1 files changed, 308 insertions, 6 deletions

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 664ff166b4c0..be6fc0d88633 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -72,6 +72,7 @@ struct vfio_iommu {
 	uint64_t		pgsize_bitmap;
 	bool			v2;
 	bool			nesting;
+	bool			dirty_page_tracking;
 };
 
 struct vfio_domain {
@@ -92,6 +93,7 @@ struct vfio_dma {
 	bool			lock_cap;	/* capable(CAP_IPC_LOCK) */
 	struct task_struct	*task;
 	struct rb_root		pfn_list;	/* Ex-user pinned pfn list */
+	unsigned long		*bitmap;
 };
 
 struct vfio_group {
@@ -126,6 +128,19 @@ struct vfio_regions {
 #define IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu)	\
 					(!list_empty(&iommu->domain_list))
 
+#define DIRTY_BITMAP_BYTES(n)	(ALIGN(n, BITS_PER_TYPE(u64)) / BITS_PER_BYTE)
+
+/*
+ * Input argument of number of bits to bitmap_set() is unsigned integer, which
+ * further casts to signed integer for unaligned multi-bit operation,
+ * __bitmap_set().
+ * Then maximum bitmap size supported is 2^31 bits divided by 2^3 bits/byte,
+ * that is 2^28 (256 MB) which maps to 2^31 * 2^12 = 2^43 (8TB) on 4K page
+ * system.
+ */
+#define DIRTY_BITMAP_PAGES_MAX	 ((u64)INT_MAX)
+#define DIRTY_BITMAP_SIZE_MAX	 DIRTY_BITMAP_BYTES(DIRTY_BITMAP_PAGES_MAX)
+
 static int put_pfn(unsigned long pfn, int prot);
 
 /*
@@ -176,6 +191,80 @@ static void vfio_unlink_dma(struct vfio_iommu *iommu, struct vfio_dma *old)
 	rb_erase(&old->node, &iommu->dma_list);
 }
 
+
+static int vfio_dma_bitmap_alloc(struct vfio_dma *dma, size_t pgsize)
+{
+	uint64_t npages = dma->size / pgsize;
+
+	if (npages > DIRTY_BITMAP_PAGES_MAX)
+		return -EINVAL;
+
+	/*
+	 * Allocate extra 64 bits that are used to calculate shift required for
+	 * bitmap_shift_left() to manipulate and club unaligned number of pages
+	 * in adjacent vfio_dma ranges.
+	 */
+	dma->bitmap = kvzalloc(DIRTY_BITMAP_BYTES(npages) + sizeof(u64),
+			       GFP_KERNEL);
+	if (!dma->bitmap)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static void vfio_dma_bitmap_free(struct vfio_dma *dma)
+{
+	kfree(dma->bitmap);
+	dma->bitmap = NULL;
+}
+
+static void vfio_dma_populate_bitmap(struct vfio_dma *dma, size_t pgsize)
+{
+	struct rb_node *p;
+
+	for (p = rb_first(&dma->pfn_list); p; p = rb_next(p)) {
+		struct vfio_pfn *vpfn = rb_entry(p, struct vfio_pfn, node);
+
+		bitmap_set(dma->bitmap, (vpfn->iova - dma->iova) / pgsize, 1);
+	}
+}
+
+static int vfio_dma_bitmap_alloc_all(struct vfio_iommu *iommu, size_t pgsize)
+{
+	struct rb_node *n;
+
+	for (n = rb_first(&iommu->dma_list); n; n = rb_next(n)) {
+		struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node);
+		int ret;
+
+		ret = vfio_dma_bitmap_alloc(dma, pgsize);
+		if (ret) {
+			struct rb_node *p;
+
+			for (p = rb_prev(n); p; p = rb_prev(p)) {
+				struct vfio_dma *dma = rb_entry(n,
+							struct vfio_dma, node);
+
+				vfio_dma_bitmap_free(dma);
+			}
+			return ret;
+		}
+		vfio_dma_populate_bitmap(dma, pgsize);
+	}
+	return 0;
+}
+
+static void vfio_dma_bitmap_free_all(struct vfio_iommu *iommu)
+{
+	struct rb_node *n;
+
+	for (n = rb_first(&iommu->dma_list); n; n = rb_next(n)) {
+		struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node);
+
+		vfio_dma_bitmap_free(dma);
+	}
+}
+
 /*
  * Helper Functions for host iova-pfn list
  */
@@ -598,6 +687,17 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data,
 			vfio_unpin_page_external(dma, iova, do_accounting);
 			goto pin_unwind;
 		}
+
+		if (iommu->dirty_page_tracking) {
+			unsigned long pgshift = __ffs(iommu->pgsize_bitmap);
+
+			/*
+			 * Bitmap populated with the smallest supported page
+			 * size
+			 */
+			bitmap_set(dma->bitmap,
+				   (iova - dma->iova) >> pgshift, 1);
+		}
 	}
 
 	ret = i;
@@ -832,6 +932,7 @@ static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma)
 	vfio_unmap_unpin(iommu, dma, true);
 	vfio_unlink_dma(iommu, dma);
 	put_task_struct(dma->task);
+	vfio_dma_bitmap_free(dma);
 	kfree(dma);
 	iommu->dma_avail++;
 }
@@ -859,6 +960,94 @@ static void vfio_update_pgsize_bitmap(struct vfio_iommu *iommu)
 	}
 }
 
+static int update_user_bitmap(u64 __user *bitmap, struct vfio_dma *dma,
+			      dma_addr_t base_iova, size_t pgsize)
+{
+	unsigned long pgshift = __ffs(pgsize);
+	unsigned long nbits = dma->size >> pgshift;
+	unsigned long bit_offset = (dma->iova - base_iova) >> pgshift;
+	unsigned long copy_offset = bit_offset / BITS_PER_LONG;
+	unsigned long shift = bit_offset % BITS_PER_LONG;
+	unsigned long leftover;
+
+	/* mark all pages dirty if all pages are pinned and mapped. */
+	if (dma->iommu_mapped)
+		bitmap_set(dma->bitmap, 0, nbits);
+
+	if (shift) {
+		bitmap_shift_left(dma->bitmap, dma->bitmap, shift,
+				  nbits + shift);
+
+		if (copy_from_user(&leftover,
+				   (const void *)(bitmap + copy_offset),
+				   sizeof(leftover)))
+			return -EFAULT;
+
+		bitmap_or(dma->bitmap, dma->bitmap, &leftover, shift);
+	}
+
+	if (copy_to_user((void *)(bitmap + copy_offset), dma->bitmap,
+			 DIRTY_BITMAP_BYTES(nbits + shift)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int vfio_iova_dirty_bitmap(u64 __user *bitmap, struct vfio_iommu *iommu,
+				  dma_addr_t iova, size_t size, size_t pgsize)
+{
+	struct vfio_dma *dma;
+	struct rb_node *n;
+	unsigned long pgshift = __ffs(pgsize);
+	int ret;
+
+	/*
+	 * GET_BITMAP request must fully cover vfio_dma mappings.  Multiple
+	 * vfio_dma mappings may be clubbed by specifying large ranges, but
+	 * there must not be any previous mappings bisected by the range.
+	 * An error will be returned if these conditions are not met.
+	 */
+	dma = vfio_find_dma(iommu, iova, 1);
+	if (dma && dma->iova != iova)
+		return -EINVAL;
+
+	dma = vfio_find_dma(iommu, iova + size - 1, 0);
+	if (dma && dma->iova + dma->size != iova + size)
+		return -EINVAL;
+
+	for (n = rb_first(&iommu->dma_list); n; n = rb_next(n)) {
+		struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node);
+
+		if (dma->iova < iova)
+			continue;
+
+		if (dma->iova > iova + size - 1)
+			break;
+
+		ret = update_user_bitmap(bitmap, dma, iova, pgsize);
+		if (ret)
+			return ret;
+
+		/*
+		 * Re-populate bitmap to include all pinned pages which are
+		 * considered as dirty but exclude pages which are unpinned and
+		 * pages which are marked dirty by vfio_dma_rw()
+		 */
+		bitmap_clear(dma->bitmap, 0, dma->size >> pgshift);
+		vfio_dma_populate_bitmap(dma, pgsize);
+	}
+	return 0;
+}
+
+static int verify_bitmap_size(uint64_t npages, uint64_t bitmap_size)
+{
+	if (!npages || !bitmap_size || (bitmap_size > DIRTY_BITMAP_SIZE_MAX) ||
+	    (bitmap_size < DIRTY_BITMAP_BYTES(npages)))
+		return -EINVAL;
+
+	return 0;
+}
+
 static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
 			     struct vfio_iommu_type1_dma_unmap *unmap)
 {
@@ -1076,7 +1265,7 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
 	unsigned long vaddr = map->vaddr;
 	size_t size = map->size;
 	int ret = 0, prot = 0;
-	uint64_t mask;
+	size_t pgsize;
 	struct vfio_dma *dma;
 
 	/* Verify that none of our __u64 fields overflow */
@@ -1091,11 +1280,11 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
 
 	mutex_lock(&iommu->lock);
 
-	mask = ((uint64_t)1 << __ffs(iommu->pgsize_bitmap)) - 1;
+	pgsize = (size_t)1 << __ffs(iommu->pgsize_bitmap);
 
-	WARN_ON(mask & PAGE_MASK);
+	WARN_ON((pgsize - 1) & PAGE_MASK);
 
-	if (!prot || !size || (size | iova | vaddr) & mask) {
+	if (!prot || !size || (size | iova | vaddr) & (pgsize - 1)) {
 		ret = -EINVAL;
 		goto out_unlock;
 	}
@@ -1172,6 +1361,12 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
 	else
 		ret = vfio_pin_map_dma(iommu, dma, size);
 
+	if (!ret && iommu->dirty_page_tracking) {
+		ret = vfio_dma_bitmap_alloc(dma, pgsize);
+		if (ret)
+			vfio_remove_dma(iommu, dma);
+	}
+
 out_unlock:
 	mutex_unlock(&iommu->lock);
 	return ret;
@@ -2318,6 +2513,104 @@ 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_DIRTY_PAGES) {
+		struct vfio_iommu_type1_dirty_bitmap dirty;
+		uint32_t mask = VFIO_IOMMU_DIRTY_PAGES_FLAG_START |
+				VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP |
+				VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP;
+		int ret = 0;
+
+		if (!iommu->v2)
+			return -EACCES;
+
+		minsz = offsetofend(struct vfio_iommu_type1_dirty_bitmap,
+				    flags);
+
+		if (copy_from_user(&dirty, (void __user *)arg, minsz))
+			return -EFAULT;
+
+		if (dirty.argsz < minsz || dirty.flags & ~mask)
+			return -EINVAL;
+
+		/* only one flag should be set at a time */
+		if (__ffs(dirty.flags) != __fls(dirty.flags))
+			return -EINVAL;
+
+		if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_START) {
+			size_t pgsize;
+
+			mutex_lock(&iommu->lock);
+			pgsize = 1 << __ffs(iommu->pgsize_bitmap);
+			if (!iommu->dirty_page_tracking) {
+				ret = vfio_dma_bitmap_alloc_all(iommu, pgsize);
+				if (!ret)
+					iommu->dirty_page_tracking = true;
+			}
+			mutex_unlock(&iommu->lock);
+			return ret;
+		} else if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP) {
+			mutex_lock(&iommu->lock);
+			if (iommu->dirty_page_tracking) {
+				iommu->dirty_page_tracking = false;
+				vfio_dma_bitmap_free_all(iommu);
+			}
+			mutex_unlock(&iommu->lock);
+			return 0;
+		} else if (dirty.flags &
+				 VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP) {
+			struct vfio_iommu_type1_dirty_bitmap_get range;
+			unsigned long pgshift;
+			size_t data_size = dirty.argsz - minsz;
+			size_t iommu_pgsize;
+
+			if (!data_size || data_size < sizeof(range))
+				return -EINVAL;
+
+			if (copy_from_user(&range, (void __user *)(arg + minsz),
+					   sizeof(range)))
+				return -EFAULT;
+
+			if (range.iova + range.size < range.iova)
+				return -EINVAL;
+			if (!access_ok((void __user *)range.bitmap.data,
+				       range.bitmap.size))
+				return -EINVAL;
+
+			pgshift = __ffs(range.bitmap.pgsize);
+			ret = verify_bitmap_size(range.size >> pgshift,
+						 range.bitmap.size);
+			if (ret)
+				return ret;
+
+			mutex_lock(&iommu->lock);
+
+			iommu_pgsize = (size_t)1 << __ffs(iommu->pgsize_bitmap);
+
+			/* allow only smallest supported pgsize */
+			if (range.bitmap.pgsize != iommu_pgsize) {
+				ret = -EINVAL;
+				goto out_unlock;
+			}
+			if (range.iova & (iommu_pgsize - 1)) {
+				ret = -EINVAL;
+				goto out_unlock;
+			}
+			if (!range.size || range.size & (iommu_pgsize - 1)) {
+				ret = -EINVAL;
+				goto out_unlock;
+			}
+
+			if (iommu->dirty_page_tracking)
+				ret = vfio_iova_dirty_bitmap(range.bitmap.data,
+						iommu, range.iova, range.size,
+						range.bitmap.pgsize);
+			else
+				ret = -EINVAL;
+out_unlock:
+			mutex_unlock(&iommu->lock);
+
+			return ret;
+		}
 	}
 
 	return -ENOTTY;
@@ -2385,10 +2678,19 @@ static int vfio_iommu_type1_dma_rw_chunk(struct vfio_iommu *iommu,
 
 	vaddr = dma->vaddr + offset;
 
-	if (write)
+	if (write) {
 		*copied = copy_to_user((void __user *)vaddr, data,
 					 count) ? 0 : count;
-	else
+		if (*copied && iommu->dirty_page_tracking) {
+			unsigned long pgshift = __ffs(iommu->pgsize_bitmap);
+			/*
+			 * Bitmap populated with the smallest supported page
+			 * size
+			 */
+			bitmap_set(dma->bitmap, offset >> pgshift,
+				   *copied >> pgshift);
+		}
+	} else
 		*copied = copy_from_user(data, (void __user *)vaddr,
 					   count) ? 0 : count;
 	if (kthread)