Add vhost-backend and VhostBackendType

Use vhost_set_backend_type to initialise a proper vhost_ops structure.
In vhost_net_init and vhost_net_start_one call conditionally TAP related
initialisation depending on the vhost backend type.

Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
Signed-off-by: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

3 files changed, 72 insertions, 2 deletions

diff --git a/hw/virtio/Makefile.objs b/hw/virtio/Makefile.objs
index 1ba53d9cc3..51e5bdb341 100644
--- a/hw/virtio/Makefile.objs
+++ b/hw/virtio/Makefile.objs
@@ -5,4 +5,4 @@ common-obj-y += virtio-mmio.o
 common-obj-$(CONFIG_VIRTIO_BLK_DATA_PLANE) += dataplane/
 
 obj-y += virtio.o virtio-balloon.o 
-obj-$(CONFIG_LINUX) += vhost.o
+obj-$(CONFIG_LINUX) += vhost.o vhost-backend.o
diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
new file mode 100644
index 0000000000..509e103408
--- /dev/null
+++ b/hw/virtio/vhost-backend.c
@@ -0,0 +1,66 @@
+/*
+ * vhost-backend
+ *
+ * Copyright (c) 2013 Virtual Open Systems Sarl.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "hw/virtio/vhost.h"
+#include "hw/virtio/vhost-backend.h"
+#include "qemu/error-report.h"
+
+#include <sys/ioctl.h>
+
+static int vhost_kernel_call(struct vhost_dev *dev, unsigned long int request,
+                             void *arg)
+{
+    int fd = (uintptr_t) dev->opaque;
+
+    assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_KERNEL);
+
+    return ioctl(fd, request, arg);
+}
+
+static int vhost_kernel_init(struct vhost_dev *dev, void *opaque)
+{
+    assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_KERNEL);
+
+    dev->opaque = opaque;
+
+    return 0;
+}
+
+static int vhost_kernel_cleanup(struct vhost_dev *dev)
+{
+    int fd = (uintptr_t) dev->opaque;
+
+    assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_KERNEL);
+
+    return close(fd);
+}
+
+static const VhostOps kernel_ops = {
+        .backend_type = VHOST_BACKEND_TYPE_KERNEL,
+        .vhost_call = vhost_kernel_call,
+        .vhost_backend_init = vhost_kernel_init,
+        .vhost_backend_cleanup = vhost_kernel_cleanup
+};
+
+int vhost_set_backend_type(struct vhost_dev *dev, VhostBackendType backend_type)
+{
+    int r = 0;
+
+    switch (backend_type) {
+    case VHOST_BACKEND_TYPE_KERNEL:
+        dev->vhost_ops = &kernel_ops;
+        break;
+    default:
+        error_report("Unknown vhost backend type\n");
+        r = -1;
+    }
+
+    return r;
+}
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 85841019c0..c1b1aad6cf 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -808,11 +808,15 @@ static void vhost_virtqueue_cleanup(struct vhost_virtqueue *vq)
 }
 
 int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
-                   bool force)
+                   VhostBackendType backend_type, bool force)
 {
     uint64_t features;
     int i, r;
 
+    if (vhost_set_backend_type(hdev, backend_type) < 0) {
+        return -1;
+    }
+
     if (hdev->vhost_ops->vhost_backend_init(hdev, opaque) < 0) {
         return -errno;
     }