On Wed, Aug 12, 2015 at 02:25:41PM +0800, Ouyang Changchun wrote:
> Based on patch by Nikolay Nikolaev:
> Vhost-user will implement the multi queue support in a similar way
> to what vhost already has - a separate thread for each queue.
> To enable the multi queue functionality - a new command line parameter
> "queues" is introduced for the vhost-user netdev.
>
> The RESET_OWNER change is based on commit:
> 294ce717e0f212ed0763307f3eab72b4a1bdf4d0
> If it is reverted, the patch need update for it accordingly.
>
> Signed-off-by: Nikolay Nikolaev <n.nikol...@virtualopensystems.com>
> Signed-off-by: Changchun Ouyang <changchun.ouy...@intel.com>
> ---
> Changes since v5:
> - fix the message descption for VHOST_RESET_OWNER in vhost-user txt
>
> Changes since v4:
> - remove the unnecessary trailing '\n'
>
> Changes since v3:
> - fix one typo and wrap one long line
>
> Changes since v2:
> - fix vq index issue for set_vring_call
> When it is the case of VHOST_SET_VRING_CALL, The vq_index is not
> initialized before it is used,
> thus it could be a random value. The random value leads to crash in vhost
> after passing down
> to vhost, as vhost use this random value to index an array index.
> - fix the typo in the doc and description
> - address vq index for reset_owner
>
> Changes since v1:
> - use s->nc.info_str when bringing up/down the backend
>
> docs/specs/vhost-user.txt | 7 ++++++-
> hw/net/vhost_net.c | 3 ++-
> hw/virtio/vhost-user.c | 11 ++++++++++-
> net/vhost-user.c | 37 ++++++++++++++++++++++++-------------
> qapi-schema.json | 6 +++++-
> qemu-options.hx | 5 +++--
> 6 files changed, 50 insertions(+), 19 deletions(-)
>
> diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
> index 70da3b1..9390f89 100644
> --- a/docs/specs/vhost-user.txt
> +++ b/docs/specs/vhost-user.txt
> @@ -135,6 +135,11 @@ As older slaves don't support negotiating protocol
> features,
> a feature bit was dedicated for this purpose:
> #define VHOST_USER_F_PROTOCOL_FEATURES 30
>
> +Multi queue support
> +-------------------
> +The protocol supports multiple queues by setting all index fields in the sent
> +messages to a properly calculated value.
> +
> Message types
> -------------
>
> @@ -198,7 +203,7 @@ Message types
>
> Id: 4
> Equivalent ioctl: VHOST_RESET_OWNER
> - Master payload: N/A
> + Master payload: vring state description
>
> Issued when a new connection is about to be closed. The Master will no
> longer own this connection (and will usually close it).
This is an interface change, isn't it?
We can't make it unconditionally, need to make it dependent
on a protocol flag.
> diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
> index 1f25cb3..9cd6c05 100644
> --- a/hw/net/vhost_net.c
> +++ b/hw/net/vhost_net.c
> @@ -159,6 +159,7 @@ 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, options->force);
> @@ -269,7 +270,7 @@ 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,
> - NULL);
> + &file);
> assert(r >= 0);
> }
> }
> diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> index 27ba035..fb11d4c 100644
> --- a/hw/virtio/vhost-user.c
> +++ b/hw/virtio/vhost-user.c
> @@ -219,7 +219,12 @@ static int vhost_user_call(struct vhost_dev *dev,
> unsigned long int request,
> break;
>
> case VHOST_USER_SET_OWNER:
> + break;
> +
> case VHOST_USER_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_USER_SET_MEM_TABLE:
> @@ -262,17 +267,20 @@ 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.state.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.state.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;
>
> @@ -280,7 +288,7 @@ 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;
> @@ -322,6 +330,7 @@ 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/net/vhost-user.c b/net/vhost-user.c
> index 1d86a2b..904d8af 100644
> --- a/net/vhost-user.c
> +++ b/net/vhost-user.c
> @@ -121,35 +121,39 @@ 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->chr->label);
> + error_report("chardev \"%s\" went up", s->nc.info_str);
> break;
> case CHR_EVENT_CLOSED:
> net_vhost_link_down(s, true);
> vhost_user_stop(s);
> - error_report("chardev \"%s\" went down", s->chr->label);
> + error_report("chardev \"%s\" went down", s->nc.info_str);
> break;
> }
> }
>
> static int net_vhost_user_init(NetClientState *peer, const char *device,
> - const char *name, CharDriverState *chr)
> + const char *name, CharDriverState *chr,
> + uint32_t queues)
> {
> NetClientState *nc;
> VhostUserState *s;
> + int i;
>
> - nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name);
> + for (i = 0; i < 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);
> + s = DO_UPCAST(VhostUserState, nc, nc);
>
> - /* 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);
> + /* We don't provide a receive callback */
> + s->nc.receive_disabled = 1;
> + s->chr = chr;
> + s->nc.queue_index = i;
>
> + qemu_chr_add_handlers(s->chr, NULL, NULL, net_vhost_user_event, s);
> + }
> return 0;
> }
>
> @@ -225,6 +229,7 @@ static int net_vhost_check_net(QemuOpts *opts, void
> *opaque)
There are two problems here:
1. we don't really know that the backend
is able to support the requested number of queues.
If not, everything will fail, silently.
A new message to query the # of queues could help, though
I'm not sure what can be done on failure. Fail connection?
2. each message (e.g. set memory table) is sent multiple times,
on the same socket.
> int net_init_vhost_user(const NetClientOptions *opts, const char *name,
> NetClientState *peer)
> {
> + uint32_t queues;
> const NetdevVhostUserOptions *vhost_user_opts;
> CharDriverState *chr;
>
> @@ -243,6 +248,12 @@ 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);
> + return net_vhost_user_init(peer, "vhost_user", name, chr, queues);
> }
> diff --git a/qapi-schema.json b/qapi-schema.json
> index f97ffa1..51e40ce 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -2444,12 +2444,16 @@
> #
> # @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': 'uint32' } }
>
> ##
> # @NetClientOptions
> diff --git a/qemu-options.hx b/qemu-options.hx
> index ec356f6..dad035e 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -1942,13 +1942,14 @@ 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
> --
> 1.8.4.2
>
