Commit 441e8106 authored by Steve Sistare's avatar Steve Sistare Committed by Alex Williamson
Browse files

vfio: interfaces to update vaddr 



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: default avatarSteve Sistare <steven.sistare@oracle.com>
Reviewed-by: default avatarCornelia Huck <cohuck@redhat.com>
Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent c1965099

include/uapi/linux/vfio.h

+19 −0
Original line number Diff line number Diff line
@@ -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
@@ -1077,12 +1080,22 @@ struct vfio_iommu_type1_info_dma_avail { 
 *

 * 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) */
@@ -1118,12 +1131,18 @@ struct vfio_bitmap { 
 *

 * If flags & VFIO_DMA_UNMAP_FLAG_ALL, unmap all addresses.  iova and size

 * must be 0.  This cannot 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

 * cannot 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[];