dev: Add a dummy VirtIO device

VirtIO transport interfaces always expect a VirtIO device
pointer. However, there are cases (in particular when using VirtIO's
MMIO interface) where we want to instantiate an interface without a
device. Add a dummy device using VirtIO device ID 0 and no queues to
handle this use case.

Change-Id: I6cbe12fd403903ef585be40279c3b1321fde48ff
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Sudhanshu Jha <sudhanshu.jha@arm.com>
Reviewed-by: Rekai Gonzalez Alberquilla <rekai.gonzalezalberquilla@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/2325
Reviewed-by: Weiping Liao <weipingliao@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

1 files changed, 14 insertions, 1 deletions

diff --git a/src/dev/virtio/base.cc b/src/dev/virtio/base.cc
index f098784d0..61dd3069f 100644
--- a/src/dev/virtio/base.cc
+++ b/src/dev/virtio/base.cc
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014 ARM Limited
+ * Copyright (c) 2014, 2016 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -41,6 +41,7 @@
 
 #include "debug/VIO.hh"
 #include "params/VirtIODeviceBase.hh"
+#include "params/VirtIODummyDevice.hh"
 
 VirtDescriptor::VirtDescriptor(PortProxy &_memProxy, VirtQueue &_queue,
                                Index descIndex)
@@ -477,3 +478,15 @@ VirtIODeviceBase::registerQueue(VirtQueue &queue)
 {
     _queues.push_back(&queue);
 }
+
+
+VirtIODummyDevice::VirtIODummyDevice(VirtIODummyDeviceParams *params)
+    : VirtIODeviceBase(params, ID_INVALID, 0, 0)
+{
+}
+
+VirtIODummyDevice *
+VirtIODummyDeviceParams::create()
+{
+    return new VirtIODummyDevice(this);
+}