OvmfPkg/Virtio: take RingBaseShift in SetQueueAddress()

For the case when an IOMMU is used for translating system physical
addresses to DMA bus master addresses, the transport-independent
virtio device drivers will be required to map their VRING areas to
bus addresses with VIRTIO_DEVICE_PROTOCOL.MapSharedBuffer() calls.

- MMIO and legacy virtio transport do not support IOMMU to translate the
  addresses hence RingBaseShift will always be set to zero.

- modern virtio transport supports IOMMU to translate the address, in
  next patch we will update the Virtio10Dxe to use RingBaseShift offset.

Suggested-by: Laszlo Ersek <lersek@redhat.com>
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: remove commit msg paragraph with VirtioLib reference]
[lersek@redhat.com: fix typo in VIRTIO_SET_QUEUE_ADDRESS comment block]
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>

1 files changed, 17 insertions, 2 deletions

diff --git a/OvmfPkg/Include/Protocol/VirtioDevice.h b/OvmfPkg/Include/Protocol/VirtioDevice.h
index 9a01932..afc27e5 100644
--- a/OvmfPkg/Include/Protocol/VirtioDevice.h
+++ b/OvmfPkg/Include/Protocol/VirtioDevice.h
@@ -156,7 +156,21 @@ EFI_STATUS
   @param[in] This             This instance of VIRTIO_DEVICE_PROTOCOL

 

   @param[in] Ring             The initialized VRING object to take the

-                              addresses from.

+                              addresses from. The caller is responsible for

+                              ensuring that on input, all Ring->NumPages pages,

+                              starting at Ring->Base, have been successfully

+                              mapped with a single call to

+                              This->MapSharedBuffer() for CommonBuffer bus

+                              master operation.

+

+  @param[in] RingBaseShift    Adding this value using UINT64 arithmetic to the

+                              addresses found in Ring translates them from

+                              system memory to bus addresses. The caller shall

+                              calculate RingBaseShift as

+                              (DeviceAddress - (UINT64)(UINTN)HostAddress),

+                              where DeviceAddress and HostAddress (i.e.,

+                              Ring->Base) were output and input parameters of

+                              This->MapSharedBuffer(), respectively.

 

   @retval EFI_SUCCESS         The data was written successfully.

   @retval EFI_UNSUPPORTED     The underlying IO device doesn't support the

@@ -166,7 +180,8 @@ typedef
 EFI_STATUS

 (EFIAPI *VIRTIO_SET_QUEUE_ADDRESS) (

   IN VIRTIO_DEVICE_PROTOCOL  *This,

-  IN VRING                   *Ring

+  IN VRING                   *Ring,

+  IN UINT64                  RingBaseShift

   );

 

 /**