[Qemu-devel] [PATCH v6 4/8] Add vhost-user skeleton

[Antonios Motakis]

Add empty vhost_call, init and cleanup for the vhost-user backend.

Signed-off-by: Antonios Motakis <address@hidden>
Signed-off-by: Nikolay Nikolaev <address@hidden>
---
 hw/net/vhost_net.c                | 57 ++++++++++++++++++++++-----------------
 hw/virtio/vhost-backend.c         | 35 ++++++++++++++++++++++++
 include/hw/virtio/vhost-backend.h |  3 ++-
 include/net/vhost_net.h           | 13 ++++++++-
 net/tap.c                         | 16 ++++++-----
 5 files changed, 91 insertions(+), 33 deletions(-)

diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index 4aaf0b4..3614e6c 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -91,43 +91,51 @@ static int vhost_net_get_fd(NetClientState *backend)
     }
 }
 
-struct vhost_net *vhost_net_init(NetClientState *backend, int devfd,
-                                 bool force)
+struct vhost_net *vhost_net_init(VhostNetOptions *options)
 {
-    int r;
+    int r = -1;
     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);
-    if (r < 0) {
-        goto fail;
+
+    if (options->backend_type == VHOST_BACKEND_TYPE_KERNEL) {
+        r = vhost_net_get_fd(options->net_backend);
+        if (r < 0) {
+            goto fail;
+        }
+
+        net->dev.backend_features =
+                tap_has_vnet_hdr(options->net_backend) ? 0 :
+                                (1 << VHOST_NET_F_VIRTIO_NET_HDR);
     }
-    net->nc = backend;
-    net->dev.backend_features = tap_has_vnet_hdr(backend) ? 0 :
-        (1 << VHOST_NET_F_VIRTIO_NET_HDR);
+
+    net->nc = options->net_backend;
     net->backend = r;
 
     net->dev.nvqs = 2;
     net->dev.vqs = net->vqs;
 
-    r = vhost_dev_init(&net->dev, devfd, "/dev/vhost-net",
-                       VHOST_BACKEND_TYPE_KERNEL, force);
+    r = vhost_dev_init(&net->dev, options->devfd, options->devpath,
+                       options->backend_type, options->force);
     if (r < 0) {
         goto fail;
     }
-    if (!tap_has_vnet_hdr_len(backend,
-                              sizeof(struct virtio_net_hdr_mrg_rxbuf))) {
-        net->dev.features &= ~(1 << VIRTIO_NET_F_MRG_RXBUF);
-    }
-    if (~net->dev.features & net->dev.backend_features) {
-        fprintf(stderr, "vhost lacks feature mask %" PRIu64 " for backend\n",
-                (uint64_t)(~net->dev.features & net->dev.backend_features));
-        vhost_dev_cleanup(&net->dev);
-        goto fail;
+    if (options->backend_type == VHOST_BACKEND_TYPE_KERNEL) {
+        if (!tap_has_vnet_hdr_len(options->net_backend,
+                        sizeof(struct virtio_net_hdr_mrg_rxbuf))) {
+            net->dev.features &= ~(1 << VIRTIO_NET_F_MRG_RXBUF);
+        }
+        if (~net->dev.features & net->dev.backend_features) {
+            fprintf(stderr, "vhost lacks feature mask %" PRIu64
+                   " for backend\n",
+                   (uint64_t)(~net->dev.features & net->dev.backend_features));
+            vhost_dev_cleanup(&net->dev);
+            goto fail;
+        }
     }
-
     /* Set sane init value. Override when guest acks. */
     vhost_net_ack_features(net, 0);
     return net;
@@ -286,8 +294,7 @@ void vhost_net_virtqueue_mask(VHostNetState *net, 
VirtIODevice *dev,
     vhost_virtqueue_mask(&net->dev, dev, idx, mask);
 }
 #else
-struct vhost_net *vhost_net_init(NetClientState *backend, int devfd,
-                                 bool force)
+struct vhost_net *vhost_net_init(VhostNetOptions *options)
 {
     error_report("vhost-net support is not compiled in");
     return NULL;
diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
index c0f11e4..1d83e1d 100644
--- a/hw/virtio/vhost-backend.c
+++ b/hw/virtio/vhost-backend.c
@@ -16,6 +16,38 @@
 #include <unistd.h>
 #include <sys/ioctl.h>
 
+static int vhost_user_call(struct vhost_dev *dev, unsigned long int request,
+        void *arg)
+{
+    assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER);
+    error_report("vhost_user_call not implemented\n");
+
+    return -1;
+}
+
+static int vhost_user_init(struct vhost_dev *dev, const char *devpath)
+{
+    assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER);
+    error_report("vhost_user_init not implemented\n");
+
+    return -1;
+}
+
+static int vhost_user_cleanup(struct vhost_dev *dev)
+{
+    assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER);
+    error_report("vhost_user_cleanup not implemented\n");
+
+    return -1;
+}
+
+static const VhostOps user_ops = {
+        .backend_type = VHOST_BACKEND_TYPE_USER,
+        .vhost_call = vhost_user_call,
+        .vhost_backend_init = vhost_user_init,
+        .vhost_backend_cleanup = vhost_user_cleanup
+};
+
 static int vhost_kernel_call(struct vhost_dev *dev, unsigned long int request,
                              void *arg)
 {
@@ -56,6 +88,9 @@ int vhost_set_backend_type(struct vhost_dev *dev, 
VhostBackendType backend_type)
     case VHOST_BACKEND_TYPE_KERNEL:
         dev->vhost_ops = &kernel_ops;
         break;
+    case VHOST_BACKEND_TYPE_USER:
+        dev->vhost_ops = &user_ops;
+        break;
     default:
         error_report("Unknown vhost backend type\n");
         r = -1;
diff --git a/include/hw/virtio/vhost-backend.h 
b/include/hw/virtio/vhost-backend.h
index 93fc55b..ef87ffa 100644
--- a/include/hw/virtio/vhost-backend.h
+++ b/include/hw/virtio/vhost-backend.h
@@ -14,7 +14,8 @@
 typedef enum VhostBackendType {
     VHOST_BACKEND_TYPE_NONE = 0,
     VHOST_BACKEND_TYPE_KERNEL = 1,
-    VHOST_BACKEND_TYPE_MAX = 2,
+    VHOST_BACKEND_TYPE_USER = 2,
+    VHOST_BACKEND_TYPE_MAX = 3,
 } VhostBackendType;
 
 struct vhost_dev;
diff --git a/include/net/vhost_net.h b/include/net/vhost_net.h
index 2d936bb..1169562 100644
--- a/include/net/vhost_net.h
+++ b/include/net/vhost_net.h
@@ -2,11 +2,22 @@
 #define VHOST_NET_H
 
 #include "net/net.h"
+#include "hw/virtio/vhost-backend.h"
+
+#define VHOST_NET_DEFAULT_PATH  "/dev/vhost-net"
 
 struct vhost_net;
 typedef struct vhost_net VHostNetState;
 
-VHostNetState *vhost_net_init(NetClientState *backend, int devfd, bool force);
+typedef struct VhostNetOptions {
+    VhostBackendType backend_type;
+    NetClientState *net_backend;
+    const char *devpath;
+    int devfd;
+    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);
diff --git a/net/tap.c b/net/tap.c
index 39c1cda..776dbc4 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -621,19 +621,23 @@ 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.backend_type = VHOST_BACKEND_TYPE_KERNEL;
+        options.net_backend = &s->nc;
+        options.devpath = VHOST_NET_DEFAULT_PATH;
+        options.force = tap->has_vhostforce && tap->vhostforce;
 
         if (tap->has_vhostfd || tap->has_vhostfds) {
-            vhostfd = monitor_handle_fd_param(cur_mon, vhostfdname);
-            if (vhostfd == -1) {
+            options.devfd = monitor_handle_fd_param(cur_mon, vhostfdname);
+            if (options.devfd == -1) {
                 return -1;
             }
         } else {
-            vhostfd = -1;
+            options.devfd = -1;
         }
 
-        s->vhost_net = vhost_net_init(&s->nc, vhostfd,
-                                      tap->has_vhostforce && tap->vhostforce);
+        s->vhost_net = vhost_net_init(&options);
         if (!s->vhost_net) {
             error_report("vhost-net requested but could not be initialized");
             return -1;
-- 
1.8.3.2