OvmfPkg/VirtioNetDxe/Events.c

   1 /** @file
   2
   3   Implements
   4   - the SNM.WaitForPacket EVT_NOTIFY_WAIT event,
   5   - the EVT_SIGNAL_EXIT_BOOT_SERVICES event
   6   for the virtio-net driver.
   7
   8   Copyright (C) 2013, Red Hat, Inc.
   9   Copyright (c) 2006 - 2012, Intel Corporation. All rights reserved.<BR>
  10
  11   SPDX-License-Identifier: BSD-2-Clause-Patent
  12
  13 **/
  14
  15 #include <Library/BaseLib.h>
  16 #include <Library/UefiBootServicesTableLib.h>
  17
  18 #include "VirtioNet.h"
  19
  20 /**
  21   Invoke a notification event
  22
  23   @param  Event                 Event whose notification function is being
  24                                 invoked.
  25   @param  Context               The pointer to the notification function's
  26                                 context, which is implementation-dependent.
  27
  28 **/
  29 VOID
  30 EFIAPI
  31 VirtioNetIsPacketAvailable (
  32   IN  EFI_EVENT  Event,
  33   IN  VOID       *Context
  34   )
  35 {
  36   //
  37   // This callback has been enqueued by an external application and is
  38   // running at TPL_CALLBACK already.
  39   //
  40   // The WaitForPacket logic is similar to that of WaitForKey. The former has
  41   // almost no documentation in either the UEFI-2.3.1+errC spec or the
  42   // DWG-2.3.1, but WaitForKey does have some.
  43   //
  44   VNET_DEV  *Dev;
  45   UINT16    RxCurUsed;
  46
  47   Dev = Context;
  48   if (Dev->Snm.State != EfiSimpleNetworkInitialized) {
  49     return;
  50   }
  51
  52   //
  53   // virtio-0.9.5, 2.4.2 Receiving Used Buffers From the Device
  54   //
  55   MemoryFence ();
  56   RxCurUsed = *Dev->RxRing.Used.Idx;
  57   MemoryFence ();
  58
  59   if (Dev->RxLastUsed != RxCurUsed) {
  60     gBS->SignalEvent (Dev->Snp.WaitForPacket);
  61   }
  62 }
  63
  64 VOID
  65 EFIAPI
  66 VirtioNetExitBoot (
  67   IN  EFI_EVENT  Event,
  68   IN  VOID       *Context
  69   )
  70 {
  71   //
  72   // This callback has been enqueued by ExitBootServices() and is running at
  73   // TPL_CALLBACK already.
  74   //
  75   // Shut down pending transfers according to DWG-2.3.1, "25.5.1 Exit Boot
  76   // Services Event".
  77   //
  78   VNET_DEV  *Dev;
  79
  80   DEBUG ((DEBUG_VERBOSE, "%a: Context=0x%p\n", __FUNCTION__, Context));
  81   Dev = Context;
  82   if (Dev->Snm.State == EfiSimpleNetworkInitialized) {
  83     Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, 0);
  84   }
  85 }