/* * Copyright 6WIND S.A., 2014 * * This work is licensed under the terms of the GNU GPL, version 2 or * (at your option) any later version. See the COPYING file in the * top-level directory. */ #ifndef _IVSHMEM_SERVER_H_ #define _IVSHMEM_SERVER_H_ /** * The ivshmem server is a daemon that creates a unix socket in listen * mode. The ivshmem clients (qemu or ivshmem-client) connect to this * unix socket. For each client, the server will create some eventfd * (see EVENTFD(2)), one per vector. These fd are transmitted to all * clients using the SCM_RIGHTS cmsg message. Therefore, each client is * able to send a notification to another client without being * "profixied" by the server. * * We use this mechanism to send interruptions between guests. * qemu is able to transform an event on a eventfd into a PCI MSI-x * interruption in the guest. * * The ivshmem server is also able to share the file descriptor * associated to the ivshmem shared memory. */ #include <sys/select.h> #include "qemu/event_notifier.h" #include "qemu/queue.h" #include "hw/misc/ivshmem.h" /** * Maximum number of notification vectors supported by the server */ #define IVSHMEM_SERVER_MAX_VECTORS 64 /** * Structure storing a peer * * Each time a client connects to an ivshmem server, a new * IvshmemServerPeer structure is created. This peer and all its * vectors are advertised to all connected clients through the connected * unix sockets. */ typedef struct IvshmemServerPeer { QTAILQ_ENTRY(IvshmemServerPeer) next; /**< next in list*/ int sock_fd; /**< connected unix sock */ int64_t id; /**< the id of the peer */ EventNotifier vectors[IVSHMEM_SERVER_MAX_VECTORS]; /**< one per vector */ unsigned vectors_count; /**< number of vectors */ } IvshmemServerPeer; QTAILQ_HEAD(IvshmemServerPeerList, IvshmemServerPeer); typedef struct IvshmemServerPeerList IvshmemServerPeerList; /** * Structure describing an ivshmem server * * This structure stores all information related to our server: the name * of the server unix socket and the list of connected peers. */ typedef struct IvshmemServer { char unix_sock_path[PATH_MAX]; /**< path to unix socket */ int sock_fd; /**< unix sock file descriptor */ char shm_path[PATH_MAX]; /**< path to shm */ bool use_shm_open; size_t shm_size; /**< size of shm */ int shm_fd; /**< shm file descriptor */ unsigned n_vectors; /**< number of vectors */ uint16_t cur_id; /**< id to be given to next client */ bool verbose; /**< true in verbose mode */ IvshmemServerPeerList peer_list; /**< list of peers */ } IvshmemServer; /** * Initialize an ivshmem server * * @server: A pointer to an uninitialized IvshmemServer structure * @unix_sock_path: The pointer to the unix socket file name * @shm_path: Path to the shared memory. The path corresponds to a POSIX * shm name or a hugetlbfs mount point. * @shm_size: Size of shared memory * @n_vectors: Number of interrupt vectors per client * @verbose: True to enable verbose mode * * Returns: 0 on success, or a negative value on error */ int ivshmem_server_init(IvshmemServer *server, const char *unix_sock_path, const char *shm_path, bool use_shm_open, size_t shm_size, unsigned n_vectors, bool verbose); /** * Open the shm, then create and bind to the unix socket * * @server: The pointer to the initialized IvshmemServer structure * * Returns: 0 on success, or a negative value on error */ int ivshmem_server_start(IvshmemServer *server); /** * Close the server * * Close connections to all clients, close the unix socket and the * shared memory file descriptor. The structure remains initialized, so * it is possible to call ivshmem_server_start() again after a call to * ivshmem_server_close(). * * @server: The ivshmem server */ void ivshmem_server_close(IvshmemServer *server); /** * Fill a fd_set with file descriptors to be monitored * * This function will fill a fd_set with all file descriptors that must * be polled (unix server socket and peers unix socket). The function * will not initialize the fd_set, it is up to the caller to do it. * * @server: The ivshmem server * @fds: The fd_set to be updated * @maxfd: Must be set to the max file descriptor + 1 in fd_set. This value is * updated if this function adds a greater fd in fd_set. */ void ivshmem_server_get_fds(const IvshmemServer *server, fd_set *fds, int *maxfd); /** * Read and handle new messages * * Given a fd_set (for instance filled by a call to select()), handle * incoming messages from peers. * * @server: The ivshmem server * @fds: The fd_set containing the file descriptors to be checked. Note that * file descriptors that are not related to our server are ignored. * @maxfd: The maximum fd in fd_set, plus one. * * Returns: 0 on success, or a negative value on error */ int ivshmem_server_handle_fds(IvshmemServer *server, fd_set *fds, int maxfd); /** * Search a peer from its identifier * * @server: The ivshmem server * @peer_id: The identifier of the peer structure * * Returns: The peer structure, or NULL if not found */ IvshmemServerPeer * ivshmem_server_search_peer(IvshmemServer *server, int64_t peer_id); /** * Dump information of this ivshmem server and its peers on stdout * * @server: The ivshmem server */ void ivshmem_server_dump(const IvshmemServer *server); #endif /* _IVSHMEM_SERVER_H_ */