1252 lines · c
1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * (c) 2017 Stefano Stabellini <stefano@aporeto.com>4 */5 6#include <linux/inet.h>7#include <linux/kthread.h>8#include <linux/list.h>9#include <linux/radix-tree.h>10#include <linux/module.h>11#include <linux/semaphore.h>12#include <linux/wait.h>13#include <net/sock.h>14#include <net/inet_common.h>15#include <net/inet_connection_sock.h>16#include <net/request_sock.h>17#include <trace/events/sock.h>18 19#include <xen/events.h>20#include <xen/grant_table.h>21#include <xen/xen.h>22#include <xen/xenbus.h>23#include <xen/interface/io/pvcalls.h>24 25#define PVCALLS_VERSIONS "1"26#define MAX_RING_ORDER XENBUS_MAX_RING_GRANT_ORDER27 28static struct pvcalls_back_global {29 struct list_head frontends;30 struct semaphore frontends_lock;31} pvcalls_back_global;32 33/*34 * Per-frontend data structure. It contains pointers to the command35 * ring, its event channel, a list of active sockets and a tree of36 * passive sockets.37 */38struct pvcalls_fedata {39 struct list_head list;40 struct xenbus_device *dev;41 struct xen_pvcalls_sring *sring;42 struct xen_pvcalls_back_ring ring;43 int irq;44 struct list_head socket_mappings;45 struct radix_tree_root socketpass_mappings;46 struct semaphore socket_lock;47};48 49struct pvcalls_ioworker {50 struct work_struct register_work;51 struct workqueue_struct *wq;52};53 54struct sock_mapping {55 struct list_head list;56 struct pvcalls_fedata *fedata;57 struct sockpass_mapping *sockpass;58 struct socket *sock;59 uint64_t id;60 grant_ref_t ref;61 struct pvcalls_data_intf *ring;62 void *bytes;63 struct pvcalls_data data;64 uint32_t ring_order;65 int irq;66 atomic_t read;67 atomic_t write;68 atomic_t io;69 atomic_t release;70 atomic_t eoi;71 void (*saved_data_ready)(struct sock *sk);72 struct pvcalls_ioworker ioworker;73};74 75struct sockpass_mapping {76 struct list_head list;77 struct pvcalls_fedata *fedata;78 struct socket *sock;79 uint64_t id;80 struct xen_pvcalls_request reqcopy;81 spinlock_t copy_lock;82 struct workqueue_struct *wq;83 struct work_struct register_work;84 void (*saved_data_ready)(struct sock *sk);85};86 87static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map);88static int pvcalls_back_release_active(struct xenbus_device *dev,89 struct pvcalls_fedata *fedata,90 struct sock_mapping *map);91 92static bool pvcalls_conn_back_read(void *opaque)93{94 struct sock_mapping *map = (struct sock_mapping *)opaque;95 struct msghdr msg;96 struct kvec vec[2];97 RING_IDX cons, prod, size, wanted, array_size, masked_prod, masked_cons;98 int32_t error;99 struct pvcalls_data_intf *intf = map->ring;100 struct pvcalls_data *data = &map->data;101 unsigned long flags;102 int ret;103 104 array_size = XEN_FLEX_RING_SIZE(map->ring_order);105 cons = intf->in_cons;106 prod = intf->in_prod;107 error = intf->in_error;108 /* read the indexes first, then deal with the data */109 virt_mb();110 111 if (error)112 return false;113 114 size = pvcalls_queued(prod, cons, array_size);115 if (size >= array_size)116 return false;117 spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags);118 if (skb_queue_empty(&map->sock->sk->sk_receive_queue)) {119 atomic_set(&map->read, 0);120 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock,121 flags);122 return true;123 }124 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags);125 wanted = array_size - size;126 masked_prod = pvcalls_mask(prod, array_size);127 masked_cons = pvcalls_mask(cons, array_size);128 129 memset(&msg, 0, sizeof(msg));130 if (masked_prod < masked_cons) {131 vec[0].iov_base = data->in + masked_prod;132 vec[0].iov_len = wanted;133 iov_iter_kvec(&msg.msg_iter, ITER_DEST, vec, 1, wanted);134 } else {135 vec[0].iov_base = data->in + masked_prod;136 vec[0].iov_len = array_size - masked_prod;137 vec[1].iov_base = data->in;138 vec[1].iov_len = wanted - vec[0].iov_len;139 iov_iter_kvec(&msg.msg_iter, ITER_DEST, vec, 2, wanted);140 }141 142 atomic_set(&map->read, 0);143 ret = inet_recvmsg(map->sock, &msg, wanted, MSG_DONTWAIT);144 WARN_ON(ret > wanted);145 if (ret == -EAGAIN) /* shouldn't happen */146 return true;147 if (!ret)148 ret = -ENOTCONN;149 spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags);150 if (ret > 0 && !skb_queue_empty(&map->sock->sk->sk_receive_queue))151 atomic_inc(&map->read);152 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags);153 154 /* write the data, then modify the indexes */155 virt_wmb();156 if (ret < 0) {157 atomic_set(&map->read, 0);158 intf->in_error = ret;159 } else160 intf->in_prod = prod + ret;161 /* update the indexes, then notify the other end */162 virt_wmb();163 notify_remote_via_irq(map->irq);164 165 return true;166}167 168static bool pvcalls_conn_back_write(struct sock_mapping *map)169{170 struct pvcalls_data_intf *intf = map->ring;171 struct pvcalls_data *data = &map->data;172 struct msghdr msg;173 struct kvec vec[2];174 RING_IDX cons, prod, size, array_size;175 int ret;176 177 atomic_set(&map->write, 0);178 179 cons = intf->out_cons;180 prod = intf->out_prod;181 /* read the indexes before dealing with the data */182 virt_mb();183 184 array_size = XEN_FLEX_RING_SIZE(map->ring_order);185 size = pvcalls_queued(prod, cons, array_size);186 if (size == 0)187 return false;188 189 memset(&msg, 0, sizeof(msg));190 msg.msg_flags |= MSG_DONTWAIT;191 if (pvcalls_mask(prod, array_size) > pvcalls_mask(cons, array_size)) {192 vec[0].iov_base = data->out + pvcalls_mask(cons, array_size);193 vec[0].iov_len = size;194 iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, vec, 1, size);195 } else {196 vec[0].iov_base = data->out + pvcalls_mask(cons, array_size);197 vec[0].iov_len = array_size - pvcalls_mask(cons, array_size);198 vec[1].iov_base = data->out;199 vec[1].iov_len = size - vec[0].iov_len;200 iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, vec, 2, size);201 }202 203 ret = inet_sendmsg(map->sock, &msg, size);204 if (ret == -EAGAIN) {205 atomic_inc(&map->write);206 atomic_inc(&map->io);207 return true;208 }209 210 /* write the data, then update the indexes */211 virt_wmb();212 if (ret < 0) {213 intf->out_error = ret;214 } else {215 intf->out_error = 0;216 intf->out_cons = cons + ret;217 prod = intf->out_prod;218 }219 /* update the indexes, then notify the other end */220 virt_wmb();221 if (prod != cons + ret) {222 atomic_inc(&map->write);223 atomic_inc(&map->io);224 }225 notify_remote_via_irq(map->irq);226 227 return true;228}229 230static void pvcalls_back_ioworker(struct work_struct *work)231{232 struct pvcalls_ioworker *ioworker = container_of(work,233 struct pvcalls_ioworker, register_work);234 struct sock_mapping *map = container_of(ioworker, struct sock_mapping,235 ioworker);236 unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS;237 238 while (atomic_read(&map->io) > 0) {239 if (atomic_read(&map->release) > 0) {240 atomic_set(&map->release, 0);241 return;242 }243 244 if (atomic_read(&map->read) > 0 &&245 pvcalls_conn_back_read(map))246 eoi_flags = 0;247 if (atomic_read(&map->write) > 0 &&248 pvcalls_conn_back_write(map))249 eoi_flags = 0;250 251 if (atomic_read(&map->eoi) > 0 && !atomic_read(&map->write)) {252 atomic_set(&map->eoi, 0);253 xen_irq_lateeoi(map->irq, eoi_flags);254 eoi_flags = XEN_EOI_FLAG_SPURIOUS;255 }256 257 atomic_dec(&map->io);258 }259}260 261static int pvcalls_back_socket(struct xenbus_device *dev,262 struct xen_pvcalls_request *req)263{264 struct pvcalls_fedata *fedata;265 int ret;266 struct xen_pvcalls_response *rsp;267 268 fedata = dev_get_drvdata(&dev->dev);269 270 if (req->u.socket.domain != AF_INET ||271 req->u.socket.type != SOCK_STREAM ||272 (req->u.socket.protocol != IPPROTO_IP &&273 req->u.socket.protocol != AF_INET))274 ret = -EAFNOSUPPORT;275 else276 ret = 0;277 278 /* leave the actual socket allocation for later */279 280 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);281 rsp->req_id = req->req_id;282 rsp->cmd = req->cmd;283 rsp->u.socket.id = req->u.socket.id;284 rsp->ret = ret;285 286 return 0;287}288 289static void pvcalls_sk_state_change(struct sock *sock)290{291 struct sock_mapping *map = sock->sk_user_data;292 293 if (map == NULL)294 return;295 296 atomic_inc(&map->read);297 notify_remote_via_irq(map->irq);298}299 300static void pvcalls_sk_data_ready(struct sock *sock)301{302 struct sock_mapping *map = sock->sk_user_data;303 struct pvcalls_ioworker *iow;304 305 trace_sk_data_ready(sock);306 307 if (map == NULL)308 return;309 310 iow = &map->ioworker;311 atomic_inc(&map->read);312 atomic_inc(&map->io);313 queue_work(iow->wq, &iow->register_work);314}315 316static struct sock_mapping *pvcalls_new_active_socket(317 struct pvcalls_fedata *fedata,318 uint64_t id,319 grant_ref_t ref,320 evtchn_port_t evtchn,321 struct socket *sock)322{323 int ret;324 struct sock_mapping *map;325 void *page;326 327 map = kzalloc(sizeof(*map), GFP_KERNEL);328 if (map == NULL) {329 sock_release(sock);330 return NULL;331 }332 333 map->fedata = fedata;334 map->sock = sock;335 map->id = id;336 map->ref = ref;337 338 ret = xenbus_map_ring_valloc(fedata->dev, &ref, 1, &page);339 if (ret < 0)340 goto out;341 map->ring = page;342 map->ring_order = map->ring->ring_order;343 /* first read the order, then map the data ring */344 virt_rmb();345 if (map->ring_order > MAX_RING_ORDER) {346 pr_warn("%s frontend requested ring_order %u, which is > MAX (%u)\n",347 __func__, map->ring_order, MAX_RING_ORDER);348 goto out;349 }350 ret = xenbus_map_ring_valloc(fedata->dev, map->ring->ref,351 (1 << map->ring_order), &page);352 if (ret < 0)353 goto out;354 map->bytes = page;355 356 ret = bind_interdomain_evtchn_to_irqhandler_lateeoi(357 fedata->dev, evtchn,358 pvcalls_back_conn_event, 0, "pvcalls-backend", map);359 if (ret < 0)360 goto out;361 map->irq = ret;362 363 map->data.in = map->bytes;364 map->data.out = map->bytes + XEN_FLEX_RING_SIZE(map->ring_order);365 366 map->ioworker.wq = alloc_ordered_workqueue("pvcalls_io", 0);367 if (!map->ioworker.wq)368 goto out;369 atomic_set(&map->io, 1);370 INIT_WORK(&map->ioworker.register_work, pvcalls_back_ioworker);371 372 down(&fedata->socket_lock);373 list_add_tail(&map->list, &fedata->socket_mappings);374 up(&fedata->socket_lock);375 376 write_lock_bh(&map->sock->sk->sk_callback_lock);377 map->saved_data_ready = map->sock->sk->sk_data_ready;378 map->sock->sk->sk_user_data = map;379 map->sock->sk->sk_data_ready = pvcalls_sk_data_ready;380 map->sock->sk->sk_state_change = pvcalls_sk_state_change;381 write_unlock_bh(&map->sock->sk->sk_callback_lock);382 383 return map;384out:385 down(&fedata->socket_lock);386 list_del(&map->list);387 pvcalls_back_release_active(fedata->dev, fedata, map);388 up(&fedata->socket_lock);389 return NULL;390}391 392static int pvcalls_back_connect(struct xenbus_device *dev,393 struct xen_pvcalls_request *req)394{395 struct pvcalls_fedata *fedata;396 int ret = -EINVAL;397 struct socket *sock;398 struct sock_mapping *map;399 struct xen_pvcalls_response *rsp;400 struct sockaddr *sa = (struct sockaddr *)&req->u.connect.addr;401 402 fedata = dev_get_drvdata(&dev->dev);403 404 if (req->u.connect.len < sizeof(sa->sa_family) ||405 req->u.connect.len > sizeof(req->u.connect.addr) ||406 sa->sa_family != AF_INET)407 goto out;408 409 ret = sock_create(AF_INET, SOCK_STREAM, 0, &sock);410 if (ret < 0)411 goto out;412 ret = inet_stream_connect(sock, sa, req->u.connect.len, 0);413 if (ret < 0) {414 sock_release(sock);415 goto out;416 }417 418 map = pvcalls_new_active_socket(fedata,419 req->u.connect.id,420 req->u.connect.ref,421 req->u.connect.evtchn,422 sock);423 if (!map)424 ret = -EFAULT;425 426out:427 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);428 rsp->req_id = req->req_id;429 rsp->cmd = req->cmd;430 rsp->u.connect.id = req->u.connect.id;431 rsp->ret = ret;432 433 return 0;434}435 436static int pvcalls_back_release_active(struct xenbus_device *dev,437 struct pvcalls_fedata *fedata,438 struct sock_mapping *map)439{440 disable_irq(map->irq);441 if (map->sock->sk != NULL) {442 write_lock_bh(&map->sock->sk->sk_callback_lock);443 map->sock->sk->sk_user_data = NULL;444 map->sock->sk->sk_data_ready = map->saved_data_ready;445 write_unlock_bh(&map->sock->sk->sk_callback_lock);446 }447 448 atomic_set(&map->release, 1);449 flush_work(&map->ioworker.register_work);450 451 xenbus_unmap_ring_vfree(dev, map->bytes);452 xenbus_unmap_ring_vfree(dev, (void *)map->ring);453 unbind_from_irqhandler(map->irq, map);454 455 sock_release(map->sock);456 kfree(map);457 458 return 0;459}460 461static int pvcalls_back_release_passive(struct xenbus_device *dev,462 struct pvcalls_fedata *fedata,463 struct sockpass_mapping *mappass)464{465 if (mappass->sock->sk != NULL) {466 write_lock_bh(&mappass->sock->sk->sk_callback_lock);467 mappass->sock->sk->sk_user_data = NULL;468 mappass->sock->sk->sk_data_ready = mappass->saved_data_ready;469 write_unlock_bh(&mappass->sock->sk->sk_callback_lock);470 }471 sock_release(mappass->sock);472 destroy_workqueue(mappass->wq);473 kfree(mappass);474 475 return 0;476}477 478static int pvcalls_back_release(struct xenbus_device *dev,479 struct xen_pvcalls_request *req)480{481 struct pvcalls_fedata *fedata;482 struct sock_mapping *map, *n;483 struct sockpass_mapping *mappass;484 int ret = 0;485 struct xen_pvcalls_response *rsp;486 487 fedata = dev_get_drvdata(&dev->dev);488 489 down(&fedata->socket_lock);490 list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) {491 if (map->id == req->u.release.id) {492 list_del(&map->list);493 up(&fedata->socket_lock);494 ret = pvcalls_back_release_active(dev, fedata, map);495 goto out;496 }497 }498 mappass = radix_tree_lookup(&fedata->socketpass_mappings,499 req->u.release.id);500 if (mappass != NULL) {501 radix_tree_delete(&fedata->socketpass_mappings, mappass->id);502 up(&fedata->socket_lock);503 ret = pvcalls_back_release_passive(dev, fedata, mappass);504 } else505 up(&fedata->socket_lock);506 507out:508 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);509 rsp->req_id = req->req_id;510 rsp->u.release.id = req->u.release.id;511 rsp->cmd = req->cmd;512 rsp->ret = ret;513 return 0;514}515 516static void __pvcalls_back_accept(struct work_struct *work)517{518 struct sockpass_mapping *mappass = container_of(519 work, struct sockpass_mapping, register_work);520 struct proto_accept_arg arg = {521 .flags = O_NONBLOCK,522 .kern = true,523 };524 struct sock_mapping *map;525 struct pvcalls_ioworker *iow;526 struct pvcalls_fedata *fedata;527 struct socket *sock;528 struct xen_pvcalls_response *rsp;529 struct xen_pvcalls_request *req;530 int notify;531 int ret = -EINVAL;532 unsigned long flags;533 534 fedata = mappass->fedata;535 /*536 * __pvcalls_back_accept can race against pvcalls_back_accept.537 * We only need to check the value of "cmd" on read. It could be538 * done atomically, but to simplify the code on the write side, we539 * use a spinlock.540 */541 spin_lock_irqsave(&mappass->copy_lock, flags);542 req = &mappass->reqcopy;543 if (req->cmd != PVCALLS_ACCEPT) {544 spin_unlock_irqrestore(&mappass->copy_lock, flags);545 return;546 }547 spin_unlock_irqrestore(&mappass->copy_lock, flags);548 549 sock = sock_alloc();550 if (sock == NULL)551 goto out_error;552 sock->type = mappass->sock->type;553 sock->ops = mappass->sock->ops;554 555 ret = inet_accept(mappass->sock, sock, &arg);556 if (ret == -EAGAIN) {557 sock_release(sock);558 return;559 }560 561 map = pvcalls_new_active_socket(fedata,562 req->u.accept.id_new,563 req->u.accept.ref,564 req->u.accept.evtchn,565 sock);566 if (!map) {567 ret = -EFAULT;568 goto out_error;569 }570 571 map->sockpass = mappass;572 iow = &map->ioworker;573 atomic_inc(&map->read);574 atomic_inc(&map->io);575 queue_work(iow->wq, &iow->register_work);576 577out_error:578 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);579 rsp->req_id = req->req_id;580 rsp->cmd = req->cmd;581 rsp->u.accept.id = req->u.accept.id;582 rsp->ret = ret;583 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify);584 if (notify)585 notify_remote_via_irq(fedata->irq);586 587 mappass->reqcopy.cmd = 0;588}589 590static void pvcalls_pass_sk_data_ready(struct sock *sock)591{592 struct sockpass_mapping *mappass = sock->sk_user_data;593 struct pvcalls_fedata *fedata;594 struct xen_pvcalls_response *rsp;595 unsigned long flags;596 int notify;597 598 trace_sk_data_ready(sock);599 600 if (mappass == NULL)601 return;602 603 fedata = mappass->fedata;604 spin_lock_irqsave(&mappass->copy_lock, flags);605 if (mappass->reqcopy.cmd == PVCALLS_POLL) {606 rsp = RING_GET_RESPONSE(&fedata->ring,607 fedata->ring.rsp_prod_pvt++);608 rsp->req_id = mappass->reqcopy.req_id;609 rsp->u.poll.id = mappass->reqcopy.u.poll.id;610 rsp->cmd = mappass->reqcopy.cmd;611 rsp->ret = 0;612 613 mappass->reqcopy.cmd = 0;614 spin_unlock_irqrestore(&mappass->copy_lock, flags);615 616 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify);617 if (notify)618 notify_remote_via_irq(mappass->fedata->irq);619 } else {620 spin_unlock_irqrestore(&mappass->copy_lock, flags);621 queue_work(mappass->wq, &mappass->register_work);622 }623}624 625static int pvcalls_back_bind(struct xenbus_device *dev,626 struct xen_pvcalls_request *req)627{628 struct pvcalls_fedata *fedata;629 int ret;630 struct sockpass_mapping *map;631 struct xen_pvcalls_response *rsp;632 633 fedata = dev_get_drvdata(&dev->dev);634 635 map = kzalloc(sizeof(*map), GFP_KERNEL);636 if (map == NULL) {637 ret = -ENOMEM;638 goto out;639 }640 641 INIT_WORK(&map->register_work, __pvcalls_back_accept);642 spin_lock_init(&map->copy_lock);643 map->wq = alloc_ordered_workqueue("pvcalls_wq", 0);644 if (!map->wq) {645 ret = -ENOMEM;646 goto out;647 }648 649 ret = sock_create(AF_INET, SOCK_STREAM, 0, &map->sock);650 if (ret < 0)651 goto out;652 653 ret = inet_bind(map->sock, (struct sockaddr *)&req->u.bind.addr,654 req->u.bind.len);655 if (ret < 0)656 goto out;657 658 map->fedata = fedata;659 map->id = req->u.bind.id;660 661 down(&fedata->socket_lock);662 ret = radix_tree_insert(&fedata->socketpass_mappings, map->id,663 map);664 up(&fedata->socket_lock);665 if (ret)666 goto out;667 668 write_lock_bh(&map->sock->sk->sk_callback_lock);669 map->saved_data_ready = map->sock->sk->sk_data_ready;670 map->sock->sk->sk_user_data = map;671 map->sock->sk->sk_data_ready = pvcalls_pass_sk_data_ready;672 write_unlock_bh(&map->sock->sk->sk_callback_lock);673 674out:675 if (ret) {676 if (map && map->sock)677 sock_release(map->sock);678 if (map && map->wq)679 destroy_workqueue(map->wq);680 kfree(map);681 }682 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);683 rsp->req_id = req->req_id;684 rsp->cmd = req->cmd;685 rsp->u.bind.id = req->u.bind.id;686 rsp->ret = ret;687 return 0;688}689 690static int pvcalls_back_listen(struct xenbus_device *dev,691 struct xen_pvcalls_request *req)692{693 struct pvcalls_fedata *fedata;694 int ret = -EINVAL;695 struct sockpass_mapping *map;696 struct xen_pvcalls_response *rsp;697 698 fedata = dev_get_drvdata(&dev->dev);699 700 down(&fedata->socket_lock);701 map = radix_tree_lookup(&fedata->socketpass_mappings, req->u.listen.id);702 up(&fedata->socket_lock);703 if (map == NULL)704 goto out;705 706 ret = inet_listen(map->sock, req->u.listen.backlog);707 708out:709 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);710 rsp->req_id = req->req_id;711 rsp->cmd = req->cmd;712 rsp->u.listen.id = req->u.listen.id;713 rsp->ret = ret;714 return 0;715}716 717static int pvcalls_back_accept(struct xenbus_device *dev,718 struct xen_pvcalls_request *req)719{720 struct pvcalls_fedata *fedata;721 struct sockpass_mapping *mappass;722 int ret = -EINVAL;723 struct xen_pvcalls_response *rsp;724 unsigned long flags;725 726 fedata = dev_get_drvdata(&dev->dev);727 728 down(&fedata->socket_lock);729 mappass = radix_tree_lookup(&fedata->socketpass_mappings,730 req->u.accept.id);731 up(&fedata->socket_lock);732 if (mappass == NULL)733 goto out_error;734 735 /*736 * Limitation of the current implementation: only support one737 * concurrent accept or poll call on one socket.738 */739 spin_lock_irqsave(&mappass->copy_lock, flags);740 if (mappass->reqcopy.cmd != 0) {741 spin_unlock_irqrestore(&mappass->copy_lock, flags);742 ret = -EINTR;743 goto out_error;744 }745 746 mappass->reqcopy = *req;747 spin_unlock_irqrestore(&mappass->copy_lock, flags);748 queue_work(mappass->wq, &mappass->register_work);749 750 /* Tell the caller we don't need to send back a notification yet */751 return -1;752 753out_error:754 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);755 rsp->req_id = req->req_id;756 rsp->cmd = req->cmd;757 rsp->u.accept.id = req->u.accept.id;758 rsp->ret = ret;759 return 0;760}761 762static int pvcalls_back_poll(struct xenbus_device *dev,763 struct xen_pvcalls_request *req)764{765 struct pvcalls_fedata *fedata;766 struct sockpass_mapping *mappass;767 struct xen_pvcalls_response *rsp;768 struct inet_connection_sock *icsk;769 struct request_sock_queue *queue;770 unsigned long flags;771 int ret;772 bool data;773 774 fedata = dev_get_drvdata(&dev->dev);775 776 down(&fedata->socket_lock);777 mappass = radix_tree_lookup(&fedata->socketpass_mappings,778 req->u.poll.id);779 up(&fedata->socket_lock);780 if (mappass == NULL)781 return -EINVAL;782 783 /*784 * Limitation of the current implementation: only support one785 * concurrent accept or poll call on one socket.786 */787 spin_lock_irqsave(&mappass->copy_lock, flags);788 if (mappass->reqcopy.cmd != 0) {789 ret = -EINTR;790 goto out;791 }792 793 mappass->reqcopy = *req;794 icsk = inet_csk(mappass->sock->sk);795 queue = &icsk->icsk_accept_queue;796 data = READ_ONCE(queue->rskq_accept_head) != NULL;797 if (data) {798 mappass->reqcopy.cmd = 0;799 ret = 0;800 goto out;801 }802 spin_unlock_irqrestore(&mappass->copy_lock, flags);803 804 /* Tell the caller we don't need to send back a notification yet */805 return -1;806 807out:808 spin_unlock_irqrestore(&mappass->copy_lock, flags);809 810 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);811 rsp->req_id = req->req_id;812 rsp->cmd = req->cmd;813 rsp->u.poll.id = req->u.poll.id;814 rsp->ret = ret;815 return 0;816}817 818static int pvcalls_back_handle_cmd(struct xenbus_device *dev,819 struct xen_pvcalls_request *req)820{821 int ret = 0;822 823 switch (req->cmd) {824 case PVCALLS_SOCKET:825 ret = pvcalls_back_socket(dev, req);826 break;827 case PVCALLS_CONNECT:828 ret = pvcalls_back_connect(dev, req);829 break;830 case PVCALLS_RELEASE:831 ret = pvcalls_back_release(dev, req);832 break;833 case PVCALLS_BIND:834 ret = pvcalls_back_bind(dev, req);835 break;836 case PVCALLS_LISTEN:837 ret = pvcalls_back_listen(dev, req);838 break;839 case PVCALLS_ACCEPT:840 ret = pvcalls_back_accept(dev, req);841 break;842 case PVCALLS_POLL:843 ret = pvcalls_back_poll(dev, req);844 break;845 default:846 {847 struct pvcalls_fedata *fedata;848 struct xen_pvcalls_response *rsp;849 850 fedata = dev_get_drvdata(&dev->dev);851 rsp = RING_GET_RESPONSE(852 &fedata->ring, fedata->ring.rsp_prod_pvt++);853 rsp->req_id = req->req_id;854 rsp->cmd = req->cmd;855 rsp->ret = -ENOTSUPP;856 break;857 }858 }859 return ret;860}861 862static void pvcalls_back_work(struct pvcalls_fedata *fedata)863{864 int notify, notify_all = 0, more = 1;865 struct xen_pvcalls_request req;866 struct xenbus_device *dev = fedata->dev;867 868 while (more) {869 while (RING_HAS_UNCONSUMED_REQUESTS(&fedata->ring)) {870 RING_COPY_REQUEST(&fedata->ring,871 fedata->ring.req_cons++,872 &req);873 874 if (!pvcalls_back_handle_cmd(dev, &req)) {875 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(876 &fedata->ring, notify);877 notify_all += notify;878 }879 }880 881 if (notify_all) {882 notify_remote_via_irq(fedata->irq);883 notify_all = 0;884 }885 886 RING_FINAL_CHECK_FOR_REQUESTS(&fedata->ring, more);887 }888}889 890static irqreturn_t pvcalls_back_event(int irq, void *dev_id)891{892 struct xenbus_device *dev = dev_id;893 struct pvcalls_fedata *fedata = NULL;894 unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS;895 896 if (dev) {897 fedata = dev_get_drvdata(&dev->dev);898 if (fedata) {899 pvcalls_back_work(fedata);900 eoi_flags = 0;901 }902 }903 904 xen_irq_lateeoi(irq, eoi_flags);905 906 return IRQ_HANDLED;907}908 909static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map)910{911 struct sock_mapping *map = sock_map;912 struct pvcalls_ioworker *iow;913 914 if (map == NULL || map->sock == NULL || map->sock->sk == NULL ||915 map->sock->sk->sk_user_data != map) {916 xen_irq_lateeoi(irq, 0);917 return IRQ_HANDLED;918 }919 920 iow = &map->ioworker;921 922 atomic_inc(&map->write);923 atomic_inc(&map->eoi);924 atomic_inc(&map->io);925 queue_work(iow->wq, &iow->register_work);926 927 return IRQ_HANDLED;928}929 930static int backend_connect(struct xenbus_device *dev)931{932 int err;933 evtchn_port_t evtchn;934 grant_ref_t ring_ref;935 struct pvcalls_fedata *fedata = NULL;936 937 fedata = kzalloc(sizeof(struct pvcalls_fedata), GFP_KERNEL);938 if (!fedata)939 return -ENOMEM;940 941 fedata->irq = -1;942 err = xenbus_scanf(XBT_NIL, dev->otherend, "port", "%u",943 &evtchn);944 if (err != 1) {945 err = -EINVAL;946 xenbus_dev_fatal(dev, err, "reading %s/event-channel",947 dev->otherend);948 goto error;949 }950 951 err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref", "%u", &ring_ref);952 if (err != 1) {953 err = -EINVAL;954 xenbus_dev_fatal(dev, err, "reading %s/ring-ref",955 dev->otherend);956 goto error;957 }958 959 err = bind_interdomain_evtchn_to_irq_lateeoi(dev, evtchn);960 if (err < 0)961 goto error;962 fedata->irq = err;963 964 err = request_threaded_irq(fedata->irq, NULL, pvcalls_back_event,965 IRQF_ONESHOT, "pvcalls-back", dev);966 if (err < 0)967 goto error;968 969 err = xenbus_map_ring_valloc(dev, &ring_ref, 1,970 (void **)&fedata->sring);971 if (err < 0)972 goto error;973 974 BACK_RING_INIT(&fedata->ring, fedata->sring, XEN_PAGE_SIZE * 1);975 fedata->dev = dev;976 977 INIT_LIST_HEAD(&fedata->socket_mappings);978 INIT_RADIX_TREE(&fedata->socketpass_mappings, GFP_KERNEL);979 sema_init(&fedata->socket_lock, 1);980 dev_set_drvdata(&dev->dev, fedata);981 982 down(&pvcalls_back_global.frontends_lock);983 list_add_tail(&fedata->list, &pvcalls_back_global.frontends);984 up(&pvcalls_back_global.frontends_lock);985 986 return 0;987 988 error:989 if (fedata->irq >= 0)990 unbind_from_irqhandler(fedata->irq, dev);991 if (fedata->sring != NULL)992 xenbus_unmap_ring_vfree(dev, fedata->sring);993 kfree(fedata);994 return err;995}996 997static int backend_disconnect(struct xenbus_device *dev)998{999 struct pvcalls_fedata *fedata;1000 struct sock_mapping *map, *n;1001 struct sockpass_mapping *mappass;1002 struct radix_tree_iter iter;1003 void **slot;1004 1005 1006 fedata = dev_get_drvdata(&dev->dev);1007 1008 down(&fedata->socket_lock);1009 list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) {1010 list_del(&map->list);1011 pvcalls_back_release_active(dev, fedata, map);1012 }1013 1014 radix_tree_for_each_slot(slot, &fedata->socketpass_mappings, &iter, 0) {1015 mappass = radix_tree_deref_slot(slot);1016 if (!mappass)1017 continue;1018 if (radix_tree_exception(mappass)) {1019 if (radix_tree_deref_retry(mappass))1020 slot = radix_tree_iter_retry(&iter);1021 } else {1022 radix_tree_delete(&fedata->socketpass_mappings,1023 mappass->id);1024 pvcalls_back_release_passive(dev, fedata, mappass);1025 }1026 }1027 up(&fedata->socket_lock);1028 1029 unbind_from_irqhandler(fedata->irq, dev);1030 xenbus_unmap_ring_vfree(dev, fedata->sring);1031 1032 list_del(&fedata->list);1033 kfree(fedata);1034 dev_set_drvdata(&dev->dev, NULL);1035 1036 return 0;1037}1038 1039static int pvcalls_back_probe(struct xenbus_device *dev,1040 const struct xenbus_device_id *id)1041{1042 int err, abort;1043 struct xenbus_transaction xbt;1044 1045again:1046 abort = 1;1047 1048 err = xenbus_transaction_start(&xbt);1049 if (err) {1050 pr_warn("%s cannot create xenstore transaction\n", __func__);1051 return err;1052 }1053 1054 err = xenbus_printf(xbt, dev->nodename, "versions", "%s",1055 PVCALLS_VERSIONS);1056 if (err) {1057 pr_warn("%s write out 'versions' failed\n", __func__);1058 goto abort;1059 }1060 1061 err = xenbus_printf(xbt, dev->nodename, "max-page-order", "%u",1062 MAX_RING_ORDER);1063 if (err) {1064 pr_warn("%s write out 'max-page-order' failed\n", __func__);1065 goto abort;1066 }1067 1068 err = xenbus_printf(xbt, dev->nodename, "function-calls",1069 XENBUS_FUNCTIONS_CALLS);1070 if (err) {1071 pr_warn("%s write out 'function-calls' failed\n", __func__);1072 goto abort;1073 }1074 1075 abort = 0;1076abort:1077 err = xenbus_transaction_end(xbt, abort);1078 if (err) {1079 if (err == -EAGAIN && !abort)1080 goto again;1081 pr_warn("%s cannot complete xenstore transaction\n", __func__);1082 return err;1083 }1084 1085 if (abort)1086 return -EFAULT;1087 1088 xenbus_switch_state(dev, XenbusStateInitWait);1089 1090 return 0;1091}1092 1093static void set_backend_state(struct xenbus_device *dev,1094 enum xenbus_state state)1095{1096 while (dev->state != state) {1097 switch (dev->state) {1098 case XenbusStateClosed:1099 switch (state) {1100 case XenbusStateInitWait:1101 case XenbusStateConnected:1102 xenbus_switch_state(dev, XenbusStateInitWait);1103 break;1104 case XenbusStateClosing:1105 xenbus_switch_state(dev, XenbusStateClosing);1106 break;1107 default:1108 WARN_ON(1);1109 }1110 break;1111 case XenbusStateInitWait:1112 case XenbusStateInitialised:1113 switch (state) {1114 case XenbusStateConnected:1115 if (backend_connect(dev))1116 return;1117 xenbus_switch_state(dev, XenbusStateConnected);1118 break;1119 case XenbusStateClosing:1120 case XenbusStateClosed:1121 xenbus_switch_state(dev, XenbusStateClosing);1122 break;1123 default:1124 WARN_ON(1);1125 }1126 break;1127 case XenbusStateConnected:1128 switch (state) {1129 case XenbusStateInitWait:1130 case XenbusStateClosing:1131 case XenbusStateClosed:1132 down(&pvcalls_back_global.frontends_lock);1133 backend_disconnect(dev);1134 up(&pvcalls_back_global.frontends_lock);1135 xenbus_switch_state(dev, XenbusStateClosing);1136 break;1137 default:1138 WARN_ON(1);1139 }1140 break;1141 case XenbusStateClosing:1142 switch (state) {1143 case XenbusStateInitWait:1144 case XenbusStateConnected:1145 case XenbusStateClosed:1146 xenbus_switch_state(dev, XenbusStateClosed);1147 break;1148 default:1149 WARN_ON(1);1150 }1151 break;1152 default:1153 WARN_ON(1);1154 }1155 }1156}1157 1158static void pvcalls_back_changed(struct xenbus_device *dev,1159 enum xenbus_state frontend_state)1160{1161 switch (frontend_state) {1162 case XenbusStateInitialising:1163 set_backend_state(dev, XenbusStateInitWait);1164 break;1165 1166 case XenbusStateInitialised:1167 case XenbusStateConnected:1168 set_backend_state(dev, XenbusStateConnected);1169 break;1170 1171 case XenbusStateClosing:1172 set_backend_state(dev, XenbusStateClosing);1173 break;1174 1175 case XenbusStateClosed:1176 set_backend_state(dev, XenbusStateClosed);1177 if (xenbus_dev_is_online(dev))1178 break;1179 device_unregister(&dev->dev);1180 break;1181 case XenbusStateUnknown:1182 set_backend_state(dev, XenbusStateClosed);1183 device_unregister(&dev->dev);1184 break;1185 1186 default:1187 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",1188 frontend_state);1189 break;1190 }1191}1192 1193static void pvcalls_back_remove(struct xenbus_device *dev)1194{1195}1196 1197static int pvcalls_back_uevent(const struct xenbus_device *xdev,1198 struct kobj_uevent_env *env)1199{1200 return 0;1201}1202 1203static const struct xenbus_device_id pvcalls_back_ids[] = {1204 { "pvcalls" },1205 { "" }1206};1207 1208static struct xenbus_driver pvcalls_back_driver = {1209 .ids = pvcalls_back_ids,1210 .probe = pvcalls_back_probe,1211 .remove = pvcalls_back_remove,1212 .uevent = pvcalls_back_uevent,1213 .otherend_changed = pvcalls_back_changed,1214};1215 1216static int __init pvcalls_back_init(void)1217{1218 int ret;1219 1220 if (!xen_domain())1221 return -ENODEV;1222 1223 ret = xenbus_register_backend(&pvcalls_back_driver);1224 if (ret < 0)1225 return ret;1226 1227 sema_init(&pvcalls_back_global.frontends_lock, 1);1228 INIT_LIST_HEAD(&pvcalls_back_global.frontends);1229 return 0;1230}1231module_init(pvcalls_back_init);1232 1233static void __exit pvcalls_back_fin(void)1234{1235 struct pvcalls_fedata *fedata, *nfedata;1236 1237 down(&pvcalls_back_global.frontends_lock);1238 list_for_each_entry_safe(fedata, nfedata,1239 &pvcalls_back_global.frontends, list) {1240 backend_disconnect(fedata->dev);1241 }1242 up(&pvcalls_back_global.frontends_lock);1243 1244 xenbus_unregister_driver(&pvcalls_back_driver);1245}1246 1247module_exit(pvcalls_back_fin);1248 1249MODULE_DESCRIPTION("Xen PV Calls backend driver");1250MODULE_AUTHOR("Stefano Stabellini <sstabellini@kernel.org>");1251MODULE_LICENSE("GPL");1252