| Message ID | 1576602651-15430-5-git-send-email-kwankhede@nvidia.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KABIs to support migration for VFIO devices | expand |
On Tue, 17 Dec 2019 22:40:49 +0530 Kirti Wankhede <kwankhede@nvidia.com> wrote: > Pages, pinned by external interface for requested IO virtual address > range, might get unpinned and unmapped while migration is active and > device is still running, that is, in pre-copy phase while guest driver > still could access those pages. Host device can write to these pages while > those were mapped. Such pages should be marked dirty so that after > migration guest driver should still be able to complete the operation. > > To get bitmap during unmap, user should set flag > VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP, bitmap memory should be allocated and > zeroed by user space application. Bitmap size and page size should be set > by user application. > > Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> > Reviewed-by: Neo Jia <cjia@nvidia.com> > --- > drivers/vfio/vfio_iommu_type1.c | 63 ++++++++++++++++++++++++++++++++++++----- > include/uapi/linux/vfio.h | 12 ++++++++ > 2 files changed, 68 insertions(+), 7 deletions(-) > > diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > index 215aecb25453..101c2b1e72b4 100644 > --- a/drivers/vfio/vfio_iommu_type1.c > +++ b/drivers/vfio/vfio_iommu_type1.c > @@ -974,7 +974,8 @@ static long verify_bitmap_size(unsigned long npages, unsigned long bitmap_size) > } > > static int vfio_dma_do_unmap(struct vfio_iommu *iommu, > - struct vfio_iommu_type1_dma_unmap *unmap) > + struct vfio_iommu_type1_dma_unmap *unmap, > + unsigned long *bitmap) > { > uint64_t mask; > struct vfio_dma *dma, *dma_last = NULL; > @@ -1049,6 +1050,15 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu, > if (dma->task->mm != current->mm) > break; > > + if ((unmap->flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) && > + (dma_last != dma)) > + vfio_iova_dirty_bitmap(iommu, dma->iova, dma->size, > + unmap->bitmap_pgsize, unmap->iova, > + bitmap); > + else > + vfio_remove_unpinned_from_pfn_list(dma, true); > + > + > if (!RB_EMPTY_ROOT(&dma->pfn_list)) { > struct vfio_iommu_type1_dma_unmap nb_unmap; > > @@ -1074,6 +1084,7 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu, > &nb_unmap); > goto again; > } > + > unmapped += dma->size; > vfio_remove_dma(iommu, dma); > } > @@ -2404,22 +2415,60 @@ static long vfio_iommu_type1_ioctl(void *iommu_data, > > } else if (cmd == VFIO_IOMMU_UNMAP_DMA) { > struct vfio_iommu_type1_dma_unmap unmap; > - long ret; > + unsigned long *bitmap = NULL; > + long ret, bsize; > > minsz = offsetofend(struct vfio_iommu_type1_dma_unmap, size); > > - if (copy_from_user(&unmap, (void __user *)arg, minsz)) > + if (copy_from_user(&unmap, (void __user *)arg, sizeof(unmap))) If we only require minsz, how are we going to copy sizeof(unmap)? This breaks existing userspace. You'll need to copy the remainder of the user data after validating that they've provided it. > return -EFAULT; > > - if (unmap.argsz < minsz || unmap.flags) > + if (unmap.argsz < minsz || > + unmap.flags & ~VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) > return -EINVAL; > > - ret = vfio_dma_do_unmap(iommu, &unmap); > + if (unmap.flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) { > + unsigned long pgshift = __ffs(unmap.bitmap_pgsize); > + uint64_t iommu_pgmask = > + ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu))) - 1; > + > + if (((unmap.bitmap_pgsize - 1) & iommu_pgmask) != > + (unmap.bitmap_pgsize - 1)) > + return -EINVAL; > + > + bsize = verify_bitmap_size(unmap.size >> pgshift, > + unmap.bitmap_size); > + if (bsize < 0) > + return bsize; > + > + bitmap = kmalloc(bsize, GFP_KERNEL); Same allocation that we cannot do. Thanks, Alex > + if (!bitmap) > + return -ENOMEM; > + > + if (copy_from_user(bitmap, (void __user *)unmap.bitmap, > + bsize)) { > + ret = -EFAULT; > + goto unmap_exit; > + } > + } > + > + ret = vfio_dma_do_unmap(iommu, &unmap, bitmap); > if (ret) > - return ret; > + goto unmap_exit; > > - return copy_to_user((void __user *)arg, &unmap, minsz) ? > + if (unmap.flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) { > + if (copy_to_user((void __user *)unmap.bitmap, bitmap, > + bsize)) { > + ret = -EFAULT; > + goto unmap_exit; > + } > + } > + > + ret = copy_to_user((void __user *)arg, &unmap, minsz) ? > -EFAULT : 0; > +unmap_exit: > + kfree(bitmap); > + return ret; > } else if (cmd == VFIO_IOMMU_DIRTY_PAGES) { > struct vfio_iommu_type1_dirty_bitmap range; > uint32_t mask = VFIO_IOMMU_DIRTY_PAGES_FLAG_START | > diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h > index 8268634e7e08..e8e044c4974d 100644 > --- a/include/uapi/linux/vfio.h > +++ b/include/uapi/linux/vfio.h > @@ -964,12 +964,24 @@ struct vfio_iommu_type1_dma_map { > * field. No guarantee is made to the user that arbitrary unmaps of iova > * or size different from those used in the original mapping call will > * succeed. > + * VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP should be set to get dirty bitmap > + * before unmapping IO virtual addresses. When this flag is set, user should > + * allocate memory to get bitmap, clear the bitmap memory by setting zero and > + * should set size of allocated memory in bitmap_size field. One bit in bitmap > + * represents per page , page of user provided page size in 'bitmap_pgsize', > + * consecutively starting from iova offset. Bit set indicates page at that > + * offset from iova is dirty. Bitmap of pages in the range of unmapped size is > + * returned in bitmap. > */ > struct vfio_iommu_type1_dma_unmap { > __u32 argsz; > __u32 flags; > +#define VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP (1 << 0) > __u64 iova; /* IO virtual address */ > __u64 size; /* Size of mapping (bytes) */ > + __u64 bitmap_pgsize; /* page size for bitmap */ > + __u64 bitmap_size; /* in bytes */ > + void __user *bitmap; /* one bit per page */ > }; > > #define VFIO_IOMMU_UNMAP_DMA _IO(VFIO_TYPE, VFIO_BASE + 14)
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 215aecb25453..101c2b1e72b4 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -974,7 +974,8 @@ static long verify_bitmap_size(unsigned long npages, unsigned long bitmap_size) } static int vfio_dma_do_unmap(struct vfio_iommu *iommu, - struct vfio_iommu_type1_dma_unmap *unmap) + struct vfio_iommu_type1_dma_unmap *unmap, + unsigned long *bitmap) { uint64_t mask; struct vfio_dma *dma, *dma_last = NULL; @@ -1049,6 +1050,15 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu, if (dma->task->mm != current->mm) break; + if ((unmap->flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) && + (dma_last != dma)) + vfio_iova_dirty_bitmap(iommu, dma->iova, dma->size, + unmap->bitmap_pgsize, unmap->iova, + bitmap); + else + vfio_remove_unpinned_from_pfn_list(dma, true); + + if (!RB_EMPTY_ROOT(&dma->pfn_list)) { struct vfio_iommu_type1_dma_unmap nb_unmap; @@ -1074,6 +1084,7 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu, &nb_unmap); goto again; } + unmapped += dma->size; vfio_remove_dma(iommu, dma); } @@ -2404,22 +2415,60 @@ static long vfio_iommu_type1_ioctl(void *iommu_data, } else if (cmd == VFIO_IOMMU_UNMAP_DMA) { struct vfio_iommu_type1_dma_unmap unmap; - long ret; + unsigned long *bitmap = NULL; + long ret, bsize; minsz = offsetofend(struct vfio_iommu_type1_dma_unmap, size); - if (copy_from_user(&unmap, (void __user *)arg, minsz)) + if (copy_from_user(&unmap, (void __user *)arg, sizeof(unmap))) return -EFAULT; - if (unmap.argsz < minsz || unmap.flags) + if (unmap.argsz < minsz || + unmap.flags & ~VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) return -EINVAL; - ret = vfio_dma_do_unmap(iommu, &unmap); + if (unmap.flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) { + unsigned long pgshift = __ffs(unmap.bitmap_pgsize); + uint64_t iommu_pgmask = + ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu))) - 1; + + if (((unmap.bitmap_pgsize - 1) & iommu_pgmask) != + (unmap.bitmap_pgsize - 1)) + return -EINVAL; + + bsize = verify_bitmap_size(unmap.size >> pgshift, + unmap.bitmap_size); + if (bsize < 0) + return bsize; + + bitmap = kmalloc(bsize, GFP_KERNEL); + if (!bitmap) + return -ENOMEM; + + if (copy_from_user(bitmap, (void __user *)unmap.bitmap, + bsize)) { + ret = -EFAULT; + goto unmap_exit; + } + } + + ret = vfio_dma_do_unmap(iommu, &unmap, bitmap); if (ret) - return ret; + goto unmap_exit; - return copy_to_user((void __user *)arg, &unmap, minsz) ? + if (unmap.flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) { + if (copy_to_user((void __user *)unmap.bitmap, bitmap, + bsize)) { + ret = -EFAULT; + goto unmap_exit; + } + } + + ret = copy_to_user((void __user *)arg, &unmap, minsz) ? -EFAULT : 0; +unmap_exit: + kfree(bitmap); + return ret; } else if (cmd == VFIO_IOMMU_DIRTY_PAGES) { struct vfio_iommu_type1_dirty_bitmap range; uint32_t mask = VFIO_IOMMU_DIRTY_PAGES_FLAG_START | diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index 8268634e7e08..e8e044c4974d 100644 --- a/include/uapi/linux/vfio.h +++ b/include/uapi/linux/vfio.h @@ -964,12 +964,24 @@ struct vfio_iommu_type1_dma_map { * field. No guarantee is made to the user that arbitrary unmaps of iova * or size different from those used in the original mapping call will * succeed. + * VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP should be set to get dirty bitmap + * before unmapping IO virtual addresses. When this flag is set, user should + * allocate memory to get bitmap, clear the bitmap memory by setting zero and + * should set size of allocated memory in bitmap_size field. One bit in bitmap + * represents per page , page of user provided page size in 'bitmap_pgsize', + * consecutively starting from iova offset. Bit set indicates page at that + * offset from iova is dirty. Bitmap of pages in the range of unmapped size is + * returned in bitmap. */ struct vfio_iommu_type1_dma_unmap { __u32 argsz; __u32 flags; +#define VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP (1 << 0) __u64 iova; /* IO virtual address */ __u64 size; /* Size of mapping (bytes) */ + __u64 bitmap_pgsize; /* page size for bitmap */ + __u64 bitmap_size; /* in bytes */ + void __user *bitmap; /* one bit per page */ }; #define VFIO_IOMMU_UNMAP_DMA _IO(VFIO_TYPE, VFIO_BASE + 14)