path: root/drivers/xen/pvcalls-back.c

/*
 * (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