On Fri, 29 Jan 2021 08:54:09 -0800
Steve Sistare <steven.sistare@xxxxxxxxxx> wrote:
> Implement VFIO_DMA_UNMAP_FLAG_VADDR, VFIO_DMA_MAP_FLAG_VADDR, and
> VFIO_UPDATE_VADDR. This is a partial implementation. Blocking is
> added in a subsequent patch.
>
> Signed-off-by: Steve Sistare <steven.sistare@xxxxxxxxxx>
> ---
> drivers/vfio/vfio_iommu_type1.c | 62 +++++++++++++++++++++++++++++++++++++----
> 1 file changed, 56 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 5823607..cbe3c65 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -74,6 +74,7 @@ struct vfio_iommu {
> bool nesting;
> bool dirty_page_tracking;
> bool pinned_page_dirty_scope;
> + int vaddr_invalid_count;
Nit, I'll move this up in the struct for alignment/hole purposes. Also
I think this should be an unsigned, we never use the negative value for
sanity checking and our number of vfio_dma entries is governed by an
unsigned int.
> };
>
> struct vfio_domain {
> @@ -92,6 +93,7 @@ struct vfio_dma {
> int prot; /* IOMMU_READ/WRITE */
> bool iommu_mapped;
> bool lock_cap; /* capable(CAP_IPC_LOCK) */
> + bool vaddr_invalid;
> struct task_struct *task;
> struct rb_root pfn_list; /* Ex-user pinned pfn list */
> unsigned long *bitmap;
> @@ -973,6 +975,8 @@ static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma)
> vfio_unlink_dma(iommu, dma);
> put_task_struct(dma->task);
> vfio_dma_bitmap_free(dma);
> + if (dma->vaddr_invalid)
> + --iommu->vaddr_invalid_count;
I'm not a fan of the -- on the left, nor the mixing with ++ on the
right. Can I move the -- to the right?
> kfree(dma);
> iommu->dma_avail++;
> }
> @@ -1103,7 +1107,8 @@ 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);
> - struct rb_node *n;
> + bool invalidate_vaddr = !!(unmap->flags & VFIO_DMA_UNMAP_FLAG_VADDR);
Nit, !! is not necessary and inconsistent with the MAP side below, will
remove here and for previous unmap_all use.
> + struct rb_node *n, *first_n, *last_n;
>
> mutex_lock(&iommu->lock);
>
> @@ -1174,7 +1179,7 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
> }
>
> ret = 0;
> - n = vfio_find_dma_first(iommu, iova, size);
> + n = first_n = vfio_find_dma_first(iommu, iova, size);
>
> while (n) {
> dma = rb_entry(n, struct vfio_dma, node);
> @@ -1190,6 +1195,16 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
> if (dma->task->mm != current->mm)
> break;
>
> + if (invalidate_vaddr) {
> + if (dma->vaddr_invalid)
> + goto unwind;
The unwind actually fits pretty well inline here and avoids the leap
frogging gotos below. last_n can also be scoped within the unwind more
easily here.
> + dma->vaddr_invalid = true;
> + iommu->vaddr_invalid_count++;
> + unmapped += dma->size;
> + n = rb_next(n);
> + continue;
> + }
> +
> if (!RB_EMPTY_ROOT(&dma->pfn_list)) {
> struct vfio_iommu_type1_dma_unmap nb_unmap;
>
> @@ -1228,6 +1243,18 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
> n = rb_next(n);
> vfio_remove_dma(iommu, dma);
> }
> + goto unlock;
> +
> +unwind:
> + last_n = n;
> +
> + for (n = first_n; n != last_n; n = rb_next(n)) {
> + dma = rb_entry(n, struct vfio_dma, node);
> + dma->vaddr_invalid = false;
> + --iommu->vaddr_invalid_count;
> + }
> + ret = -EINVAL;
> + unmapped = 0;
>
> unlock:
> mutex_unlock(&iommu->lock);
> @@ -1329,6 +1356,7 @@ 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 set_vaddr = map->flags & VFIO_DMA_MAP_FLAG_VADDR;
> dma_addr_t iova = map->iova;
> unsigned long vaddr = map->vaddr;
> size_t size = map->size;
> @@ -1346,13 +1374,16 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
> if (map->flags & VFIO_DMA_MAP_FLAG_READ)
> prot |= IOMMU_READ;
>
> + if ((prot && set_vaddr) || (!prot && !set_vaddr))
> + 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;
> }
> @@ -1363,7 +1394,20 @@ 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 (set_vaddr) {
> + if (!dma) {
> + ret = -ENOENT;
> + } else if (!dma->vaddr_invalid || dma->iova != iova ||
> + dma->size != size) {
> + ret = -EINVAL;
> + } else {
> + dma->vaddr = vaddr;
> + dma->vaddr_invalid = false;
> + --iommu->vaddr_invalid_count;
> + }
> + goto out_unlock;
> + } else if (dma) {
> ret = -EEXIST;
> goto out_unlock;
> }
> @@ -1387,6 +1431,7 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
> iommu->dma_avail--;
> dma->iova = iova;
> dma->vaddr = vaddr;
> + dma->vaddr_invalid = false;
> dma->prot = prot;
>
> /*
> @@ -2483,6 +2528,7 @@ static void *vfio_iommu_type1_open(unsigned long arg)
> INIT_LIST_HEAD(&iommu->iova_list);
> iommu->dma_list = RB_ROOT;
> iommu->dma_avail = dma_entry_limit;
> + iommu->vaddr_invalid_count = 0;
Nit, we can drop this.
> mutex_init(&iommu->lock);
> BLOCKING_INIT_NOTIFIER_HEAD(&iommu->notifier);
>
> @@ -2555,6 +2601,7 @@ 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)
> @@ -2709,7 +2756,8 @@ 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);
>
> @@ -2728,6 +2776,7 @@ 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;
> @@ -2741,7 +2790,8 @@ static int vfio_iommu_type1_unmap_dma(struct vfio_iommu *iommu,
> return -EINVAL;
>
> if ((unmap.flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) &&
> - (unmap.flags & VFIO_DMA_UNMAP_FLAG_ALL))
> + (unmap.flags & (VFIO_DMA_UNMAP_FLAG_ALL |
> + VFIO_DMA_UNMAP_FLAG_VADDR)))
> return -EINVAL;
>
> if (unmap.flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) {
