vhost_net_init will use VhostNetOptions to get all its arguments

vhost_dev_init will replace devfd and devpath with a single opaque argument.
This is initialised with a file descriptor. When TAP is used (through
vhost_net), open /dev/vhost-net and pass the fd as an opaque parameter in
VhostNetOptions. The same applies to vhost-scsi - open /dev/vhost-scsi and
pass the fd.

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>

hw/net/vhost_net.c

@@ -94,32 +94,34 @@ static int vhost_net_get_fd(NetClientState *backend)
     }
 }
 
-struct vhost_net *vhost_net_init(NetClientState *backend, int devfd,
+struct vhost_net *vhost_net_init(VhostNetOptions *options)
-                                 bool force)
 {
     int r;
     struct vhost_net *net = g_malloc(sizeof *net);
-    if (!backend) {
+
-        fprintf(stderr, "vhost-net requires backend to be setup\n");
+    if (!options->net_backend) {
+        fprintf(stderr, "vhost-net requires net backend to be setup\n");
         goto fail;
     }
-    r = vhost_net_get_fd(backend);
+
+    r = vhost_net_get_fd(options->net_backend);
     if (r < 0) {
         goto fail;
     }
-    net->nc = backend;
+    net->nc = options->net_backend;
-    net->dev.backend_features = qemu_has_vnet_hdr(backend) ? 0 :
+    net->dev.backend_features = qemu_has_vnet_hdr(options->net_backend) ? 0 :
         (1 << VHOST_NET_F_VIRTIO_NET_HDR);
     net->backend = r;
 
     net->dev.nvqs = 2;
     net->dev.vqs = net->vqs;
 
-    r = vhost_dev_init(&net->dev, devfd, "/dev/vhost-net", force);
+    r = vhost_dev_init(&net->dev, options->opaque,
+                       options->force);
     if (r < 0) {
         goto fail;
     }
-    if (!qemu_has_vnet_hdr_len(backend,
+    if (!qemu_has_vnet_hdr_len(options->net_backend,
                                sizeof(struct virtio_net_hdr_mrg_rxbuf))) {
         net->dev.features &= ~(1 << VIRTIO_NET_F_MRG_RXBUF);
     }
@@ -311,8 +313,7 @@ VHostNetState *get_vhost_net(NetClientState *nc)
     return vhost_net;
 }
 #else
-struct vhost_net *vhost_net_init(NetClientState *backend, int devfd,
+struct vhost_net *vhost_net_init(VhostNetOptions *options)
-                                 bool force)
 {
     error_report("vhost-net support is not compiled in");
     return NULL;

hw/scsi/vhost-scsi.c

@@ -210,6 +210,13 @@ static void vhost_scsi_realize(DeviceState *dev, Error **errp)
             error_setg(errp, "vhost-scsi: unable to parse vhostfd");
             return;
         }
+    } else {
+        vhostfd = open("/dev/vhost-scsi", O_RDWR);
+        if (vhostfd < 0) {
+            error_setg(errp, "vhost-scsi: open vhost char device failed: %s",
+                       strerror(errno));
+            return;
+        }
     }
 
     virtio_scsi_common_realize(dev, &err);
@@ -222,7 +229,8 @@ static void vhost_scsi_realize(DeviceState *dev, Error **errp)
     s->dev.vqs = g_new(struct vhost_virtqueue, s->dev.nvqs);
     s->dev.vq_index = 0;
 
-    ret = vhost_dev_init(&s->dev, vhostfd, "/dev/vhost-scsi", true);
+    ret = vhost_dev_init(&s->dev, (void *)(uintptr_t)vhostfd,
+                         true);
     if (ret < 0) {
         error_setg(errp, "vhost-scsi: vhost initialization failed: %s",
                    strerror(-ret));

hw/virtio/vhost.c

@@ -808,19 +808,13 @@ static void vhost_virtqueue_cleanup(struct vhost_virtqueue *vq)
     event_notifier_cleanup(&vq->masked_notifier);
 }
 
-int vhost_dev_init(struct vhost_dev *hdev, int devfd, const char *devpath,
+int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
                    bool force)
 {
     uint64_t features;
     int i, r;
-    if (devfd >= 0) {
+    hdev->control = (uintptr_t) opaque;;
-        hdev->control = devfd;
+
-    } else {
-        hdev->control = open(devpath, O_RDWR);
-        if (hdev->control < 0) {
-            return -errno;
-        }
-    }
     r = ioctl(hdev->control, VHOST_SET_OWNER, NULL);
     if (r < 0) {
         goto fail;

include/hw/virtio/vhost.h

@@ -51,7 +51,7 @@ struct vhost_dev {
     hwaddr mem_changed_end_addr;
 };
 
-int vhost_dev_init(struct vhost_dev *hdev, int devfd, const char *devpath,
+int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
                    bool force);
 void vhost_dev_cleanup(struct vhost_dev *hdev);
 bool vhost_dev_query(struct vhost_dev *hdev, VirtIODevice *vdev);

include/net/vhost_net.h

@@ -6,7 +6,13 @@
 struct vhost_net;
 typedef struct vhost_net VHostNetState;
 
-VHostNetState *vhost_net_init(NetClientState *backend, int devfd, bool force);
+typedef struct VhostNetOptions {
+    NetClientState *net_backend;
+    void *opaque;
+    bool force;
+} VhostNetOptions;
+
+struct vhost_net *vhost_net_init(VhostNetOptions *options);
 
 bool vhost_net_query(VHostNetState *net, VirtIODevice *dev);
 int vhost_net_start(VirtIODevice *dev, NetClientState *ncs, int total_queues);

net/tap.c

@@ -594,6 +594,7 @@ static int net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
                             int vnet_hdr, int fd)
 {
     TAPState *s;
+    int vhostfd;
 
     s = net_tap_fd_init(peer, model, name, fd, vnet_hdr);
     if (!s) {
@@ -624,7 +625,10 @@ static int net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
 
     if (tap->has_vhost ? tap->vhost :
         vhostfdname || (tap->has_vhostforce && tap->vhostforce)) {
-        int vhostfd;
+        VhostNetOptions options;
+
+        options.net_backend = &s->nc;
+        options.force = tap->has_vhostforce && tap->vhostforce;
 
         if (tap->has_vhostfd || tap->has_vhostfds) {
             vhostfd = monitor_handle_fd_param(cur_mon, vhostfdname);
@@ -632,11 +636,16 @@ static int net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
                 return -1;
             }
         } else {
-            vhostfd = -1;
+            vhostfd = open("/dev/vhost-net", O_RDWR);
+            if (vhostfd < 0) {
+                error_report("tap: open vhost char device failed: %s",
+                           strerror(errno));
+                return -1;
+            }
         }
+        options.opaque = (void *)(uintptr_t)vhostfd;
 
-        s->vhost_net = vhost_net_init(&s->nc, vhostfd,
+        s->vhost_net = vhost_net_init(&options);
-                                      tap->has_vhostforce && tap->vhostforce);
         if (!s->vhost_net) {
             error_report("vhost-net requested but could not be initialized");
             return -1;