OvmfPkg/VirtioScsiDxe: map virtio-scsi request and response buffers

When device is behind the IOMMU, driver is require to pass the device
address of virtio request, response and any memory referenced by those
request/response to the bus master.

The patch uses IOMMU-like member functions from VIRTIO_DEVICE_PROTOCOL to
map request and response buffers system physical address to the device
address.

- If the buffer need to be accessed by both the processor and a bus
  master then map with BusMasterCommonBuffer.

- If the buffer need to be accessed for a write operation by a bus master
  then map with BusMasterWrite.

  However, after a BusMasterWrite Unmap() failure, error reporting via
  EFI_EXT_SCSI_PASS_THRU_SCSI_REQUEST_PACKET would be very complex,
  therefore we map such buffers too with BusMasterCommonBuffer.

- If the buffer need to be accessed for a read  operation by a bus master
  then map with BusMasterRead.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
[lersek@redhat.com: restore lost sentence/paragraph in commit message]
[lersek@redhat.com: reindent/reflow "InDataBuffer" comment block]
[lersek@redhat.com: cast arg, not result, of EFI_SIZE_TO_PAGES() to UINTN]
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>

0 files changed, 0 insertions, 0 deletions