1 | /* |
2 | * Copyright 6WIND S.A., 2014 |
3 | * |
4 | * This work is licensed under the terms of the GNU GPL, version 2 or |
5 | * (at your option) any later version. See the COPYING file in the |
6 | * top-level directory. |
7 | */ |
8 | |
9 | #ifndef IVSHMEM_SERVER_H |
10 | #define IVSHMEM_SERVER_H |
11 | |
12 | /** |
13 | * The ivshmem server is a daemon that creates a unix socket in listen |
14 | * mode. The ivshmem clients (qemu or ivshmem-client) connect to this |
15 | * unix socket. For each client, the server will create some eventfd |
16 | * (see EVENTFD(2)), one per vector. These fd are transmitted to all |
17 | * clients using the SCM_RIGHTS cmsg message. Therefore, each client is |
18 | * able to send a notification to another client without being |
19 | * "profixied" by the server. |
20 | * |
21 | * We use this mechanism to send interruptions between guests. |
22 | * qemu is able to transform an event on a eventfd into a PCI MSI-x |
23 | * interruption in the guest. |
24 | * |
25 | * The ivshmem server is also able to share the file descriptor |
26 | * associated to the ivshmem shared memory. |
27 | */ |
28 | |
29 | #include <sys/select.h> |
30 | |
31 | #include "qemu/event_notifier.h" |
32 | #include "qemu/queue.h" |
33 | #include "hw/misc/ivshmem.h" |
34 | |
35 | /** |
36 | * Maximum number of notification vectors supported by the server |
37 | */ |
38 | #define IVSHMEM_SERVER_MAX_VECTORS 64 |
39 | |
40 | /** |
41 | * Structure storing a peer |
42 | * |
43 | * Each time a client connects to an ivshmem server, a new |
44 | * IvshmemServerPeer structure is created. This peer and all its |
45 | * vectors are advertised to all connected clients through the connected |
46 | * unix sockets. |
47 | */ |
48 | typedef struct IvshmemServerPeer { |
49 | QTAILQ_ENTRY(IvshmemServerPeer) next; /**< next in list*/ |
50 | int sock_fd; /**< connected unix sock */ |
51 | int64_t id; /**< the id of the peer */ |
52 | EventNotifier vectors[IVSHMEM_SERVER_MAX_VECTORS]; /**< one per vector */ |
53 | unsigned vectors_count; /**< number of vectors */ |
54 | } IvshmemServerPeer; |
55 | |
56 | /** |
57 | * Structure describing an ivshmem server |
58 | * |
59 | * This structure stores all information related to our server: the name |
60 | * of the server unix socket and the list of connected peers. |
61 | */ |
62 | typedef struct IvshmemServer { |
63 | char unix_sock_path[PATH_MAX]; /**< path to unix socket */ |
64 | int sock_fd; /**< unix sock file descriptor */ |
65 | char shm_path[PATH_MAX]; /**< path to shm */ |
66 | bool use_shm_open; |
67 | size_t shm_size; /**< size of shm */ |
68 | int shm_fd; /**< shm file descriptor */ |
69 | unsigned n_vectors; /**< number of vectors */ |
70 | uint16_t cur_id; /**< id to be given to next client */ |
71 | bool verbose; /**< true in verbose mode */ |
72 | QTAILQ_HEAD(, IvshmemServerPeer) peer_list; /**< list of peers */ |
73 | } IvshmemServer; |
74 | |
75 | /** |
76 | * Initialize an ivshmem server |
77 | * |
78 | * @server: A pointer to an uninitialized IvshmemServer structure |
79 | * @unix_sock_path: The pointer to the unix socket file name |
80 | * @shm_path: Path to the shared memory. The path corresponds to a POSIX |
81 | * shm name or a hugetlbfs mount point. |
82 | * @shm_size: Size of shared memory |
83 | * @n_vectors: Number of interrupt vectors per client |
84 | * @verbose: True to enable verbose mode |
85 | * |
86 | * Returns: 0 on success, or a negative value on error |
87 | */ |
88 | int |
89 | ivshmem_server_init(IvshmemServer *server, const char *unix_sock_path, |
90 | const char *shm_path, bool use_shm_open, |
91 | size_t shm_size, unsigned n_vectors, |
92 | bool verbose); |
93 | |
94 | /** |
95 | * Open the shm, then create and bind to the unix socket |
96 | * |
97 | * @server: The pointer to the initialized IvshmemServer structure |
98 | * |
99 | * Returns: 0 on success, or a negative value on error |
100 | */ |
101 | int ivshmem_server_start(IvshmemServer *server); |
102 | |
103 | /** |
104 | * Close the server |
105 | * |
106 | * Close connections to all clients, close the unix socket and the |
107 | * shared memory file descriptor. The structure remains initialized, so |
108 | * it is possible to call ivshmem_server_start() again after a call to |
109 | * ivshmem_server_close(). |
110 | * |
111 | * @server: The ivshmem server |
112 | */ |
113 | void ivshmem_server_close(IvshmemServer *server); |
114 | |
115 | /** |
116 | * Fill a fd_set with file descriptors to be monitored |
117 | * |
118 | * This function will fill a fd_set with all file descriptors that must |
119 | * be polled (unix server socket and peers unix socket). The function |
120 | * will not initialize the fd_set, it is up to the caller to do it. |
121 | * |
122 | * @server: The ivshmem server |
123 | * @fds: The fd_set to be updated |
124 | * @maxfd: Must be set to the max file descriptor + 1 in fd_set. This value is |
125 | * updated if this function adds a greater fd in fd_set. |
126 | */ |
127 | void |
128 | ivshmem_server_get_fds(const IvshmemServer *server, fd_set *fds, int *maxfd); |
129 | |
130 | /** |
131 | * Read and handle new messages |
132 | * |
133 | * Given a fd_set (for instance filled by a call to select()), handle |
134 | * incoming messages from peers. |
135 | * |
136 | * @server: The ivshmem server |
137 | * @fds: The fd_set containing the file descriptors to be checked. Note that |
138 | * file descriptors that are not related to our server are ignored. |
139 | * @maxfd: The maximum fd in fd_set, plus one. |
140 | * |
141 | * Returns: 0 on success, or a negative value on error |
142 | */ |
143 | int ivshmem_server_handle_fds(IvshmemServer *server, fd_set *fds, int maxfd); |
144 | |
145 | /** |
146 | * Search a peer from its identifier |
147 | * |
148 | * @server: The ivshmem server |
149 | * @peer_id: The identifier of the peer structure |
150 | * |
151 | * Returns: The peer structure, or NULL if not found |
152 | */ |
153 | IvshmemServerPeer * |
154 | ivshmem_server_search_peer(IvshmemServer *server, int64_t peer_id); |
155 | |
156 | /** |
157 | * Dump information of this ivshmem server and its peers on stdout |
158 | * |
159 | * @server: The ivshmem server |
160 | */ |
161 | void ivshmem_server_dump(const IvshmemServer *server); |
162 | |
163 | #endif /* IVSHMEM_SERVER_H */ |
164 | |