@ -850,6 +850,81 @@ static unsigned long vfio_pgsize_bitmap(struct vfio_iommu *iommu) > return bitmap; > } > > +/* > + * start_iova is the reference from where bitmaping started. This is called > + * from DMA_UNMAP where start_iova can be different than iova Why not simply call this with a pointer to the bitmap relative to the start of the iova? > + */ > + > +static int vfio_iova_dirty_bitmap(struct vfio_iommu *iommu, dma_addr_t iova, > + size_t size, dma_addr_t start_iova, > + unsigned long *bitmap) > +{ > + struct vfio_dma *dma; > + dma_addr_t temp_iova = iova; > + > + dma = vfio_find_dma(iommu, iova, size); > + if (!dma) The UAPI did not define that the user can only ask for the dirty bitmap across a mapped range. > + return -EINVAL; > + > + /* > + * Range should be from a single mapping created by map request. > + */ The UAPI also did not specify this as a requirement. > + > + if ((iova < dma->iova) || > + ((dma->iova + dma->size) < (iova + size))) > + return -EINVAL; Nor this. So the actual implemented UAPI is that the user must call this over some portion of, but not exceeding a single previously mapped DMA range. Why so restrictive? > + > + while (temp_iova < iova + size) { > + struct vfio_pfn *vpfn = NULL; > + > + vpfn = vfio_find_vpfn(dma, temp_iova); > + if (vpfn) > + __bitmap_set(bitmap, vpfn->iova - start_iova, 1); > + > + temp_iova += PAGE_SIZE; Seems like waking the rb tree would be far more efficient. Also, if dma->iommu_mapped, mark all pages dirty until we figure out how to avoid it. > + } > + > + return 0; > +} > + > +static int verify_bitmap_size(unsigned long npages, unsigned long bitmap_size) > +{ > + unsigned long bsize = ALIGN(npages, BITS_PER_LONG) / 8; > + > + if ((bitmap_size == 0) || (bitmap_size < bsize)) > + return -EINVAL; > + return 0; > +} > + > +static int vfio_iova_get_dirty_bitmap(struct vfio_iommu *iommu, > + struct vfio_iommu_type1_dirty_bitmap *range) > +{ > + unsigned long *bitmap; > + int ret; > + > + ret = verify_bitmap_size(range->size >> PAGE_SHIFT, range->bitmap_size); > + if (ret) > + return ret; > + > + /* one bit per page */ > + bitmap = bitmap_zalloc(range->size >> PAGE_SHIFT, GFP_KERNEL); This creates a DoS vector, we need to be able to directly use the user bitmap or chunk words into it using a confined size (ex. a user can with args 0 to UIN64_MAX). Thanks, Alex > + if (!bitmap) > + return -ENOMEM; > + > + mutex_lock(&iommu->lock); > + ret = vfio_iova_dirty_bitmap(iommu, range->iova, range->size, > + range->iova, bitmap); > + mutex_unlock(&iommu->lock); > + > + if (!ret) { > + if (copy_to_user(range->bitmap, bitmap, range->bitmap_size)) > + ret = -EFAULT; > + } > + > + bitmap_free(bitmap); > + return ret; > +} > + > static int vfio_dma_do_unmap(struct vfio_iommu *iommu, > struct vfio_iommu_type1_dma_unmap *unmap) > { > @@ -2297,6 +2372,23 @@ static long vfio_iommu_type1_ioctl(void *iommu_data, > > return copy_to_user((void __user *)arg, &unmap, minsz) ? > -EFAULT : 0; > + } else if (cmd == VFIO_IOMMU_GET_DIRTY_BITMAP) { > + struct vfio_iommu_type1_dirty_bitmap range; > + > + /* Supported for v2 version only */ > + if (!iommu->v2) > + return -EACCES; > + > + minsz = offsetofend(struct vfio_iommu_type1_dirty_bitmap, > + bitmap); > + > + if (copy_from_user(&range, (void __user *)arg, minsz)) > + return -EFAULT; > + > + if (range.argsz < minsz) > + return -EINVAL; > + > + return vfio_iova_get_dirty_bitmap(iommu, &range); > } > > return -ENOTTY;
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 2ada8e6cdb88..ac176e672857 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -850,6 +850,81 @@ static unsigned long vfio_pgsize_bitmap(struct vfio_iommu *iommu) return bitmap; } +/* + * start_iova is the reference from where bitmaping started. This is called + * from DMA_UNMAP where start_iova can be different than iova + */ + +static int vfio_iova_dirty_bitmap(struct vfio_iommu *iommu, dma_addr_t iova, + size_t size, dma_addr_t start_iova, + unsigned long *bitmap) +{ + struct vfio_dma *dma; + dma_addr_t temp_iova = iova; + + dma = vfio_find_dma(iommu, iova, size); + if (!dma) + return -EINVAL; + + /* + * Range should be from a single mapping created by map request. + */ + + if ((iova < dma->iova) || + ((dma->iova + dma->size) < (iova + size))) + return -EINVAL; + + while (temp_iova < iova + size) { + struct vfio_pfn *vpfn = NULL; + + vpfn = vfio_find_vpfn(dma, temp_iova); + if (vpfn) + __bitmap_set(bitmap, vpfn->iova - start_iova, 1); + + temp_iova += PAGE_SIZE; + } + + return 0; +} + +static int verify_bitmap_size(unsigned long npages, unsigned long bitmap_size) +{ + unsigned long bsize = ALIGN(npages, BITS_PER_LONG) / 8; + + if ((bitmap_size == 0) || (bitmap_size < bsize)) + return -EINVAL; + return 0; +} + +static int vfio_iova_get_dirty_bitmap(struct vfio_iommu *iommu, + struct vfio_iommu_type1_dirty_bitmap *range) +{ + unsigned long *bitmap; + int ret; + + ret = verify_bitmap_size(range->size >> PAGE_SHIFT, range->bitmap_size); + if (ret) + return ret; + + /* one bit per page */ + bitmap = bitmap_zalloc(range->size >> PAGE_SHIFT, GFP_KERNEL); + if (!bitmap) + return -ENOMEM; + + mutex_lock(&iommu->lock); + ret = vfio_iova_dirty_bitmap(iommu, range->iova, range->size, + range->iova, bitmap); + mutex_unlock(&iommu->lock); + + if (!ret) { + if (copy_to_user(range->bitmap, bitmap, range->bitmap_size)) + ret = -EFAULT; + } + + bitmap_free(bitmap); + return ret; +} + static int vfio_dma_do_unmap(struct vfio_iommu *iommu, struct vfio_iommu_type1_dma_unmap *unmap) { @@ -2297,6 +2372,23 @@ static long vfio_iommu_type1_ioctl(void *iommu_data, return copy_to_user((void __user *)arg, &unmap, minsz) ? -EFAULT : 0; + } else if (cmd == VFIO_IOMMU_GET_DIRTY_BITMAP) { + struct vfio_iommu_type1_dirty_bitmap range; + + /* Supported for v2 version only */ + if (!iommu->v2) + return -EACCES; + + minsz = offsetofend(struct vfio_iommu_type1_dirty_bitmap, + bitmap); + + if (copy_from_user(&range, (void __user *)arg, minsz)) + return -EFAULT; + + if (range.argsz < minsz) + return -EINVAL; + + return vfio_iova_get_dirty_bitmap(iommu, &range); } return -ENOTTY;