The Tx and Rx rings are accessed by both guest and hypervisor, allocate
the rings using newly added VirtIo->AllocateSharedPages() and map it with
BusMasterCommonBuffer so that it can be accessed by both guest and
hypervisor.

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/VirtioNetDxe/VirtioNet.h     |  2 +
 OvmfPkg/VirtioNetDxe/Events.c        |  7 ++++
 OvmfPkg/VirtioNetDxe/SnpInitialize.c | 40 ++++++++++++++++----
 OvmfPkg/VirtioNetDxe/SnpShutdown.c   |  2 +
 4 files changed, 43 insertions(+), 8 deletions(-)

diff --git a/OvmfPkg/VirtioNetDxe/VirtioNet.h b/OvmfPkg/VirtioNetDxe/VirtioNet.h
index 710859bc6115..d80d441b50a4 100644
--- a/OvmfPkg/VirtioNetDxe/VirtioNet.h
+++ b/OvmfPkg/VirtioNetDxe/VirtioNet.h
@@ -82,10 +82,12 @@ typedef struct {
   EFI_HANDLE                  MacHandle;         // VirtioNetDriverBindingStart
 
   VRING                       RxRing;            // VirtioNetInitRing
+  VOID                        *RxRingMap;        // VirtioRingMap
   UINT8                       *RxBuf;            // VirtioNetInitRx
   UINT16                      RxLastUsed;        // VirtioNetInitRx
 
   VRING                       TxRing;            // VirtioNetInitRing
+  VOID                        *TxRingMap;        // VirtioRingMap
   UINT16                      TxMaxPending;      // VirtioNetInitTx
   UINT16                      TxCurPending;      // VirtioNetInitTx
   UINT16                      *TxFreeStack;      // VirtioNetInitTx
diff --git a/OvmfPkg/VirtioNetDxe/Events.c b/OvmfPkg/VirtioNetDxe/Events.c
index 5be1af6ffbee..6950c4d56df1 100644
--- a/OvmfPkg/VirtioNetDxe/Events.c
+++ b/OvmfPkg/VirtioNetDxe/Events.c
@@ -88,4 +88,11 @@ VirtioNetExitBoot (
   if (Dev->Snm.State == EfiSimpleNetworkInitialized) {
     Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, 0);
   }
+
+  //
+  // Unmap Tx and Rx rings so that hypervisor will not be able get readable data
+  // after device is reset.
+  //
+  Dev->VirtIo->UnmapSharedBuffer (Dev->VirtIo, Dev->TxRingMap);
+  Dev->VirtIo->UnmapSharedBuffer (Dev->VirtIo, Dev->RxRingMap);
 }
diff --git a/OvmfPkg/VirtioNetDxe/SnpInitialize.c b/OvmfPkg/VirtioNetDxe/SnpInitialize.c
index 0ecfe044a977..803a38bd4239 100644
--- a/OvmfPkg/VirtioNetDxe/SnpInitialize.c
+++ b/OvmfPkg/VirtioNetDxe/SnpInitialize.c
@@ -35,11 +35,13 @@
                            the network device.
   @param[out]    Ring      The virtio-ring inside the VNET_DEV structure,
                            corresponding to Selector.
+  @param[out]    Mapping   A token return from the VirtioRingMap().
 
   @retval EFI_UNSUPPORTED  The queue size reported by the virtio-net device is
                            too small.
   @return                  Status codes from VIRTIO_CFG_WRITE(),
-                           VIRTIO_CFG_READ() and VirtioRingInit().
+                           VIRTIO_CFG_READ(), VirtioRingInit() and
+                           VirtioRingMap().
   @retval EFI_SUCCESS      Ring initialized.
 */
 
@@ -49,11 +51,13 @@ EFIAPI
 VirtioNetInitRing (
   IN OUT VNET_DEV *Dev,
   IN     UINT16   Selector,
-  OUT    VRING    *Ring
+  OUT    VRING    *Ring,
+  OUT    VOID     **Mapping
   )
 {
   EFI_STATUS Status;
   UINT16     QueueSize;
+  UINT64     RingBaseShift;
 
   //
   // step 4b -- allocate selected queue
@@ -79,30 +83,38 @@ VirtioNetInitRing (
     return Status;
   }
 
+  Status = VirtioRingMap (Dev->VirtIo, Ring, &RingBaseShift, Mapping);
+  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 release the ring resources.
   //
   Status = Dev->VirtIo->SetQueueNum (Dev->VirtIo, QueueSize);
   if (EFI_ERROR (Status)) {
-    goto ReleaseQueue;
+    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, Ring, 0);
+  Status = Dev->VirtIo->SetQueueAddress (Dev->VirtIo, Ring, RingBaseShift);
   if (EFI_ERROR (Status)) {
-    goto ReleaseQueue;
+    goto UnmapQueue;
   }
 
   return EFI_SUCCESS;
 
+UnmapQueue:
+  Dev->VirtIo->UnmapSharedBuffer (Dev->VirtIo, Mapping);
+
 ReleaseQueue:
   VirtioRingUninit (Dev->VirtIo, Ring);
 
@@ -456,12 +468,22 @@ VirtioNetInitialize (
   //
   // step 4b, 4c -- allocate and report virtqueues
   //
-  Status = VirtioNetInitRing (Dev, VIRTIO_NET_Q_RX, &Dev->RxRing);
+  Status = VirtioNetInitRing (
+             Dev,
+             VIRTIO_NET_Q_RX,
+             &Dev->RxRing,
+             &Dev->RxRingMap
+             );
   if (EFI_ERROR (Status)) {
     goto DeviceFailed;
   }
 
-  Status = VirtioNetInitRing (Dev, VIRTIO_NET_Q_TX, &Dev->TxRing);
+  Status = VirtioNetInitRing (
+             Dev,
+             VIRTIO_NET_Q_TX,
+             &Dev->TxRing,
+             &Dev->TxRingMap
+             );
   if (EFI_ERROR (Status)) {
     goto ReleaseRxRing;
   }
@@ -510,9 +532,11 @@ AbortDevice:
   Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, 0);
 
 ReleaseTxRing:
+  Dev->VirtIo->UnmapSharedBuffer (Dev->VirtIo, Dev->TxRingMap);
   VirtioRingUninit (Dev->VirtIo, &Dev->TxRing);
 
 ReleaseRxRing:
+  Dev->VirtIo->UnmapSharedBuffer (Dev->VirtIo, Dev->RxRingMap);
   VirtioRingUninit (Dev->VirtIo, &Dev->RxRing);
 
 DeviceFailed:
diff --git a/OvmfPkg/VirtioNetDxe/SnpShutdown.c b/OvmfPkg/VirtioNetDxe/SnpShutdown.c
index 5e84191fbbdd..36f3253e77ad 100644
--- a/OvmfPkg/VirtioNetDxe/SnpShutdown.c
+++ b/OvmfPkg/VirtioNetDxe/SnpShutdown.c
@@ -67,7 +67,9 @@ VirtioNetShutdown (
   Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, 0);
   VirtioNetShutdownRx (Dev);
   VirtioNetShutdownTx (Dev);
+  Dev->VirtIo->UnmapSharedBuffer (Dev->VirtIo, Dev->TxRingMap);
   VirtioRingUninit (Dev->VirtIo, &Dev->TxRing);
+  Dev->VirtIo->UnmapSharedBuffer (Dev->VirtIo, Dev->RxRingMap);
   VirtioRingUninit (Dev->VirtIo, &Dev->RxRing);
 
   Dev->Snm.State = EfiSimpleNetworkStarted;
-- 
2.7.4

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