[PATCH v1 06/14] OvmfPkg/VirtioLib: Add functions to map/unmap VRING

[Brijesh Singh <brijesh.singh@amd.com>]

Add functions to map and unmap the ring buffer with BusMasterCommonBuffer.

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>
---
 OvmfPkg/Include/Library/VirtioLib.h   | 41 +++++++++++++++
 OvmfPkg/Library/VirtioLib/VirtioLib.c | 52 ++++++++++++++++++++
 2 files changed, 93 insertions(+)

diff --git a/OvmfPkg/Include/Library/VirtioLib.h b/OvmfPkg/Include/Library/VirtioLib.h
index 610654225de7..877961af0514 100644
--- a/OvmfPkg/Include/Library/VirtioLib.h
+++ b/OvmfPkg/Include/Library/VirtioLib.h
@@ -62,6 +62,47 @@ VirtioRingInit (
 
 /**
 
+  Map the ring buffer so that it can be accessed equally by both guest
+  and hypervisor.
+
+  @param[in]      VirtIo    The virtio device instance.
+
+  @param[in]      Ring      The virtio ring to map.
+
+  @param[out]     Mapping   A resulting value to pass to Unmap().
+
+  @retval         Value returned from VirtIo->MapSharedBuffer()
+**/
+EFI_STATUS
+EFIAPI
+VirtioRingMap (
+  IN  VIRTIO_DEVICE_PROTOCOL *VirtIo,
+  IN  VRING                  *Ring,
+  OUT VOID                   **Mapping
+  );
+
+/**
+
+  Unmap the ring buffer mapped using VirtioRingMap()
+
+  @param[in]      VirtIo    The virtio device instance.
+
+  @param[in]      Ring      The virtio ring to unmap.
+
+  @param[in]      Mapping   A value obtained through Map().
+
+  @retval         Value returned from VirtIo->UnmapSharedBuffer()
+**/
+EFI_STATUS
+EFIAPI
+VirtioRingUnmap (
+  IN  VIRTIO_DEVICE_PROTOCOL *VirtIo,
+  IN  VRING                  *Ring,
+  IN  VOID                   *Mapping
+  );
+
+/**
+
   Tear down the internal resources of a configured virtio ring.
 
   The caller is responsible to stop the host from using this ring before
diff --git a/OvmfPkg/Library/VirtioLib/VirtioLib.c b/OvmfPkg/Library/VirtioLib/VirtioLib.c
index 50e5ec28ea1b..09a3f9b7f2e5 100644
--- a/OvmfPkg/Library/VirtioLib/VirtioLib.c
+++ b/OvmfPkg/Library/VirtioLib/VirtioLib.c
@@ -640,3 +640,55 @@ VirtioUnmapSharedBuffer (
 {
   return VirtIo->UnmapSharedBuffer (VirtIo, Mapping);
 }
+
+/**
+
+  Map the ring buffer so that it can be accessed equally by both guest
+  and hypervisor.
+
+  @param[in]      VirtIo    The virtio device instance.
+
+  @param[in]      Ring      The virtio ring to map.
+
+  @param[out]     Mapping   A resulting value to pass to Unmap().
+
+  @retval         Value returned from VirtIo->MapSharedBuffer()
+**/
+EFI_STATUS
+EFIAPI
+VirtioRingMap (
+  IN  VIRTIO_DEVICE_PROTOCOL *VirtIo,
+  IN  VRING                  *Ring,
+  OUT VOID                   **Mapping
+  )
+{
+  UINTN                 NumberOfBytes;
+
+  NumberOfBytes = Ring->NumPages * EFI_PAGE_SIZE;
+
+  return VirtioMapSharedBufferCommon (VirtIo, Ring->Base,
+           NumberOfBytes, Mapping);
+}
+
+/**
+
+  Unmap the ring buffer mapped using VirtioRingMap()
+
+  @param[in]      VirtIo    The virtio device instance.
+
+  @param[in]      Ring      The virtio ring to unmap.
+
+  @param[in]      Mapping   A value obtained through Map().
+
+  @retval         Value returned from VirtIo->UnmapSharedBuffer()
+**/
+EFI_STATUS
+EFIAPI
+VirtioRingUnmap (
+  IN  VIRTIO_DEVICE_PROTOCOL *VirtIo,
+  IN  VRING                  *Ring,
+  IN  VOID                   *Mapping
+  )
+{
+  return VirtioUnmapSharedBuffer (VirtIo, Mapping);
+}
-- 
2.7.4