[Qemu-devel] [PULL 2/6] Revert "vhost-user: add multi queue support"

[Michael S. Tsirkin]

This reverts commit 830d70db692e374b55555f4407f96a1ceefdcc97.

The interface isn't fully backwards-compatible, which is bad.
Let's redo this properly after 2.4.

Signed-off-by: Michael S. Tsirkin <address@hidden>
---
 qapi-schema.json          |  6 +-----
 hw/net/vhost_net.c        |  3 +--
 hw/virtio/vhost-user.c    | 11 +----------
 net/vhost-user.c          | 37 +++++++++++++------------------------
 docs/specs/vhost-user.txt |  5 -----
 qemu-options.hx           |  5 ++---
 6 files changed, 18 insertions(+), 49 deletions(-)

diff --git a/qapi-schema.json b/qapi-schema.json
index 1285b8c..a0a45f7 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -2466,16 +2466,12 @@
 #
 # @vhostforce: #optional vhost on for non-MSIX virtio guests (default: false).
 #
-# @queues: #optional number of queues to be created for multiqueue vhost-user
-#          (default: 1) (Since 2.4)
-#
 # Since 2.1
 ##
 { 'struct': 'NetdevVhostUserOptions',
   'data': {
     'chardev':        'str',
-    '*vhostforce':    'bool',
-    '*queues':        'uint32' } }
+    '*vhostforce':    'bool' } }
 
 ##
 # @NetClientOptions
diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index 9bd360b..5c1d11f 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -160,7 +160,6 @@ struct vhost_net *vhost_net_init(VhostNetOptions *options)
 
     net->dev.nvqs = 2;
     net->dev.vqs = net->vqs;
-    net->dev.vq_index = net->nc->queue_index;
 
     r = vhost_dev_init(&net->dev, options->opaque,
                        options->backend_type);
@@ -287,7 +286,7 @@ static void vhost_net_stop_one(struct vhost_net *net,
         for (file.index = 0; file.index < net->dev.nvqs; ++file.index) {
             const VhostOps *vhost_ops = net->dev.vhost_ops;
             int r = vhost_ops->vhost_call(&net->dev, VHOST_RESET_OWNER,
-                                          &file);
+                                          NULL);
             assert(r >= 0);
         }
     }
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index d6f2163..e7ab829 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -210,12 +210,7 @@ static int vhost_user_call(struct vhost_dev *dev, unsigned 
long int request,
         break;
 
     case VHOST_SET_OWNER:
-        break;
-
     case VHOST_RESET_OWNER:
-        memcpy(&msg.state, arg, sizeof(struct vhost_vring_state));
-        msg.state.index += dev->vq_index;
-        msg.size = sizeof(m.state);
         break;
 
     case VHOST_SET_MEM_TABLE:
@@ -258,20 +253,17 @@ static int vhost_user_call(struct vhost_dev *dev, 
unsigned long int request,
     case VHOST_SET_VRING_NUM:
     case VHOST_SET_VRING_BASE:
         memcpy(&msg.state, arg, sizeof(struct vhost_vring_state));
-        msg.state.index += dev->vq_index;
         msg.size = sizeof(m.state);
         break;
 
     case VHOST_GET_VRING_BASE:
         memcpy(&msg.state, arg, sizeof(struct vhost_vring_state));
-        msg.state.index += dev->vq_index;
         msg.size = sizeof(m.state);
         need_reply = 1;
         break;
 
     case VHOST_SET_VRING_ADDR:
         memcpy(&msg.addr, arg, sizeof(struct vhost_vring_addr));
-        msg.addr.index += dev->vq_index;
         msg.size = sizeof(m.addr);
         break;
 
@@ -279,7 +271,7 @@ static int vhost_user_call(struct vhost_dev *dev, unsigned 
long int request,
     case VHOST_SET_VRING_CALL:
     case VHOST_SET_VRING_ERR:
         file = arg;
-        msg.u64 = (file->index + dev->vq_index) & VHOST_USER_VRING_IDX_MASK;
+        msg.u64 = file->index & VHOST_USER_VRING_IDX_MASK;
         msg.size = sizeof(m.u64);
         if (ioeventfd_enabled() && file->fd > 0) {
             fds[fd_num++] = file->fd;
@@ -321,7 +313,6 @@ static int vhost_user_call(struct vhost_dev *dev, unsigned 
long int request,
                 error_report("Received bad msg size.");
                 return -1;
             }
-            msg.state.index -= dev->vq_index;
             memcpy(arg, &msg.state, sizeof(struct vhost_vring_state));
             break;
         default:
diff --git a/net/vhost-user.c b/net/vhost-user.c
index b51bc04..93dcecd 100644
--- a/net/vhost-user.c
+++ b/net/vhost-user.c
@@ -120,39 +120,35 @@ static void net_vhost_user_event(void *opaque, int event)
     case CHR_EVENT_OPENED:
         vhost_user_start(s);
         net_vhost_link_down(s, false);
-        error_report("chardev \"%s\" went up", s->nc.info_str);
+        error_report("chardev \"%s\" went up", s->chr->label);
         break;
     case CHR_EVENT_CLOSED:
         net_vhost_link_down(s, true);
         vhost_user_stop(s);
-        error_report("chardev \"%s\" went down", s->nc.info_str);
+        error_report("chardev \"%s\" went down", s->chr->label);
         break;
     }
 }
 
 static int net_vhost_user_init(NetClientState *peer, const char *device,
-                               const char *name, CharDriverState *chr,
-                               uint32_t queues)
+                               const char *name, CharDriverState *chr)
 {
     NetClientState *nc;
     VhostUserState *s;
-    int i;
 
-    for (i = 0; i < queues; i++) {
-        nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name);
+    nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name);
 
-        snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user%d to %s",
-                 i, chr->label);
+    snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user to %s",
+             chr->label);
 
-        s = DO_UPCAST(VhostUserState, nc, nc);
+    s = DO_UPCAST(VhostUserState, nc, nc);
 
-        /* We don't provide a receive callback */
-        s->nc.receive_disabled = 1;
-        s->chr = chr;
-        s->nc.queue_index = i;
+    /* We don't provide a receive callback */
+    s->nc.receive_disabled = 1;
+    s->chr = chr;
+
+    qemu_chr_add_handlers(s->chr, NULL, NULL, net_vhost_user_event, s);
 
-        qemu_chr_add_handlers(s->chr, NULL, NULL, net_vhost_user_event, s);
-    }
     return 0;
 }
 
@@ -230,7 +226,6 @@ static int net_vhost_check_net(void *opaque, QemuOpts 
*opts, Error **errp)
 int net_init_vhost_user(const NetClientOptions *opts, const char *name,
                         NetClientState *peer, Error **errp)
 {
-    uint32_t queues;
     const NetdevVhostUserOptions *vhost_user_opts;
     CharDriverState *chr;
 
@@ -248,12 +243,6 @@ int net_init_vhost_user(const NetClientOptions *opts, 
const char *name,
         return -1;
     }
 
-    /* number of queues for multiqueue */
-    if (vhost_user_opts->has_queues) {
-        queues = vhost_user_opts->queues;
-    } else {
-        queues = 1;
-    }
 
-    return net_vhost_user_init(peer, "vhost_user", name, chr, queues);
+    return net_vhost_user_init(peer, "vhost_user", name, chr);
 }
diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
index 2c8e934..650bb18 100644
--- a/docs/specs/vhost-user.txt
+++ b/docs/specs/vhost-user.txt
@@ -127,11 +127,6 @@ in the ancillary data:
 If Master is unable to send the full message or receives a wrong reply it will
 close the connection. An optional reconnection mechanism can be implemented.
 
-Multi queue support
--------------------
-The protocol supports multiple queues by setting all index fields in the sent
-messages to a properly calculated value.
-
 Message types
 -------------
 
diff --git a/qemu-options.hx b/qemu-options.hx
index 7b8efbf..8c9add9 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1963,14 +1963,13 @@ The hubport netdev lets you connect a NIC to a QEMU 
"vlan" instead of a single
 netdev.  @code{-net} and @code{-device} with parameter @option{vlan} create the
 required hub automatically.
 
address@hidden -netdev vhost-user,address@hidden,vhostforce=on|off][,queues=n]
address@hidden -netdev vhost-user,address@hidden,vhostforce=on|off]
 
 Establish a vhost-user netdev, backed by a chardev @var{id}. The chardev should
 be a unix domain socket backed one. The vhost-user uses a specifically defined
 protocol to pass vhost ioctl replacement messages to an application on the 
other
 end of the socket. On non-MSIX guests, the feature can be forced with
address@hidden Use 'address@hidden' to specify the number of queues to
-be created for multiqueue vhost-user.
address@hidden
 
 Example:
 @example
-- 
MST