On Mon, Jul 11, 2016 at 02:56:52PM +0000, Dexuan Cui wrote: > Hyper-V Sockets (hv_sock) supplies a byte-stream based communication > mechanism between the host and the guest. It's somewhat like TCP over > VMBus, but the transportation layer (VMBus) is much simpler than IP. > > With Hyper-V Sockets, applications between the host and the guest can talk > to each other directly by the traditional BSD-style socket APIs. > > Hyper-V Sockets is only available on new Windows hosts, like Windows Server > 2016. More info is in this article "Make your own integration services": > https://msdn.microsoft.com/en-us/virtualization/hyperv_on_windows/develop/make_mgmt_service > > The patch implements the necessary support in the guest side by introducing > a new socket address family AF_HYPERV. > > Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx> > Cc: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx> > Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> > Cc: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> > Cc: Cathy Avery <cavery@xxxxxxxxxx> > Cc: Olaf Hering <olaf@xxxxxxxxx> > --- > > You can also get the patch by (commit 5dde7975): > https://github.com/dcui/linux/tree/decui/hv_sock/net-next/20160711_v16 > > > For the change log before v12, please see https://lkml.org/lkml/2016/5/15/31 > > In v12, the changes are mainly the following: > > 1) remove the module params as David suggested. > > 2) use 5 exact pages for VMBus send/recv rings, respectively. > The host side's design of the feature requires 5 exact pages for recv/send > rings respectively -- this is suboptimal considering memory consumption, > however unluckily we have to live with it, before the host comes up with > a new design in the future. :-( > > 3) remove the per-connection static send/recv buffers > Instead, we allocate and free the buffers dynamically only when we recv/send > data. This means: when a connection is idle, no memory is consumed as > recv/send buffers at all. > > In v13: > I return ENOMEM on buffer alllocation failure > > Actually "man read/write" says "Other errors may occur, depending on the > object connected to fd". "man send/recv" indeed lists ENOMEM. > Considering AF_HYPERV is a new socket type, ENOMEM seems OK here. > In the long run, I think we should add a new API in the VMBus driver, > allowing data copy from VMBus ringbuffer into user mode buffer directly. > This way, we can even eliminate this temporary buffer. > > In v14: > fix some coding style issues pointed out by David. > > In v15: > Just some stylistic changes addressing comments from Joe Perches and > Olaf Hering -- thank you! > - add a GPL blurb. > - define a new macro PAGE_SIZE_4K and use it to replace PAGE_SIZE > - change sk_to_hvsock/hvsock_to_sk() from macros to inline functions > - remove a not-very-useful pr_err() > - fix some typos in comment and coding style issues. > > In v16: > Made stylistic changes addressing comments from Vitaly Kuznetsov. > Thank you very much for the detailed comments, Vitaly! > > Looking forward to your comments! > > MAINTAINERS | 2 + > include/linux/hyperv.h | 13 + > include/linux/socket.h | 4 +- > include/net/af_hvsock.h | 78 +++ > include/uapi/linux/hyperv.h | 23 + > net/Kconfig | 1 + > net/Makefile | 1 + > net/hv_sock/Kconfig | 10 + > net/hv_sock/Makefile | 3 + > net/hv_sock/af_hvsock.c | 1509 +++++++++++++++++++++++++++++++++++++++++++ > 10 files changed, 1643 insertions(+), 1 deletion(-) ... > +static LIST_HEAD(hvsock_bound_list); > +static LIST_HEAD(hvsock_connected_list); > +static DEFINE_MUTEX(hvsock_mutex); > + > +static struct sock *hvsock_find_bound_socket(const struct sockaddr_hv *addr) > +{ > + struct hvsock_sock *hvsk; > + > + list_for_each_entry(hvsk, &hvsock_bound_list, bound_list) { > + if (!uuid_le_cmp(addr->shv_service_guid, > + hvsk->local_addr.shv_service_guid)) > + return hvsock_to_sk(hvsk); > + } > + return NULL; > +} > + > +static struct sock *hvsock_find_connected_socket_by_channel( > + const struct vmbus_channel *channel) > +{ > + struct hvsock_sock *hvsk; > + > + list_for_each_entry(hvsk, &hvsock_connected_list, connected_list) { > + if (hvsk->channel == channel) > + return hvsock_to_sk(hvsk); > + } > + return NULL; > +} How does this work from performance point of view if there are many connected sockets and/or high frequency of new connections? AFAICS most other families use a hash table for socket lookup. > +static void get_ringbuffer_rw_status(struct vmbus_channel *channel, > + bool *can_read, bool *can_write) > +{ > + u32 avl_read_bytes, avl_write_bytes, dummy; > + > + if (can_read) { > + hv_get_ringbuffer_availbytes(&channel->inbound, > + &avl_read_bytes, > + &dummy); > + /* 0-size payload means FIN */ > + *can_read = avl_read_bytes >= HVSOCK_PKT_LEN(0); > + } > + > + if (can_write) { > + hv_get_ringbuffer_availbytes(&channel->outbound, > + &dummy, > + &avl_write_bytes); > + > + /* We only write if there is enough space */ > + *can_write = avl_write_bytes > HVSOCK_PKT_LEN(PAGE_SIZE); I'm not sure where does this come from but is this really supposed to be PAGE_SIZE (not the fixed 4KB PAGE_SIZE_4K)? > +static int hvsock_open_connection(struct vmbus_channel *channel) > +{ > + struct hvsock_sock *hvsk, *new_hvsk; > + uuid_le *instance, *service_id; > + unsigned char conn_from_host; > + struct sockaddr_hv hv_addr; > + struct sock *sk, *new_sk; > + int ret; > + > + instance = &channel->offermsg.offer.if_instance; > + service_id = &channel->offermsg.offer.if_type; > + > + /* The first byte != 0 means the host initiated the connection. */ > + conn_from_host = channel->offermsg.offer.u.pipe.user_def[0]; > + > + mutex_lock(&hvsock_mutex); > + > + hvsock_addr_init(&hv_addr, conn_from_host ? *service_id : *instance); > + sk = hvsock_find_bound_socket(&hv_addr); > + > + if (!sk || (conn_from_host && sk->sk_state != SS_LISTEN) || > + (!conn_from_host && sk->sk_state != SS_CONNECTING)) { > + ret = -ENXIO; > + goto out; > + } > + > + if (conn_from_host) { > + if (sk->sk_ack_backlog >= sk->sk_max_ack_backlog) { > + ret = -ECONNREFUSED; > + goto out; > + } > + > + new_sk = hvsock_create(sock_net(sk), NULL, GFP_KERNEL, > + sk->sk_type); > + if (!new_sk) { > + ret = -ENOMEM; > + goto out; > + } > + > + new_sk->sk_state = SS_CONNECTING; > + new_hvsk = sk_to_hvsock(new_sk); > + new_hvsk->channel = channel; > + hvsock_addr_init(&new_hvsk->local_addr, *service_id); > + hvsock_addr_init(&new_hvsk->remote_addr, *instance); > + } else { > + hvsk = sk_to_hvsock(sk); > + hvsk->channel = channel; > + } > + > + set_channel_read_state(channel, false); > + ret = vmbus_open(channel, RINGBUFFER_HVSOCK_SND_SIZE, > + RINGBUFFER_HVSOCK_RCV_SIZE, NULL, 0, > + hvsock_on_channel_cb, conn_from_host ? new_sk : sk); > + if (ret != 0) { > + if (conn_from_host) { > + new_hvsk->channel = NULL; > + sock_put(new_sk); > + } else { > + hvsk->channel = NULL; > + } > + goto out; > + } > + > + vmbus_set_chn_rescind_callback(channel, hvsock_close_connection); > + > + /* see get_ringbuffer_rw_status() */ > + set_channel_pending_send_size(channel, HVSOCK_PKT_LEN(PAGE_SIZE) + 1); Same question. > + > + if (conn_from_host) { > + new_sk->sk_state = SS_CONNECTED; > + > + sock_hold(&new_hvsk->sk); > + list_add(&new_hvsk->connected_list, &hvsock_connected_list); > + > + hvsock_enqueue_accept(sk, new_sk); > + } else { > + sk->sk_state = SS_CONNECTED; > + sk->sk_socket->state = SS_CONNECTED; > + > + sock_hold(&hvsk->sk); > + list_add(&hvsk->connected_list, &hvsock_connected_list); > + } > + > + sk->sk_state_change(sk); > +out: > + mutex_unlock(&hvsock_mutex); > + return ret; > +} ... > +static int hvsock_create_sock(struct net *net, struct socket *sock, > + int protocol, int kern) > +{ > + struct sock *sk; > + > + if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN)) > + return -EPERM; Looks like any application wanting to use hyper-v sockets will need rather high privileges. It would make sense if these sockets were reserved for privileged tasks like VM management. But according to the commit message, hv_sock is supposed to be used for regular application to application communication. Requiring CAP_{SYS,NET}_ADMIN looks like an overkill to me. > + > + if (protocol != 0 && protocol != SHV_PROTO_RAW) > + return -EPROTONOSUPPORT; > + > + switch (sock->type) { > + case SOCK_STREAM: > + sock->ops = &hvsock_ops; > + break; > + default: > + return -ESOCKTNOSUPPORT; > + } > + > + sock->state = SS_UNCONNECTED; > + > + sk = hvsock_create(net, sock, GFP_KERNEL, 0); > + return sk ? 0 : -ENOMEM; > +} Michal Kubecek _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
