OpenCloudOS-Kernel/drivers/xen/pvcalls-front.c

1296 lines
32 KiB
C
Raw Normal View History

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 Based on 3 normalized pattern(s): 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 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 [author] [kishon] [vijay] [abraham] [i] [kishon]@[ti] [com] 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 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 [author] [graeme] [gregory] [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i] [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema] [hk] [hemahk]@[ti] [com] 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 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1105 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-27 14:55:06 +08:00
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* (c) 2017 Stefano Stabellini <stefano@aporeto.com>
*/
#include <linux/module.h>
xen/pvcalls: implement socket command and handle events Send a PVCALLS_SOCKET command to the backend, use the masked req_prod_pvt as req_id. This way, req_id is guaranteed to be between 0 and PVCALLS_NR_REQ_PER_RING. We already have a slot in the rsp array ready for the response, and there cannot be two outstanding responses with the same req_id. Wait for the response by waiting on the inflight_req waitqueue and check for the req_id field in rsp[req_id]. Use atomic accesses and barriers to read the field. Note that the barriers are simple smp barriers (as opposed to virt barriers) because they are for internal frontend synchronization, not frontend<->backend communication. Once a response is received, clear the corresponding rsp slot by setting req_id to PVCALLS_INVALID_ID. Note that PVCALLS_INVALID_ID is invalid only from the frontend point of view. It is not part of the PVCalls protocol. pvcalls_front_event_handler is in charge of copying responses from the ring to the appropriate rsp slot. It is done by copying the body of the response first, then by copying req_id atomically. After the copies, wake up anybody waiting on waitqueue. socket_lock protects accesses to the ring. Convert the pointer to sock_mapping into an uintptr_t and use it as id for the new socket to pass to the backend. The struct will be fully initialized later on connect or bind. sock->sk->sk_send_head is not used for ip sockets: reuse the field to store a pointer to the struct sock_mapping corresponding to the socket. This way, we can easily get the struct sock_mapping from the struct socket. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-10-31 06:40:54 +08:00
#include <linux/net.h>
#include <linux/socket.h>
#include <net/sock.h>
#include <xen/events.h>
#include <xen/grant_table.h>
#include <xen/xen.h>
#include <xen/xenbus.h>
#include <xen/interface/io/pvcalls.h>
xen/pvcalls: implement socket command and handle events Send a PVCALLS_SOCKET command to the backend, use the masked req_prod_pvt as req_id. This way, req_id is guaranteed to be between 0 and PVCALLS_NR_REQ_PER_RING. We already have a slot in the rsp array ready for the response, and there cannot be two outstanding responses with the same req_id. Wait for the response by waiting on the inflight_req waitqueue and check for the req_id field in rsp[req_id]. Use atomic accesses and barriers to read the field. Note that the barriers are simple smp barriers (as opposed to virt barriers) because they are for internal frontend synchronization, not frontend<->backend communication. Once a response is received, clear the corresponding rsp slot by setting req_id to PVCALLS_INVALID_ID. Note that PVCALLS_INVALID_ID is invalid only from the frontend point of view. It is not part of the PVCalls protocol. pvcalls_front_event_handler is in charge of copying responses from the ring to the appropriate rsp slot. It is done by copying the body of the response first, then by copying req_id atomically. After the copies, wake up anybody waiting on waitqueue. socket_lock protects accesses to the ring. Convert the pointer to sock_mapping into an uintptr_t and use it as id for the new socket to pass to the backend. The struct will be fully initialized later on connect or bind. sock->sk->sk_send_head is not used for ip sockets: reuse the field to store a pointer to the struct sock_mapping corresponding to the socket. This way, we can easily get the struct sock_mapping from the struct socket. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-10-31 06:40:54 +08:00
#include "pvcalls-front.h"
#define PVCALLS_INVALID_ID UINT_MAX
#define PVCALLS_RING_ORDER XENBUS_MAX_RING_GRANT_ORDER
#define PVCALLS_NR_RSP_PER_RING __CONST_RING_SIZE(xen_pvcalls, XEN_PAGE_SIZE)
#define PVCALLS_FRONT_MAX_SPIN 5000
static struct proto pvcalls_proto = {
.name = "PVCalls",
.owner = THIS_MODULE,
.obj_size = sizeof(struct sock),
};
struct pvcalls_bedata {
struct xen_pvcalls_front_ring ring;
grant_ref_t ref;
int irq;
struct list_head socket_mappings;
spinlock_t socket_lock;
wait_queue_head_t inflight_req;
struct xen_pvcalls_response rsp[PVCALLS_NR_RSP_PER_RING];
};
/* Only one front/back connection supported. */
static struct xenbus_device *pvcalls_front_dev;
static atomic_t pvcalls_refcount;
/* first increment refcount, then proceed */
#define pvcalls_enter() { \
atomic_inc(&pvcalls_refcount); \
}
/* first complete other operations, then decrement refcount */
#define pvcalls_exit() { \
atomic_dec(&pvcalls_refcount); \
}
struct sock_mapping {
bool active_socket;
struct list_head list;
struct socket *sock;
atomic_t refcount;
union {
struct {
int irq;
grant_ref_t ref;
struct pvcalls_data_intf *ring;
struct pvcalls_data data;
struct mutex in_mutex;
struct mutex out_mutex;
wait_queue_head_t inflight_conn_req;
} active;
struct {
/*
* Socket status, needs to be 64-bit aligned due to the
* test_and_* functions which have this requirement on arm64.
*/
#define PVCALLS_STATUS_UNINITALIZED 0
#define PVCALLS_STATUS_BIND 1
#define PVCALLS_STATUS_LISTEN 2
uint8_t status __attribute__((aligned(8)));
/*
* Internal state-machine flags.
* Only one accept operation can be inflight for a socket.
* Only one poll operation can be inflight for a given socket.
* flags needs to be 64-bit aligned due to the test_and_*
* functions which have this requirement on arm64.
*/
#define PVCALLS_FLAG_ACCEPT_INFLIGHT 0
#define PVCALLS_FLAG_POLL_INFLIGHT 1
#define PVCALLS_FLAG_POLL_RET 2
uint8_t flags __attribute__((aligned(8)));
uint32_t inflight_req_id;
struct sock_mapping *accept_map;
wait_queue_head_t inflight_accept_req;
} passive;
};
};
static inline struct sock_mapping *pvcalls_enter_sock(struct socket *sock)
{
struct sock_mapping *map;
if (!pvcalls_front_dev ||
dev_get_drvdata(&pvcalls_front_dev->dev) == NULL)
return ERR_PTR(-ENOTCONN);
map = (struct sock_mapping *)sock->sk->sk_send_head;
if (map == NULL)
return ERR_PTR(-ENOTSOCK);
pvcalls_enter();
atomic_inc(&map->refcount);
return map;
}
static inline void pvcalls_exit_sock(struct socket *sock)
{
struct sock_mapping *map;
map = (struct sock_mapping *)sock->sk->sk_send_head;
atomic_dec(&map->refcount);
pvcalls_exit();
}
xen/pvcalls: implement socket command and handle events Send a PVCALLS_SOCKET command to the backend, use the masked req_prod_pvt as req_id. This way, req_id is guaranteed to be between 0 and PVCALLS_NR_REQ_PER_RING. We already have a slot in the rsp array ready for the response, and there cannot be two outstanding responses with the same req_id. Wait for the response by waiting on the inflight_req waitqueue and check for the req_id field in rsp[req_id]. Use atomic accesses and barriers to read the field. Note that the barriers are simple smp barriers (as opposed to virt barriers) because they are for internal frontend synchronization, not frontend<->backend communication. Once a response is received, clear the corresponding rsp slot by setting req_id to PVCALLS_INVALID_ID. Note that PVCALLS_INVALID_ID is invalid only from the frontend point of view. It is not part of the PVCalls protocol. pvcalls_front_event_handler is in charge of copying responses from the ring to the appropriate rsp slot. It is done by copying the body of the response first, then by copying req_id atomically. After the copies, wake up anybody waiting on waitqueue. socket_lock protects accesses to the ring. Convert the pointer to sock_mapping into an uintptr_t and use it as id for the new socket to pass to the backend. The struct will be fully initialized later on connect or bind. sock->sk->sk_send_head is not used for ip sockets: reuse the field to store a pointer to the struct sock_mapping corresponding to the socket. This way, we can easily get the struct sock_mapping from the struct socket. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-10-31 06:40:54 +08:00
static inline int get_request(struct pvcalls_bedata *bedata, int *req_id)
{
*req_id = bedata->ring.req_prod_pvt & (RING_SIZE(&bedata->ring) - 1);
if (RING_FULL(&bedata->ring) ||
bedata->rsp[*req_id].req_id != PVCALLS_INVALID_ID)
return -EAGAIN;
return 0;
}
static bool pvcalls_front_write_todo(struct sock_mapping *map)
{
struct pvcalls_data_intf *intf = map->active.ring;
RING_IDX cons, prod, size = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
int32_t error;
error = intf->out_error;
if (error == -ENOTCONN)
return false;
if (error != 0)
return true;
cons = intf->out_cons;
prod = intf->out_prod;
return !!(size - pvcalls_queued(prod, cons, size));
}
static bool pvcalls_front_read_todo(struct sock_mapping *map)
{
struct pvcalls_data_intf *intf = map->active.ring;
RING_IDX cons, prod;
int32_t error;
cons = intf->in_cons;
prod = intf->in_prod;
error = intf->in_error;
return (error != 0 ||
pvcalls_queued(prod, cons,
XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER)) != 0);
}
static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id)
{
xen/pvcalls: implement socket command and handle events Send a PVCALLS_SOCKET command to the backend, use the masked req_prod_pvt as req_id. This way, req_id is guaranteed to be between 0 and PVCALLS_NR_REQ_PER_RING. We already have a slot in the rsp array ready for the response, and there cannot be two outstanding responses with the same req_id. Wait for the response by waiting on the inflight_req waitqueue and check for the req_id field in rsp[req_id]. Use atomic accesses and barriers to read the field. Note that the barriers are simple smp barriers (as opposed to virt barriers) because they are for internal frontend synchronization, not frontend<->backend communication. Once a response is received, clear the corresponding rsp slot by setting req_id to PVCALLS_INVALID_ID. Note that PVCALLS_INVALID_ID is invalid only from the frontend point of view. It is not part of the PVCalls protocol. pvcalls_front_event_handler is in charge of copying responses from the ring to the appropriate rsp slot. It is done by copying the body of the response first, then by copying req_id atomically. After the copies, wake up anybody waiting on waitqueue. socket_lock protects accesses to the ring. Convert the pointer to sock_mapping into an uintptr_t and use it as id for the new socket to pass to the backend. The struct will be fully initialized later on connect or bind. sock->sk->sk_send_head is not used for ip sockets: reuse the field to store a pointer to the struct sock_mapping corresponding to the socket. This way, we can easily get the struct sock_mapping from the struct socket. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-10-31 06:40:54 +08:00
struct xenbus_device *dev = dev_id;
struct pvcalls_bedata *bedata;
struct xen_pvcalls_response *rsp;
uint8_t *src, *dst;
int req_id = 0, more = 0, done = 0;
if (dev == NULL)
return IRQ_HANDLED;
pvcalls_enter();
bedata = dev_get_drvdata(&dev->dev);
if (bedata == NULL) {
pvcalls_exit();
return IRQ_HANDLED;
}
again:
while (RING_HAS_UNCONSUMED_RESPONSES(&bedata->ring)) {
rsp = RING_GET_RESPONSE(&bedata->ring, bedata->ring.rsp_cons);
req_id = rsp->req_id;
if (rsp->cmd == PVCALLS_POLL) {
struct sock_mapping *map = (struct sock_mapping *)(uintptr_t)
rsp->u.poll.id;
clear_bit(PVCALLS_FLAG_POLL_INFLIGHT,
(void *)&map->passive.flags);
/*
* clear INFLIGHT, then set RET. It pairs with
* the checks at the beginning of
* pvcalls_front_poll_passive.
*/
smp_wmb();
set_bit(PVCALLS_FLAG_POLL_RET,
(void *)&map->passive.flags);
} else {
dst = (uint8_t *)&bedata->rsp[req_id] +
sizeof(rsp->req_id);
src = (uint8_t *)rsp + sizeof(rsp->req_id);
memcpy(dst, src, sizeof(*rsp) - sizeof(rsp->req_id));
/*
* First copy the rest of the data, then req_id. It is
* paired with the barrier when accessing bedata->rsp.
*/
smp_wmb();
bedata->rsp[req_id].req_id = req_id;
}
xen/pvcalls: implement socket command and handle events Send a PVCALLS_SOCKET command to the backend, use the masked req_prod_pvt as req_id. This way, req_id is guaranteed to be between 0 and PVCALLS_NR_REQ_PER_RING. We already have a slot in the rsp array ready for the response, and there cannot be two outstanding responses with the same req_id. Wait for the response by waiting on the inflight_req waitqueue and check for the req_id field in rsp[req_id]. Use atomic accesses and barriers to read the field. Note that the barriers are simple smp barriers (as opposed to virt barriers) because they are for internal frontend synchronization, not frontend<->backend communication. Once a response is received, clear the corresponding rsp slot by setting req_id to PVCALLS_INVALID_ID. Note that PVCALLS_INVALID_ID is invalid only from the frontend point of view. It is not part of the PVCalls protocol. pvcalls_front_event_handler is in charge of copying responses from the ring to the appropriate rsp slot. It is done by copying the body of the response first, then by copying req_id atomically. After the copies, wake up anybody waiting on waitqueue. socket_lock protects accesses to the ring. Convert the pointer to sock_mapping into an uintptr_t and use it as id for the new socket to pass to the backend. The struct will be fully initialized later on connect or bind. sock->sk->sk_send_head is not used for ip sockets: reuse the field to store a pointer to the struct sock_mapping corresponding to the socket. This way, we can easily get the struct sock_mapping from the struct socket. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-10-31 06:40:54 +08:00
done = 1;
bedata->ring.rsp_cons++;
}
RING_FINAL_CHECK_FOR_RESPONSES(&bedata->ring, more);
if (more)
goto again;
if (done)
wake_up(&bedata->inflight_req);
pvcalls_exit();
return IRQ_HANDLED;
}
static void pvcalls_front_free_map(struct pvcalls_bedata *bedata,
struct sock_mapping *map)
{
int i;
unbind_from_irqhandler(map->active.irq, map);
spin_lock(&bedata->socket_lock);
if (!list_empty(&map->list))
list_del_init(&map->list);
spin_unlock(&bedata->socket_lock);
for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++)
gnttab_end_foreign_access(map->active.ring->ref[i], NULL);
gnttab_end_foreign_access(map->active.ref, NULL);
free_page((unsigned long)map->active.ring);
kfree(map);
}
static irqreturn_t pvcalls_front_conn_handler(int irq, void *sock_map)
{
struct sock_mapping *map = sock_map;
if (map == NULL)
return IRQ_HANDLED;
wake_up_interruptible(&map->active.inflight_conn_req);
return IRQ_HANDLED;
}
xen/pvcalls: implement socket command and handle events Send a PVCALLS_SOCKET command to the backend, use the masked req_prod_pvt as req_id. This way, req_id is guaranteed to be between 0 and PVCALLS_NR_REQ_PER_RING. We already have a slot in the rsp array ready for the response, and there cannot be two outstanding responses with the same req_id. Wait for the response by waiting on the inflight_req waitqueue and check for the req_id field in rsp[req_id]. Use atomic accesses and barriers to read the field. Note that the barriers are simple smp barriers (as opposed to virt barriers) because they are for internal frontend synchronization, not frontend<->backend communication. Once a response is received, clear the corresponding rsp slot by setting req_id to PVCALLS_INVALID_ID. Note that PVCALLS_INVALID_ID is invalid only from the frontend point of view. It is not part of the PVCalls protocol. pvcalls_front_event_handler is in charge of copying responses from the ring to the appropriate rsp slot. It is done by copying the body of the response first, then by copying req_id atomically. After the copies, wake up anybody waiting on waitqueue. socket_lock protects accesses to the ring. Convert the pointer to sock_mapping into an uintptr_t and use it as id for the new socket to pass to the backend. The struct will be fully initialized later on connect or bind. sock->sk->sk_send_head is not used for ip sockets: reuse the field to store a pointer to the struct sock_mapping corresponding to the socket. This way, we can easily get the struct sock_mapping from the struct socket. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-10-31 06:40:54 +08:00
int pvcalls_front_socket(struct socket *sock)
{
struct pvcalls_bedata *bedata;
struct sock_mapping *map = NULL;
struct xen_pvcalls_request *req;
int notify, req_id, ret;
/*
* PVCalls only supports domain AF_INET,
* type SOCK_STREAM and protocol 0 sockets for now.
*
* Check socket type here, AF_INET and protocol checks are done
* by the caller.
*/
if (sock->type != SOCK_STREAM)
return -EOPNOTSUPP;
pvcalls_enter();
if (!pvcalls_front_dev) {
pvcalls_exit();
return -EACCES;
}
bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
map = kzalloc(sizeof(*map), GFP_KERNEL);
if (map == NULL) {
pvcalls_exit();
return -ENOMEM;
}
spin_lock(&bedata->socket_lock);
ret = get_request(bedata, &req_id);
if (ret < 0) {
kfree(map);
spin_unlock(&bedata->socket_lock);
pvcalls_exit();
return ret;
}
/*
* sock->sk->sk_send_head is not used for ip sockets: reuse the
* field to store a pointer to the struct sock_mapping
* corresponding to the socket. This way, we can easily get the
* struct sock_mapping from the struct socket.
*/
sock->sk->sk_send_head = (void *)map;
list_add_tail(&map->list, &bedata->socket_mappings);
req = RING_GET_REQUEST(&bedata->ring, req_id);
req->req_id = req_id;
req->cmd = PVCALLS_SOCKET;
req->u.socket.id = (uintptr_t) map;
req->u.socket.domain = AF_INET;
req->u.socket.type = SOCK_STREAM;
req->u.socket.protocol = IPPROTO_IP;
bedata->ring.req_prod_pvt++;
RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
spin_unlock(&bedata->socket_lock);
if (notify)
notify_remote_via_irq(bedata->irq);
wait_event(bedata->inflight_req,
READ_ONCE(bedata->rsp[req_id].req_id) == req_id);
/* read req_id, then the content */
smp_rmb();
ret = bedata->rsp[req_id].ret;
bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
pvcalls_exit();
return ret;
}
pvcalls-front: Avoid get_free_pages(GFP_KERNEL) under spinlock The problem is that we call this with a spin lock held. The call tree is: pvcalls_front_accept() holds bedata->socket_lock. -> create_active() -> __get_free_pages() uses GFP_KERNEL The create_active() function is only called from pvcalls_front_accept() with a spin_lock held, The allocation is not allowed to sleep and GFP_KERNEL is not sufficient. This issue was detected by using the Coccinelle software. v2: Add a function doing the allocations which is called outside the lock and passing the allocated data to create_active(). v3: Use the matching deallocators i.e., free_page() and free_pages(), respectively. v4: It would be better to pre-populate map (struct sock_mapping), rather than introducing one more new struct. v5: Since allocating the data outside of this call it should also be freed outside, when create_active() fails. Move kzalloc(sizeof(*map2), GFP_ATOMIC) outside spinlock and use GFP_KERNEL instead. v6: Drop the superfluous calls. Suggested-by: Juergen Gross <jgross@suse.com> Suggested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Suggested-by: Stefano Stabellini <sstabellini@kernel.org> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn> Acked-by: Stefano Stabellini <sstabellini@kernel.org> CC: Julia Lawall <julia.lawall@lip6.fr> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: Juergen Gross <jgross@suse.com> CC: Stefano Stabellini <sstabellini@kernel.org> CC: xen-devel@lists.xenproject.org CC: linux-kernel@vger.kernel.org Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-12-05 10:35:50 +08:00
static void free_active_ring(struct sock_mapping *map)
{
pvcalls-front: fix potential null dereference static checker warning: drivers/xen/pvcalls-front.c:373 alloc_active_ring() error: we previously assumed 'map->active.ring' could be null (see line 357) drivers/xen/pvcalls-front.c 351 static int alloc_active_ring(struct sock_mapping *map) 352 { 353 void *bytes; 354 355 map->active.ring = (struct pvcalls_data_intf *) 356 get_zeroed_page(GFP_KERNEL); 357 if (!map->active.ring) ^^^^^^^^^^^^^^^^^ Check 358 goto out; 359 360 map->active.ring->ring_order = PVCALLS_RING_ORDER; 361 bytes = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 362 PVCALLS_RING_ORDER); 363 if (!bytes) 364 goto out; 365 366 map->active.data.in = bytes; 367 map->active.data.out = bytes + 368 XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER); 369 370 return 0; 371 372 out: --> 373 free_active_ring(map); ^^^ Add null check on map->active.ring before dereferencing it to avoid any NULL pointer dereferences. Fixes: 9f51c05dc41a ("pvcalls-front: Avoid get_free_pages(GFP_KERNEL) under spinlock") Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Suggested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: Juergen Gross <jgross@suse.com> CC: Stefano Stabellini <sstabellini@kernel.org> CC: Dan Carpenter <dan.carpenter@oracle.com> CC: xen-devel@lists.xenproject.org CC: linux-kernel@vger.kernel.org Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2019-01-15 10:31:27 +08:00
if (!map->active.ring)
return;
free_pages_exact(map->active.data.in,
PAGE_SIZE << map->active.ring->ring_order);
pvcalls-front: Avoid get_free_pages(GFP_KERNEL) under spinlock The problem is that we call this with a spin lock held. The call tree is: pvcalls_front_accept() holds bedata->socket_lock. -> create_active() -> __get_free_pages() uses GFP_KERNEL The create_active() function is only called from pvcalls_front_accept() with a spin_lock held, The allocation is not allowed to sleep and GFP_KERNEL is not sufficient. This issue was detected by using the Coccinelle software. v2: Add a function doing the allocations which is called outside the lock and passing the allocated data to create_active(). v3: Use the matching deallocators i.e., free_page() and free_pages(), respectively. v4: It would be better to pre-populate map (struct sock_mapping), rather than introducing one more new struct. v5: Since allocating the data outside of this call it should also be freed outside, when create_active() fails. Move kzalloc(sizeof(*map2), GFP_ATOMIC) outside spinlock and use GFP_KERNEL instead. v6: Drop the superfluous calls. Suggested-by: Juergen Gross <jgross@suse.com> Suggested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Suggested-by: Stefano Stabellini <sstabellini@kernel.org> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn> Acked-by: Stefano Stabellini <sstabellini@kernel.org> CC: Julia Lawall <julia.lawall@lip6.fr> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: Juergen Gross <jgross@suse.com> CC: Stefano Stabellini <sstabellini@kernel.org> CC: xen-devel@lists.xenproject.org CC: linux-kernel@vger.kernel.org Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-12-05 10:35:50 +08:00
free_page((unsigned long)map->active.ring);
}
static int alloc_active_ring(struct sock_mapping *map)
{
void *bytes;
map->active.ring = (struct pvcalls_data_intf *)
get_zeroed_page(GFP_KERNEL);
if (!map->active.ring)
goto out;
map->active.ring->ring_order = PVCALLS_RING_ORDER;
bytes = alloc_pages_exact(PAGE_SIZE << PVCALLS_RING_ORDER,
GFP_KERNEL | __GFP_ZERO);
pvcalls-front: Avoid get_free_pages(GFP_KERNEL) under spinlock The problem is that we call this with a spin lock held. The call tree is: pvcalls_front_accept() holds bedata->socket_lock. -> create_active() -> __get_free_pages() uses GFP_KERNEL The create_active() function is only called from pvcalls_front_accept() with a spin_lock held, The allocation is not allowed to sleep and GFP_KERNEL is not sufficient. This issue was detected by using the Coccinelle software. v2: Add a function doing the allocations which is called outside the lock and passing the allocated data to create_active(). v3: Use the matching deallocators i.e., free_page() and free_pages(), respectively. v4: It would be better to pre-populate map (struct sock_mapping), rather than introducing one more new struct. v5: Since allocating the data outside of this call it should also be freed outside, when create_active() fails. Move kzalloc(sizeof(*map2), GFP_ATOMIC) outside spinlock and use GFP_KERNEL instead. v6: Drop the superfluous calls. Suggested-by: Juergen Gross <jgross@suse.com> Suggested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Suggested-by: Stefano Stabellini <sstabellini@kernel.org> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn> Acked-by: Stefano Stabellini <sstabellini@kernel.org> CC: Julia Lawall <julia.lawall@lip6.fr> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: Juergen Gross <jgross@suse.com> CC: Stefano Stabellini <sstabellini@kernel.org> CC: xen-devel@lists.xenproject.org CC: linux-kernel@vger.kernel.org Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-12-05 10:35:50 +08:00
if (!bytes)
goto out;
map->active.data.in = bytes;
map->active.data.out = bytes +
XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
return 0;
out:
free_active_ring(map);
return -ENOMEM;
}
static int create_active(struct sock_mapping *map, evtchn_port_t *evtchn)
{
void *bytes;
int ret, irq = -1, i;
*evtchn = 0;
init_waitqueue_head(&map->active.inflight_conn_req);
pvcalls-front: Avoid get_free_pages(GFP_KERNEL) under spinlock The problem is that we call this with a spin lock held. The call tree is: pvcalls_front_accept() holds bedata->socket_lock. -> create_active() -> __get_free_pages() uses GFP_KERNEL The create_active() function is only called from pvcalls_front_accept() with a spin_lock held, The allocation is not allowed to sleep and GFP_KERNEL is not sufficient. This issue was detected by using the Coccinelle software. v2: Add a function doing the allocations which is called outside the lock and passing the allocated data to create_active(). v3: Use the matching deallocators i.e., free_page() and free_pages(), respectively. v4: It would be better to pre-populate map (struct sock_mapping), rather than introducing one more new struct. v5: Since allocating the data outside of this call it should also be freed outside, when create_active() fails. Move kzalloc(sizeof(*map2), GFP_ATOMIC) outside spinlock and use GFP_KERNEL instead. v6: Drop the superfluous calls. Suggested-by: Juergen Gross <jgross@suse.com> Suggested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Suggested-by: Stefano Stabellini <sstabellini@kernel.org> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn> Acked-by: Stefano Stabellini <sstabellini@kernel.org> CC: Julia Lawall <julia.lawall@lip6.fr> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: Juergen Gross <jgross@suse.com> CC: Stefano Stabellini <sstabellini@kernel.org> CC: xen-devel@lists.xenproject.org CC: linux-kernel@vger.kernel.org Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-12-05 10:35:50 +08:00
bytes = map->active.data.in;
for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++)
map->active.ring->ref[i] = gnttab_grant_foreign_access(
pvcalls_front_dev->otherend_id,
pfn_to_gfn(virt_to_pfn(bytes) + i), 0);
map->active.ref = gnttab_grant_foreign_access(
pvcalls_front_dev->otherend_id,
pfn_to_gfn(virt_to_pfn((void *)map->active.ring)), 0);
ret = xenbus_alloc_evtchn(pvcalls_front_dev, evtchn);
if (ret)
goto out_error;
irq = bind_evtchn_to_irqhandler(*evtchn, pvcalls_front_conn_handler,
0, "pvcalls-frontend", map);
if (irq < 0) {
ret = irq;
goto out_error;
}
map->active.irq = irq;
map->active_socket = true;
mutex_init(&map->active.in_mutex);
mutex_init(&map->active.out_mutex);
return 0;
out_error:
if (*evtchn > 0)
xenbus_free_evtchn(pvcalls_front_dev, *evtchn);
return ret;
}
int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr,
int addr_len, int flags)
{
struct pvcalls_bedata *bedata;
struct sock_mapping *map = NULL;
struct xen_pvcalls_request *req;
int notify, req_id, ret;
evtchn_port_t evtchn;
if (addr->sa_family != AF_INET || sock->type != SOCK_STREAM)
return -EOPNOTSUPP;
map = pvcalls_enter_sock(sock);
if (IS_ERR(map))
return PTR_ERR(map);
bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
pvcalls-front: Avoid get_free_pages(GFP_KERNEL) under spinlock The problem is that we call this with a spin lock held. The call tree is: pvcalls_front_accept() holds bedata->socket_lock. -> create_active() -> __get_free_pages() uses GFP_KERNEL The create_active() function is only called from pvcalls_front_accept() with a spin_lock held, The allocation is not allowed to sleep and GFP_KERNEL is not sufficient. This issue was detected by using the Coccinelle software. v2: Add a function doing the allocations which is called outside the lock and passing the allocated data to create_active(). v3: Use the matching deallocators i.e., free_page() and free_pages(), respectively. v4: It would be better to pre-populate map (struct sock_mapping), rather than introducing one more new struct. v5: Since allocating the data outside of this call it should also be freed outside, when create_active() fails. Move kzalloc(sizeof(*map2), GFP_ATOMIC) outside spinlock and use GFP_KERNEL instead. v6: Drop the superfluous calls. Suggested-by: Juergen Gross <jgross@suse.com> Suggested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Suggested-by: Stefano Stabellini <sstabellini@kernel.org> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn> Acked-by: Stefano Stabellini <sstabellini@kernel.org> CC: Julia Lawall <julia.lawall@lip6.fr> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: Juergen Gross <jgross@suse.com> CC: Stefano Stabellini <sstabellini@kernel.org> CC: xen-devel@lists.xenproject.org CC: linux-kernel@vger.kernel.org Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-12-05 10:35:50 +08:00
ret = alloc_active_ring(map);
if (ret < 0) {
pvcalls_exit_sock(sock);
return ret;
}
spin_lock(&bedata->socket_lock);
ret = get_request(bedata, &req_id);
if (ret < 0) {
spin_unlock(&bedata->socket_lock);
pvcalls-front: Avoid get_free_pages(GFP_KERNEL) under spinlock The problem is that we call this with a spin lock held. The call tree is: pvcalls_front_accept() holds bedata->socket_lock. -> create_active() -> __get_free_pages() uses GFP_KERNEL The create_active() function is only called from pvcalls_front_accept() with a spin_lock held, The allocation is not allowed to sleep and GFP_KERNEL is not sufficient. This issue was detected by using the Coccinelle software. v2: Add a function doing the allocations which is called outside the lock and passing the allocated data to create_active(). v3: Use the matching deallocators i.e., free_page() and free_pages(), respectively. v4: It would be better to pre-populate map (struct sock_mapping), rather than introducing one more new struct. v5: Since allocating the data outside of this call it should also be freed outside, when create_active() fails. Move kzalloc(sizeof(*map2), GFP_ATOMIC) outside spinlock and use GFP_KERNEL instead. v6: Drop the superfluous calls. Suggested-by: Juergen Gross <jgross@suse.com> Suggested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Suggested-by: Stefano Stabellini <sstabellini@kernel.org> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn> Acked-by: Stefano Stabellini <sstabellini@kernel.org> CC: Julia Lawall <julia.lawall@lip6.fr> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: Juergen Gross <jgross@suse.com> CC: Stefano Stabellini <sstabellini@kernel.org> CC: xen-devel@lists.xenproject.org CC: linux-kernel@vger.kernel.org Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-12-05 10:35:50 +08:00
free_active_ring(map);
pvcalls_exit_sock(sock);
return ret;
}
ret = create_active(map, &evtchn);
if (ret < 0) {
spin_unlock(&bedata->socket_lock);
pvcalls-front: Avoid get_free_pages(GFP_KERNEL) under spinlock The problem is that we call this with a spin lock held. The call tree is: pvcalls_front_accept() holds bedata->socket_lock. -> create_active() -> __get_free_pages() uses GFP_KERNEL The create_active() function is only called from pvcalls_front_accept() with a spin_lock held, The allocation is not allowed to sleep and GFP_KERNEL is not sufficient. This issue was detected by using the Coccinelle software. v2: Add a function doing the allocations which is called outside the lock and passing the allocated data to create_active(). v3: Use the matching deallocators i.e., free_page() and free_pages(), respectively. v4: It would be better to pre-populate map (struct sock_mapping), rather than introducing one more new struct. v5: Since allocating the data outside of this call it should also be freed outside, when create_active() fails. Move kzalloc(sizeof(*map2), GFP_ATOMIC) outside spinlock and use GFP_KERNEL instead. v6: Drop the superfluous calls. Suggested-by: Juergen Gross <jgross@suse.com> Suggested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Suggested-by: Stefano Stabellini <sstabellini@kernel.org> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn> Acked-by: Stefano Stabellini <sstabellini@kernel.org> CC: Julia Lawall <julia.lawall@lip6.fr> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: Juergen Gross <jgross@suse.com> CC: Stefano Stabellini <sstabellini@kernel.org> CC: xen-devel@lists.xenproject.org CC: linux-kernel@vger.kernel.org Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-12-05 10:35:50 +08:00
free_active_ring(map);
pvcalls_exit_sock(sock);
return ret;
}
req = RING_GET_REQUEST(&bedata->ring, req_id);
req->req_id = req_id;
req->cmd = PVCALLS_CONNECT;
req->u.connect.id = (uintptr_t)map;
req->u.connect.len = addr_len;
req->u.connect.flags = flags;
req->u.connect.ref = map->active.ref;
req->u.connect.evtchn = evtchn;
memcpy(req->u.connect.addr, addr, sizeof(*addr));
map->sock = sock;
bedata->ring.req_prod_pvt++;
RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
spin_unlock(&bedata->socket_lock);
if (notify)
notify_remote_via_irq(bedata->irq);
wait_event(bedata->inflight_req,
READ_ONCE(bedata->rsp[req_id].req_id) == req_id);
/* read req_id, then the content */
smp_rmb();
ret = bedata->rsp[req_id].ret;
bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
pvcalls_exit_sock(sock);
return ret;
}
static int __write_ring(struct pvcalls_data_intf *intf,
struct pvcalls_data *data,
struct iov_iter *msg_iter,
int len)
{
RING_IDX cons, prod, size, masked_prod, masked_cons;
RING_IDX array_size = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
int32_t error;
error = intf->out_error;
if (error < 0)
return error;
cons = intf->out_cons;
prod = intf->out_prod;
/* read indexes before continuing */
virt_mb();
size = pvcalls_queued(prod, cons, array_size);
if (size > array_size)
return -EINVAL;
if (size == array_size)
return 0;
if (len > array_size - size)
len = array_size - size;
masked_prod = pvcalls_mask(prod, array_size);
masked_cons = pvcalls_mask(cons, array_size);
if (masked_prod < masked_cons) {
len = copy_from_iter(data->out + masked_prod, len, msg_iter);
} else {
if (len > array_size - masked_prod) {
int ret = copy_from_iter(data->out + masked_prod,
array_size - masked_prod, msg_iter);
if (ret != array_size - masked_prod) {
len = ret;
goto out;
}
len = ret + copy_from_iter(data->out, len - ret, msg_iter);
} else {
len = copy_from_iter(data->out + masked_prod, len, msg_iter);
}
}
out:
/* write to ring before updating pointer */
virt_wmb();
intf->out_prod += len;
return len;
}
int pvcalls_front_sendmsg(struct socket *sock, struct msghdr *msg,
size_t len)
{
struct sock_mapping *map;
int sent, tot_sent = 0;
int count = 0, flags;
flags = msg->msg_flags;
if (flags & (MSG_CONFIRM|MSG_DONTROUTE|MSG_EOR|MSG_OOB))
return -EOPNOTSUPP;
map = pvcalls_enter_sock(sock);
if (IS_ERR(map))
return PTR_ERR(map);
mutex_lock(&map->active.out_mutex);
if ((flags & MSG_DONTWAIT) && !pvcalls_front_write_todo(map)) {
mutex_unlock(&map->active.out_mutex);
pvcalls_exit_sock(sock);
return -EAGAIN;
}
if (len > INT_MAX)
len = INT_MAX;
again:
count++;
sent = __write_ring(map->active.ring,
&map->active.data, &msg->msg_iter,
len);
if (sent > 0) {
len -= sent;
tot_sent += sent;
notify_remote_via_irq(map->active.irq);
}
if (sent >= 0 && len > 0 && count < PVCALLS_FRONT_MAX_SPIN)
goto again;
if (sent < 0)
tot_sent = sent;
mutex_unlock(&map->active.out_mutex);
pvcalls_exit_sock(sock);
return tot_sent;
}
static int __read_ring(struct pvcalls_data_intf *intf,
struct pvcalls_data *data,
struct iov_iter *msg_iter,
size_t len, int flags)
{
RING_IDX cons, prod, size, masked_prod, masked_cons;
RING_IDX array_size = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
int32_t error;
cons = intf->in_cons;
prod = intf->in_prod;
error = intf->in_error;
/* get pointers before reading from the ring */
virt_rmb();
size = pvcalls_queued(prod, cons, array_size);
masked_prod = pvcalls_mask(prod, array_size);
masked_cons = pvcalls_mask(cons, array_size);
if (size == 0)
return error ?: size;
if (len > size)
len = size;
if (masked_prod > masked_cons) {
len = copy_to_iter(data->in + masked_cons, len, msg_iter);
} else {
if (len > (array_size - masked_cons)) {
int ret = copy_to_iter(data->in + masked_cons,
array_size - masked_cons, msg_iter);
if (ret != array_size - masked_cons) {
len = ret;
goto out;
}
len = ret + copy_to_iter(data->in, len - ret, msg_iter);
} else {
len = copy_to_iter(data->in + masked_cons, len, msg_iter);
}
}
out:
/* read data from the ring before increasing the index */
virt_mb();
if (!(flags & MSG_PEEK))
intf->in_cons += len;
return len;
}
int pvcalls_front_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
int flags)
{
int ret;
struct sock_mapping *map;
if (flags & (MSG_CMSG_CLOEXEC|MSG_ERRQUEUE|MSG_OOB|MSG_TRUNC))
return -EOPNOTSUPP;
map = pvcalls_enter_sock(sock);
if (IS_ERR(map))
return PTR_ERR(map);
mutex_lock(&map->active.in_mutex);
if (len > XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER))
len = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
while (!(flags & MSG_DONTWAIT) && !pvcalls_front_read_todo(map)) {
wait_event_interruptible(map->active.inflight_conn_req,
pvcalls_front_read_todo(map));
}
ret = __read_ring(map->active.ring, &map->active.data,
&msg->msg_iter, len, flags);
if (ret > 0)
notify_remote_via_irq(map->active.irq);
if (ret == 0)
ret = (flags & MSG_DONTWAIT) ? -EAGAIN : 0;
if (ret == -ENOTCONN)
ret = 0;
mutex_unlock(&map->active.in_mutex);
pvcalls_exit_sock(sock);
return ret;
}
int pvcalls_front_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
{
struct pvcalls_bedata *bedata;
struct sock_mapping *map = NULL;
struct xen_pvcalls_request *req;
int notify, req_id, ret;
if (addr->sa_family != AF_INET || sock->type != SOCK_STREAM)
return -EOPNOTSUPP;
map = pvcalls_enter_sock(sock);
if (IS_ERR(map))
return PTR_ERR(map);
bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
spin_lock(&bedata->socket_lock);
ret = get_request(bedata, &req_id);
if (ret < 0) {
spin_unlock(&bedata->socket_lock);
pvcalls_exit_sock(sock);
return ret;
}
req = RING_GET_REQUEST(&bedata->ring, req_id);
req->req_id = req_id;
map->sock = sock;
req->cmd = PVCALLS_BIND;
req->u.bind.id = (uintptr_t)map;
memcpy(req->u.bind.addr, addr, sizeof(*addr));
req->u.bind.len = addr_len;
init_waitqueue_head(&map->passive.inflight_accept_req);
map->active_socket = false;
bedata->ring.req_prod_pvt++;
RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
spin_unlock(&bedata->socket_lock);
if (notify)
notify_remote_via_irq(bedata->irq);
wait_event(bedata->inflight_req,
READ_ONCE(bedata->rsp[req_id].req_id) == req_id);
/* read req_id, then the content */
smp_rmb();
ret = bedata->rsp[req_id].ret;
bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
map->passive.status = PVCALLS_STATUS_BIND;
pvcalls_exit_sock(sock);
return 0;
}
int pvcalls_front_listen(struct socket *sock, int backlog)
{
struct pvcalls_bedata *bedata;
struct sock_mapping *map;
struct xen_pvcalls_request *req;
int notify, req_id, ret;
map = pvcalls_enter_sock(sock);
if (IS_ERR(map))
return PTR_ERR(map);
bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
if (map->passive.status != PVCALLS_STATUS_BIND) {
pvcalls_exit_sock(sock);
return -EOPNOTSUPP;
}
spin_lock(&bedata->socket_lock);
ret = get_request(bedata, &req_id);
if (ret < 0) {
spin_unlock(&bedata->socket_lock);
pvcalls_exit_sock(sock);
return ret;
}
req = RING_GET_REQUEST(&bedata->ring, req_id);
req->req_id = req_id;
req->cmd = PVCALLS_LISTEN;
req->u.listen.id = (uintptr_t) map;
req->u.listen.backlog = backlog;
bedata->ring.req_prod_pvt++;
RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
spin_unlock(&bedata->socket_lock);
if (notify)
notify_remote_via_irq(bedata->irq);
wait_event(bedata->inflight_req,
READ_ONCE(bedata->rsp[req_id].req_id) == req_id);
/* read req_id, then the content */
smp_rmb();
ret = bedata->rsp[req_id].ret;
bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
map->passive.status = PVCALLS_STATUS_LISTEN;
pvcalls_exit_sock(sock);
return ret;
}
int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags)
{
struct pvcalls_bedata *bedata;
struct sock_mapping *map;
struct sock_mapping *map2 = NULL;
struct xen_pvcalls_request *req;
int notify, req_id, ret, nonblock;
evtchn_port_t evtchn;
map = pvcalls_enter_sock(sock);
if (IS_ERR(map))
return PTR_ERR(map);
bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
if (map->passive.status != PVCALLS_STATUS_LISTEN) {
pvcalls_exit_sock(sock);
return -EINVAL;
}
nonblock = flags & SOCK_NONBLOCK;
/*
* Backend only supports 1 inflight accept request, will return
* errors for the others
*/
if (test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
(void *)&map->passive.flags)) {
req_id = READ_ONCE(map->passive.inflight_req_id);
if (req_id != PVCALLS_INVALID_ID &&
READ_ONCE(bedata->rsp[req_id].req_id) == req_id) {
map2 = map->passive.accept_map;
goto received;
}
if (nonblock) {
pvcalls_exit_sock(sock);
return -EAGAIN;
}
if (wait_event_interruptible(map->passive.inflight_accept_req,
!test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
(void *)&map->passive.flags))) {
pvcalls_exit_sock(sock);
return -EINTR;
}
}
pvcalls-front: Avoid get_free_pages(GFP_KERNEL) under spinlock The problem is that we call this with a spin lock held. The call tree is: pvcalls_front_accept() holds bedata->socket_lock. -> create_active() -> __get_free_pages() uses GFP_KERNEL The create_active() function is only called from pvcalls_front_accept() with a spin_lock held, The allocation is not allowed to sleep and GFP_KERNEL is not sufficient. This issue was detected by using the Coccinelle software. v2: Add a function doing the allocations which is called outside the lock and passing the allocated data to create_active(). v3: Use the matching deallocators i.e., free_page() and free_pages(), respectively. v4: It would be better to pre-populate map (struct sock_mapping), rather than introducing one more new struct. v5: Since allocating the data outside of this call it should also be freed outside, when create_active() fails. Move kzalloc(sizeof(*map2), GFP_ATOMIC) outside spinlock and use GFP_KERNEL instead. v6: Drop the superfluous calls. Suggested-by: Juergen Gross <jgross@suse.com> Suggested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Suggested-by: Stefano Stabellini <sstabellini@kernel.org> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn> Acked-by: Stefano Stabellini <sstabellini@kernel.org> CC: Julia Lawall <julia.lawall@lip6.fr> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: Juergen Gross <jgross@suse.com> CC: Stefano Stabellini <sstabellini@kernel.org> CC: xen-devel@lists.xenproject.org CC: linux-kernel@vger.kernel.org Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-12-05 10:35:50 +08:00
map2 = kzalloc(sizeof(*map2), GFP_KERNEL);
if (map2 == NULL) {
clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
(void *)&map->passive.flags);
pvcalls-front: Avoid get_free_pages(GFP_KERNEL) under spinlock The problem is that we call this with a spin lock held. The call tree is: pvcalls_front_accept() holds bedata->socket_lock. -> create_active() -> __get_free_pages() uses GFP_KERNEL The create_active() function is only called from pvcalls_front_accept() with a spin_lock held, The allocation is not allowed to sleep and GFP_KERNEL is not sufficient. This issue was detected by using the Coccinelle software. v2: Add a function doing the allocations which is called outside the lock and passing the allocated data to create_active(). v3: Use the matching deallocators i.e., free_page() and free_pages(), respectively. v4: It would be better to pre-populate map (struct sock_mapping), rather than introducing one more new struct. v5: Since allocating the data outside of this call it should also be freed outside, when create_active() fails. Move kzalloc(sizeof(*map2), GFP_ATOMIC) outside spinlock and use GFP_KERNEL instead. v6: Drop the superfluous calls. Suggested-by: Juergen Gross <jgross@suse.com> Suggested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Suggested-by: Stefano Stabellini <sstabellini@kernel.org> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn> Acked-by: Stefano Stabellini <sstabellini@kernel.org> CC: Julia Lawall <julia.lawall@lip6.fr> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: Juergen Gross <jgross@suse.com> CC: Stefano Stabellini <sstabellini@kernel.org> CC: xen-devel@lists.xenproject.org CC: linux-kernel@vger.kernel.org Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-12-05 10:35:50 +08:00
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;
}
pvcalls-front: Avoid get_free_pages(GFP_KERNEL) under spinlock The problem is that we call this with a spin lock held. The call tree is: pvcalls_front_accept() holds bedata->socket_lock. -> create_active() -> __get_free_pages() uses GFP_KERNEL The create_active() function is only called from pvcalls_front_accept() with a spin_lock held, The allocation is not allowed to sleep and GFP_KERNEL is not sufficient. This issue was detected by using the Coccinelle software. v2: Add a function doing the allocations which is called outside the lock and passing the allocated data to create_active(). v3: Use the matching deallocators i.e., free_page() and free_pages(), respectively. v4: It would be better to pre-populate map (struct sock_mapping), rather than introducing one more new struct. v5: Since allocating the data outside of this call it should also be freed outside, when create_active() fails. Move kzalloc(sizeof(*map2), GFP_ATOMIC) outside spinlock and use GFP_KERNEL instead. v6: Drop the superfluous calls. Suggested-by: Juergen Gross <jgross@suse.com> Suggested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Suggested-by: Stefano Stabellini <sstabellini@kernel.org> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn> Acked-by: Stefano Stabellini <sstabellini@kernel.org> CC: Julia Lawall <julia.lawall@lip6.fr> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: Juergen Gross <jgross@suse.com> CC: Stefano Stabellini <sstabellini@kernel.org> CC: xen-devel@lists.xenproject.org CC: linux-kernel@vger.kernel.org Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-12-05 10:35:50 +08:00
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);
pvcalls-front: Avoid get_free_pages(GFP_KERNEL) under spinlock The problem is that we call this with a spin lock held. The call tree is: pvcalls_front_accept() holds bedata->socket_lock. -> create_active() -> __get_free_pages() uses GFP_KERNEL The create_active() function is only called from pvcalls_front_accept() with a spin_lock held, The allocation is not allowed to sleep and GFP_KERNEL is not sufficient. This issue was detected by using the Coccinelle software. v2: Add a function doing the allocations which is called outside the lock and passing the allocated data to create_active(). v3: Use the matching deallocators i.e., free_page() and free_pages(), respectively. v4: It would be better to pre-populate map (struct sock_mapping), rather than introducing one more new struct. v5: Since allocating the data outside of this call it should also be freed outside, when create_active() fails. Move kzalloc(sizeof(*map2), GFP_ATOMIC) outside spinlock and use GFP_KERNEL instead. v6: Drop the superfluous calls. Suggested-by: Juergen Gross <jgross@suse.com> Suggested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Suggested-by: Stefano Stabellini <sstabellini@kernel.org> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn> Acked-by: Stefano Stabellini <sstabellini@kernel.org> CC: Julia Lawall <julia.lawall@lip6.fr> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: Juergen Gross <jgross@suse.com> CC: Stefano Stabellini <sstabellini@kernel.org> CC: xen-devel@lists.xenproject.org CC: linux-kernel@vger.kernel.org Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-12-05 10:35:50 +08:00
free_active_ring(map2);
kfree(map2);
pvcalls_exit_sock(sock);
pvcalls-front: Avoid get_free_pages(GFP_KERNEL) under spinlock The problem is that we call this with a spin lock held. The call tree is: pvcalls_front_accept() holds bedata->socket_lock. -> create_active() -> __get_free_pages() uses GFP_KERNEL The create_active() function is only called from pvcalls_front_accept() with a spin_lock held, The allocation is not allowed to sleep and GFP_KERNEL is not sufficient. This issue was detected by using the Coccinelle software. v2: Add a function doing the allocations which is called outside the lock and passing the allocated data to create_active(). v3: Use the matching deallocators i.e., free_page() and free_pages(), respectively. v4: It would be better to pre-populate map (struct sock_mapping), rather than introducing one more new struct. v5: Since allocating the data outside of this call it should also be freed outside, when create_active() fails. Move kzalloc(sizeof(*map2), GFP_ATOMIC) outside spinlock and use GFP_KERNEL instead. v6: Drop the superfluous calls. Suggested-by: Juergen Gross <jgross@suse.com> Suggested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Suggested-by: Stefano Stabellini <sstabellini@kernel.org> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn> Acked-by: Stefano Stabellini <sstabellini@kernel.org> CC: Julia Lawall <julia.lawall@lip6.fr> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: Juergen Gross <jgross@suse.com> CC: Stefano Stabellini <sstabellini@kernel.org> CC: xen-devel@lists.xenproject.org CC: linux-kernel@vger.kernel.org Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-12-05 10:35:50 +08:00
return ret;
}
pvcalls-front: Avoid get_free_pages(GFP_KERNEL) under spinlock The problem is that we call this with a spin lock held. The call tree is: pvcalls_front_accept() holds bedata->socket_lock. -> create_active() -> __get_free_pages() uses GFP_KERNEL The create_active() function is only called from pvcalls_front_accept() with a spin_lock held, The allocation is not allowed to sleep and GFP_KERNEL is not sufficient. This issue was detected by using the Coccinelle software. v2: Add a function doing the allocations which is called outside the lock and passing the allocated data to create_active(). v3: Use the matching deallocators i.e., free_page() and free_pages(), respectively. v4: It would be better to pre-populate map (struct sock_mapping), rather than introducing one more new struct. v5: Since allocating the data outside of this call it should also be freed outside, when create_active() fails. Move kzalloc(sizeof(*map2), GFP_ATOMIC) outside spinlock and use GFP_KERNEL instead. v6: Drop the superfluous calls. Suggested-by: Juergen Gross <jgross@suse.com> Suggested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Suggested-by: Stefano Stabellini <sstabellini@kernel.org> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn> Acked-by: Stefano Stabellini <sstabellini@kernel.org> CC: Julia Lawall <julia.lawall@lip6.fr> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: Juergen Gross <jgross@suse.com> CC: Stefano Stabellini <sstabellini@kernel.org> CC: xen-devel@lists.xenproject.org CC: linux-kernel@vger.kernel.org Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-12-05 10:35:50 +08:00
ret = create_active(map2, &evtchn);
if (ret < 0) {
pvcalls-front: Avoid get_free_pages(GFP_KERNEL) under spinlock The problem is that we call this with a spin lock held. The call tree is: pvcalls_front_accept() holds bedata->socket_lock. -> create_active() -> __get_free_pages() uses GFP_KERNEL The create_active() function is only called from pvcalls_front_accept() with a spin_lock held, The allocation is not allowed to sleep and GFP_KERNEL is not sufficient. This issue was detected by using the Coccinelle software. v2: Add a function doing the allocations which is called outside the lock and passing the allocated data to create_active(). v3: Use the matching deallocators i.e., free_page() and free_pages(), respectively. v4: It would be better to pre-populate map (struct sock_mapping), rather than introducing one more new struct. v5: Since allocating the data outside of this call it should also be freed outside, when create_active() fails. Move kzalloc(sizeof(*map2), GFP_ATOMIC) outside spinlock and use GFP_KERNEL instead. v6: Drop the superfluous calls. Suggested-by: Juergen Gross <jgross@suse.com> Suggested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Suggested-by: Stefano Stabellini <sstabellini@kernel.org> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn> Acked-by: Stefano Stabellini <sstabellini@kernel.org> CC: Julia Lawall <julia.lawall@lip6.fr> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: Juergen Gross <jgross@suse.com> CC: Stefano Stabellini <sstabellini@kernel.org> CC: xen-devel@lists.xenproject.org CC: linux-kernel@vger.kernel.org Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-12-05 10:35:50 +08:00
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, NULL);
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,
.not_essential = true,
};
static int __init pvcalls_frontend_init(void)
{
if (!xen_domain())
return -ENODEV;
pr_info("Initialising Xen pvcalls frontend driver\n");
return xenbus_register_frontend(&pvcalls_front_driver);
}
module_init(pvcalls_frontend_init);
MODULE_DESCRIPTION("Xen PV Calls frontend driver");
MODULE_AUTHOR("Stefano Stabellini <sstabellini@kernel.org>");
MODULE_LICENSE("GPL");