Author | Tokens | Token Proportion | Commits | Commit Proportion |
---|---|---|---|---|
Stefano Stabellini | 6196 | 94.91% | 20 | 64.52% |
Wen Yang | 264 | 4.04% | 2 | 6.45% |
Dan Carpenter | 16 | 0.25% | 2 | 6.45% |
Boris Ostrovsky | 15 | 0.23% | 1 | 3.23% |
Yan Yankovskyi | 11 | 0.17% | 1 | 3.23% |
Linus Torvalds | 10 | 0.15% | 1 | 3.23% |
Colin Ian King | 7 | 0.11% | 1 | 3.23% |
Al Viro | 5 | 0.08% | 1 | 3.23% |
Thomas Gleixner | 2 | 0.03% | 1 | 3.23% |
Gustavo A. R. Silva | 2 | 0.03% | 1 | 3.23% |
Total | 6528 | 31 |
// SPDX-License-Identifier: GPL-2.0-or-later /* * (c) 2017 Stefano Stabellini <stefano@aporeto.com> */ #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 static struct proto pvcalls_proto = { .name = "PVCalls", .owner = THIS_MODULE, .obj_size = sizeof(struct sock), }; 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; atomic_t refcount; 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, needs to be 64-bit aligned due to the * test_and_* functions which have this requirement on arm64. */ #define PVCALLS_STATUS_UNINITALIZED 0 #define PVCALLS_STATUS_BIND 1 #define PVCALLS_STATUS_LISTEN 2 uint8_t status __attribute__((aligned(8))); /* * 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. * flags needs to be 64-bit aligned due to the test_and_* * functions which have this requirement on arm64. */ #define PVCALLS_FLAG_ACCEPT_INFLIGHT 0 #define PVCALLS_FLAG_POLL_INFLIGHT 1 #define PVCALLS_FLAG_POLL_RET 2 uint8_t flags __attribute__((aligned(8))); uint32_t inflight_req_id; struct sock_mapping *accept_map; wait_queue_head_t inflight_accept_req; } passive; }; }; static inline struct sock_mapping *pvcalls_enter_sock(struct socket *sock) { struct sock_mapping *map; if (!pvcalls_front_dev || dev_get_drvdata(&pvcalls_front_dev->dev) == NULL) return ERR_PTR(-ENOTCONN); map = (struct sock_mapping *)sock->sk->sk_send_head; if (map == NULL) return ERR_PTR(-ENOTSOCK); pvcalls_enter(); atomic_inc(&map->refcount); return map; } static inline void pvcalls_exit_sock(struct socket *sock) { struct sock_mapping *map; map = (struct sock_mapping *)sock->sk->sk_send_head; atomic_dec(&map->refcount); pvcalls_exit(); } 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 void free_active_ring(struct sock_mapping *map) { if (!map->active.ring) return; free_pages((unsigned long)map->active.data.in, map->active.ring->ring_order); free_page((unsigned long)map->active.ring); } static int alloc_active_ring(struct sock_mapping *map) { void *bytes; map->active.ring = (struct pvcalls_data_intf *) get_zeroed_page(GFP_KERNEL); if (!map->active.ring) goto out; map->active.ring->ring_order = PVCALLS_RING_ORDER; bytes = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, PVCALLS_RING_ORDER); if (!bytes) goto out; map->active.data.in = bytes; map->active.data.out = bytes + XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER); return 0; out: free_active_ring(map); return -ENOMEM; } static int create_active(struct sock_mapping *map, evtchn_port_t *evtchn) { void *bytes; int ret = -ENOMEM, irq = -1, i; *evtchn = 0; init_waitqueue_head(&map->active.inflight_conn_req); bytes = map->active.data.in; 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); 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); 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_port_t evtchn; if (addr->sa_family != AF_INET || sock->type != SOCK_STREAM) return -EOPNOTSUPP; map = pvcalls_enter_sock(sock); if (IS_ERR(map)) return PTR_ERR(map); bedata = dev_get_drvdata(&pvcalls_front_dev->dev); ret = alloc_active_ring(map); if (ret < 0) { pvcalls_exit_sock(sock); return ret; } spin_lock(&bedata->socket_lock); ret = get_request(bedata, &req_id); if (ret < 0) { spin_unlock(&bedata->socket_lock); free_active_ring(map); pvcalls_exit_sock(sock); return ret; } ret = create_active(map, &evtchn); if (ret < 0) { spin_unlock(&bedata->socket_lock); free_active_ring(map); pvcalls_exit_sock(sock); 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_sock(sock); 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 (size == array_size) return 0; 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 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; map = pvcalls_enter_sock(sock); if (IS_ERR(map)) return PTR_ERR(map); mutex_lock(&map->active.out_mutex); if ((flags & MSG_DONTWAIT) && !pvcalls_front_write_todo(map)) { mutex_unlock(&map->active.out_mutex); pvcalls_exit_sock(sock); 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_sock(sock); 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(); 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 error ?: size; 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) { int ret; struct sock_mapping *map; if (flags & (MSG_CMSG_CLOEXEC|MSG_ERRQUEUE|MSG_OOB|MSG_TRUNC)) return -EOPNOTSUPP; map = pvcalls_enter_sock(sock); if (IS_ERR(map)) return PTR_ERR(map); 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_sock(sock); 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; map = pvcalls_enter_sock(sock); if (IS_ERR(map)) return PTR_ERR(map); bedata = dev_get_drvdata(&pvcalls_front_dev->dev); spin_lock(&bedata->socket_lock); ret = get_request(bedata, &req_id); if (ret < 0) { spin_unlock(&bedata->socket_lock); pvcalls_exit_sock(sock); 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_sock(sock); 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; map = pvcalls_enter_sock(sock); if (IS_ERR(map)) return PTR_ERR(map); bedata = dev_get_drvdata(&pvcalls_front_dev->dev); if (map->passive.status != PVCALLS_STATUS_BIND) { pvcalls_exit_sock(sock); return -EOPNOTSUPP; } spin_lock(&bedata->socket_lock); ret = get_request(bedata, &req_id); if (ret < 0) { spin_unlock(&bedata->socket_lock); pvcalls_exit_sock(sock); 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_sock(sock); 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, nonblock; evtchn_port_t evtchn; map = pvcalls_enter_sock(sock); if (IS_ERR(map)) return PTR_ERR(map); bedata = dev_get_drvdata(&pvcalls_front_dev->dev); if (map->passive.status != PVCALLS_STATUS_LISTEN) { pvcalls_exit_sock(sock); 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_sock(sock); 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_sock(sock); return -EINTR; } } map2 = kzalloc(sizeof(*map2), GFP_KERNEL); if (map2 == NULL) { clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, (void *)&map->passive.flags); pvcalls_exit_sock(sock); return -ENOMEM; } ret = alloc_active_ring(map2); if (ret < 0) { clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, (void *)&map->passive.flags); kfree(map2); pvcalls_exit_sock(sock); return ret; } 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); free_active_ring(map2); kfree(map2); pvcalls_exit_sock(sock); return ret; } ret = create_active(map2, &evtchn); if (ret < 0) { free_active_ring(map2); kfree(map2); clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, (void *)&map->passive.flags); spin_unlock(&bedata->socket_lock); pvcalls_exit_sock(sock); 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_sock(sock); return -EAGAIN; } if (wait_event_interruptible(bedata->inflight_req, READ_ONCE(bedata->rsp[req_id].req_id) == req_id)) { pvcalls_exit_sock(sock); return -EINTR; } /* read req_id, then the content */ smp_rmb(); received: map2->sock = newsock; newsock->sk = sk_alloc(sock_net(sock->sk), PF_INET, GFP_KERNEL, &pvcalls_proto, false); 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_sock(sock); 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_sock(sock); 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; map = pvcalls_enter_sock(sock); if (IS_ERR(map)) return EPOLLNVAL; bedata = dev_get_drvdata(&pvcalls_front_dev->dev); 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_sock(sock); 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; map = pvcalls_enter_sock(sock); if (IS_ERR(map)) { if (PTR_ERR(map) == -ENOTCONN) return -EIO; else return 0; } bedata = dev_get_drvdata(&pvcalls_front_dev->dev); spin_lock(&bedata->socket_lock); ret = get_request(bedata, &req_id); if (ret < 0) { spin_unlock(&bedata->socket_lock); pvcalls_exit_sock(sock); 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 way to guarantee this is to see that no pvcalls * (other than us) is in progress on this socket. */ while (atomic_read(&map->refcount) > 1) cpu_relax(); pvcalls_front_free_map(bedata, map); } else { wake_up(&bedata->inflight_req); wake_up(&map->passive.inflight_accept_req); while (atomic_read(&map->refcount) > 1) cpu_relax(); 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 && READ_ONCE(map->passive.inflight_req_id) != 0) { 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, i; evtchn_port_t evtchn; 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");
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