[v2,0/2] use vfio_dma_rw to read/write IOVAs from CPU side

Message

Yan Zhao Jan. 15, 2020, 3:41 a.m. UTC

It is better for a device model to use IOVAs to read/write memory.
And because the rw operations come from CPUs, it is not necessary to call
vfio_pin_pages() to pin those pages.

patch 1 introduces interface vfio_dma_rw in vfio to read/write IOVAs
without pinning user space pages.

patch 2 let gvt switch from kvm side rw interface to vfio_dma_rw.

v2 changelog:
- rename vfio_iova_rw to vfio_dma_rw, vfio iommu driver ops .iova_rw
to .dma_rw. (Alex).
- change iova and len from unsigned long to dma_addr_t and size_t,
respectively. (Alex)
- fix possible overflow in dma->vaddr + iova - dma->iova + offset (Alex)
- split DMAs from on page boundary to on max available size to eliminate
  redundant searching of vfio_dma and switching mm. (Alex)
- add a check for IOMMU_WRITE permission.

Yan Zhao (2):
  vfio: introduce vfio_dma_rw to read/write a range of IOVAs
  drm/i915/gvt: subsitute kvm_read/write_guest with vfio_dma_rw

 drivers/gpu/drm/i915/gvt/kvmgt.c | 26 +++--------
 drivers/vfio/vfio.c              | 45 +++++++++++++++++++
 drivers/vfio/vfio_iommu_type1.c  | 76 ++++++++++++++++++++++++++++++++
 include/linux/vfio.h             |  5 +++
 4 files changed, 133 insertions(+), 19 deletions(-)