cachepc-qemu

Fork of AMDESE/qemu with changes for cachepc side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-qemu
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ivshmem-server.h (5649B)

      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 */
     48typedef 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 */
     62typedef 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 */
     88int
     89ivshmem_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 */
    101int 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 */
    113void 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 */
    127void
    128ivshmem_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 */
    143int 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 */
    153IvshmemServerPeer *
    154ivshmem_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 */
    161void ivshmem_server_dump(const IvshmemServer *server);
    162
    163#endif /* IVSHMEM_SERVER_H */