main-loop: remove qemu_fd_register(), win32/slirp/socket specific

Open-code the socket registration where it's needed, to avoid
artificially used or unclear generic interface.

Furthermore, the following patches are going to make socket handling use
FD-only inside QEMU, but we need to handle win32 SOCKET from libslirp.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Message-Id: <20230221124802.4103554-12-marcandre.lureau@redhat.com>

include/qemu/main-loop.h

@@ -387,8 +387,6 @@ void qemu_cond_timedwait_iothread(QemuCond *cond, int ms);
 
 /* internal interfaces */
 
-void qemu_fd_register(int fd);
-
 #define qemu_bh_new(cb, opaque) \
     qemu_bh_new_full((cb), (opaque), (stringify(cb)))
 QEMUBH *qemu_bh_new_full(QEMUBHFunc *cb, void *opaque, const char *name);

net/slirp.c

@@ -248,7 +248,13 @@ static void net_slirp_timer_mod(void *timer, int64_t expire_timer,
 
 static void net_slirp_register_poll_fd(int fd, void *opaque)
 {
-    qemu_fd_register(fd);
+#ifdef WIN32
+    AioContext *ctxt = qemu_get_aio_context();
+
+    qemu_socket_select(fd, event_notifier_get_handle(&ctxt->notifier),
+                       FD_READ | FD_ACCEPT | FD_CLOSE |
+                       FD_CONNECT | FD_WRITE | FD_OOB, NULL);
+#endif
 }
 
 static void net_slirp_unregister_poll_fd(int fd, void *opaque)

util/main-loop.c

@@ -252,10 +252,6 @@ static int max_priority;
 static int glib_pollfds_idx;
 static int glib_n_poll_fds;
 
-void qemu_fd_register(int fd)
-{
-}
-
 static void glib_pollfds_fill(int64_t *cur_timeout)
 {
     GMainContext *context = g_main_context_default();
@@ -414,13 +410,6 @@ void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
     }
 }
 
-void qemu_fd_register(int fd)
-{
-    qemu_socket_select(fd, event_notifier_get_handle(&qemu_aio_context->notifier),
-                       FD_READ | FD_ACCEPT | FD_CLOSE |
-                       FD_CONNECT | FD_WRITE | FD_OOB, NULL);
-}
-
 static int pollfds_fill(GArray *pollfds, fd_set *rfds, fd_set *wfds,
                         fd_set *xfds)
 {