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/*
* 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 <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_ */
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