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: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Steve Sistare 2021-01-29 08:54:07 -08:00 committed by Alex Williamson
parent c196509953
commit 441e8106a2

View File

@ -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[];