On Tue, Sep 08, 2015 at 03:38:46PM +0800, Yuanhan Liu wrote: > From: Ouyang Changchun <changchun.ouy...@intel.com> > > This patch is initially based a patch from Nikolay Nikolaev. > > Here is the latest version for adding vhost-user multiple queue support, > by creating a nc and vhost_net pair for each queue. > > What differs from last version is that this patch addresses two major > concerns from Michael, and fixes one hidden bug. > > - Concern #1: no feedback when the backend can't support # of > requested queues(by providing queues=# option). > > Here we address this issue by querying VHOST_USER_PROTOCOL_F_MQ > protocol features first, if not set, it means the backend don't > support mq feature, and let max_queues be 1. Otherwise, we send > another message, VHOST_USER_GET_QUEUE_NUM, for getting the max_queues > the backend supports. > > At vhost-user initiation stage(net_vhost_user_start), we then initiate > one queue first, which, in the meantime, also gets the max_queues. > We then do a simple compare: if requested_queues > max_queues, we > exit(I guess it's safe to exit here, as the vm is not running yet). > > - Concern #2: some messages are sent more times than necessary. > > We came an agreement with Michael that we could categorize vhost > user messages to 2 types: none-vring specific messages, which should > be sent only once, and vring specific messages, which should be sent > per queue. > > Here I introduced a helper function vhost_user_one_time_request(), > which lists following messages as none-vring specific messages: > > VHOST_USER_GET_FEATURES > VHOST_USER_SET_FEATURES > VHOST_USER_GET_PROTOCOL_FEATURES > VHOST_USER_SET_PROTOCOL_FEATURES > VHOST_USER_SET_OWNER > VHOST_USER_RESET_DEVICE > VHOST_USER_SET_MEM_TABLE > VHOST_USER_GET_QUEUE_NUM > > For above messages, we simply ignore them when they are not sent the first > time. > > I also observed a hidden bug from last version. We register the char dev > event handler N times, which is not necessary, as well as buggy: A later > register overwrites the former one, as qemu_chr_add_handlers() will not > chain those handlers, but instead overwrites the old one. So, in theory, > invoking qemu_chr_add_handlers N times will not end up with calling the > handler N times. > > However, the reason the handler is invoked N times is because we start > the backend(the connection server) first, and hence when net_vhost_user_init() > is executed, the connection is already established, and > qemu_chr_add_handlers() > then invoke the handler immediately, which just looks like we invoke the > handler(net_vhost_user_event) directly from net_vhost_user_init(). > > The solution I came up with is to make VhostUserState as an upper level > structure, making it includes N nc and vhost_net pairs: > > struct VhostUserNetPeer { > NetClientState *nc; > VHostNetState *vhost_net; > }; > > typedef struct VhostUserState { > CharDriverState *chr; > bool running; > int queues; > struct VhostUserNetPeer peers[]; > } VhostUserState; > > Signed-off-by: Nikolay Nikolaev <n.nikol...@virtualopensystems.com> > Signed-off-by: Changchun Ouyang <changchun.ouy...@intel.com> > Signed-off-by: Yuanhan Liu <yuanhan....@linux.intel.com> > --- > docs/specs/vhost-user.txt | 13 +++++ > hw/virtio/vhost-user.c | 31 ++++++++++- > include/net/net.h | 1 + > net/vhost-user.c | 136 > ++++++++++++++++++++++++++++++++-------------- > qapi-schema.json | 6 +- > qemu-options.hx | 5 +- > 6 files changed, 146 insertions(+), 46 deletions(-) > > diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt > index 43db9b4..99d79be 100644 > --- a/docs/specs/vhost-user.txt > +++ b/docs/specs/vhost-user.txt > @@ -135,6 +135,19 @@ As older slaves don't support negotiating protocol > features, > a feature bit was dedicated for this purpose: > #define VHOST_USER_F_PROTOCOL_FEATURES 30 > > +Multiple queue support > +------------------- > +Multiple queue is treated as a protocal extension, hence the slave has to > +implement protocol features first. Multiple queues is supported only when > +the protocol feature VHOST_USER_PROTOCOL_F_MQ(bit 0) is set. > + > +The max # of queues the slave support can be queried with message > +VHOST_USER_GET_PROTOCOL_FEATURES. Master should stop when the # of requested > +queues is bigger than that. > + > +As all queues share one connection, the master use a unique index for each > +queue in the sent message to identify one specified queue. > +
Please also document that only 2 queues are enabled initially. More queues are enabled dynamically. To enable more queues, the new message needs to be sent (added by patch 7). > Message types > ------------- > > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c > index 8046bc0..11e46b5 100644 > --- a/hw/virtio/vhost-user.c > +++ b/hw/virtio/vhost-user.c > @@ -187,6 +187,23 @@ static int vhost_user_write(struct vhost_dev *dev, > VhostUserMsg *msg, > 0 : -1; > } > > +static bool vhost_user_one_time_request(VhostUserRequest request) > +{ > + switch (request) { > + case VHOST_USER_GET_FEATURES: > + case VHOST_USER_SET_FEATURES: > + case VHOST_USER_GET_PROTOCOL_FEATURES: > + case VHOST_USER_SET_PROTOCOL_FEATURES: > + case VHOST_USER_SET_OWNER: > + case VHOST_USER_RESET_DEVICE: > + case VHOST_USER_SET_MEM_TABLE: > + case VHOST_USER_GET_QUEUE_NUM: > + return true; > + default: > + return false; > + } > +} > + > static int vhost_user_call(struct vhost_dev *dev, unsigned long int request, > void *arg) > { > @@ -206,6 +223,14 @@ static int vhost_user_call(struct vhost_dev *dev, > unsigned long int request, > else > msg_request = request; > > + /* > + * For none-vring specific requests, like VHOST_USER_GET_FEATURES, > + * we just need send it once in the first time. For later such > + * request, we just ignore it. > + */ > + if (vhost_user_one_time_request(msg_request) && dev->vq_index != 0) > + return 0; > + > msg.request = msg_request; > msg.flags = VHOST_USER_VERSION; > msg.size = 0; > @@ -268,17 +293,20 @@ static int vhost_user_call(struct vhost_dev *dev, > unsigned long int request, > case VHOST_USER_SET_VRING_NUM: > case VHOST_USER_SET_VRING_BASE: > memcpy(&msg.state, arg, sizeof(struct vhost_vring_state)); > + msg.addr.index += dev->vq_index; > msg.size = sizeof(m.state); > break; > > case VHOST_USER_GET_VRING_BASE: > memcpy(&msg.state, arg, sizeof(struct vhost_vring_state)); > + msg.addr.index += dev->vq_index; > msg.size = sizeof(m.state); > need_reply = 1; > break; > > case VHOST_USER_SET_VRING_ADDR: > memcpy(&msg.addr, arg, sizeof(struct vhost_vring_addr)); > + msg.addr.index += dev->vq_index; > msg.size = sizeof(m.addr); > break; > > @@ -286,7 +314,7 @@ static int vhost_user_call(struct vhost_dev *dev, > unsigned long int request, > case VHOST_USER_SET_VRING_CALL: > case VHOST_USER_SET_VRING_ERR: > file = arg; > - msg.u64 = file->index & VHOST_USER_VRING_IDX_MASK; > + msg.u64 = (file->index + dev->vq_index) & VHOST_USER_VRING_IDX_MASK; > msg.size = sizeof(m.u64); > if (ioeventfd_enabled() && file->fd > 0) { > fds[fd_num++] = file->fd; > @@ -330,6 +358,7 @@ 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/include/net/net.h b/include/net/net.h > index 6a6cbef..6f20656 100644 > --- a/include/net/net.h > +++ b/include/net/net.h > @@ -92,6 +92,7 @@ struct NetClientState { > NetClientDestructor *destructor; > unsigned int queue_index; > unsigned rxfilter_notify_enabled:1; > + void *opaque; > }; > > typedef struct NICState { > diff --git a/net/vhost-user.c b/net/vhost-user.c > index 2d6bbe5..7d4ac69 100644 > --- a/net/vhost-user.c > +++ b/net/vhost-user.c > @@ -15,10 +15,16 @@ > #include "qemu/config-file.h" > #include "qemu/error-report.h" > > +struct VhostUserNetPeer { > + NetClientState *nc; > + VHostNetState *vhost_net; > +}; > + > typedef struct VhostUserState { > - NetClientState nc; > CharDriverState *chr; > - VHostNetState *vhost_net; > + bool running; > + int queues; > + struct VhostUserNetPeer peers[]; > } VhostUserState; > > typedef struct VhostUserChardevProps { > @@ -29,48 +35,75 @@ typedef struct VhostUserChardevProps { > > VHostNetState *vhost_user_get_vhost_net(NetClientState *nc) > { > - VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc); > + VhostUserState *s = nc->opaque; > assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER); > - return s->vhost_net; > -} > - > -static int vhost_user_running(VhostUserState *s) > -{ > - return (s->vhost_net) ? 1 : 0; > + return s->peers[nc->queue_index].vhost_net; > } > > static int vhost_user_start(VhostUserState *s) > { > VhostNetOptions options; > + VHostNetState *vhost_net; > + int max_queues; > + int i = 0; > > - if (vhost_user_running(s)) { > + if (s->running) > return 0; > - } > > options.backend_type = VHOST_BACKEND_TYPE_USER; > - options.net_backend = &s->nc; > options.opaque = s->chr; > > - s->vhost_net = vhost_net_init(&options); > + options.net_backend = s->peers[i].nc; > + vhost_net = s->peers[i++].vhost_net = vhost_net_init(&options); > + > + max_queues = vhost_net_get_max_queues(vhost_net); > + if (s->queues >= max_queues) { > + error_report("you are asking more queues than supported: %d\n", > + max_queues); > + return -1; > + } > + > + for (; i < s->queues; i++) { > + options.net_backend = s->peers[i].nc; > + > + s->peers[i].vhost_net = vhost_net_init(&options); > + if (!s->peers[i].vhost_net) > + return -1; > + } > + s->running = true; > > - return vhost_user_running(s) ? 0 : -1; > + return 0; > } > > static void vhost_user_stop(VhostUserState *s) > { > - if (vhost_user_running(s)) { > - vhost_net_cleanup(s->vhost_net); > + int i; > + VHostNetState *vhost_net; > + > + if (!s->running) > + return; > + > + for (i = 0; i < s->queues; i++) { > + vhost_net = s->peers[i].vhost_net; > + if (vhost_net) > + vhost_net_cleanup(vhost_net); > } > > - s->vhost_net = 0; > + s->running = false; > } > > static void vhost_user_cleanup(NetClientState *nc) > { > - VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc); > + VhostUserState *s = nc->opaque; > + VHostNetState *vhost_net = s->peers[nc->queue_index].vhost_net; > + > + if (vhost_net) > + vhost_net_cleanup(vhost_net); > > - vhost_user_stop(s); > qemu_purge_queued_packets(nc); > + > + if (nc->queue_index == s->queues - 1) > + free(s); > } > > static bool vhost_user_has_vnet_hdr(NetClientState *nc) > @@ -89,7 +122,7 @@ static bool vhost_user_has_ufo(NetClientState *nc) > > static NetClientInfo net_vhost_user_info = { > .type = NET_CLIENT_OPTIONS_KIND_VHOST_USER, > - .size = sizeof(VhostUserState), > + .size = sizeof(NetClientState), > .cleanup = vhost_user_cleanup, > .has_vnet_hdr = vhost_user_has_vnet_hdr, > .has_ufo = vhost_user_has_ufo, > @@ -97,18 +130,25 @@ static NetClientInfo net_vhost_user_info = { > > static void net_vhost_link_down(VhostUserState *s, bool link_down) > { > - s->nc.link_down = link_down; > + NetClientState *nc; > + int i; > > - if (s->nc.peer) { > - s->nc.peer->link_down = link_down; > - } > + for (i = 0; i < s->queues; i++) { > + nc = s->peers[i].nc; > > - if (s->nc.info->link_status_changed) { > - s->nc.info->link_status_changed(&s->nc); > - } > + nc->link_down = link_down; > + > + if (nc->peer) { > + nc->peer->link_down = link_down; > + } > > - if (s->nc.peer && s->nc.peer->info->link_status_changed) { > - s->nc.peer->info->link_status_changed(s->nc.peer); > + if (nc->info->link_status_changed) { > + nc->info->link_status_changed(nc); > + } > + > + if (nc->peer && nc->peer->info->link_status_changed) { > + nc->peer->info->link_status_changed(nc->peer); > + } > } > } > > @@ -118,7 +158,8 @@ static void net_vhost_user_event(void *opaque, int event) > > switch (event) { > case CHR_EVENT_OPENED: > - vhost_user_start(s); > + if (vhost_user_start(s) < 0) > + exit(1); > net_vhost_link_down(s, false); > error_report("chardev \"%s\" went up", s->chr->label); > break; > @@ -131,24 +172,28 @@ static void net_vhost_user_event(void *opaque, int > event) > } > > static int net_vhost_user_init(NetClientState *peer, const char *device, > - const char *name, CharDriverState *chr) > + const char *name, VhostUserState *s) > { > NetClientState *nc; > - VhostUserState *s; > + CharDriverState *chr = s->chr; > + int i; > > - nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name); > + for (i = 0; i < s->queues; i++) { > + nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name); > > - snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user to %s", > - chr->label); > + snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user%d to %s", > + i, chr->label); > > - s = DO_UPCAST(VhostUserState, nc, nc); > + /* We don't provide a receive callback */ > + nc->receive_disabled = 1; > > - /* We don't provide a receive callback */ > - s->nc.receive_disabled = 1; > - s->chr = chr; > - nc->queue_index = 0; > + nc->queue_index = i; > + nc->opaque = s; > > - qemu_chr_add_handlers(s->chr, NULL, NULL, net_vhost_user_event, s); > + s->peers[i].nc = nc; > + } > + > + qemu_chr_add_handlers(chr, NULL, NULL, net_vhost_user_event, s); > > return 0; > } > @@ -227,8 +272,10 @@ 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) > { > + int queues; > const NetdevVhostUserOptions *vhost_user_opts; > CharDriverState *chr; > + VhostUserState *s; > > assert(opts->kind == NET_CLIENT_OPTIONS_KIND_VHOST_USER); > vhost_user_opts = opts->vhost_user; > @@ -244,6 +291,11 @@ int net_init_vhost_user(const NetClientOptions *opts, > const char *name, > return -1; > } > > + queues = vhost_user_opts->has_queues ? vhost_user_opts->queues : 1; > + s = g_malloc0(sizeof(VhostUserState) + > + queues * sizeof(struct VhostUserNetPeer)); > + s->queues = queues; > + s->chr = chr; > > - return net_vhost_user_init(peer, "vhost_user", name, chr); > + return net_vhost_user_init(peer, "vhost_user", name, s); > } > diff --git a/qapi-schema.json b/qapi-schema.json > index 67fef37..55c33db 100644 > --- a/qapi-schema.json > +++ b/qapi-schema.json > @@ -2480,12 +2480,16 @@ > # > # @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 2.5) > +# > # Since 2.1 > ## > { 'struct': 'NetdevVhostUserOptions', > 'data': { > 'chardev': 'str', > - '*vhostforce': 'bool' } } > + '*vhostforce': 'bool', > + '*queues': 'int' } } > > ## > # @NetClientOptions > diff --git a/qemu-options.hx b/qemu-options.hx > index 77f5853..5bfa7a3 100644 > --- a/qemu-options.hx > +++ b/qemu-options.hx > @@ -1963,13 +1963,14 @@ 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. > > -@item -netdev vhost-user,chardev=@var{id}[,vhostforce=on|off] > +@item -netdev vhost-user,chardev=@var{id}[,vhostforce=on|off][,queues=n] > > 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 > -@var{vhostforce}. > +@var{vhostforce}. Use 'queues=@var{n}' to specify the number of queues to > +be created for multiqueue vhost-user. > > Example: > @example > -- > 1.9.0 >