OvmfPkg: VirtioNetDxe: WaitForPacket and EXIT_BOOT_SERVICES event callbacks

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@14417 6f19259b-4bc3-4df7-8a09-765794883524

OvmfPkg/VirtioNetDxe/Events.c

@@ -0,0 +1,90 @@
+/** @file
+
+  Implements
+  - the SNM.WaitForPacket EVT_NOTIFY_WAIT event,
+  - the EVT_SIGNAL_EXIT_BOOT_SERVICES event
+  for the virtio-net driver.
+
+  Copyright (C) 2013, Red Hat, Inc.
+  Copyright (c) 2006 - 2012, Intel Corporation. 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
+  distribution. The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
+  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include <Library/BaseLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+
+#include "VirtioNet.h"
+
+/**
+  Invoke a notification event
+
+  @param  Event                 Event whose notification function is being
+                                invoked.
+  @param  Context               The pointer to the notification function's
+                                context, which is implementation-dependent.
+
+**/
+
+VOID
+EFIAPI
+VirtioNetIsPacketAvailable (
+  IN  EFI_EVENT Event,
+  IN  VOID      *Context
+  )
+{
+  //
+  // This callback has been enqueued by an external application and is
+  // running at TPL_CALLBACK already.
+  //
+  // The WaitForPacket logic is similar to that of WaitForKey. The former has
+  // almost no documentation in either the UEFI-2.3.1+errC spec or the
+  // DWG-2.3.1, but WaitForKey does have some.
+  //
+  VNET_DEV *Dev;
+  UINT16   RxCurUsed;
+
+  Dev = Context;
+  if (Dev->Snm.State != EfiSimpleNetworkInitialized) {
+    return;
+  }
+
+  //
+  // virtio-0.9.5, 2.4.2 Receiving Used Buffers From the Device
+  //
+  MemoryFence ();
+  RxCurUsed = *Dev->RxRing.Used.Idx;
+
+  if (Dev->RxLastUsed != RxCurUsed) {
+    gBS->SignalEvent (&Dev->Snp.WaitForPacket);
+  }
+}
+
+VOID
+EFIAPI
+VirtioNetExitBoot (
+  IN  EFI_EVENT Event,
+  IN  VOID      *Context
+  )
+{
+  //
+  // This callback has been enqueued by ExitBootServices() and is running at
+  // TPL_CALLBACK already.
+  //
+  // Shut down pending transfers according to DWG-2.3.1, "25.5.1 Exit Boot
+  // Services Event".
+  //
+  VNET_DEV *Dev;
+
+  Dev = Context;
+  if (Dev->Snm.State == EfiSimpleNetworkInitialized) {
+    VIRTIO_CFG_WRITE (Dev, Generic.VhdrDeviceStatus, 0);
+  }
+}