| /* |
| * (c) 2017 Stefano Stabellini <stefano@aporeto.com> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/net.h> |
| #include <linux/socket.h> |
| |
| #include <net/sock.h> |
| |
| #include <xen/events.h> |
| #include <xen/grant_table.h> |
| #include <xen/xen.h> |
| #include <xen/xenbus.h> |
| #include <xen/interface/io/pvcalls.h> |
| |
| #include "pvcalls-front.h" |
| |
| #define PVCALLS_INVALID_ID UINT_MAX |
| #define PVCALLS_RING_ORDER XENBUS_MAX_RING_GRANT_ORDER |
| #define PVCALLS_NR_RSP_PER_RING __CONST_RING_SIZE(xen_pvcalls, XEN_PAGE_SIZE) |
| #define PVCALLS_FRONT_MAX_SPIN 5000 |
| |
| struct pvcalls_bedata { |
| struct xen_pvcalls_front_ring ring; |
| grant_ref_t ref; |
| int irq; |
| |
| struct list_head socket_mappings; |
| spinlock_t socket_lock; |
| |
| wait_queue_head_t inflight_req; |
| struct xen_pvcalls_response rsp[PVCALLS_NR_RSP_PER_RING]; |
| }; |
| /* Only one front/back connection supported. */ |
| static struct xenbus_device *pvcalls_front_dev; |
| static atomic_t pvcalls_refcount; |
| |
| /* first increment refcount, then proceed */ |
| #define pvcalls_enter() { \ |
| atomic_inc(&pvcalls_refcount); \ |
| } |
| |
| /* first complete other operations, then decrement refcount */ |
| #define pvcalls_exit() { \ |
| atomic_dec(&pvcalls_refcount); \ |
| } |
| |
| struct sock_mapping { |
| bool active_socket; |
| struct list_head list; |
| struct socket *sock; |
| union { |
| struct { |
| int irq; |
| grant_ref_t ref; |
| struct pvcalls_data_intf *ring; |
| struct pvcalls_data data; |
| struct mutex in_mutex; |
| struct mutex out_mutex; |
| |
| wait_queue_head_t inflight_conn_req; |
| } active; |
| struct { |
| /* Socket status */ |
| #define PVCALLS_STATUS_UNINITALIZED 0 |
| #define PVCALLS_STATUS_BIND 1 |
| #define PVCALLS_STATUS_LISTEN 2 |
| uint8_t status; |
| /* |
| * Internal state-machine flags. |
| * Only one accept operation can be inflight for a socket. |
| * Only one poll operation can be inflight for a given socket. |
| */ |
| #define PVCALLS_FLAG_ACCEPT_INFLIGHT 0 |
| #define PVCALLS_FLAG_POLL_INFLIGHT 1 |
| #define PVCALLS_FLAG_POLL_RET 2 |
| uint8_t flags; |
| uint32_t inflight_req_id; |
| struct sock_mapping *accept_map; |
| wait_queue_head_t inflight_accept_req; |
| } passive; |
| }; |
| }; |
| |
| static inline int get_request(struct pvcalls_bedata *bedata, int *req_id) |
| { |
| *req_id = bedata->ring.req_prod_pvt & (RING_SIZE(&bedata->ring) - 1); |
| if (RING_FULL(&bedata->ring) || |
| bedata->rsp[*req_id].req_id != PVCALLS_INVALID_ID) |
| return -EAGAIN; |
| return 0; |
| } |
| |
| static bool pvcalls_front_write_todo(struct sock_mapping *map) |
| { |
| struct pvcalls_data_intf *intf = map->active.ring; |
| RING_IDX cons, prod, size = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER); |
| int32_t error; |
| |
| error = intf->out_error; |
| if (error == -ENOTCONN) |
| return false; |
| if (error != 0) |
| return true; |
| |
| cons = intf->out_cons; |
| prod = intf->out_prod; |
| return !!(size - pvcalls_queued(prod, cons, size)); |
| } |
| |
| static bool pvcalls_front_read_todo(struct sock_mapping *map) |
| { |
| struct pvcalls_data_intf *intf = map->active.ring; |
| RING_IDX cons, prod; |
| int32_t error; |
| |
| cons = intf->in_cons; |
| prod = intf->in_prod; |
| error = intf->in_error; |
| return (error != 0 || |
| pvcalls_queued(prod, cons, |
| XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER)) != 0); |
| } |
| |
| static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id) |
| { |
| struct xenbus_device *dev = dev_id; |
| struct pvcalls_bedata *bedata; |
| struct xen_pvcalls_response *rsp; |
| uint8_t *src, *dst; |
| int req_id = 0, more = 0, done = 0; |
| |
| if (dev == NULL) |
| return IRQ_HANDLED; |
| |
| pvcalls_enter(); |
| bedata = dev_get_drvdata(&dev->dev); |
| if (bedata == NULL) { |
| pvcalls_exit(); |
| return IRQ_HANDLED; |
| } |
| |
| again: |
| while (RING_HAS_UNCONSUMED_RESPONSES(&bedata->ring)) { |
| rsp = RING_GET_RESPONSE(&bedata->ring, bedata->ring.rsp_cons); |
| |
| req_id = rsp->req_id; |
| if (rsp->cmd == PVCALLS_POLL) { |
| struct sock_mapping *map = (struct sock_mapping *)(uintptr_t) |
| rsp->u.poll.id; |
| |
| clear_bit(PVCALLS_FLAG_POLL_INFLIGHT, |
| (void *)&map->passive.flags); |
| /* |
| * clear INFLIGHT, then set RET. It pairs with |
| * the checks at the beginning of |
| * pvcalls_front_poll_passive. |
| */ |
| smp_wmb(); |
| set_bit(PVCALLS_FLAG_POLL_RET, |
| (void *)&map->passive.flags); |
| } else { |
| dst = (uint8_t *)&bedata->rsp[req_id] + |
| sizeof(rsp->req_id); |
| src = (uint8_t *)rsp + sizeof(rsp->req_id); |
| memcpy(dst, src, sizeof(*rsp) - sizeof(rsp->req_id)); |
| /* |
| * First copy the rest of the data, then req_id. It is |
| * paired with the barrier when accessing bedata->rsp. |
| */ |
| smp_wmb(); |
| bedata->rsp[req_id].req_id = req_id; |
| } |
| |
| done = 1; |
| bedata->ring.rsp_cons++; |
| } |
| |
| RING_FINAL_CHECK_FOR_RESPONSES(&bedata->ring, more); |
| if (more) |
| goto again; |
| if (done) |
| wake_up(&bedata->inflight_req); |
| pvcalls_exit(); |
| return IRQ_HANDLED; |
| } |
| |
| static void pvcalls_front_free_map(struct pvcalls_bedata *bedata, |
| struct sock_mapping *map) |
| { |
| int i; |
| |
| unbind_from_irqhandler(map->active.irq, map); |
| |
| spin_lock(&bedata->socket_lock); |
| if (!list_empty(&map->list)) |
| list_del_init(&map->list); |
| spin_unlock(&bedata->socket_lock); |
| |
| for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++) |
| gnttab_end_foreign_access(map->active.ring->ref[i], 0, 0); |
| gnttab_end_foreign_access(map->active.ref, 0, 0); |
| free_page((unsigned long)map->active.ring); |
| |
| kfree(map); |
| } |
| |
| static irqreturn_t pvcalls_front_conn_handler(int irq, void *sock_map) |
| { |
| struct sock_mapping *map = sock_map; |
| |
| if (map == NULL) |
| return IRQ_HANDLED; |
| |
| wake_up_interruptible(&map->active.inflight_conn_req); |
| |
| return IRQ_HANDLED; |
| } |
| |
| int pvcalls_front_socket(struct socket *sock) |
| { |
| struct pvcalls_bedata *bedata; |
| struct sock_mapping *map = NULL; |
| struct xen_pvcalls_request *req; |
| int notify, req_id, ret; |
| |
| /* |
| * PVCalls only supports domain AF_INET, |
| * type SOCK_STREAM and protocol 0 sockets for now. |
| * |
| * Check socket type here, AF_INET and protocol checks are done |
| * by the caller. |
| */ |
| if (sock->type != SOCK_STREAM) |
| return -EOPNOTSUPP; |
| |
| pvcalls_enter(); |
| if (!pvcalls_front_dev) { |
| pvcalls_exit(); |
| return -EACCES; |
| } |
| bedata = dev_get_drvdata(&pvcalls_front_dev->dev); |
| |
| map = kzalloc(sizeof(*map), GFP_KERNEL); |
| if (map == NULL) { |
| pvcalls_exit(); |
| return -ENOMEM; |
| } |
| |
| spin_lock(&bedata->socket_lock); |
| |
| ret = get_request(bedata, &req_id); |
| if (ret < 0) { |
| kfree(map); |
| spin_unlock(&bedata->socket_lock); |
| pvcalls_exit(); |
| return ret; |
| } |
| |
| /* |
| * sock->sk->sk_send_head is not used for ip sockets: reuse the |
| * field to store a pointer to the struct sock_mapping |
| * corresponding to the socket. This way, we can easily get the |
| * struct sock_mapping from the struct socket. |
| */ |
| sock->sk->sk_send_head = (void *)map; |
| list_add_tail(&map->list, &bedata->socket_mappings); |
| |
| req = RING_GET_REQUEST(&bedata->ring, req_id); |
| req->req_id = req_id; |
| req->cmd = PVCALLS_SOCKET; |
| req->u.socket.id = (uintptr_t) map; |
| req->u.socket.domain = AF_INET; |
| req->u.socket.type = SOCK_STREAM; |
| req->u.socket.protocol = IPPROTO_IP; |
| |
| bedata->ring.req_prod_pvt++; |
| RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify); |
| spin_unlock(&bedata->socket_lock); |
| if (notify) |
| notify_remote_via_irq(bedata->irq); |
| |
| wait_event(bedata->inflight_req, |
| READ_ONCE(bedata->rsp[req_id].req_id) == req_id); |
| |
| /* read req_id, then the content */ |
| smp_rmb(); |
| ret = bedata->rsp[req_id].ret; |
| bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID; |
| |
| pvcalls_exit(); |
| return ret; |
| } |
| |
| static int create_active(struct sock_mapping *map, int *evtchn) |
| { |
| void *bytes; |
| int ret = -ENOMEM, irq = -1, i; |
| |
| *evtchn = -1; |
| init_waitqueue_head(&map->active.inflight_conn_req); |
| |
| map->active.ring = (struct pvcalls_data_intf *) |
| __get_free_page(GFP_KERNEL | __GFP_ZERO); |
| if (map->active.ring == NULL) |
| goto out_error; |
| map->active.ring->ring_order = PVCALLS_RING_ORDER; |
| bytes = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, |
| PVCALLS_RING_ORDER); |
| if (bytes == NULL) |
| goto out_error; |
| for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++) |
| map->active.ring->ref[i] = gnttab_grant_foreign_access( |
| pvcalls_front_dev->otherend_id, |
| pfn_to_gfn(virt_to_pfn(bytes) + i), 0); |
| |
| map->active.ref = gnttab_grant_foreign_access( |
| pvcalls_front_dev->otherend_id, |
| pfn_to_gfn(virt_to_pfn((void *)map->active.ring)), 0); |
| |
| map->active.data.in = bytes; |
| map->active.data.out = bytes + |
| XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER); |
| |
| ret = xenbus_alloc_evtchn(pvcalls_front_dev, evtchn); |
| if (ret) |
| goto out_error; |
| irq = bind_evtchn_to_irqhandler(*evtchn, pvcalls_front_conn_handler, |
| 0, "pvcalls-frontend", map); |
| if (irq < 0) { |
| ret = irq; |
| goto out_error; |
| } |
| |
| map->active.irq = irq; |
| map->active_socket = true; |
| mutex_init(&map->active.in_mutex); |
| mutex_init(&map->active.out_mutex); |
| |
| return 0; |
| |
| out_error: |
| if (*evtchn >= 0) |
| xenbus_free_evtchn(pvcalls_front_dev, *evtchn); |
| kfree(map->active.data.in); |
| kfree(map->active.ring); |
| return ret; |
| } |
| |
| int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr, |
| int addr_len, int flags) |
| { |
| struct pvcalls_bedata *bedata; |
| struct sock_mapping *map = NULL; |
| struct xen_pvcalls_request *req; |
| int notify, req_id, ret, evtchn; |
| |
| if (addr->sa_family != AF_INET || sock->type != SOCK_STREAM) |
| return -EOPNOTSUPP; |
| |
| pvcalls_enter(); |
| if (!pvcalls_front_dev) { |
| pvcalls_exit(); |
| return -ENOTCONN; |
| } |
| |
| bedata = dev_get_drvdata(&pvcalls_front_dev->dev); |
| |
| map = (struct sock_mapping *)sock->sk->sk_send_head; |
| if (!map) { |
| pvcalls_exit(); |
| return -ENOTSOCK; |
| } |
| |
| spin_lock(&bedata->socket_lock); |
| ret = get_request(bedata, &req_id); |
| if (ret < 0) { |
| spin_unlock(&bedata->socket_lock); |
| pvcalls_exit(); |
| return ret; |
| } |
| ret = create_active(map, &evtchn); |
| if (ret < 0) { |
| spin_unlock(&bedata->socket_lock); |
| pvcalls_exit(); |
| return ret; |
| } |
| |
| req = RING_GET_REQUEST(&bedata->ring, req_id); |
| req->req_id = req_id; |
| req->cmd = PVCALLS_CONNECT; |
| req->u.connect.id = (uintptr_t)map; |
| req->u.connect.len = addr_len; |
| req->u.connect.flags = flags; |
| req->u.connect.ref = map->active.ref; |
| req->u.connect.evtchn = evtchn; |
| memcpy(req->u.connect.addr, addr, sizeof(*addr)); |
| |
| map->sock = sock; |
| |
| bedata->ring.req_prod_pvt++; |
| RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify); |
| spin_unlock(&bedata->socket_lock); |
| |
| if (notify) |
| notify_remote_via_irq(bedata->irq); |
| |
| wait_event(bedata->inflight_req, |
| READ_ONCE(bedata->rsp[req_id].req_id) == req_id); |
| |
| /* read req_id, then the content */ |
| smp_rmb(); |
| ret = bedata->rsp[req_id].ret; |
| bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID; |
| pvcalls_exit(); |
| return ret; |
| } |
| |
| static int __write_ring(struct pvcalls_data_intf *intf, |
| struct pvcalls_data *data, |
| struct iov_iter *msg_iter, |
| int len) |
| { |
| RING_IDX cons, prod, size, masked_prod, masked_cons; |
| RING_IDX array_size = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER); |
| int32_t error; |
| |
| error = intf->out_error; |
| if (error < 0) |
| return error; |
| cons = intf->out_cons; |
| prod = intf->out_prod; |
| /* read indexes before continuing */ |
| virt_mb(); |
| |
| size = pvcalls_queued(prod, cons, array_size); |
| if (size >= array_size) |
| return -EINVAL; |
| if (len > array_size - size) |
| len = array_size - size; |
| |
| masked_prod = pvcalls_mask(prod, array_size); |
| masked_cons = pvcalls_mask(cons, array_size); |
| |
| if (masked_prod < masked_cons) { |
| len = copy_from_iter(data->out + masked_prod, len, msg_iter); |
| } else { |
| if (len > array_size - masked_prod) { |
| int ret = copy_from_iter(data->out + masked_prod, |
| array_size - masked_prod, msg_iter); |
| if (ret != array_size - masked_prod) { |
| len = ret; |
| goto out; |
| } |
| len = ret + copy_from_iter(data->out, len - ret, msg_iter); |
| } else { |
| len = copy_from_iter(data->out + masked_prod, len, msg_iter); |
| } |
| } |
| out: |
| /* write to ring before updating pointer */ |
| virt_wmb(); |
| intf->out_prod += len; |
| |
| return len; |
| } |
| |
| int pvcalls_front_sendmsg(struct socket *sock, struct msghdr *msg, |
| size_t len) |
| { |
| struct pvcalls_bedata *bedata; |
| struct sock_mapping *map; |
| int sent, tot_sent = 0; |
| int count = 0, flags; |
| |
| flags = msg->msg_flags; |
| if (flags & (MSG_CONFIRM|MSG_DONTROUTE|MSG_EOR|MSG_OOB)) |
| return -EOPNOTSUPP; |
| |
| pvcalls_enter(); |
| if (!pvcalls_front_dev) { |
| pvcalls_exit(); |
| return -ENOTCONN; |
| } |
| bedata = dev_get_drvdata(&pvcalls_front_dev->dev); |
| |
| map = (struct sock_mapping *) sock->sk->sk_send_head; |
| if (!map) { |
| pvcalls_exit(); |
| return -ENOTSOCK; |
| } |
| |
| mutex_lock(&map->active.out_mutex); |
| if ((flags & MSG_DONTWAIT) && !pvcalls_front_write_todo(map)) { |
| mutex_unlock(&map->active.out_mutex); |
| pvcalls_exit(); |
| return -EAGAIN; |
| } |
| if (len > INT_MAX) |
| len = INT_MAX; |
| |
| again: |
| count++; |
| sent = __write_ring(map->active.ring, |
| &map->active.data, &msg->msg_iter, |
| len); |
| if (sent > 0) { |
| len -= sent; |
| tot_sent += sent; |
| notify_remote_via_irq(map->active.irq); |
| } |
| if (sent >= 0 && len > 0 && count < PVCALLS_FRONT_MAX_SPIN) |
| goto again; |
| if (sent < 0) |
| tot_sent = sent; |
| |
| mutex_unlock(&map->active.out_mutex); |
| pvcalls_exit(); |
| return tot_sent; |
| } |
| |
| static int __read_ring(struct pvcalls_data_intf *intf, |
| struct pvcalls_data *data, |
| struct iov_iter *msg_iter, |
| size_t len, int flags) |
| { |
| RING_IDX cons, prod, size, masked_prod, masked_cons; |
| RING_IDX array_size = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER); |
| int32_t error; |
| |
| cons = intf->in_cons; |
| prod = intf->in_prod; |
| error = intf->in_error; |
| /* get pointers before reading from the ring */ |
| virt_rmb(); |
| if (error < 0) |
| return error; |
| |
| size = pvcalls_queued(prod, cons, array_size); |
| masked_prod = pvcalls_mask(prod, array_size); |
| masked_cons = pvcalls_mask(cons, array_size); |
| |
| if (size == 0) |
| return 0; |
| |
| if (len > size) |
| len = size; |
| |
| if (masked_prod > masked_cons) { |
| len = copy_to_iter(data->in + masked_cons, len, msg_iter); |
| } else { |
| if (len > (array_size - masked_cons)) { |
| int ret = copy_to_iter(data->in + masked_cons, |
| array_size - masked_cons, msg_iter); |
| if (ret != array_size - masked_cons) { |
| len = ret; |
| goto out; |
| } |
| len = ret + copy_to_iter(data->in, len - ret, msg_iter); |
| } else { |
| len = copy_to_iter(data->in + masked_cons, len, msg_iter); |
| } |
| } |
| out: |
| /* read data from the ring before increasing the index */ |
| virt_mb(); |
| if (!(flags & MSG_PEEK)) |
| intf->in_cons += len; |
| |
| return len; |
| } |
| |
| int pvcalls_front_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, |
| int flags) |
| { |
| struct pvcalls_bedata *bedata; |
| int ret; |
| struct sock_mapping *map; |
| |
| if (flags & (MSG_CMSG_CLOEXEC|MSG_ERRQUEUE|MSG_OOB|MSG_TRUNC)) |
| return -EOPNOTSUPP; |
| |
| pvcalls_enter(); |
| if (!pvcalls_front_dev) { |
| pvcalls_exit(); |
| return -ENOTCONN; |
| } |
| bedata = dev_get_drvdata(&pvcalls_front_dev->dev); |
| |
| map = (struct sock_mapping *) sock->sk->sk_send_head; |
| if (!map) { |
| pvcalls_exit(); |
| return -ENOTSOCK; |
| } |
| |
| mutex_lock(&map->active.in_mutex); |
| if (len > XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER)) |
| len = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER); |
| |
| while (!(flags & MSG_DONTWAIT) && !pvcalls_front_read_todo(map)) { |
| wait_event_interruptible(map->active.inflight_conn_req, |
| pvcalls_front_read_todo(map)); |
| } |
| ret = __read_ring(map->active.ring, &map->active.data, |
| &msg->msg_iter, len, flags); |
| |
| if (ret > 0) |
| notify_remote_via_irq(map->active.irq); |
| if (ret == 0) |
| ret = (flags & MSG_DONTWAIT) ? -EAGAIN : 0; |
| if (ret == -ENOTCONN) |
| ret = 0; |
| |
| mutex_unlock(&map->active.in_mutex); |
| pvcalls_exit(); |
| return ret; |
| } |
| |
| int pvcalls_front_bind(struct socket *sock, struct sockaddr *addr, int addr_len) |
| { |
| struct pvcalls_bedata *bedata; |
| struct sock_mapping *map = NULL; |
| struct xen_pvcalls_request *req; |
| int notify, req_id, ret; |
| |
| if (addr->sa_family != AF_INET || sock->type != SOCK_STREAM) |
| return -EOPNOTSUPP; |
| |
| pvcalls_enter(); |
| if (!pvcalls_front_dev) { |
| pvcalls_exit(); |
| return -ENOTCONN; |
| } |
| bedata = dev_get_drvdata(&pvcalls_front_dev->dev); |
| |
| map = (struct sock_mapping *) sock->sk->sk_send_head; |
| if (map == NULL) { |
| pvcalls_exit(); |
| return -ENOTSOCK; |
| } |
| |
| spin_lock(&bedata->socket_lock); |
| ret = get_request(bedata, &req_id); |
| if (ret < 0) { |
| spin_unlock(&bedata->socket_lock); |
| pvcalls_exit(); |
| return ret; |
| } |
| req = RING_GET_REQUEST(&bedata->ring, req_id); |
| req->req_id = req_id; |
| map->sock = sock; |
| req->cmd = PVCALLS_BIND; |
| req->u.bind.id = (uintptr_t)map; |
| memcpy(req->u.bind.addr, addr, sizeof(*addr)); |
| req->u.bind.len = addr_len; |
| |
| init_waitqueue_head(&map->passive.inflight_accept_req); |
| |
| map->active_socket = false; |
| |
| bedata->ring.req_prod_pvt++; |
| RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify); |
| spin_unlock(&bedata->socket_lock); |
| if (notify) |
| notify_remote_via_irq(bedata->irq); |
| |
| wait_event(bedata->inflight_req, |
| READ_ONCE(bedata->rsp[req_id].req_id) == req_id); |
| |
| /* read req_id, then the content */ |
| smp_rmb(); |
| ret = bedata->rsp[req_id].ret; |
| bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID; |
| |
| map->passive.status = PVCALLS_STATUS_BIND; |
| pvcalls_exit(); |
| return 0; |
| } |
| |
| int pvcalls_front_listen(struct socket *sock, int backlog) |
| { |
| struct pvcalls_bedata *bedata; |
| struct sock_mapping *map; |
| struct xen_pvcalls_request *req; |
| int notify, req_id, ret; |
| |
| pvcalls_enter(); |
| if (!pvcalls_front_dev) { |
| pvcalls_exit(); |
| return -ENOTCONN; |
| } |
| bedata = dev_get_drvdata(&pvcalls_front_dev->dev); |
| |
| map = (struct sock_mapping *) sock->sk->sk_send_head; |
| if (!map) { |
| pvcalls_exit(); |
| return -ENOTSOCK; |
| } |
| |
| if (map->passive.status != PVCALLS_STATUS_BIND) { |
| pvcalls_exit(); |
| return -EOPNOTSUPP; |
| } |
| |
| spin_lock(&bedata->socket_lock); |
| ret = get_request(bedata, &req_id); |
| if (ret < 0) { |
| spin_unlock(&bedata->socket_lock); |
| pvcalls_exit(); |
| return ret; |
| } |
| req = RING_GET_REQUEST(&bedata->ring, req_id); |
| req->req_id = req_id; |
| req->cmd = PVCALLS_LISTEN; |
| req->u.listen.id = (uintptr_t) map; |
| req->u.listen.backlog = backlog; |
| |
| bedata->ring.req_prod_pvt++; |
| RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify); |
| spin_unlock(&bedata->socket_lock); |
| if (notify) |
| notify_remote_via_irq(bedata->irq); |
| |
| wait_event(bedata->inflight_req, |
| READ_ONCE(bedata->rsp[req_id].req_id) == req_id); |
| |
| /* read req_id, then the content */ |
| smp_rmb(); |
| ret = bedata->rsp[req_id].ret; |
| bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID; |
| |
| map->passive.status = PVCALLS_STATUS_LISTEN; |
| pvcalls_exit(); |
| return ret; |
| } |
| |
| int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags) |
| { |
| struct pvcalls_bedata *bedata; |
| struct sock_mapping *map; |
| struct sock_mapping *map2 = NULL; |
| struct xen_pvcalls_request *req; |
| int notify, req_id, ret, evtchn, nonblock; |
| |
| pvcalls_enter(); |
| if (!pvcalls_front_dev) { |
| pvcalls_exit(); |
| return -ENOTCONN; |
| } |
| bedata = dev_get_drvdata(&pvcalls_front_dev->dev); |
| |
| map = (struct sock_mapping *) sock->sk->sk_send_head; |
| if (!map) { |
| pvcalls_exit(); |
| return -ENOTSOCK; |
| } |
| |
| if (map->passive.status != PVCALLS_STATUS_LISTEN) { |
| pvcalls_exit(); |
| return -EINVAL; |
| } |
| |
| nonblock = flags & SOCK_NONBLOCK; |
| /* |
| * Backend only supports 1 inflight accept request, will return |
| * errors for the others |
| */ |
| if (test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, |
| (void *)&map->passive.flags)) { |
| req_id = READ_ONCE(map->passive.inflight_req_id); |
| if (req_id != PVCALLS_INVALID_ID && |
| READ_ONCE(bedata->rsp[req_id].req_id) == req_id) { |
| map2 = map->passive.accept_map; |
| goto received; |
| } |
| if (nonblock) { |
| pvcalls_exit(); |
| return -EAGAIN; |
| } |
| if (wait_event_interruptible(map->passive.inflight_accept_req, |
| !test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, |
| (void *)&map->passive.flags))) { |
| pvcalls_exit(); |
| return -EINTR; |
| } |
| } |
| |
| spin_lock(&bedata->socket_lock); |
| ret = get_request(bedata, &req_id); |
| if (ret < 0) { |
| clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, |
| (void *)&map->passive.flags); |
| spin_unlock(&bedata->socket_lock); |
| pvcalls_exit(); |
| return ret; |
| } |
| map2 = kzalloc(sizeof(*map2), GFP_ATOMIC); |
| if (map2 == NULL) { |
| clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, |
| (void *)&map->passive.flags); |
| spin_unlock(&bedata->socket_lock); |
| pvcalls_exit(); |
| return -ENOMEM; |
| } |
| ret = create_active(map2, &evtchn); |
| if (ret < 0) { |
| kfree(map2); |
| clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, |
| (void *)&map->passive.flags); |
| spin_unlock(&bedata->socket_lock); |
| pvcalls_exit(); |
| return ret; |
| } |
| list_add_tail(&map2->list, &bedata->socket_mappings); |
| |
| req = RING_GET_REQUEST(&bedata->ring, req_id); |
| req->req_id = req_id; |
| req->cmd = PVCALLS_ACCEPT; |
| req->u.accept.id = (uintptr_t) map; |
| req->u.accept.ref = map2->active.ref; |
| req->u.accept.id_new = (uintptr_t) map2; |
| req->u.accept.evtchn = evtchn; |
| map->passive.accept_map = map2; |
| |
| bedata->ring.req_prod_pvt++; |
| RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify); |
| spin_unlock(&bedata->socket_lock); |
| if (notify) |
| notify_remote_via_irq(bedata->irq); |
| /* We could check if we have received a response before returning. */ |
| if (nonblock) { |
| WRITE_ONCE(map->passive.inflight_req_id, req_id); |
| pvcalls_exit(); |
| return -EAGAIN; |
| } |
| |
| if (wait_event_interruptible(bedata->inflight_req, |
| READ_ONCE(bedata->rsp[req_id].req_id) == req_id)) { |
| pvcalls_exit(); |
| return -EINTR; |
| } |
| /* read req_id, then the content */ |
| smp_rmb(); |
| |
| received: |
| map2->sock = newsock; |
| newsock->sk = kzalloc(sizeof(*newsock->sk), GFP_KERNEL); |
| if (!newsock->sk) { |
| bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID; |
| map->passive.inflight_req_id = PVCALLS_INVALID_ID; |
| clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, |
| (void *)&map->passive.flags); |
| pvcalls_front_free_map(bedata, map2); |
| pvcalls_exit(); |
| return -ENOMEM; |
| } |
| newsock->sk->sk_send_head = (void *)map2; |
| |
| ret = bedata->rsp[req_id].ret; |
| bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID; |
| map->passive.inflight_req_id = PVCALLS_INVALID_ID; |
| |
| clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, (void *)&map->passive.flags); |
| wake_up(&map->passive.inflight_accept_req); |
| |
| pvcalls_exit(); |
| return ret; |
| } |
| |
| static __poll_t pvcalls_front_poll_passive(struct file *file, |
| struct pvcalls_bedata *bedata, |
| struct sock_mapping *map, |
| poll_table *wait) |
| { |
| int notify, req_id, ret; |
| struct xen_pvcalls_request *req; |
| |
| if (test_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, |
| (void *)&map->passive.flags)) { |
| uint32_t req_id = READ_ONCE(map->passive.inflight_req_id); |
| |
| if (req_id != PVCALLS_INVALID_ID && |
| READ_ONCE(bedata->rsp[req_id].req_id) == req_id) |
| return EPOLLIN | EPOLLRDNORM; |
| |
| poll_wait(file, &map->passive.inflight_accept_req, wait); |
| return 0; |
| } |
| |
| if (test_and_clear_bit(PVCALLS_FLAG_POLL_RET, |
| (void *)&map->passive.flags)) |
| return EPOLLIN | EPOLLRDNORM; |
| |
| /* |
| * First check RET, then INFLIGHT. No barriers necessary to |
| * ensure execution ordering because of the conditional |
| * instructions creating control dependencies. |
| */ |
| |
| if (test_and_set_bit(PVCALLS_FLAG_POLL_INFLIGHT, |
| (void *)&map->passive.flags)) { |
| poll_wait(file, &bedata->inflight_req, wait); |
| return 0; |
| } |
| |
| spin_lock(&bedata->socket_lock); |
| ret = get_request(bedata, &req_id); |
| if (ret < 0) { |
| spin_unlock(&bedata->socket_lock); |
| return ret; |
| } |
| req = RING_GET_REQUEST(&bedata->ring, req_id); |
| req->req_id = req_id; |
| req->cmd = PVCALLS_POLL; |
| req->u.poll.id = (uintptr_t) map; |
| |
| bedata->ring.req_prod_pvt++; |
| RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify); |
| spin_unlock(&bedata->socket_lock); |
| if (notify) |
| notify_remote_via_irq(bedata->irq); |
| |
| poll_wait(file, &bedata->inflight_req, wait); |
| return 0; |
| } |
| |
| static __poll_t pvcalls_front_poll_active(struct file *file, |
| struct pvcalls_bedata *bedata, |
| struct sock_mapping *map, |
| poll_table *wait) |
| { |
| __poll_t mask = 0; |
| int32_t in_error, out_error; |
| struct pvcalls_data_intf *intf = map->active.ring; |
| |
| out_error = intf->out_error; |
| in_error = intf->in_error; |
| |
| poll_wait(file, &map->active.inflight_conn_req, wait); |
| if (pvcalls_front_write_todo(map)) |
| mask |= EPOLLOUT | EPOLLWRNORM; |
| if (pvcalls_front_read_todo(map)) |
| mask |= EPOLLIN | EPOLLRDNORM; |
| if (in_error != 0 || out_error != 0) |
| mask |= EPOLLERR; |
| |
| return mask; |
| } |
| |
| __poll_t pvcalls_front_poll(struct file *file, struct socket *sock, |
| poll_table *wait) |
| { |
| struct pvcalls_bedata *bedata; |
| struct sock_mapping *map; |
| __poll_t ret; |
| |
| pvcalls_enter(); |
| if (!pvcalls_front_dev) { |
| pvcalls_exit(); |
| return EPOLLNVAL; |
| } |
| bedata = dev_get_drvdata(&pvcalls_front_dev->dev); |
| |
| map = (struct sock_mapping *) sock->sk->sk_send_head; |
| if (!map) { |
| pvcalls_exit(); |
| return EPOLLNVAL; |
| } |
| if (map->active_socket) |
| ret = pvcalls_front_poll_active(file, bedata, map, wait); |
| else |
| ret = pvcalls_front_poll_passive(file, bedata, map, wait); |
| pvcalls_exit(); |
| return ret; |
| } |
| |
| int pvcalls_front_release(struct socket *sock) |
| { |
| struct pvcalls_bedata *bedata; |
| struct sock_mapping *map; |
| int req_id, notify, ret; |
| struct xen_pvcalls_request *req; |
| |
| if (sock->sk == NULL) |
| return 0; |
| |
| pvcalls_enter(); |
| if (!pvcalls_front_dev) { |
| pvcalls_exit(); |
| return -EIO; |
| } |
| |
| bedata = dev_get_drvdata(&pvcalls_front_dev->dev); |
| |
| map = (struct sock_mapping *) sock->sk->sk_send_head; |
| if (map == NULL) { |
| pvcalls_exit(); |
| return 0; |
| } |
| |
| spin_lock(&bedata->socket_lock); |
| ret = get_request(bedata, &req_id); |
| if (ret < 0) { |
| spin_unlock(&bedata->socket_lock); |
| pvcalls_exit(); |
| return ret; |
| } |
| sock->sk->sk_send_head = NULL; |
| |
| req = RING_GET_REQUEST(&bedata->ring, req_id); |
| req->req_id = req_id; |
| req->cmd = PVCALLS_RELEASE; |
| req->u.release.id = (uintptr_t)map; |
| |
| bedata->ring.req_prod_pvt++; |
| RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify); |
| spin_unlock(&bedata->socket_lock); |
| if (notify) |
| notify_remote_via_irq(bedata->irq); |
| |
| wait_event(bedata->inflight_req, |
| READ_ONCE(bedata->rsp[req_id].req_id) == req_id); |
| |
| if (map->active_socket) { |
| /* |
| * Set in_error and wake up inflight_conn_req to force |
| * recvmsg waiters to exit. |
| */ |
| map->active.ring->in_error = -EBADF; |
| wake_up_interruptible(&map->active.inflight_conn_req); |
| |
| /* |
| * We need to make sure that sendmsg/recvmsg on this socket have |
| * not started before we've cleared sk_send_head here. The |
| * easiest (though not optimal) way to guarantee this is to see |
| * that no pvcall (other than us) is in progress. |
| */ |
| while (atomic_read(&pvcalls_refcount) > 1) |
| cpu_relax(); |
| |
| pvcalls_front_free_map(bedata, map); |
| } else { |
| spin_lock(&bedata->socket_lock); |
| list_del(&map->list); |
| spin_unlock(&bedata->socket_lock); |
| if (READ_ONCE(map->passive.inflight_req_id) != |
| PVCALLS_INVALID_ID) { |
| pvcalls_front_free_map(bedata, |
| map->passive.accept_map); |
| } |
| kfree(map); |
| } |
| WRITE_ONCE(bedata->rsp[req_id].req_id, PVCALLS_INVALID_ID); |
| |
| pvcalls_exit(); |
| return 0; |
| } |
| |
| static const struct xenbus_device_id pvcalls_front_ids[] = { |
| { "pvcalls" }, |
| { "" } |
| }; |
| |
| static int pvcalls_front_remove(struct xenbus_device *dev) |
| { |
| struct pvcalls_bedata *bedata; |
| struct sock_mapping *map = NULL, *n; |
| |
| bedata = dev_get_drvdata(&pvcalls_front_dev->dev); |
| dev_set_drvdata(&dev->dev, NULL); |
| pvcalls_front_dev = NULL; |
| if (bedata->irq >= 0) |
| unbind_from_irqhandler(bedata->irq, dev); |
| |
| list_for_each_entry_safe(map, n, &bedata->socket_mappings, list) { |
| map->sock->sk->sk_send_head = NULL; |
| if (map->active_socket) { |
| map->active.ring->in_error = -EBADF; |
| wake_up_interruptible(&map->active.inflight_conn_req); |
| } |
| } |
| |
| smp_mb(); |
| while (atomic_read(&pvcalls_refcount) > 0) |
| cpu_relax(); |
| list_for_each_entry_safe(map, n, &bedata->socket_mappings, list) { |
| if (map->active_socket) { |
| /* No need to lock, refcount is 0 */ |
| pvcalls_front_free_map(bedata, map); |
| } else { |
| list_del(&map->list); |
| kfree(map); |
| } |
| } |
| if (bedata->ref != -1) |
| gnttab_end_foreign_access(bedata->ref, 0, 0); |
| kfree(bedata->ring.sring); |
| kfree(bedata); |
| xenbus_switch_state(dev, XenbusStateClosed); |
| return 0; |
| } |
| |
| static int pvcalls_front_probe(struct xenbus_device *dev, |
| const struct xenbus_device_id *id) |
| { |
| int ret = -ENOMEM, evtchn, i; |
| unsigned int max_page_order, function_calls, len; |
| char *versions; |
| grant_ref_t gref_head = 0; |
| struct xenbus_transaction xbt; |
| struct pvcalls_bedata *bedata = NULL; |
| struct xen_pvcalls_sring *sring; |
| |
| if (pvcalls_front_dev != NULL) { |
| dev_err(&dev->dev, "only one PV Calls connection supported\n"); |
| return -EINVAL; |
| } |
| |
| versions = xenbus_read(XBT_NIL, dev->otherend, "versions", &len); |
| if (IS_ERR(versions)) |
| return PTR_ERR(versions); |
| if (!len) |
| return -EINVAL; |
| if (strcmp(versions, "1")) { |
| kfree(versions); |
| return -EINVAL; |
| } |
| kfree(versions); |
| max_page_order = xenbus_read_unsigned(dev->otherend, |
| "max-page-order", 0); |
| if (max_page_order < PVCALLS_RING_ORDER) |
| return -ENODEV; |
| function_calls = xenbus_read_unsigned(dev->otherend, |
| "function-calls", 0); |
| /* See XENBUS_FUNCTIONS_CALLS in pvcalls.h */ |
| if (function_calls != 1) |
| return -ENODEV; |
| pr_info("%s max-page-order is %u\n", __func__, max_page_order); |
| |
| bedata = kzalloc(sizeof(struct pvcalls_bedata), GFP_KERNEL); |
| if (!bedata) |
| return -ENOMEM; |
| |
| dev_set_drvdata(&dev->dev, bedata); |
| pvcalls_front_dev = dev; |
| init_waitqueue_head(&bedata->inflight_req); |
| INIT_LIST_HEAD(&bedata->socket_mappings); |
| spin_lock_init(&bedata->socket_lock); |
| bedata->irq = -1; |
| bedata->ref = -1; |
| |
| for (i = 0; i < PVCALLS_NR_RSP_PER_RING; i++) |
| bedata->rsp[i].req_id = PVCALLS_INVALID_ID; |
| |
| sring = (struct xen_pvcalls_sring *) __get_free_page(GFP_KERNEL | |
| __GFP_ZERO); |
| if (!sring) |
| goto error; |
| SHARED_RING_INIT(sring); |
| FRONT_RING_INIT(&bedata->ring, sring, XEN_PAGE_SIZE); |
| |
| ret = xenbus_alloc_evtchn(dev, &evtchn); |
| if (ret) |
| goto error; |
| |
| bedata->irq = bind_evtchn_to_irqhandler(evtchn, |
| pvcalls_front_event_handler, |
| 0, "pvcalls-frontend", dev); |
| if (bedata->irq < 0) { |
| ret = bedata->irq; |
| goto error; |
| } |
| |
| ret = gnttab_alloc_grant_references(1, &gref_head); |
| if (ret < 0) |
| goto error; |
| ret = gnttab_claim_grant_reference(&gref_head); |
| if (ret < 0) |
| goto error; |
| bedata->ref = ret; |
| gnttab_grant_foreign_access_ref(bedata->ref, dev->otherend_id, |
| virt_to_gfn((void *)sring), 0); |
| |
| again: |
| ret = xenbus_transaction_start(&xbt); |
| if (ret) { |
| xenbus_dev_fatal(dev, ret, "starting transaction"); |
| goto error; |
| } |
| ret = xenbus_printf(xbt, dev->nodename, "version", "%u", 1); |
| if (ret) |
| goto error_xenbus; |
| ret = xenbus_printf(xbt, dev->nodename, "ring-ref", "%d", bedata->ref); |
| if (ret) |
| goto error_xenbus; |
| ret = xenbus_printf(xbt, dev->nodename, "port", "%u", |
| evtchn); |
| if (ret) |
| goto error_xenbus; |
| ret = xenbus_transaction_end(xbt, 0); |
| if (ret) { |
| if (ret == -EAGAIN) |
| goto again; |
| xenbus_dev_fatal(dev, ret, "completing transaction"); |
| goto error; |
| } |
| xenbus_switch_state(dev, XenbusStateInitialised); |
| |
| return 0; |
| |
| error_xenbus: |
| xenbus_transaction_end(xbt, 1); |
| xenbus_dev_fatal(dev, ret, "writing xenstore"); |
| error: |
| pvcalls_front_remove(dev); |
| return ret; |
| } |
| |
| static void pvcalls_front_changed(struct xenbus_device *dev, |
| enum xenbus_state backend_state) |
| { |
| switch (backend_state) { |
| case XenbusStateReconfiguring: |
| case XenbusStateReconfigured: |
| case XenbusStateInitialising: |
| case XenbusStateInitialised: |
| case XenbusStateUnknown: |
| break; |
| |
| case XenbusStateInitWait: |
| break; |
| |
| case XenbusStateConnected: |
| xenbus_switch_state(dev, XenbusStateConnected); |
| break; |
| |
| case XenbusStateClosed: |
| if (dev->state == XenbusStateClosed) |
| break; |
| /* Missed the backend's CLOSING state */ |
| /* fall through */ |
| case XenbusStateClosing: |
| xenbus_frontend_closed(dev); |
| break; |
| } |
| } |
| |
| static struct xenbus_driver pvcalls_front_driver = { |
| .ids = pvcalls_front_ids, |
| .probe = pvcalls_front_probe, |
| .remove = pvcalls_front_remove, |
| .otherend_changed = pvcalls_front_changed, |
| }; |
| |
| static int __init pvcalls_frontend_init(void) |
| { |
| if (!xen_domain()) |
| return -ENODEV; |
| |
| pr_info("Initialising Xen pvcalls frontend driver\n"); |
| |
| return xenbus_register_frontend(&pvcalls_front_driver); |
| } |
| |
| module_init(pvcalls_frontend_init); |
| |
| MODULE_DESCRIPTION("Xen PV Calls frontend driver"); |
| MODULE_AUTHOR("Stefano Stabellini <sstabellini@kernel.org>"); |
| MODULE_LICENSE("GPL"); |