OvmfPkg/VirtioBlkDxe: map VRING using VirtioRingMap()

When device is behind the IOMMU then driver need to pass the device
address when programing the bus master. The patch uses VirtioRingMap() to
map the VRING system physical address to device address.

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>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>

OvmfPkg/VirtioBlkDxe/VirtioBlk.c

@@ -580,7 +580,8 @@ VirtioBlkDriverBindingSupported (
                            virtio-blk attributes the host provides.
 
   @return                  Error codes from VirtioRingInit() or
-                           VIRTIO_CFG_READ() / VIRTIO_CFG_WRITE().
+                           VIRTIO_CFG_READ() / VIRTIO_CFG_WRITE or
+                           VirtioRingMap().
 
 **/
 
@@ -601,6 +602,7 @@ VirtioBlkInit (
   UINT8      AlignmentOffset;
   UINT32     OptIoSize;
   UINT16     QueueSize;
+  UINT64     RingBaseShift;
 
   PhysicalBlockExp = 0;
   AlignmentOffset = 0;
@@ -729,25 +731,42 @@ VirtioBlkInit (
   }
 
   //
-  // Additional steps for MMIO: align the queue appropriately, and set the
+  // If anything fails from here on, we must release the ring resources
-  // size. If anything fails from here on, we must release the ring resources.
   //
-  Status = Dev->VirtIo->SetQueueNum (Dev->VirtIo, QueueSize);
+  Status = VirtioRingMap (
+             Dev->VirtIo,
+             &Dev->Ring,
+             &RingBaseShift,
+             &Dev->RingMap
+             );
   if (EFI_ERROR (Status)) {
     goto ReleaseQueue;
   }
 
+  //
+  // Additional steps for MMIO: align the queue appropriately, and set the
+  // size. If anything fails from here on, we must unmap the ring resources.
+  //
+  Status = Dev->VirtIo->SetQueueNum (Dev->VirtIo, QueueSize);
+  if (EFI_ERROR (Status)) {
+    goto UnmapQueue;
+  }
+
   Status = Dev->VirtIo->SetQueueAlign (Dev->VirtIo, EFI_PAGE_SIZE);
   if (EFI_ERROR (Status)) {
-    goto ReleaseQueue;
+    goto UnmapQueue;
   }
 
   //
   // step 4c -- Report GPFN (guest-physical frame number) of queue.
   //
-  Status = Dev->VirtIo->SetQueueAddress (Dev->VirtIo, &Dev->Ring, 0);
+  Status = Dev->VirtIo->SetQueueAddress (
+                          Dev->VirtIo,
+                          &Dev->Ring,
+                          RingBaseShift
+                          );
   if (EFI_ERROR (Status)) {
-    goto ReleaseQueue;
+    goto UnmapQueue;
   }
 
 
@@ -758,7 +777,7 @@ VirtioBlkInit (
     Features &= ~(UINT64)VIRTIO_F_VERSION_1;
     Status = Dev->VirtIo->SetGuestFeatures (Dev->VirtIo, Features);
     if (EFI_ERROR (Status)) {
-      goto ReleaseQueue;
+      goto UnmapQueue;
     }
   }
 
@@ -768,7 +787,7 @@ VirtioBlkInit (
   NextDevStat |= VSTAT_DRIVER_OK;
   Status = Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, NextDevStat);
   if (EFI_ERROR (Status)) {
-    goto ReleaseQueue;
+    goto UnmapQueue;
   }
 
   //
@@ -811,6 +830,9 @@ VirtioBlkInit (
   }
   return EFI_SUCCESS;
 
+UnmapQueue:
+  Dev->VirtIo->UnmapSharedBuffer (Dev->VirtIo, Dev->RingMap);
+
 ReleaseQueue:
   VirtioRingUninit (Dev->VirtIo, &Dev->Ring);
 
@@ -849,6 +871,7 @@ VirtioBlkUninit (
   //
   Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, 0);
 
+  Dev->VirtIo->UnmapSharedBuffer (Dev->VirtIo, Dev->RingMap);
   VirtioRingUninit (Dev->VirtIo, &Dev->Ring);
 
   SetMem (&Dev->BlockIo,      sizeof Dev->BlockIo,      0x00);
@@ -885,6 +908,12 @@ VirtioBlkExitBoot (
   //
   Dev = Context;
   Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, 0);
+
+  //
+  // Unmap the ring buffer so that hypervisor will not be able to get
+  // readable data after device is reset.
+  //
+  Dev->VirtIo->UnmapSharedBuffer (Dev->VirtIo, Dev->RingMap);
 }
 
 /**

OvmfPkg/VirtioBlkDxe/VirtioBlk.h

@@ -41,6 +41,7 @@ typedef struct {
   VRING                  Ring;                 // VirtioRingInit      2
   EFI_BLOCK_IO_PROTOCOL  BlockIo;              // VirtioBlkInit       1
   EFI_BLOCK_IO_MEDIA     BlockIoMedia;         // VirtioBlkInit       1
+  VOID                   *RingMap;             // VirtioRingMap       2
 } VBLK_DEV;
 
 #define VIRTIO_BLK_FROM_BLOCK_IO(BlockIoPointer) \