linux/drivers/xen/pvcalls-back.c

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/*
* (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/inet.h>
#include <linux/kthread.h>
#include <linux/list.h>
#include <linux/radix-tree.h>
#include <linux/module.h>
#include <linux/semaphore.h>
#include <linux/wait.h>
#include <net/sock.h>
#include <net/inet_common.h>
#include <net/inet_connection_sock.h>
#include <net/request_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>
#define PVCALLS_VERSIONS "1"
#define MAX_RING_ORDER XENBUS_MAX_RING_GRANT_ORDER
struct pvcalls_back_global {
struct list_head frontends;
struct semaphore frontends_lock;
} pvcalls_back_global;
/*
* Per-frontend data structure. It contains pointers to the command
* ring, its event channel, a list of active sockets and a tree of
* passive sockets.
*/
struct pvcalls_fedata {
struct list_head list;
struct xenbus_device *dev;
struct xen_pvcalls_sring *sring;
struct xen_pvcalls_back_ring ring;
int irq;
struct list_head socket_mappings;
struct radix_tree_root socketpass_mappings;
struct semaphore socket_lock;
};
struct pvcalls_ioworker {
struct work_struct register_work;
struct workqueue_struct *wq;
};
struct sock_mapping {
struct list_head list;
struct pvcalls_fedata *fedata;
struct sockpass_mapping *sockpass;
struct socket *sock;
uint64_t id;
grant_ref_t ref;
struct pvcalls_data_intf *ring;
void *bytes;
struct pvcalls_data data;
uint32_t ring_order;
int irq;
atomic_t read;
atomic_t write;
atomic_t io;
atomic_t release;
void (*saved_data_ready)(struct sock *sk);
struct pvcalls_ioworker ioworker;
};
struct sockpass_mapping {
struct list_head list;
struct pvcalls_fedata *fedata;
struct socket *sock;
uint64_t id;
struct xen_pvcalls_request reqcopy;
spinlock_t copy_lock;
struct workqueue_struct *wq;
struct work_struct register_work;
void (*saved_data_ready)(struct sock *sk);
};
static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map);
static int pvcalls_back_release_active(struct xenbus_device *dev,
struct pvcalls_fedata *fedata,
struct sock_mapping *map);
static void pvcalls_conn_back_read(void *opaque)
{
struct sock_mapping *map = (struct sock_mapping *)opaque;
struct msghdr msg;
struct kvec vec[2];
RING_IDX cons, prod, size, wanted, array_size, masked_prod, masked_cons;
int32_t error;
struct pvcalls_data_intf *intf = map->ring;
struct pvcalls_data *data = &map->data;
unsigned long flags;
int ret;
array_size = XEN_FLEX_RING_SIZE(map->ring_order);
cons = intf->in_cons;
prod = intf->in_prod;
error = intf->in_error;
/* read the indexes first, then deal with the data */
virt_mb();
if (error)
return;
size = pvcalls_queued(prod, cons, array_size);
if (size >= array_size)
return;
spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags);
if (skb_queue_empty(&map->sock->sk->sk_receive_queue)) {
atomic_set(&map->read, 0);
spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock,
flags);
return;
}
spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags);
wanted = array_size - size;
masked_prod = pvcalls_mask(prod, array_size);
masked_cons = pvcalls_mask(cons, array_size);
memset(&msg, 0, sizeof(msg));
if (masked_prod < masked_cons) {
vec[0].iov_base = data->in + masked_prod;
vec[0].iov_len = wanted;
iov_iter_kvec(&msg.msg_iter, WRITE, vec, 1, wanted);
} else {
vec[0].iov_base = data->in + masked_prod;
vec[0].iov_len = array_size - masked_prod;
vec[1].iov_base = data->in;
vec[1].iov_len = wanted - vec[0].iov_len;
iov_iter_kvec(&msg.msg_iter, WRITE, vec, 2, wanted);
}
atomic_set(&map->read, 0);
ret = inet_recvmsg(map->sock, &msg, wanted, MSG_DONTWAIT);
WARN_ON(ret > wanted);
if (ret == -EAGAIN) /* shouldn't happen */
return;
if (!ret)
ret = -ENOTCONN;
spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags);
if (ret > 0 && !skb_queue_empty(&map->sock->sk->sk_receive_queue))
atomic_inc(&map->read);
spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags);
/* write the data, then modify the indexes */
virt_wmb();
if (ret < 0) {
atomic_set(&map->read, 0);
intf->in_error = ret;
} else
intf->in_prod = prod + ret;
/* update the indexes, then notify the other end */
virt_wmb();
notify_remote_via_irq(map->irq);
return;
}
static void pvcalls_conn_back_write(struct sock_mapping *map)
{
struct pvcalls_data_intf *intf = map->ring;
struct pvcalls_data *data = &map->data;
struct msghdr msg;
struct kvec vec[2];
RING_IDX cons, prod, size, array_size;
int ret;
cons = intf->out_cons;
prod = intf->out_prod;
/* read the indexes before dealing with the data */
virt_mb();
array_size = XEN_FLEX_RING_SIZE(map->ring_order);
size = pvcalls_queued(prod, cons, array_size);
if (size == 0)
return;
memset(&msg, 0, sizeof(msg));
msg.msg_flags |= MSG_DONTWAIT;
if (pvcalls_mask(prod, array_size) > pvcalls_mask(cons, array_size)) {
vec[0].iov_base = data->out + pvcalls_mask(cons, array_size);
vec[0].iov_len = size;
iov_iter_kvec(&msg.msg_iter, READ, vec, 1, size);
} else {
vec[0].iov_base = data->out + pvcalls_mask(cons, array_size);
vec[0].iov_len = array_size - pvcalls_mask(cons, array_size);
vec[1].iov_base = data->out;
vec[1].iov_len = size - vec[0].iov_len;
iov_iter_kvec(&msg.msg_iter, READ, vec, 2, size);
}
atomic_set(&map->write, 0);
ret = inet_sendmsg(map->sock, &msg, size);
if (ret == -EAGAIN || (ret >= 0 && ret < size)) {
atomic_inc(&map->write);
atomic_inc(&map->io);
}
if (ret == -EAGAIN)
return;
/* write the data, then update the indexes */
virt_wmb();
if (ret < 0) {
intf->out_error = ret;
} else {
intf->out_error = 0;
intf->out_cons = cons + ret;
prod = intf->out_prod;
}
/* update the indexes, then notify the other end */
virt_wmb();
if (prod != cons + ret)
atomic_inc(&map->write);
notify_remote_via_irq(map->irq);
}
static void pvcalls_back_ioworker(struct work_struct *work)
{
struct pvcalls_ioworker *ioworker = container_of(work,
struct pvcalls_ioworker, register_work);
struct sock_mapping *map = container_of(ioworker, struct sock_mapping,
ioworker);
while (atomic_read(&map->io) > 0) {
if (atomic_read(&map->release) > 0) {
atomic_set(&map->release, 0);
return;
}
if (atomic_read(&map->read) > 0)
pvcalls_conn_back_read(map);
if (atomic_read(&map->write) > 0)
pvcalls_conn_back_write(map);
atomic_dec(&map->io);
}
}
static int pvcalls_back_socket(struct xenbus_device *dev,
struct xen_pvcalls_request *req)
{
struct pvcalls_fedata *fedata;
int ret;
struct xen_pvcalls_response *rsp;
fedata = dev_get_drvdata(&dev->dev);
if (req->u.socket.domain != AF_INET ||
req->u.socket.type != SOCK_STREAM ||
(req->u.socket.protocol != IPPROTO_IP &&
req->u.socket.protocol != AF_INET))
ret = -EAFNOSUPPORT;
else
ret = 0;
/* leave the actual socket allocation for later */
rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
rsp->req_id = req->req_id;
rsp->cmd = req->cmd;
rsp->u.socket.id = req->u.socket.id;
rsp->ret = ret;
return 0;
}
static void pvcalls_sk_state_change(struct sock *sock)
{
struct sock_mapping *map = sock->sk_user_data;
if (map == NULL)
return;
atomic_inc(&map->read);
notify_remote_via_irq(map->irq);
}
static void pvcalls_sk_data_ready(struct sock *sock)
{
struct sock_mapping *map = sock->sk_user_data;
struct pvcalls_ioworker *iow;
if (map == NULL)
return;
iow = &map->ioworker;
atomic_inc(&map->read);
atomic_inc(&map->io);
queue_work(iow->wq, &iow->register_work);
}
static struct sock_mapping *pvcalls_new_active_socket(
struct pvcalls_fedata *fedata,
uint64_t id,
grant_ref_t ref,
uint32_t evtchn,
struct socket *sock)
{
int ret;
struct sock_mapping *map;
void *page;
map = kzalloc(sizeof(*map), GFP_KERNEL);
if (map == NULL)
return NULL;
map->fedata = fedata;
map->sock = sock;
map->id = id;
map->ref = ref;
ret = xenbus_map_ring_valloc(fedata->dev, &ref, 1, &page);
if (ret < 0)
goto out;
map->ring = page;
map->ring_order = map->ring->ring_order;
/* first read the order, then map the data ring */
virt_rmb();
if (map->ring_order > MAX_RING_ORDER) {
pr_warn("%s frontend requested ring_order %u, which is > MAX (%u)\n",
__func__, map->ring_order, MAX_RING_ORDER);
goto out;
}
ret = xenbus_map_ring_valloc(fedata->dev, map->ring->ref,
(1 << map->ring_order), &page);
if (ret < 0)
goto out;
map->bytes = page;
ret = bind_interdomain_evtchn_to_irqhandler(fedata->dev->otherend_id,
evtchn,
pvcalls_back_conn_event,
0,
"pvcalls-backend",
map);
if (ret < 0)
goto out;
map->irq = ret;
map->data.in = map->bytes;
map->data.out = map->bytes + XEN_FLEX_RING_SIZE(map->ring_order);
map->ioworker.wq = alloc_workqueue("pvcalls_io", WQ_UNBOUND, 1);
if (!map->ioworker.wq)
goto out;
atomic_set(&map->io, 1);
INIT_WORK(&map->ioworker.register_work, pvcalls_back_ioworker);
down(&fedata->socket_lock);
list_add_tail(&map->list, &fedata->socket_mappings);
up(&fedata->socket_lock);
write_lock_bh(&map->sock->sk->sk_callback_lock);
map->saved_data_ready = map->sock->sk->sk_data_ready;
map->sock->sk->sk_user_data = map;
map->sock->sk->sk_data_ready = pvcalls_sk_data_ready;
map->sock->sk->sk_state_change = pvcalls_sk_state_change;
write_unlock_bh(&map->sock->sk->sk_callback_lock);
return map;
out:
down(&fedata->socket_lock);
list_del(&map->list);
pvcalls_back_release_active(fedata->dev, fedata, map);
up(&fedata->socket_lock);
return NULL;
}
static int pvcalls_back_connect(struct xenbus_device *dev,
struct xen_pvcalls_request *req)
{
struct pvcalls_fedata *fedata;
int ret = -EINVAL;
struct socket *sock;
struct sock_mapping *map;
struct xen_pvcalls_response *rsp;
struct sockaddr *sa = (struct sockaddr *)&req->u.connect.addr;
fedata = dev_get_drvdata(&dev->dev);
if (req->u.connect.len < sizeof(sa->sa_family) ||
req->u.connect.len > sizeof(req->u.connect.addr) ||
sa->sa_family != AF_INET)
goto out;
ret = sock_create(AF_INET, SOCK_STREAM, 0, &sock);
if (ret < 0)
goto out;
ret = inet_stream_connect(sock, sa, req->u.connect.len, 0);
if (ret < 0) {
sock_release(sock);
goto out;
}
map = pvcalls_new_active_socket(fedata,
req->u.connect.id,
req->u.connect.ref,
req->u.connect.evtchn,
sock);
if (!map) {
ret = -EFAULT;
sock_release(sock);
}
out:
rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
rsp->req_id = req->req_id;
rsp->cmd = req->cmd;
rsp->u.connect.id = req->u.connect.id;
rsp->ret = ret;
return 0;
}
static int pvcalls_back_release_active(struct xenbus_device *dev,
struct pvcalls_fedata *fedata,
struct sock_mapping *map)
{
disable_irq(map->irq);
if (map->sock->sk != NULL) {
write_lock_bh(&map->sock->sk->sk_callback_lock);
map->sock->sk->sk_user_data = NULL;
map->sock->sk->sk_data_ready = map->saved_data_ready;
write_unlock_bh(&map->sock->sk->sk_callback_lock);
}
atomic_set(&map->release, 1);
flush_work(&map->ioworker.register_work);
xenbus_unmap_ring_vfree(dev, map->bytes);
xenbus_unmap_ring_vfree(dev, (void *)map->ring);
unbind_from_irqhandler(map->irq, map);
sock_release(map->sock);
kfree(map);
return 0;
}
static int pvcalls_back_release_passive(struct xenbus_device *dev,
struct pvcalls_fedata *fedata,
struct sockpass_mapping *mappass)
{
if (mappass->sock->sk != NULL) {
write_lock_bh(&mappass->sock->sk->sk_callback_lock);
mappass->sock->sk->sk_user_data = NULL;
mappass->sock->sk->sk_data_ready = mappass->saved_data_ready;
write_unlock_bh(&mappass->sock->sk->sk_callback_lock);
}
sock_release(mappass->sock);
flush_workqueue(mappass->wq);
destroy_workqueue(mappass->wq);
kfree(mappass);
return 0;
}
static int pvcalls_back_release(struct xenbus_device *dev,
struct xen_pvcalls_request *req)
{
struct pvcalls_fedata *fedata;
struct sock_mapping *map, *n;
struct sockpass_mapping *mappass;
int ret = 0;
struct xen_pvcalls_response *rsp;
fedata = dev_get_drvdata(&dev->dev);
down(&fedata->socket_lock);
list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) {
if (map->id == req->u.release.id) {
list_del(&map->list);
up(&fedata->socket_lock);
ret = pvcalls_back_release_active(dev, fedata, map);
goto out;
}
}
mappass = radix_tree_lookup(&fedata->socketpass_mappings,
req->u.release.id);
if (mappass != NULL) {
radix_tree_delete(&fedata->socketpass_mappings, mappass->id);
up(&fedata->socket_lock);
ret = pvcalls_back_release_passive(dev, fedata, mappass);
} else
up(&fedata->socket_lock);
out:
rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
rsp->req_id = req->req_id;
rsp->u.release.id = req->u.release.id;
rsp->cmd = req->cmd;
rsp->ret = ret;
return 0;
}
static void __pvcalls_back_accept(struct work_struct *work)
{
struct sockpass_mapping *mappass = container_of(
work, struct sockpass_mapping, register_work);
struct sock_mapping *map;
struct pvcalls_ioworker *iow;
struct pvcalls_fedata *fedata;
struct socket *sock;
struct xen_pvcalls_response *rsp;
struct xen_pvcalls_request *req;
int notify;
int ret = -EINVAL;
unsigned long flags;
fedata = mappass->fedata;
/*
* __pvcalls_back_accept can race against pvcalls_back_accept.
* We only need to check the value of "cmd" on read. It could be
* done atomically, but to simplify the code on the write side, we
* use a spinlock.
*/
spin_lock_irqsave(&mappass->copy_lock, flags);
req = &mappass->reqcopy;
if (req->cmd != PVCALLS_ACCEPT) {
spin_unlock_irqrestore(&mappass->copy_lock, flags);
return;
}
spin_unlock_irqrestore(&mappass->copy_lock, flags);
sock = sock_alloc();
if (sock == NULL)
goto out_error;
sock->type = mappass->sock->type;
sock->ops = mappass->sock->ops;
ret = inet_accept(mappass->sock, sock, O_NONBLOCK, true);
if (ret == -EAGAIN) {
sock_release(sock);
return;
}
map = pvcalls_new_active_socket(fedata,
req->u.accept.id_new,
req->u.accept.ref,
req->u.accept.evtchn,
sock);
if (!map) {
ret = -EFAULT;
sock_release(sock);
goto out_error;
}
map->sockpass = mappass;
iow = &map->ioworker;
atomic_inc(&map->read);
atomic_inc(&map->io);
queue_work(iow->wq, &iow->register_work);
out_error:
rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
rsp->req_id = req->req_id;
rsp->cmd = req->cmd;
rsp->u.accept.id = req->u.accept.id;
rsp->ret = ret;
RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify);
if (notify)
notify_remote_via_irq(fedata->irq);
mappass->reqcopy.cmd = 0;
}
static void pvcalls_pass_sk_data_ready(struct sock *sock)
{
struct sockpass_mapping *mappass = sock->sk_user_data;
struct pvcalls_fedata *fedata;
struct xen_pvcalls_response *rsp;
unsigned long flags;
int notify;
if (mappass == NULL)
return;
fedata = mappass->fedata;
spin_lock_irqsave(&mappass->copy_lock, flags);
if (mappass->reqcopy.cmd == PVCALLS_POLL) {
rsp = RING_GET_RESPONSE(&fedata->ring,
fedata->ring.rsp_prod_pvt++);
rsp->req_id = mappass->reqcopy.req_id;
rsp->u.poll.id = mappass->reqcopy.u.poll.id;
rsp->cmd = mappass->reqcopy.cmd;
rsp->ret = 0;
mappass->reqcopy.cmd = 0;
spin_unlock_irqrestore(&mappass->copy_lock, flags);
RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify);
if (notify)
notify_remote_via_irq(mappass->fedata->irq);
} else {
spin_unlock_irqrestore(&mappass->copy_lock, flags);
queue_work(mappass->wq, &mappass->register_work);
}
}
static int pvcalls_back_bind(struct xenbus_device *dev,
struct xen_pvcalls_request *req)
{
struct pvcalls_fedata *fedata;
int ret;
struct sockpass_mapping *map;
struct xen_pvcalls_response *rsp;
fedata = dev_get_drvdata(&dev->dev);
map = kzalloc(sizeof(*map), GFP_KERNEL);
if (map == NULL) {
ret = -ENOMEM;
goto out;
}
INIT_WORK(&map->register_work, __pvcalls_back_accept);
spin_lock_init(&map->copy_lock);
map->wq = alloc_workqueue("pvcalls_wq", WQ_UNBOUND, 1);
if (!map->wq) {
ret = -ENOMEM;
goto out;
}
ret = sock_create(AF_INET, SOCK_STREAM, 0, &map->sock);
if (ret < 0)
goto out;
ret = inet_bind(map->sock, (struct sockaddr *)&req->u.bind.addr,
req->u.bind.len);
if (ret < 0)
goto out;
map->fedata = fedata;
map->id = req->u.bind.id;
down(&fedata->socket_lock);
ret = radix_tree_insert(&fedata->socketpass_mappings, map->id,
map);
up(&fedata->socket_lock);
if (ret)
goto out;
write_lock_bh(&map->sock->sk->sk_callback_lock);
map->saved_data_ready = map->sock->sk->sk_data_ready;
map->sock->sk->sk_user_data = map;
map->sock->sk->sk_data_ready = pvcalls_pass_sk_data_ready;
write_unlock_bh(&map->sock->sk->sk_callback_lock);
out:
if (ret) {
if (map && map->sock)
sock_release(map->sock);
if (map && map->wq)
destroy_workqueue(map->wq);
kfree(map);
}
rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
rsp->req_id = req->req_id;
rsp->cmd = req->cmd;
rsp->u.bind.id = req->u.bind.id;
rsp->ret = ret;
return 0;
}
static int pvcalls_back_listen(struct xenbus_device *dev,
struct xen_pvcalls_request *req)
{
struct pvcalls_fedata *fedata;
int ret = -EINVAL;
struct sockpass_mapping *map;
struct xen_pvcalls_response *rsp;
fedata = dev_get_drvdata(&dev->dev);
down(&fedata->socket_lock);
map = radix_tree_lookup(&fedata->socketpass_mappings, req->u.listen.id);
up(&fedata->socket_lock);
if (map == NULL)
goto out;
ret = inet_listen(map->sock, req->u.listen.backlog);
out:
rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
rsp->req_id = req->req_id;
rsp->cmd = req->cmd;
rsp->u.listen.id = req->u.listen.id;
rsp->ret = ret;
return 0;
}
static int pvcalls_back_accept(struct xenbus_device *dev,
struct xen_pvcalls_request *req)
{
struct pvcalls_fedata *fedata;
struct sockpass_mapping *mappass;
int ret = -EINVAL;
struct xen_pvcalls_response *rsp;
unsigned long flags;
fedata = dev_get_drvdata(&dev->dev);
down(&fedata->socket_lock);
mappass = radix_tree_lookup(&fedata->socketpass_mappings,
req->u.accept.id);
up(&fedata->socket_lock);
if (mappass == NULL)
goto out_error;
/*
* Limitation of the current implementation: only support one
* concurrent accept or poll call on one socket.
*/
spin_lock_irqsave(&mappass->copy_lock, flags);
if (mappass->reqcopy.cmd != 0) {
spin_unlock_irqrestore(&mappass->copy_lock, flags);
ret = -EINTR;
goto out_error;
}
mappass->reqcopy = *req;
spin_unlock_irqrestore(&mappass->copy_lock, flags);
queue_work(mappass->wq, &mappass->register_work);
/* Tell the caller we don't need to send back a notification yet */
return -1;
out_error:
rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
rsp->req_id = req->req_id;
rsp->cmd = req->cmd;
rsp->u.accept.id = req->u.accept.id;
rsp->ret = ret;
return 0;
}
static int pvcalls_back_poll(struct xenbus_device *dev,
struct xen_pvcalls_request *req)
{
struct pvcalls_fedata *fedata;
struct sockpass_mapping *mappass;
struct xen_pvcalls_response *rsp;
struct inet_connection_sock *icsk;
struct request_sock_queue *queue;
unsigned long flags;
int ret;
bool data;
fedata = dev_get_drvdata(&dev->dev);
down(&fedata->socket_lock);
mappass = radix_tree_lookup(&fedata->socketpass_mappings,
req->u.poll.id);
up(&fedata->socket_lock);
if (mappass == NULL)
return -EINVAL;
/*
* Limitation of the current implementation: only support one
* concurrent accept or poll call on one socket.
*/
spin_lock_irqsave(&mappass->copy_lock, flags);
if (mappass->reqcopy.cmd != 0) {
ret = -EINTR;
goto out;
}
mappass->reqcopy = *req;
icsk = inet_csk(mappass->sock->sk);
queue = &icsk->icsk_accept_queue;
data = queue->rskq_accept_head != NULL;
if (data) {
mappass->reqcopy.cmd = 0;
ret = 0;
goto out;
}
spin_unlock_irqrestore(&mappass->copy_lock, flags);
/* Tell the caller we don't need to send back a notification yet */
return -1;
out:
spin_unlock_irqrestore(&mappass->copy_lock, flags);
rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
rsp->req_id = req->req_id;
rsp->cmd = req->cmd;
rsp->u.poll.id = req->u.poll.id;
rsp->ret = ret;
return 0;
}
static int pvcalls_back_handle_cmd(struct xenbus_device *dev,
struct xen_pvcalls_request *req)
{
int ret = 0;
switch (req->cmd) {
case PVCALLS_SOCKET:
ret = pvcalls_back_socket(dev, req);
break;
case PVCALLS_CONNECT:
ret = pvcalls_back_connect(dev, req);
break;
case PVCALLS_RELEASE:
ret = pvcalls_back_release(dev, req);
break;
case PVCALLS_BIND:
ret = pvcalls_back_bind(dev, req);
break;
case PVCALLS_LISTEN:
ret = pvcalls_back_listen(dev, req);
break;
case PVCALLS_ACCEPT:
ret = pvcalls_back_accept(dev, req);
break;
case PVCALLS_POLL:
ret = pvcalls_back_poll(dev, req);
break;
default:
{
struct pvcalls_fedata *fedata;
struct xen_pvcalls_response *rsp;
fedata = dev_get_drvdata(&dev->dev);
rsp = RING_GET_RESPONSE(
&fedata->ring, fedata->ring.rsp_prod_pvt++);
rsp->req_id = req->req_id;
rsp->cmd = req->cmd;
rsp->ret = -ENOTSUPP;
break;
}
}
return ret;
}
static void pvcalls_back_work(struct pvcalls_fedata *fedata)
{
int notify, notify_all = 0, more = 1;
struct xen_pvcalls_request req;
struct xenbus_device *dev = fedata->dev;
while (more) {
while (RING_HAS_UNCONSUMED_REQUESTS(&fedata->ring)) {
RING_COPY_REQUEST(&fedata->ring,
fedata->ring.req_cons++,
&req);
if (!pvcalls_back_handle_cmd(dev, &req)) {
RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(
&fedata->ring, notify);
notify_all += notify;
}
}
if (notify_all) {
notify_remote_via_irq(fedata->irq);
notify_all = 0;
}
RING_FINAL_CHECK_FOR_REQUESTS(&fedata->ring, more);
}
}
static irqreturn_t pvcalls_back_event(int irq, void *dev_id)
{
struct xenbus_device *dev = dev_id;
struct pvcalls_fedata *fedata = NULL;
if (dev == NULL)
return IRQ_HANDLED;
fedata = dev_get_drvdata(&dev->dev);
if (fedata == NULL)
return IRQ_HANDLED;
pvcalls_back_work(fedata);
return IRQ_HANDLED;
}
static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map)
{
struct sock_mapping *map = sock_map;
struct pvcalls_ioworker *iow;
if (map == NULL || map->sock == NULL || map->sock->sk == NULL ||
map->sock->sk->sk_user_data != map)
return IRQ_HANDLED;
iow = &map->ioworker;
atomic_inc(&map->write);
atomic_inc(&map->io);
queue_work(iow->wq, &iow->register_work);
return IRQ_HANDLED;
}
static int backend_connect(struct xenbus_device *dev)
{
int err, evtchn;
grant_ref_t ring_ref;
struct pvcalls_fedata *fedata = NULL;
fedata = kzalloc(sizeof(struct pvcalls_fedata), GFP_KERNEL);
if (!fedata)
return -ENOMEM;
fedata->irq = -1;
err = xenbus_scanf(XBT_NIL, dev->otherend, "port", "%u",
&evtchn);
if (err != 1) {
err = -EINVAL;
xenbus_dev_fatal(dev, err, "reading %s/event-channel",
dev->otherend);
goto error;
}
err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref", "%u", &ring_ref);
if (err != 1) {
err = -EINVAL;
xenbus_dev_fatal(dev, err, "reading %s/ring-ref",
dev->otherend);
goto error;
}
err = bind_interdomain_evtchn_to_irq(dev->otherend_id, evtchn);
if (err < 0)
goto error;
fedata->irq = err;
err = request_threaded_irq(fedata->irq, NULL, pvcalls_back_event,
IRQF_ONESHOT, "pvcalls-back", dev);
if (err < 0)
goto error;
err = xenbus_map_ring_valloc(dev, &ring_ref, 1,
(void **)&fedata->sring);
if (err < 0)
goto error;
BACK_RING_INIT(&fedata->ring, fedata->sring, XEN_PAGE_SIZE * 1);
fedata->dev = dev;
INIT_LIST_HEAD(&fedata->socket_mappings);
INIT_RADIX_TREE(&fedata->socketpass_mappings, GFP_KERNEL);
sema_init(&fedata->socket_lock, 1);
dev_set_drvdata(&dev->dev, fedata);
down(&pvcalls_back_global.frontends_lock);
list_add_tail(&fedata->list, &pvcalls_back_global.frontends);
up(&pvcalls_back_global.frontends_lock);
return 0;
error:
if (fedata->irq >= 0)
unbind_from_irqhandler(fedata->irq, dev);
if (fedata->sring != NULL)
xenbus_unmap_ring_vfree(dev, fedata->sring);
kfree(fedata);
return err;
}
static int backend_disconnect(struct xenbus_device *dev)
{
struct pvcalls_fedata *fedata;
struct sock_mapping *map, *n;
struct sockpass_mapping *mappass;
struct radix_tree_iter iter;
void **slot;
fedata = dev_get_drvdata(&dev->dev);
down(&fedata->socket_lock);
list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) {
list_del(&map->list);
pvcalls_back_release_active(dev, fedata, map);
}
radix_tree_for_each_slot(slot, &fedata->socketpass_mappings, &iter, 0) {
mappass = radix_tree_deref_slot(slot);
if (!mappass)
continue;
if (radix_tree_exception(mappass)) {
if (radix_tree_deref_retry(mappass))
slot = radix_tree_iter_retry(&iter);
} else {
radix_tree_delete(&fedata->socketpass_mappings,
mappass->id);
pvcalls_back_release_passive(dev, fedata, mappass);
}
}
up(&fedata->socket_lock);
unbind_from_irqhandler(fedata->irq, dev);
xenbus_unmap_ring_vfree(dev, fedata->sring);
list_del(&fedata->list);
kfree(fedata);
dev_set_drvdata(&dev->dev, NULL);
return 0;
}
static int pvcalls_back_probe(struct xenbus_device *dev,
const struct xenbus_device_id *id)
{
int err, abort;
struct xenbus_transaction xbt;
again:
abort = 1;
err = xenbus_transaction_start(&xbt);
if (err) {
pr_warn("%s cannot create xenstore transaction\n", __func__);
return err;
}
err = xenbus_printf(xbt, dev->nodename, "versions", "%s",
PVCALLS_VERSIONS);
if (err) {
pr_warn("%s write out 'versions' failed\n", __func__);
goto abort;
}
err = xenbus_printf(xbt, dev->nodename, "max-page-order", "%u",
MAX_RING_ORDER);
if (err) {
pr_warn("%s write out 'max-page-order' failed\n", __func__);
goto abort;
}
err = xenbus_printf(xbt, dev->nodename, "function-calls",
XENBUS_FUNCTIONS_CALLS);
if (err) {
pr_warn("%s write out 'function-calls' failed\n", __func__);
goto abort;
}
abort = 0;
abort:
err = xenbus_transaction_end(xbt, abort);
if (err) {
if (err == -EAGAIN && !abort)
goto again;
pr_warn("%s cannot complete xenstore transaction\n", __func__);
return err;
}
if (abort)
return -EFAULT;
xenbus_switch_state(dev, XenbusStateInitWait);
return 0;
}
static void set_backend_state(struct xenbus_device *dev,
enum xenbus_state state)
{
while (dev->state != state) {
switch (dev->state) {
case XenbusStateClosed:
switch (state) {
case XenbusStateInitWait:
case XenbusStateConnected:
xenbus_switch_state(dev, XenbusStateInitWait);
break;
case XenbusStateClosing:
xenbus_switch_state(dev, XenbusStateClosing);
break;
default:
WARN_ON(1);
}
break;
case XenbusStateInitWait:
case XenbusStateInitialised:
switch (state) {
case XenbusStateConnected:
backend_connect(dev);
xenbus_switch_state(dev, XenbusStateConnected);
break;
case XenbusStateClosing:
case XenbusStateClosed:
xenbus_switch_state(dev, XenbusStateClosing);
break;
default:
WARN_ON(1);
}
break;
case XenbusStateConnected:
switch (state) {
case XenbusStateInitWait:
case XenbusStateClosing:
case XenbusStateClosed:
down(&pvcalls_back_global.frontends_lock);
backend_disconnect(dev);
up(&pvcalls_back_global.frontends_lock);
xenbus_switch_state(dev, XenbusStateClosing);
break;
default:
WARN_ON(1);
}
break;
case XenbusStateClosing:
switch (state) {
case XenbusStateInitWait:
case XenbusStateConnected:
case XenbusStateClosed:
xenbus_switch_state(dev, XenbusStateClosed);
break;
default:
WARN_ON(1);
}
break;
default:
WARN_ON(1);
}
}
}
static void pvcalls_back_changed(struct xenbus_device *dev,
enum xenbus_state frontend_state)
{
switch (frontend_state) {
case XenbusStateInitialising:
set_backend_state(dev, XenbusStateInitWait);
break;
case XenbusStateInitialised:
case XenbusStateConnected:
set_backend_state(dev, XenbusStateConnected);
break;
case XenbusStateClosing:
set_backend_state(dev, XenbusStateClosing);
break;
case XenbusStateClosed:
set_backend_state(dev, XenbusStateClosed);
if (xenbus_dev_is_online(dev))
break;
device_unregister(&dev->dev);
break;
case XenbusStateUnknown:
set_backend_state(dev, XenbusStateClosed);
device_unregister(&dev->dev);
break;
default:
xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
frontend_state);
break;
}
}
static int pvcalls_back_remove(struct xenbus_device *dev)
{
return 0;
}
static int pvcalls_back_uevent(struct xenbus_device *xdev,
struct kobj_uevent_env *env)
{
return 0;
}
static const struct xenbus_device_id pvcalls_back_ids[] = {
{ "pvcalls" },
{ "" }
};
static struct xenbus_driver pvcalls_back_driver = {
.ids = pvcalls_back_ids,
.probe = pvcalls_back_probe,
.remove = pvcalls_back_remove,
.uevent = pvcalls_back_uevent,
.otherend_changed = pvcalls_back_changed,
};
static int __init pvcalls_back_init(void)
{
int ret;
if (!xen_domain())
return -ENODEV;
ret = xenbus_register_backend(&pvcalls_back_driver);
if (ret < 0)
return ret;
sema_init(&pvcalls_back_global.frontends_lock, 1);
INIT_LIST_HEAD(&pvcalls_back_global.frontends);
return 0;
}
module_init(pvcalls_back_init);
static void __exit pvcalls_back_fin(void)
{
struct pvcalls_fedata *fedata, *nfedata;
down(&pvcalls_back_global.frontends_lock);
list_for_each_entry_safe(fedata, nfedata,
&pvcalls_back_global.frontends, list) {
backend_disconnect(fedata->dev);
}
up(&pvcalls_back_global.frontends_lock);
xenbus_unregister_driver(&pvcalls_back_driver);
}
module_exit(pvcalls_back_fin);
MODULE_DESCRIPTION("Xen PV Calls backend driver");
MODULE_AUTHOR("Stefano Stabellini <sstabellini@kernel.org>");
MODULE_LICENSE("GPL");