Define interfaces that allow the underlying memory object of an iova
range to be mapped to a new host virtual address in the host process:
- VFIO_DMA_UNMAP_FLAG_VADDR for VFIO_IOMMU_UNMAP_DMA
- VFIO_DMA_MAP_FLAG_VADDR flag for VFIO_IOMMU_MAP_DMA
- VFIO_UPDATE_VADDR extension for VFIO_CHECK_EXTENSION
Unmap vaddr invalidates the host virtual address in an iova range, and
blocks vfio translation of host virtual addresses. DMA to already-mapped
pages continues. Map vaddr updates the base VA and resumes translation.
See comments in uapi/linux/vfio.h for more details.
Signed-off-by: Steve Sistare <steven.sistare@xxxxxxxxxx>
---
include/uapi/linux/vfio.h | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 55578b6..85bb89a 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -49,6 +49,9 @@
/* Supports VFIO_DMA_UNMAP_FLAG_ALL */
#define VFIO_UNMAP_ALL 9
+/* Supports the vaddr flag for DMA map and unmap */
+#define VFIO_UPDATE_VADDR 10
+
/*
* The IOCTL interface is designed for extensibility by embedding the
* structure length (argsz) and flags into structures passed between
@@ -1049,12 +1052,22 @@ struct vfio_iommu_type1_info_cap_migration {
*
* Map process virtual addresses to IO virtual addresses using the
* provided struct vfio_dma_map. Caller sets argsz. READ &/ WRITE required.
+ *
+ * If flags & VFIO_DMA_MAP_FLAG_VADDR, update the base vaddr for iova, and
+ * unblock translation of host virtual addresses in the iova range. The vaddr
+ * must have previously been invalidated with VFIO_DMA_UNMAP_FLAG_VADDR. To
+ * maintain memory consistency within the user application, the updated vaddr
+ * must address the same memory object as originally mapped. Failure to do so
+ * will result in user memory corruption and/or device misbehavior. iova and
+ * size must match those in the original MAP_DMA call. Protection is not
+ * changed, and the READ & WRITE flags must be 0.
*/
struct vfio_iommu_type1_dma_map {
__u32 argsz;
__u32 flags;
#define VFIO_DMA_MAP_FLAG_READ (1 << 0) /* readable from device */
#define VFIO_DMA_MAP_FLAG_WRITE (1 << 1) /* writable from device */
+#define VFIO_DMA_MAP_FLAG_VADDR (1 << 2)
__u64 vaddr; /* Process virtual address */
__u64 iova; /* IO virtual address */
__u64 size; /* Size of mapping (bytes) */
@@ -1090,12 +1103,18 @@ struct vfio_bitmap {
*
* If flags & VFIO_DMA_UNMAP_FLAG_ALL, unmap all addresses. iova and size
* must be 0. This may not be combined with the get-dirty-bitmap flag.
+ *
+ * If flags & VFIO_DMA_UNMAP_FLAG_VADDR, do not unmap, but invalidate host
+ * virtual addresses in the iova range. Tasks that attempt to translate an
+ * iova's vaddr will block. DMA to already-mapped pages continues. This may
+ * not be combined with the get-dirty-bitmap flag.
*/
struct vfio_iommu_type1_dma_unmap {
__u32 argsz;
__u32 flags;
#define VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP (1 << 0)
#define VFIO_DMA_UNMAP_FLAG_ALL (1 << 1)
+#define VFIO_DMA_UNMAP_FLAG_VADDR (1 << 2)
__u64 iova; /* IO virtual address */
__u64 size; /* Size of mapping (bytes) */
__u8 data[];
--
1.8.3.1
