diff options
Diffstat (limited to 'contrib/ivshmem-server/ivshmem-server.h')
| -rw-r--r-- | contrib/ivshmem-server/ivshmem-server.h | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/contrib/ivshmem-server/ivshmem-server.h b/contrib/ivshmem-server/ivshmem-server.h new file mode 100644 index 0000000..bf7de7a --- /dev/null +++ b/contrib/ivshmem-server/ivshmem-server.h @@ -0,0 +1,167 @@ +/* + * 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 beeing + * "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 <limits.h> +#include <sys/select.h> +#include <stdint.h> +#include <stdbool.h> + +#include "qemu/event_notifier.h" +#include "qemu/queue.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 */ + long 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 */ + size_t shm_size; /**< size of shm */ + int shm_fd; /**< shm file descriptor */ + unsigned n_vectors; /**< number of vectors */ + long 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. To use a real file, for instance in a hugetlbfs, + * it is possible to use /../../abspath/to/file. + * @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, 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, long 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_ */ |