[PATCH V2 6/9] vfio/type1: implement interfaces to update vaddr

[Steve Sistare <steven.sistare@xxxxxxxxxx>]

Implement VFIO_DMA_UNMAP_FLAG_VADDR, VFIO_DMA_MAP_FLAG_VADDR, and
VFIO_UPDATE_VADDR.  This is a partial implementation.  Blocking is
added in the next patch.

Signed-off-by: Steve Sistare <steven.sistare@xxxxxxxxxx>
---
 drivers/vfio/vfio_iommu_type1.c | 54 ++++++++++++++++++++++++++++++++++++++---
 1 file changed, 51 insertions(+), 3 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index ef83018..c307f62 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -92,6 +92,7 @@ struct vfio_dma {
 	int			prot;		/* IOMMU_READ/WRITE */
 	bool			iommu_mapped;
 	bool			lock_cap;	/* capable(CAP_IPC_LOCK) */
+	bool			vaddr_valid;
 	struct task_struct	*task;
 	struct rb_root		pfn_list;	/* Ex-user pinned pfn list */
 	unsigned long		*bitmap;
@@ -1101,6 +1102,7 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
 	dma_addr_t iova = unmap->iova;
 	unsigned long size = unmap->size;
 	bool unmap_all = !!(unmap->flags & VFIO_DMA_UNMAP_FLAG_ALL);
+	bool invalidate = !!(unmap->flags & VFIO_DMA_UNMAP_FLAG_VADDR);
 
 	mutex_lock(&iommu->lock);
 
@@ -1181,6 +1183,18 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
 		if (dma->task->mm != current->mm)
 			break;
 
+		if (invalidate) {
+			if (!dma->vaddr_valid)
+				goto unwind;
+			dma->vaddr_valid = false;
+			unmapped += dma->size;
+			size -= dma->iova + dma->size - iova;
+			iova = dma->iova + dma->size;
+			if (iova == 0)
+				break;
+			continue;
+		}
+
 		if (!RB_EMPTY_ROOT(&dma->pfn_list)) {
 			struct vfio_iommu_type1_dma_unmap nb_unmap;
 
@@ -1218,6 +1232,20 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
 		unmapped += dma->size;
 		vfio_remove_dma(iommu, dma);
 	}
+	goto unlock;
+
+unwind:
+	iova = unmap->iova;
+	size = unmap_all ? SIZE_MAX : unmap->size;
+	dma_last = dma;
+	while ((dma = vfio_find_dma_first(iommu, iova, size)) &&
+	       dma != dma_last) {
+		dma->vaddr_valid = true;
+		size -= dma->iova + dma->size - iova;
+		iova = dma->iova + dma->size;
+	}
+	ret = -EINVAL;
+	unmapped = 0;
 
 unlock:
 	mutex_unlock(&iommu->lock);
@@ -1319,6 +1347,7 @@ static bool vfio_iommu_iova_dma_valid(struct vfio_iommu *iommu,
 static int vfio_dma_do_map(struct vfio_iommu *iommu,
 			   struct vfio_iommu_type1_dma_map *map)
 {
+	bool update = map->flags & VFIO_DMA_MAP_FLAG_VADDR;
 	dma_addr_t iova = map->iova;
 	unsigned long vaddr = map->vaddr;
 	size_t size = map->size;
@@ -1336,13 +1365,16 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
 	if (map->flags & VFIO_DMA_MAP_FLAG_READ)
 		prot |= IOMMU_READ;
 
+	if ((prot && update) || (!prot && !update))
+		return -EINVAL;
+
 	mutex_lock(&iommu->lock);
 
 	pgsize = (size_t)1 << __ffs(iommu->pgsize_bitmap);
 
 	WARN_ON((pgsize - 1) & PAGE_MASK);
 
-	if (!prot || !size || (size | iova | vaddr) & (pgsize - 1)) {
+	if (!size || (size | iova | vaddr) & (pgsize - 1)) {
 		ret = -EINVAL;
 		goto out_unlock;
 	}
@@ -1353,7 +1385,19 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
 		goto out_unlock;
 	}
 
-	if (vfio_find_dma(iommu, iova, size)) {
+	dma = vfio_find_dma(iommu, iova, size);
+	if (update) {
+		if (!dma) {
+			ret = -ENOENT;
+		} else if (dma->vaddr_valid || dma->iova != iova ||
+			   dma->size != size) {
+			ret = -EINVAL;
+		} else {
+			dma->vaddr = vaddr;
+			dma->vaddr_valid = true;
+		}
+		goto out_unlock;
+	} else if (dma) {
 		ret = -EEXIST;
 		goto out_unlock;
 	}
@@ -1377,6 +1421,7 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
 	iommu->dma_avail--;
 	dma->iova = iova;
 	dma->vaddr = vaddr;
+	dma->vaddr_valid = true;
 	dma->prot = prot;
 
 	/*
@@ -2545,6 +2590,7 @@ static int vfio_iommu_type1_check_extension(struct vfio_iommu *iommu,
 	case VFIO_TYPE1v2_IOMMU:
 	case VFIO_TYPE1_NESTING_IOMMU:
 	case VFIO_UNMAP_ALL:
+	case VFIO_UPDATE_VADDR:
 		return 1;
 	case VFIO_DMA_CC_IOMMU:
 		if (!iommu)
@@ -2699,7 +2745,8 @@ static int vfio_iommu_type1_map_dma(struct vfio_iommu *iommu,
 {
 	struct vfio_iommu_type1_dma_map map;
 	unsigned long minsz;
-	uint32_t mask = VFIO_DMA_MAP_FLAG_READ | VFIO_DMA_MAP_FLAG_WRITE;
+	uint32_t mask = VFIO_DMA_MAP_FLAG_READ | VFIO_DMA_MAP_FLAG_WRITE |
+			VFIO_DMA_MAP_FLAG_VADDR;
 
 	minsz = offsetofend(struct vfio_iommu_type1_dma_map, size);
 
@@ -2718,6 +2765,7 @@ static int vfio_iommu_type1_unmap_dma(struct vfio_iommu *iommu,
 	struct vfio_iommu_type1_dma_unmap unmap;
 	struct vfio_bitmap bitmap = { 0 };
 	uint32_t mask = VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP |
+			VFIO_DMA_UNMAP_FLAG_VADDR |
 			VFIO_DMA_UNMAP_FLAG_ALL;
 	unsigned long minsz;
 	int ret;
-- 
1.8.3.1