[PATCH v3 18/23] OvmfPkg/VirtioNetDxe: map transmit buffer host address to device address

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

Update VirtioNetTransmit() function, to map the callers transmit buffer
host address to a device address.

Since the transmit buffers are returned back to caller in
VirtioNetGetStatus() hence we maintain a simple list to maintain 1:1
mapping between host address to device address. The list is consulted
when we return back the callers buffer after data is successfully
transmitted.

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        |  17 +++
 OvmfPkg/VirtioNetDxe/SnpGetStatus.c     |  29 ++++-
 OvmfPkg/VirtioNetDxe/SnpSharedHelpers.c | 119 ++++++++++++++++++++
 OvmfPkg/VirtioNetDxe/SnpTransmit.c      |  30 +++--
 4 files changed, 184 insertions(+), 11 deletions(-)

diff --git a/OvmfPkg/VirtioNetDxe/VirtioNet.h b/OvmfPkg/VirtioNetDxe/VirtioNet.h
index 3efe95a735d8..ac75bdeeb449 100644
--- a/OvmfPkg/VirtioNetDxe/VirtioNet.h
+++ b/OvmfPkg/VirtioNetDxe/VirtioNet.h
@@ -269,6 +269,23 @@ VirtioNetShutdownTx (
   IN OUT VNET_DEV *Dev
   );
 
+EFI_STATUS
+EFIAPI
+VirtioMapTxBuf (
+  IN  VNET_DEV              *Dev,
+  IN  EFI_PHYSICAL_ADDRESS  HostAddress,
+  IN  UINTN                 NumberOfBytes,
+  OUT EFI_PHYSICAL_ADDRESS  *DeviceAddress
+  );
+
+EFI_STATUS
+EFIAPI
+VirtioUnmapTxBuf (
+  IN  VNET_DEV              *Dev,
+  OUT EFI_PHYSICAL_ADDRESS  *HostAddress,
+  IN  EFI_PHYSICAL_ADDRESS  DeviceAddress
+  );
+
 //
 // event callbacks
 //
diff --git a/OvmfPkg/VirtioNetDxe/SnpGetStatus.c b/OvmfPkg/VirtioNetDxe/SnpGetStatus.c
index 694940ea1d97..d532551456d0 100644
--- a/OvmfPkg/VirtioNetDxe/SnpGetStatus.c
+++ b/OvmfPkg/VirtioNetDxe/SnpGetStatus.c
@@ -5,6 +5,7 @@
 
   Copyright (C) 2013, Red Hat, Inc.
   Copyright (c) 2006 - 2014, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2017, AMD Inc, All rights reserved.<BR>
 
   This program and the accompanying materials are licensed and made available
   under the terms and conditions of the BSD License which accompanies this
@@ -47,7 +48,8 @@
   @retval EFI_INVALID_PARAMETER One or more of the parameters has an
                                 unsupported value.
   @retval EFI_DEVICE_ERROR      The command could not be sent to the network
-                                interface.
+                                interface or failed to map TxBuf to bus master
+                                address.
   @retval EFI_UNSUPPORTED       This function is not supported by the network
                                 interface.
 
@@ -126,8 +128,10 @@ VirtioNetGetStatus (
       *TxBuf = NULL;
     }
     else {
-      UINT16 UsedElemIdx;
-      UINT32 DescIdx;
+      UINT16                UsedElemIdx;
+      UINT32                DescIdx;
+      EFI_PHYSICAL_ADDRESS  BufferAddress;
+      EFI_PHYSICAL_ADDRESS  DeviceAddress;
 
       //
       // fetch the first descriptor among those that the hypervisor reports
@@ -141,9 +145,26 @@ VirtioNetGetStatus (
       ASSERT (DescIdx < (UINT32) (2 * Dev->TxMaxPending - 1));
 
       //
+      // Ring descriptor contains the device address of buffer.
+      // Lets unmap the device address and get its corresponding
+      // host buffer address.
+      //
+      DeviceAddress = Dev->TxRing.Desc[DescIdx + 1].Addr;
+      Status = VirtioUnmapTxBuf (
+                 Dev,
+                 &BufferAddress,
+                 DeviceAddress
+                 );
+      if (EFI_ERROR (Status)) {
+        Status = EFI_DEVICE_ERROR;
+        goto Exit;
+      }
+
+      //
+      //
       // report buffer address to caller that has been enqueued by caller
       //
-      *TxBuf = (VOID *)(UINTN) Dev->TxRing.Desc[DescIdx + 1].Addr;
+      *TxBuf = (VOID *)(UINTN) BufferAddress;
 
       //
       // now this descriptor can be used again to enqueue a transmit buffer
diff --git a/OvmfPkg/VirtioNetDxe/SnpSharedHelpers.c b/OvmfPkg/VirtioNetDxe/SnpSharedHelpers.c
index aeb9e6605f0d..5e1c610c4a18 100644
--- a/OvmfPkg/VirtioNetDxe/SnpSharedHelpers.c
+++ b/OvmfPkg/VirtioNetDxe/SnpSharedHelpers.c
@@ -14,10 +14,29 @@
 
 **/
 
+#include <Library/BaseLib.h>
 #include <Library/MemoryAllocationLib.h>
 
 #include "VirtioNet.h"
 
+#define PRIVATE_TXBUF_SIGNATURE  SIGNATURE_32 ('t', 'x', 'b', 'f')
+typedef struct {
+  UINT32                Signature;
+  LIST_ENTRY            Link;
+  EFI_PHYSICAL_ADDRESS  HostAddress;
+  EFI_PHYSICAL_ADDRESS  DeviceAddress;
+  VOID                  *Mapping;
+} PRIVATE_TXBUF_ENTRY;
+#define PRIVATE_TXBUF_FROM_LINK(a) CR (a, PRIVATE_TXBUF_ENTRY, Link, \
+                                       PRIVATE_TXBUF_SIGNATURE)
+
+//
+// List of Txbuf queued
+//
+STATIC LIST_ENTRY mTxBufMapList = INITIALIZE_LIST_HEAD_VARIABLE (
+                                    mTxBufMapList
+                                    );
+
 /**
   Release RX and TX resources on the boundary of the
   EfiSimpleNetworkInitialized state.
@@ -63,3 +82,103 @@ VirtioNetShutdownTx (
 
   FreePool (Dev->TxFreeStack);
 }
+
+EFI_STATUS
+EFIAPI
+VirtioMapTxBuf (
+  IN  VNET_DEV               *Dev,
+  IN  EFI_PHYSICAL_ADDRESS   HostAddress,
+  IN  UINTN                  NumberOfBytes,
+  OUT EFI_PHYSICAL_ADDRESS   *DeviceAddress
+  )
+{
+  EFI_STATUS             Status;
+  PRIVATE_TXBUF_ENTRY   *Private;
+
+  Private = AllocatePool (sizeof (*Private));
+  if (Private == NULL) {
+    return EFI_OUT_OF_RESOURCES;
+  }
+
+  Private->Signature = PRIVATE_TXBUF_SIGNATURE;
+  Private->HostAddress = HostAddress;
+
+  Status = VirtioMapAllBytesInSharedBuffer (
+             Dev->VirtIo,
+             VirtioOperationBusMasterRead,
+             (VOID *) (UINTN) Private->HostAddress,
+             NumberOfBytes,
+             &Private->DeviceAddress,
+             &Private->Mapping
+             );
+  if (EFI_ERROR (Status)) {
+    goto FreePool;
+  }
+
+  *DeviceAddress = Private->DeviceAddress;
+
+  //
+  // Add the mapping information into internal list so that we can retrieve
+  // the HostAddress from Unmap().
+  //
+  InsertTailList (&mTxBufMapList, &Private->Link);
+
+  return EFI_SUCCESS;
+
+FreePool:
+  FreePool (Private);
+  return Status;
+}
+
+EFI_STATUS
+EFIAPI
+VirtioUnmapTxBuf (
+  IN  VNET_DEV               *Dev,
+  OUT EFI_PHYSICAL_ADDRESS   *HostAddress,
+  IN  EFI_PHYSICAL_ADDRESS   DeviceAddress
+  )
+{
+  EFI_STATUS             Status;
+  PRIVATE_TXBUF_ENTRY   *Private;
+  LIST_ENTRY            *Link;
+  BOOLEAN                Found;
+
+  //
+  //set Private to suppress incorrect compiler/analyzer warnings
+  //
+  Private = NULL;
+
+  //
+  // Iterate through internal txbuf list to find mapping for a given
+  // DeviceAddress.
+  //
+  Found = FALSE;
+  for (Link = GetFirstNode (&mTxBufMapList)
+       ; !IsNull (&mTxBufMapList, Link)
+       ; Link = GetNextNode (&mTxBufMapList, Link)
+      ) {
+    Private = PRIVATE_TXBUF_FROM_LINK (Link);
+    if (Private->DeviceAddress == DeviceAddress) {
+      Found = TRUE;
+      break;
+    }
+  }
+
+  //
+  // We failed to find mapping for the given DeviceAddress
+  // (this should never happen)
+  //
+  ASSERT (Found);
+
+  Status = Dev->VirtIo->UnmapSharedBuffer (Dev->VirtIo, Private->Mapping);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  *HostAddress = Private->HostAddress;
+
+  RemoveEntryList (&Private->Link);
+  FreePool (Private);
+
+  return EFI_SUCCESS;
+}
diff --git a/OvmfPkg/VirtioNetDxe/SnpTransmit.c b/OvmfPkg/VirtioNetDxe/SnpTransmit.c
index 7ca40d5d0650..f71953c92c99 100644
--- a/OvmfPkg/VirtioNetDxe/SnpTransmit.c
+++ b/OvmfPkg/VirtioNetDxe/SnpTransmit.c
@@ -55,7 +55,8 @@
   @retval EFI_INVALID_PARAMETER One or more of the parameters has an
                                 unsupported value.
   @retval EFI_DEVICE_ERROR      The command could not be sent to the network
-                                interface.
+                                interface or failed to map the Buffer to
+                                bus master address.
   @retval EFI_UNSUPPORTED       This function is not supported by the network
                                 interface.
 
@@ -73,11 +74,12 @@ VirtioNetTransmit (
   IN UINT16                      *Protocol OPTIONAL
   )
 {
-  VNET_DEV   *Dev;
-  EFI_TPL    OldTpl;
-  EFI_STATUS Status;
-  UINT16     DescIdx;
-  UINT16     AvailIdx;
+  VNET_DEV              *Dev;
+  EFI_TPL               OldTpl;
+  EFI_STATUS            Status;
+  UINT16                DescIdx;
+  UINT16                AvailIdx;
+  EFI_PHYSICAL_ADDRESS  DeviceAddress;
 
   if (This == NULL || BufferSize == 0 || Buffer == NULL) {
     return EFI_INVALID_PARAMETER;
@@ -144,10 +146,24 @@ VirtioNetTransmit (
   }
 
   //
+  // Map the transmit buffer HostAddress to a DeviceAddress
+  //
+  Status = VirtioMapTxBuf (
+             Dev,
+             (EFI_PHYSICAL_ADDRESS) (UINTN) Buffer,
+             BufferSize,
+             &DeviceAddress
+             );
+  if (EFI_ERROR (Status)) {
+    Status = EFI_DEVICE_ERROR;
+    goto Exit;
+  }
+
+  //
   // virtio-0.9.5, 2.4.1 Supplying Buffers to The Device
   //
   DescIdx = Dev->TxFreeStack[Dev->TxCurPending++];
-  Dev->TxRing.Desc[DescIdx + 1].Addr  = (UINTN) Buffer;
+  Dev->TxRing.Desc[DescIdx + 1].Addr  = (UINTN) DeviceAddress;
   Dev->TxRing.Desc[DescIdx + 1].Len   = (UINT32) BufferSize;
 
   //
-- 
2.7.4