OvmfPkg/VirtioNetDxe: alloc RxBuf using AllocateSharedPages()

When device is behind the IOMMU, VirtioNetDxe is required to use the
device address in bus master operations. RxBuf is allocated using
AllocatePool() which returns the system physical address.

The patch uses VIRTIO_DEVICE_PROTOCOL.AllocateSharedPages() to allocate
the RxBuf and map with VirtioMapAllBytesInSharedBuffer() so that we can
obtain the device address for RxBuf.

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>
Tested-by: Laszlo Ersek <lersek@redhat.com>

5 files changed, 75 insertions, 21 deletions

diff --git a/OvmfPkg/VirtioNetDxe/SnpInitialize.c b/OvmfPkg/VirtioNetDxe/SnpInitialize.c
index 8eabdbf..b739875 100644
--- a/OvmfPkg/VirtioNetDxe/SnpInitialize.c
+++ b/OvmfPkg/VirtioNetDxe/SnpInitialize.c
@@ -242,8 +242,9 @@ VirtioNetInitTx (
   @param[in,out] Dev       The VNET_DEV driver instance about to enter the

                            EfiSimpleNetworkInitialized state.

 

-  @retval EFI_OUT_OF_RESOURCES  Failed to allocate RX destination area.

-  @return                       Status codes from VIRTIO_CFG_WRITE().

+  @return                       Status codes from VIRTIO_CFG_WRITE() or

+                                VIRTIO_DEVICE_PROTOCOL.AllocateSharedPages or

+                                VirtioMapAllBytesInSharedBuffer().

   @retval EFI_SUCCESS           RX setup successful. The device is live and may

                                 already be writing to the receive area.

 */

@@ -255,13 +256,15 @@ VirtioNetInitRx (
   IN OUT VNET_DEV *Dev

   )

 {

-  EFI_STATUS Status;

-  UINTN      VirtioNetReqSize;

-  UINTN      RxBufSize;

-  UINT16     RxAlwaysPending;

-  UINTN      PktIdx;

-  UINT16     DescIdx;

-  UINT8      *RxPtr;

+  EFI_STATUS            Status;

+  UINTN                 VirtioNetReqSize;

+  UINTN                 RxBufSize;

+  UINT16                RxAlwaysPending;

+  UINTN                 PktIdx;

+  UINT16                DescIdx;

+  UINTN                 NumBytes;

+  EFI_PHYSICAL_ADDRESS  RxBufDeviceAddress;

+  VOID                  *RxBuffer;

 

   //

   // In VirtIo 1.0, the NumBuffers field is mandatory. In 0.9.5, it depends on

@@ -286,11 +289,39 @@ VirtioNetInitRx (
   //

   RxAlwaysPending = (UINT16) MIN (Dev->RxRing.QueueSize / 2, VNET_MAX_PENDING);

 

-  Dev->RxBuf = AllocatePool (RxAlwaysPending * RxBufSize);

-  if (Dev->RxBuf == NULL) {

-    return EFI_OUT_OF_RESOURCES;

+  //

+  // The RxBuf is shared between guest and hypervisor, use

+  // AllocateSharedPages() to allocate this memory region and map it with

+  // BusMasterCommonBuffer so that it can be accessed by both guest and

+  // hypervisor.

+  //

+  NumBytes = RxAlwaysPending * RxBufSize;

+  Dev->RxBufNrPages = EFI_SIZE_TO_PAGES (NumBytes);

+  Status = Dev->VirtIo->AllocateSharedPages (

+                          Dev->VirtIo,

+                          Dev->RxBufNrPages,

+                          &RxBuffer

+                          );

+  if (EFI_ERROR (Status)) {

+    return Status;

   }

 

+  ZeroMem (RxBuffer, NumBytes);

+

+  Status = VirtioMapAllBytesInSharedBuffer (

+             Dev->VirtIo,

+             VirtioOperationBusMasterCommonBuffer,

+             RxBuffer,

+             NumBytes,

+             &Dev->RxBufDeviceBase,

+             &Dev->RxBufMap

+             );

+  if (EFI_ERROR (Status)) {

+    goto FreeSharedBuffer;

+  }

+

+  Dev->RxBuf = RxBuffer;

+

   //

   // virtio-0.9.5, 2.4.2 Receiving Used Buffers From the Device

   //

@@ -310,7 +341,7 @@ VirtioNetInitRx (
   // link each chain into (from) the available ring as well

   //

   DescIdx = 0;

-  RxPtr = Dev->RxBuf;

+  RxBufDeviceAddress = Dev->RxBufDeviceBase;

   for (PktIdx = 0; PktIdx < RxAlwaysPending; ++PktIdx) {

     //

     // virtio-0.9.5, 2.4.1.2 Updating the Available Ring

@@ -321,16 +352,16 @@ VirtioNetInitRx (
     //

     // virtio-0.9.5, 2.4.1.1 Placing Buffers into the Descriptor Table

     //

-    Dev->RxRing.Desc[DescIdx].Addr  = (UINTN) RxPtr;

+    Dev->RxRing.Desc[DescIdx].Addr  = RxBufDeviceAddress;

     Dev->RxRing.Desc[DescIdx].Len   = (UINT32) VirtioNetReqSize;

     Dev->RxRing.Desc[DescIdx].Flags = VRING_DESC_F_WRITE | VRING_DESC_F_NEXT;

     Dev->RxRing.Desc[DescIdx].Next  = (UINT16) (DescIdx + 1);

-    RxPtr += Dev->RxRing.Desc[DescIdx++].Len;

+    RxBufDeviceAddress += Dev->RxRing.Desc[DescIdx++].Len;

 

-    Dev->RxRing.Desc[DescIdx].Addr  = (UINTN) RxPtr;

+    Dev->RxRing.Desc[DescIdx].Addr  = RxBufDeviceAddress;

     Dev->RxRing.Desc[DescIdx].Len   = (UINT32) (RxBufSize - VirtioNetReqSize);

     Dev->RxRing.Desc[DescIdx].Flags = VRING_DESC_F_WRITE;

-    RxPtr += Dev->RxRing.Desc[DescIdx++].Len;

+    RxBufDeviceAddress += Dev->RxRing.Desc[DescIdx++].Len;

   }

 

   //

@@ -351,10 +382,21 @@ VirtioNetInitRx (
   Status = Dev->VirtIo->SetQueueNotify (Dev->VirtIo, VIRTIO_NET_Q_RX);

   if (EFI_ERROR (Status)) {

     Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, 0);

-    FreePool (Dev->RxBuf);

+    goto UnmapSharedBuffer;

   }

 

   return Status;

+

+UnmapSharedBuffer:

+  Dev->VirtIo->UnmapSharedBuffer (Dev->VirtIo, Dev->RxBufMap);

+

+FreeSharedBuffer:

+  Dev->VirtIo->FreeSharedPages (

+                 Dev->VirtIo,

+                 Dev->RxBufNrPages,

+                 RxBuffer

+                 );

+  return Status;

 }

 

 

diff --git a/OvmfPkg/VirtioNetDxe/SnpReceive.c b/OvmfPkg/VirtioNetDxe/SnpReceive.c
index 99abd7e..c424896 100644
--- a/OvmfPkg/VirtioNetDxe/SnpReceive.c
+++ b/OvmfPkg/VirtioNetDxe/SnpReceive.c
@@ -82,6 +82,7 @@ VirtioNetReceive (
   UINT8      *RxPtr;

   UINT16     AvailIdx;

   EFI_STATUS NotifyStatus;

+  UINTN      RxBufOffset;

 

   if (This == NULL || BufferSize == NULL || Buffer == NULL) {

     return EFI_INVALID_PARAMETER;

@@ -143,7 +144,9 @@ VirtioNetReceive (
     *HeaderSize = Dev->Snm.MediaHeaderSize;

   }

 

-  RxPtr = (UINT8 *)(UINTN) Dev->RxRing.Desc[DescIdx + 1].Addr;

+  RxBufOffset = (UINTN)(Dev->RxRing.Desc[DescIdx + 1].Addr -

+                        Dev->RxBufDeviceBase);

+  RxPtr = Dev->RxBuf + RxBufOffset;

   CopyMem (Buffer, RxPtr, RxLen);

 

   if (DestAddr != NULL) {

diff --git a/OvmfPkg/VirtioNetDxe/SnpSharedHelpers.c b/OvmfPkg/VirtioNetDxe/SnpSharedHelpers.c
index 57c7395..ee4f9ed 100644
--- a/OvmfPkg/VirtioNetDxe/SnpSharedHelpers.c
+++ b/OvmfPkg/VirtioNetDxe/SnpSharedHelpers.c
@@ -39,7 +39,12 @@ VirtioNetShutdownRx (
   IN OUT VNET_DEV *Dev

   )

 {

-  FreePool (Dev->RxBuf);

+  Dev->VirtIo->UnmapSharedBuffer (Dev->VirtIo, Dev->RxBufMap);

+  Dev->VirtIo->FreeSharedPages (

+                 Dev->VirtIo,

+                 Dev->RxBufNrPages,

+                 Dev->RxBuf

+                 );

 }

 

 

diff --git a/OvmfPkg/VirtioNetDxe/TechNotes.txt b/OvmfPkg/VirtioNetDxe/TechNotes.txt
index 37250b1..fedbaee 100644
--- a/OvmfPkg/VirtioNetDxe/TechNotes.txt
+++ b/OvmfPkg/VirtioNetDxe/TechNotes.txt
@@ -247,7 +247,7 @@ In VirtioNetInitRx, the guest allocates the fixed size Receive Destination
 Area, which accommodates all packets delivered asynchronously by the host. To

 each packet, a slice of this area is dedicated; each slice is further

 subdivided into virtio-net request header and network packet data. The

-(guest-physical) addresses of these sub-slices are denoted with A2, A3, A4 and

+(device-physical) addresses of these sub-slices are denoted with A2, A3, A4 and

 so on. Importantly, an even-subscript "A" always belongs to a virtio-net

 request header, while an odd-subscript "A" always belongs to a packet

 sub-slice.

diff --git a/OvmfPkg/VirtioNetDxe/VirtioNet.h b/OvmfPkg/VirtioNetDxe/VirtioNet.h
index 6762fc9..995593f 100644
--- a/OvmfPkg/VirtioNetDxe/VirtioNet.h
+++ b/OvmfPkg/VirtioNetDxe/VirtioNet.h
@@ -4,6 +4,7 @@
   Protocol instances for virtio-net devices.

 

   Copyright (C) 2013, Red Hat, Inc.

+  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

@@ -86,6 +87,9 @@ typedef struct {
                                                  // VirtioNetInitRing

   UINT8                       *RxBuf;            // VirtioNetInitRx

   UINT16                      RxLastUsed;        // VirtioNetInitRx

+  UINTN                       RxBufNrPages;      // VirtioNetInitRx

+  EFI_PHYSICAL_ADDRESS        RxBufDeviceBase;   // VirtioNetInitRx

+  VOID                        *RxBufMap;         // VirtioNetInitRx

 

   VRING                       TxRing;            // VirtioNetInitRing

   VOID                        *TxRingMap;        // VirtioRingMap and