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>