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1294 lines
32 KiB
1294 lines
32 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* (c) 2017 Stefano Stabellini <[email protected]> |
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*/ |
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|
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#include <linux/module.h> |
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#include <linux/net.h> |
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#include <linux/socket.h> |
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|
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#include <net/sock.h> |
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|
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#include <xen/events.h> |
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#include <xen/grant_table.h> |
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#include <xen/xen.h> |
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#include <xen/xenbus.h> |
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#include <xen/interface/io/pvcalls.h> |
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|
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#include "pvcalls-front.h" |
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|
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#define PVCALLS_INVALID_ID UINT_MAX |
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#define PVCALLS_RING_ORDER XENBUS_MAX_RING_GRANT_ORDER |
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#define PVCALLS_NR_RSP_PER_RING __CONST_RING_SIZE(xen_pvcalls, XEN_PAGE_SIZE) |
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#define PVCALLS_FRONT_MAX_SPIN 5000 |
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|
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static struct proto pvcalls_proto = { |
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.name = "PVCalls", |
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.owner = THIS_MODULE, |
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.obj_size = sizeof(struct sock), |
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}; |
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|
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struct pvcalls_bedata { |
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struct xen_pvcalls_front_ring ring; |
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grant_ref_t ref; |
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int irq; |
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|
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struct list_head socket_mappings; |
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spinlock_t socket_lock; |
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|
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wait_queue_head_t inflight_req; |
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struct xen_pvcalls_response rsp[PVCALLS_NR_RSP_PER_RING]; |
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}; |
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/* Only one front/back connection supported. */ |
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static struct xenbus_device *pvcalls_front_dev; |
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static atomic_t pvcalls_refcount; |
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|
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/* first increment refcount, then proceed */ |
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#define pvcalls_enter() { \ |
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atomic_inc(&pvcalls_refcount); \ |
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} |
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|
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/* first complete other operations, then decrement refcount */ |
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#define pvcalls_exit() { \ |
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atomic_dec(&pvcalls_refcount); \ |
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} |
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|
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struct sock_mapping { |
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bool active_socket; |
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struct list_head list; |
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struct socket *sock; |
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atomic_t refcount; |
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union { |
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struct { |
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int irq; |
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grant_ref_t ref; |
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struct pvcalls_data_intf *ring; |
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struct pvcalls_data data; |
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struct mutex in_mutex; |
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struct mutex out_mutex; |
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|
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wait_queue_head_t inflight_conn_req; |
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} active; |
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struct { |
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/* |
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* Socket status, needs to be 64-bit aligned due to the |
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* test_and_* functions which have this requirement on arm64. |
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*/ |
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#define PVCALLS_STATUS_UNINITALIZED 0 |
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#define PVCALLS_STATUS_BIND 1 |
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#define PVCALLS_STATUS_LISTEN 2 |
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uint8_t status __attribute__((aligned(8))); |
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/* |
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* Internal state-machine flags. |
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* Only one accept operation can be inflight for a socket. |
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* Only one poll operation can be inflight for a given socket. |
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* flags needs to be 64-bit aligned due to the test_and_* |
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* functions which have this requirement on arm64. |
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*/ |
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#define PVCALLS_FLAG_ACCEPT_INFLIGHT 0 |
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#define PVCALLS_FLAG_POLL_INFLIGHT 1 |
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#define PVCALLS_FLAG_POLL_RET 2 |
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uint8_t flags __attribute__((aligned(8))); |
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uint32_t inflight_req_id; |
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struct sock_mapping *accept_map; |
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wait_queue_head_t inflight_accept_req; |
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} passive; |
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}; |
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}; |
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|
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static inline struct sock_mapping *pvcalls_enter_sock(struct socket *sock) |
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{ |
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struct sock_mapping *map; |
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|
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if (!pvcalls_front_dev || |
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dev_get_drvdata(&pvcalls_front_dev->dev) == NULL) |
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return ERR_PTR(-ENOTCONN); |
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|
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map = (struct sock_mapping *)sock->sk->sk_send_head; |
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if (map == NULL) |
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return ERR_PTR(-ENOTSOCK); |
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|
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pvcalls_enter(); |
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atomic_inc(&map->refcount); |
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return map; |
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} |
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|
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static inline void pvcalls_exit_sock(struct socket *sock) |
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{ |
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struct sock_mapping *map; |
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|
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map = (struct sock_mapping *)sock->sk->sk_send_head; |
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atomic_dec(&map->refcount); |
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pvcalls_exit(); |
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} |
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|
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static inline int get_request(struct pvcalls_bedata *bedata, int *req_id) |
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{ |
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*req_id = bedata->ring.req_prod_pvt & (RING_SIZE(&bedata->ring) - 1); |
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if (RING_FULL(&bedata->ring) || |
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bedata->rsp[*req_id].req_id != PVCALLS_INVALID_ID) |
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return -EAGAIN; |
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return 0; |
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} |
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|
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static bool pvcalls_front_write_todo(struct sock_mapping *map) |
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{ |
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struct pvcalls_data_intf *intf = map->active.ring; |
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RING_IDX cons, prod, size = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER); |
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int32_t error; |
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|
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error = intf->out_error; |
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if (error == -ENOTCONN) |
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return false; |
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if (error != 0) |
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return true; |
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|
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cons = intf->out_cons; |
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prod = intf->out_prod; |
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return !!(size - pvcalls_queued(prod, cons, size)); |
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} |
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|
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static bool pvcalls_front_read_todo(struct sock_mapping *map) |
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{ |
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struct pvcalls_data_intf *intf = map->active.ring; |
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RING_IDX cons, prod; |
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int32_t error; |
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|
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cons = intf->in_cons; |
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prod = intf->in_prod; |
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error = intf->in_error; |
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return (error != 0 || |
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pvcalls_queued(prod, cons, |
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XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER)) != 0); |
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} |
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|
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static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id) |
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{ |
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struct xenbus_device *dev = dev_id; |
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struct pvcalls_bedata *bedata; |
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struct xen_pvcalls_response *rsp; |
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uint8_t *src, *dst; |
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int req_id = 0, more = 0, done = 0; |
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|
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if (dev == NULL) |
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return IRQ_HANDLED; |
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|
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pvcalls_enter(); |
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bedata = dev_get_drvdata(&dev->dev); |
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if (bedata == NULL) { |
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pvcalls_exit(); |
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return IRQ_HANDLED; |
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} |
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|
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again: |
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while (RING_HAS_UNCONSUMED_RESPONSES(&bedata->ring)) { |
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rsp = RING_GET_RESPONSE(&bedata->ring, bedata->ring.rsp_cons); |
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|
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req_id = rsp->req_id; |
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if (rsp->cmd == PVCALLS_POLL) { |
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struct sock_mapping *map = (struct sock_mapping *)(uintptr_t) |
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rsp->u.poll.id; |
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|
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clear_bit(PVCALLS_FLAG_POLL_INFLIGHT, |
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(void *)&map->passive.flags); |
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/* |
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* clear INFLIGHT, then set RET. It pairs with |
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* the checks at the beginning of |
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* pvcalls_front_poll_passive. |
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*/ |
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smp_wmb(); |
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set_bit(PVCALLS_FLAG_POLL_RET, |
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(void *)&map->passive.flags); |
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} else { |
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dst = (uint8_t *)&bedata->rsp[req_id] + |
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sizeof(rsp->req_id); |
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src = (uint8_t *)rsp + sizeof(rsp->req_id); |
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memcpy(dst, src, sizeof(*rsp) - sizeof(rsp->req_id)); |
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/* |
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* First copy the rest of the data, then req_id. It is |
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* paired with the barrier when accessing bedata->rsp. |
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*/ |
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smp_wmb(); |
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bedata->rsp[req_id].req_id = req_id; |
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} |
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|
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done = 1; |
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bedata->ring.rsp_cons++; |
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} |
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RING_FINAL_CHECK_FOR_RESPONSES(&bedata->ring, more); |
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if (more) |
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goto again; |
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if (done) |
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wake_up(&bedata->inflight_req); |
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pvcalls_exit(); |
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return IRQ_HANDLED; |
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} |
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|
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static void pvcalls_front_free_map(struct pvcalls_bedata *bedata, |
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struct sock_mapping *map) |
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{ |
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int i; |
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|
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unbind_from_irqhandler(map->active.irq, map); |
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|
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spin_lock(&bedata->socket_lock); |
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if (!list_empty(&map->list)) |
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list_del_init(&map->list); |
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spin_unlock(&bedata->socket_lock); |
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|
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for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++) |
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gnttab_end_foreign_access(map->active.ring->ref[i], 0, 0); |
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gnttab_end_foreign_access(map->active.ref, 0, 0); |
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free_page((unsigned long)map->active.ring); |
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kfree(map); |
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} |
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static irqreturn_t pvcalls_front_conn_handler(int irq, void *sock_map) |
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{ |
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struct sock_mapping *map = sock_map; |
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|
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if (map == NULL) |
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return IRQ_HANDLED; |
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wake_up_interruptible(&map->active.inflight_conn_req); |
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|
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return IRQ_HANDLED; |
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} |
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int pvcalls_front_socket(struct socket *sock) |
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{ |
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struct pvcalls_bedata *bedata; |
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struct sock_mapping *map = NULL; |
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struct xen_pvcalls_request *req; |
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int notify, req_id, ret; |
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|
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/* |
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* PVCalls only supports domain AF_INET, |
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* type SOCK_STREAM and protocol 0 sockets for now. |
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* |
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* Check socket type here, AF_INET and protocol checks are done |
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* by the caller. |
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*/ |
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if (sock->type != SOCK_STREAM) |
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return -EOPNOTSUPP; |
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pvcalls_enter(); |
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if (!pvcalls_front_dev) { |
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pvcalls_exit(); |
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return -EACCES; |
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} |
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bedata = dev_get_drvdata(&pvcalls_front_dev->dev); |
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map = kzalloc(sizeof(*map), GFP_KERNEL); |
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if (map == NULL) { |
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pvcalls_exit(); |
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return -ENOMEM; |
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} |
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spin_lock(&bedata->socket_lock); |
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ret = get_request(bedata, &req_id); |
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if (ret < 0) { |
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kfree(map); |
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spin_unlock(&bedata->socket_lock); |
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pvcalls_exit(); |
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return ret; |
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} |
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/* |
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* sock->sk->sk_send_head is not used for ip sockets: reuse the |
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* field to store a pointer to the struct sock_mapping |
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* corresponding to the socket. This way, we can easily get the |
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* struct sock_mapping from the struct socket. |
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*/ |
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sock->sk->sk_send_head = (void *)map; |
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list_add_tail(&map->list, &bedata->socket_mappings); |
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req = RING_GET_REQUEST(&bedata->ring, req_id); |
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req->req_id = req_id; |
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req->cmd = PVCALLS_SOCKET; |
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req->u.socket.id = (uintptr_t) map; |
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req->u.socket.domain = AF_INET; |
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req->u.socket.type = SOCK_STREAM; |
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req->u.socket.protocol = IPPROTO_IP; |
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bedata->ring.req_prod_pvt++; |
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RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify); |
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spin_unlock(&bedata->socket_lock); |
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if (notify) |
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notify_remote_via_irq(bedata->irq); |
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wait_event(bedata->inflight_req, |
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READ_ONCE(bedata->rsp[req_id].req_id) == req_id); |
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|
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/* read req_id, then the content */ |
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smp_rmb(); |
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ret = bedata->rsp[req_id].ret; |
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bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID; |
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pvcalls_exit(); |
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return ret; |
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} |
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static void free_active_ring(struct sock_mapping *map) |
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{ |
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if (!map->active.ring) |
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return; |
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|
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free_pages((unsigned long)map->active.data.in, |
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map->active.ring->ring_order); |
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free_page((unsigned long)map->active.ring); |
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} |
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|
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static int alloc_active_ring(struct sock_mapping *map) |
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{ |
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void *bytes; |
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|
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map->active.ring = (struct pvcalls_data_intf *) |
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get_zeroed_page(GFP_KERNEL); |
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if (!map->active.ring) |
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goto out; |
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|
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map->active.ring->ring_order = PVCALLS_RING_ORDER; |
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bytes = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, |
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PVCALLS_RING_ORDER); |
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if (!bytes) |
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goto out; |
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|
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map->active.data.in = bytes; |
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map->active.data.out = bytes + |
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XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER); |
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|
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return 0; |
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|
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out: |
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free_active_ring(map); |
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return -ENOMEM; |
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} |
|
|
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static int create_active(struct sock_mapping *map, evtchn_port_t *evtchn) |
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{ |
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void *bytes; |
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int ret, irq = -1, i; |
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|
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*evtchn = 0; |
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init_waitqueue_head(&map->active.inflight_conn_req); |
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|
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bytes = map->active.data.in; |
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for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++) |
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map->active.ring->ref[i] = gnttab_grant_foreign_access( |
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pvcalls_front_dev->otherend_id, |
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pfn_to_gfn(virt_to_pfn(bytes) + i), 0); |
|
|
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map->active.ref = gnttab_grant_foreign_access( |
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pvcalls_front_dev->otherend_id, |
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pfn_to_gfn(virt_to_pfn((void *)map->active.ring)), 0); |
|
|
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ret = xenbus_alloc_evtchn(pvcalls_front_dev, evtchn); |
|
if (ret) |
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goto out_error; |
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irq = bind_evtchn_to_irqhandler(*evtchn, pvcalls_front_conn_handler, |
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0, "pvcalls-frontend", map); |
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if (irq < 0) { |
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ret = irq; |
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goto out_error; |
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} |
|
|
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map->active.irq = irq; |
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map->active_socket = true; |
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mutex_init(&map->active.in_mutex); |
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mutex_init(&map->active.out_mutex); |
|
|
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return 0; |
|
|
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out_error: |
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if (*evtchn > 0) |
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xenbus_free_evtchn(pvcalls_front_dev, *evtchn); |
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return ret; |
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} |
|
|
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int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr, |
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int addr_len, int flags) |
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{ |
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struct pvcalls_bedata *bedata; |
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struct sock_mapping *map = NULL; |
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struct xen_pvcalls_request *req; |
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int notify, req_id, ret; |
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evtchn_port_t evtchn; |
|
|
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if (addr->sa_family != AF_INET || sock->type != SOCK_STREAM) |
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return -EOPNOTSUPP; |
|
|
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map = pvcalls_enter_sock(sock); |
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if (IS_ERR(map)) |
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return PTR_ERR(map); |
|
|
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bedata = dev_get_drvdata(&pvcalls_front_dev->dev); |
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ret = alloc_active_ring(map); |
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if (ret < 0) { |
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pvcalls_exit_sock(sock); |
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return ret; |
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} |
|
|
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spin_lock(&bedata->socket_lock); |
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ret = get_request(bedata, &req_id); |
|
if (ret < 0) { |
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spin_unlock(&bedata->socket_lock); |
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free_active_ring(map); |
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pvcalls_exit_sock(sock); |
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return ret; |
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} |
|
ret = create_active(map, &evtchn); |
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if (ret < 0) { |
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spin_unlock(&bedata->socket_lock); |
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free_active_ring(map); |
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pvcalls_exit_sock(sock); |
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return ret; |
|
} |
|
|
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req = RING_GET_REQUEST(&bedata->ring, req_id); |
|
req->req_id = req_id; |
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req->cmd = PVCALLS_CONNECT; |
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req->u.connect.id = (uintptr_t)map; |
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req->u.connect.len = addr_len; |
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req->u.connect.flags = flags; |
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req->u.connect.ref = map->active.ref; |
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req->u.connect.evtchn = evtchn; |
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memcpy(req->u.connect.addr, addr, sizeof(*addr)); |
|
|
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map->sock = sock; |
|
|
|
bedata->ring.req_prod_pvt++; |
|
RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify); |
|
spin_unlock(&bedata->socket_lock); |
|
|
|
if (notify) |
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notify_remote_via_irq(bedata->irq); |
|
|
|
wait_event(bedata->inflight_req, |
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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, |
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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); |
|
} |
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} |
|
out: |
|
/* write to ring before updating pointer */ |
|
virt_wmb(); |
|
intf->out_prod += len; |
|
|
|
return len; |
|
} |
|
|
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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; |
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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 */ |
|
fallthrough; |
|
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 <[email protected]>"); |
|
MODULE_LICENSE("GPL");
|
|
|