ivshmem: use little-endian int64_t for the protocol

The current ivshmem protocol uses 'long' for integers. But the
sizeof(long) depends on the host and the endianess is not defined, which
may cause portability troubles.

Instead, switch to using little-endian int64_t. This breaks the
protocol, except on x64 little-endian host where this change
should be compatible.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Claudio Fontana <claudio.fontana@huawei.com>

7 files changed, 54 insertions, 41 deletions

diff --git a/contrib/ivshmem-client/ivshmem-client.c b/contrib/ivshmem-client/ivshmem-client.c
index 076e3ec31c..31619d80e9 100644
--- a/contrib/ivshmem-client/ivshmem-client.c
+++ b/contrib/ivshmem-client/ivshmem-client.c
@@ -24,7 +24,7 @@
 
 /* read message from the unix socket */
 static int
-ivshmem_client_read_one_msg(IvshmemClient *client, long *index, int *fd)
+ivshmem_client_read_one_msg(IvshmemClient *client, int64_t *index, int *fd)
 {
     int ret;
     struct msghdr msg;
@@ -45,7 +45,7 @@ ivshmem_client_read_one_msg(IvshmemClient *client, long *index, int *fd)
     msg.msg_controllen = sizeof(msg_control);
 
     ret = recvmsg(client->sock_fd, &msg, 0);
-    if (ret < 0) {
+    if (ret < sizeof(*index)) {
         IVSHMEM_CLIENT_DEBUG(client, "cannot read message: %s\n",
                              strerror(errno));
         return -1;
@@ -55,6 +55,7 @@ ivshmem_client_read_one_msg(IvshmemClient *client, long *index, int *fd)
         return -1;
     }
 
+    *index = GINT64_FROM_LE(*index);
     *fd = -1;
 
     for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
@@ -91,7 +92,7 @@ static int
 ivshmem_client_handle_server_msg(IvshmemClient *client)
 {
     IvshmemClientPeer *peer;
-    long peer_id;
+    int64_t peer_id;
     int ret, fd;
 
     ret = ivshmem_client_read_one_msg(client, &peer_id, &fd);
@@ -107,11 +108,11 @@ ivshmem_client_handle_server_msg(IvshmemClient *client)
 
         if (peer == NULL || peer == &client->local) {
             IVSHMEM_CLIENT_DEBUG(client, "receive delete for invalid "
-                                 "peer %ld\n", peer_id);
+                                 "peer %" PRId64 "\n", peer_id);
             return -1;
         }
 
-        IVSHMEM_CLIENT_DEBUG(client, "delete peer id = %ld\n", peer_id);
+        IVSHMEM_CLIENT_DEBUG(client, "delete peer id = %" PRId64 "\n", peer_id);
         ivshmem_client_free_peer(client, peer);
         return 0;
     }
@@ -122,12 +123,12 @@ ivshmem_client_handle_server_msg(IvshmemClient *client)
         peer->id = peer_id;
         peer->vectors_count = 0;
         QTAILQ_INSERT_TAIL(&client->peer_list, peer, next);
-        IVSHMEM_CLIENT_DEBUG(client, "new peer id = %ld\n", peer_id);
+        IVSHMEM_CLIENT_DEBUG(client, "new peer id = %" PRId64 "\n", peer_id);
     }
 
     /* new vector */
-    IVSHMEM_CLIENT_DEBUG(client, "  new vector %d (fd=%d) for peer id %ld\n",
-                         peer->vectors_count, fd, peer->id);
+    IVSHMEM_CLIENT_DEBUG(client, "  new vector %d (fd=%d) for peer id %"
+                         PRId64 "\n", peer->vectors_count, fd, peer->id);
     if (peer->vectors_count >= G_N_ELEMENTS(peer->vectors)) {
         IVSHMEM_CLIENT_DEBUG(client, "Too many vectors received, failing");
         return -1;
@@ -180,7 +181,7 @@ ivshmem_client_connect(IvshmemClient *client)
 {
     struct sockaddr_un sun;
     int fd, ret;
-    long tmp;
+    int64_t tmp;
 
     IVSHMEM_CLIENT_DEBUG(client, "connect to client %s\n",
                          client->unix_sock_path);
@@ -219,7 +220,7 @@ ivshmem_client_connect(IvshmemClient *client)
         IVSHMEM_CLIENT_DEBUG(client, "cannot read from server (2)\n");
         goto err_close;
     }
-    IVSHMEM_CLIENT_DEBUG(client, "our_id=%ld\n", client->local.id);
+    IVSHMEM_CLIENT_DEBUG(client, "our_id=%" PRId64 "\n", client->local.id);
 
     /* now, we expect shared mem fd + a -1 index, note that shm fd
      * is not used */
@@ -350,13 +351,13 @@ ivshmem_client_notify(const IvshmemClient *client,
     int fd;
 
     if (vector >= peer->vectors_count) {
-        IVSHMEM_CLIENT_DEBUG(client, "invalid vector %u on peer %ld\n",
+        IVSHMEM_CLIENT_DEBUG(client, "invalid vector %u on peer %" PRId64 "\n",
                              vector, peer->id);
         return -1;
     }
     fd = peer->vectors[vector];
-    IVSHMEM_CLIENT_DEBUG(client, "notify peer %ld on vector %d, fd %d\n",
-                         peer->id, vector, fd);
+    IVSHMEM_CLIENT_DEBUG(client, "notify peer %" PRId64
+                         " on vector %d, fd %d\n", peer->id, vector, fd);
 
     kick = 1;
     if (write(fd, &kick, sizeof(kick)) != sizeof(kick)) {
@@ -402,7 +403,7 @@ ivshmem_client_notify_broadcast(const IvshmemClient *client)
 
 /* lookup peer from its id */
 IvshmemClientPeer *
-ivshmem_client_search_peer(IvshmemClient *client, long peer_id)
+ivshmem_client_search_peer(IvshmemClient *client, int64_t peer_id)
 {
     IvshmemClientPeer *peer;
 
@@ -427,7 +428,7 @@ ivshmem_client_dump(const IvshmemClient *client)
 
     /* dump local infos */
     peer = &client->local;
-    printf("our_id = %ld\n", peer->id);
+    printf("our_id = %" PRId64 "\n", peer->id);
     for (vector = 0; vector < peer->vectors_count; vector++) {
         printf("  vector %d is enabled (fd=%d)\n", vector,
                peer->vectors[vector]);
@@ -435,7 +436,7 @@ ivshmem_client_dump(const IvshmemClient *client)
 
     /* dump peers */
     QTAILQ_FOREACH(peer, &client->peer_list, next) {
-        printf("peer_id = %ld\n", peer->id);
+        printf("peer_id = %" PRId64 "\n", peer->id);
 
         for (vector = 0; vector < peer->vectors_count; vector++) {
             printf("  vector %d is enabled (fd=%d)\n", vector,
diff --git a/contrib/ivshmem-client/ivshmem-client.h b/contrib/ivshmem-client/ivshmem-client.h
index 9215f3420e..3a4f809682 100644
--- a/contrib/ivshmem-client/ivshmem-client.h
+++ b/contrib/ivshmem-client/ivshmem-client.h
@@ -43,7 +43,7 @@
  */
 typedef struct IvshmemClientPeer {
     QTAILQ_ENTRY(IvshmemClientPeer) next;    /**< next in list*/
-    long id;                                 /**< the id of the peer */
+    int64_t id;                              /**< the id of the peer */
     int vectors[IVSHMEM_CLIENT_MAX_VECTORS]; /**< one fd per vector */
     unsigned vectors_count;                  /**< number of vectors */
 } IvshmemClientPeer;
@@ -198,7 +198,7 @@ int ivshmem_client_notify_broadcast(const IvshmemClient *client);
  * Returns:  The peer structure, or NULL if not found
  */
 IvshmemClientPeer *
-ivshmem_client_search_peer(IvshmemClient *client, long peer_id);
+ivshmem_client_search_peer(IvshmemClient *client, int64_t peer_id);
 
 /**
  * Dump information of this ivshmem client on stdout
diff --git a/contrib/ivshmem-client/main.c b/contrib/ivshmem-client/main.c
index 28dd81e5a1..c004870ae3 100644
--- a/contrib/ivshmem-client/main.c
+++ b/contrib/ivshmem-client/main.c
@@ -179,7 +179,8 @@ ivshmem_client_notification_cb(const IvshmemClient *client,
 {
     (void)client;
     (void)arg;
-    printf("receive notification from peer_id=%ld vector=%d\n", peer->id, vect);
+    printf("receive notification from peer_id=%" PRId64 " vector=%u\n",
+           peer->id, vect);
 }
 
 int
diff --git a/contrib/ivshmem-server/ivshmem-server.c b/contrib/ivshmem-server/ivshmem-server.c
index e8693dec3c..5e5239ce45 100644
--- a/contrib/ivshmem-server/ivshmem-server.c
+++ b/contrib/ivshmem-server/ivshmem-server.c
@@ -33,7 +33,7 @@
 
 /* send message to a client unix socket */
 static int
-ivshmem_server_send_one_msg(int sock_fd, long peer_id, int fd)
+ivshmem_server_send_one_msg(int sock_fd, int64_t peer_id, int fd)
 {
     int ret;
     struct msghdr msg;
@@ -44,6 +44,7 @@ ivshmem_server_send_one_msg(int sock_fd, long peer_id, int fd)
     } msg_control;
     struct cmsghdr *cmsg;
 
+    peer_id = GINT64_TO_LE(peer_id);
     iov[0].iov_base = &peer_id;
     iov[0].iov_len = sizeof(peer_id);
 
@@ -79,7 +80,7 @@ ivshmem_server_free_peer(IvshmemServer *server, IvshmemServerPeer *peer)
     unsigned vector;
     IvshmemServerPeer *other_peer;
 
-    IVSHMEM_SERVER_DEBUG(server, "free peer %ld\n", peer->id);
+    IVSHMEM_SERVER_DEBUG(server, "free peer %" PRId64 "\n", peer->id);
     close(peer->sock_fd);
     QTAILQ_REMOVE(&server->peer_list, peer, next);
 
@@ -209,7 +210,7 @@ ivshmem_server_handle_new_conn(IvshmemServer *server)
     }
 
     QTAILQ_INSERT_TAIL(&server->peer_list, peer, next);
-    IVSHMEM_SERVER_DEBUG(server, "new peer id = %ld\n",
+    IVSHMEM_SERVER_DEBUG(server, "new peer id = %" PRId64 "\n",
                          peer->id);
     return 0;
 
@@ -459,7 +460,7 @@ ivshmem_server_handle_fds(IvshmemServer *server, fd_set *fds, int maxfd)
 
 /* lookup peer from its id */
 IvshmemServerPeer *
-ivshmem_server_search_peer(IvshmemServer *server, long peer_id)
+ivshmem_server_search_peer(IvshmemServer *server, int64_t peer_id)
 {
     IvshmemServerPeer *peer;
 
@@ -480,7 +481,7 @@ ivshmem_server_dump(const IvshmemServer *server)
 
     /* dump peers */
     QTAILQ_FOREACH(peer, &server->peer_list, next) {
-        printf("peer_id = %ld\n", peer->id);
+        printf("peer_id = %" PRId64 "\n", peer->id);
 
         for (vector = 0; vector < peer->vectors_count; vector++) {
             printf("  vector %d is enabled (fd=%d)\n", vector,
diff --git a/contrib/ivshmem-server/ivshmem-server.h b/contrib/ivshmem-server/ivshmem-server.h
index 89c905fa63..c9359a0a8a 100644
--- a/contrib/ivshmem-server/ivshmem-server.h
+++ b/contrib/ivshmem-server/ivshmem-server.h
@@ -51,7 +51,7 @@
 typedef struct IvshmemServerPeer {
     QTAILQ_ENTRY(IvshmemServerPeer) next;    /**< next in list*/
     int sock_fd;                             /**< connected unix sock */
-    long id;                                 /**< the id of the peer */
+    int64_t id;                              /**< the id of the peer */
     EventNotifier vectors[IVSHMEM_SERVER_MAX_VECTORS]; /**< one per vector */
     unsigned vectors_count;                  /**< number of vectors */
 } IvshmemServerPeer;
@@ -155,7 +155,7 @@ int ivshmem_server_handle_fds(IvshmemServer *server, fd_set *fds, int maxfd);
  * Returns:  The peer structure, or NULL if not found
  */
 IvshmemServerPeer *
-ivshmem_server_search_peer(IvshmemServer *server, long peer_id);
+ivshmem_server_search_peer(IvshmemServer *server, int64_t peer_id);
 
 /**
  * Dump information of this ivshmem server and its peers on stdout
diff --git a/docs/specs/ivshmem_device_spec.txt b/docs/specs/ivshmem_device_spec.txt
index 3435116b37..d318d65c32 100644
--- a/docs/specs/ivshmem_device_spec.txt
+++ b/docs/specs/ivshmem_device_spec.txt
@@ -61,7 +61,7 @@ This server code is available in qemu.git/contrib/ivshmem-server.
 
 The server must be started on the host before any guest.
 It creates a shared memory object then waits for clients to connect on a unix
-socket.
+socket. All the messages are little-endian int64_t integer.
 
 For each client (QEMU process) that connects to the server:
 - the server sends a protocol version, if client does not support it, the client
diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index e9dae834da..83d7bd3e5f 100644
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -276,7 +276,7 @@ static void ivshmem_receive(void *opaque, const uint8_t *buf, int size)
 
 static int ivshmem_can_receive(void * opaque)
 {
-    return sizeof(long);
+    return sizeof(int64_t);
 }
 
 static void ivshmem_event(void *opaque, int event)
@@ -516,7 +516,7 @@ static bool fifo_update_and_get(IVShmemState *s, const uint8_t *buf, int size,
     const uint8_t *p;
     uint32_t num;
 
-    assert(len <= sizeof(long)); /* limitation of the fifo */
+    assert(len <= sizeof(int64_t)); /* limitation of the fifo */
     if (fifo8_is_empty(&s->incoming_fifo) && size == len) {
         memcpy(data, buf, size);
         return true;
@@ -524,7 +524,7 @@ static bool fifo_update_and_get(IVShmemState *s, const uint8_t *buf, int size,
 
     IVSHMEM_DPRINTF("short read of %d bytes\n", size);
 
-    num = MIN(size, sizeof(long) - fifo8_num_used(&s->incoming_fifo));
+    num = MIN(size, sizeof(int64_t) - fifo8_num_used(&s->incoming_fifo));
     fifo8_push_all(&s->incoming_fifo, buf, num);
 
     if (fifo8_num_used(&s->incoming_fifo) < len) {
@@ -546,6 +546,17 @@ static bool fifo_update_and_get(IVShmemState *s, const uint8_t *buf, int size,
     return true;
 }
 
+static bool fifo_update_and_get_i64(IVShmemState *s,
+                                    const uint8_t *buf, int size, int64_t *i64)
+{
+    if (fifo_update_and_get(s, buf, size, i64, sizeof(*i64))) {
+        *i64 = GINT64_FROM_LE(*i64);
+        return true;
+    }
+
+    return false;
+}
+
 static int ivshmem_add_kvm_msi_virq(IVShmemState *s, int vector)
 {
     PCIDevice *pdev = PCI_DEVICE(s);
@@ -603,23 +614,23 @@ static void ivshmem_read(void *opaque, const uint8_t *buf, int size)
     IVShmemState *s = opaque;
     int incoming_fd;
     int new_eventfd;
-    long incoming_posn;
+    int64_t incoming_posn;
     Error *err = NULL;
     Peer *peer;
 
-    if (!fifo_update_and_get(s, buf, size,
-                             &incoming_posn, sizeof(incoming_posn))) {
+    if (!fifo_update_and_get_i64(s, buf, size, &incoming_posn)) {
         return;
     }
 
     if (incoming_posn < -1) {
-        IVSHMEM_DPRINTF("invalid incoming_posn %ld\n", incoming_posn);
+        IVSHMEM_DPRINTF("invalid incoming_posn %" PRId64 "\n", incoming_posn);
         return;
     }
 
     /* pick off s->server_chr->msgfd and store it, posn should accompany msg */
     incoming_fd = qemu_chr_fe_get_msgfd(s->server_chr);
-    IVSHMEM_DPRINTF("posn is %ld, fd is %d\n", incoming_posn, incoming_fd);
+    IVSHMEM_DPRINTF("posn is %" PRId64 ", fd is %d\n",
+                    incoming_posn, incoming_fd);
 
     /* make sure we have enough space for this peer */
     if (incoming_posn >= s->nb_peers) {
@@ -641,7 +652,7 @@ static void ivshmem_read(void *opaque, const uint8_t *buf, int size)
             s->vm_id = incoming_posn;
         } else {
             /* otherwise an fd == -1 means an existing peer has gone away */
-            IVSHMEM_DPRINTF("posn %ld has gone away\n", incoming_posn);
+            IVSHMEM_DPRINTF("posn %" PRId64 " has gone away\n", incoming_posn);
             close_peer_eventfds(s, incoming_posn);
         }
         return;
@@ -697,7 +708,7 @@ static void ivshmem_read(void *opaque, const uint8_t *buf, int size)
     new_eventfd = peer->nb_eventfds++;
 
     /* this is an eventfd for a particular peer VM */
-    IVSHMEM_DPRINTF("eventfds[%ld][%d] = %d\n", incoming_posn,
+    IVSHMEM_DPRINTF("eventfds[%" PRId64 "][%d] = %d\n", incoming_posn,
                     new_eventfd, incoming_fd);
     event_notifier_init_fd(&peer->eventfds[new_eventfd], incoming_fd);
     fcntl_setfl(incoming_fd, O_NONBLOCK); /* msix/irqfd poll non block */
@@ -715,10 +726,9 @@ static void ivshmem_check_version(void *opaque, const uint8_t * buf, int size)
 {
     IVShmemState *s = opaque;
     int tmp;
-    long version;
+    int64_t version;
 
-    if (!fifo_update_and_get(s, buf, size,
-                             &version, sizeof(version))) {
+    if (!fifo_update_and_get_i64(s, buf, size, &version)) {
         return;
     }
 
@@ -873,7 +883,7 @@ static void pci_ivshmem_realize(PCIDevice *dev, Error **errp)
         s->ivshmem_size = size;
     }
 
-    fifo8_create(&s->incoming_fifo, sizeof(long));
+    fifo8_create(&s->incoming_fifo, sizeof(int64_t));
 
     /* IRQFD requires MSI */
     if (ivshmem_has_feature(s, IVSHMEM_IOEVENTFD) &&