xref: /qemu/include/qemu/vhost-user-server.h (revision 8b7b9c5c)
1 /*
2  * Sharing QEMU devices via vhost-user protocol
3  *
4  * Copyright (c) Coiby Xu <coiby.xu@gmail.com>.
5  * Copyright (c) 2020 Red Hat, Inc.
6  *
7  * This work is licensed under the terms of the GNU GPL, version 2 or
8  * later.  See the COPYING file in the top-level directory.
9  */
10 
11 #ifndef VHOST_USER_SERVER_H
12 #define VHOST_USER_SERVER_H
13 
14 #include "subprojects/libvhost-user/libvhost-user.h" /* only for the type definitions */
15 #include "io/channel-socket.h"
16 #include "io/channel-file.h"
17 #include "io/net-listener.h"
18 #include "qapi/error.h"
19 #include "standard-headers/linux/virtio_blk.h"
20 
21 /* A kick fd that we monitor on behalf of libvhost-user */
22 typedef struct VuFdWatch {
23     VuDev *vu_dev;
24     int fd; /*kick fd*/
25     void *pvt;
26     vu_watch_cb cb;
27     QTAILQ_ENTRY(VuFdWatch) next;
28 } VuFdWatch;
29 
30 /**
31  * VuServer:
32  * A vhost-user server instance with user-defined VuDevIface callbacks.
33  * Vhost-user device backends can be implemented using VuServer. VuDevIface
34  * callbacks and virtqueue kicks run in the given AioContext.
35  */
36 typedef struct {
37     QIONetListener *listener;
38     QEMUBH *restart_listener_bh;
39     AioContext *ctx;
40     int max_queues;
41     const VuDevIface *vu_iface;
42 
43     unsigned int in_flight; /* atomic */
44 
45     /* Protected by ctx lock */
46     bool in_qio_channel_yield;
47     bool wait_idle;
48     VuDev vu_dev;
49     QIOChannel *ioc; /* The I/O channel with the client */
50     QIOChannelSocket *sioc; /* The underlying data channel with the client */
51     QTAILQ_HEAD(, VuFdWatch) vu_fd_watches;
52 
53     Coroutine *co_trip; /* coroutine for processing VhostUserMsg */
54 } VuServer;
55 
56 bool vhost_user_server_start(VuServer *server,
57                              SocketAddress *unix_socket,
58                              AioContext *ctx,
59                              uint16_t max_queues,
60                              const VuDevIface *vu_iface,
61                              Error **errp);
62 
63 void vhost_user_server_stop(VuServer *server);
64 
65 void vhost_user_server_inc_in_flight(VuServer *server);
66 void vhost_user_server_dec_in_flight(VuServer *server);
67 bool vhost_user_server_has_in_flight(VuServer *server);
68 
69 void vhost_user_server_attach_aio_context(VuServer *server, AioContext *ctx);
70 void vhost_user_server_detach_aio_context(VuServer *server);
71 
72 #endif /* VHOST_USER_SERVER_H */
73