1 /* 2 * QEMU coroutine sleep 3 * 4 * Copyright IBM, Corp. 2011 5 * 6 * Authors: 7 * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> 8 * 9 * This work is licensed under the terms of the GNU LGPL, version 2 or later. 10 * See the COPYING.LIB file in the top-level directory. 11 * 12 */ 13 14 #include "qemu/osdep.h" 15 #include "qemu/coroutine.h" 16 #include "qemu/coroutine_int.h" 17 #include "qemu/timer.h" 18 #include "block/aio.h" 19 20 static const char *qemu_co_sleep_ns__scheduled = "qemu_co_sleep_ns"; 21 22 struct QemuCoSleepState { 23 Coroutine *co; 24 QEMUTimer *ts; 25 QemuCoSleepState **user_state_pointer; 26 }; 27 28 void qemu_co_sleep_wake(QemuCoSleepState *sleep_state) 29 { 30 /* Write of schedule protected by barrier write in aio_co_schedule */ 31 const char *scheduled = qatomic_cmpxchg(&sleep_state->co->scheduled, 32 qemu_co_sleep_ns__scheduled, NULL); 33 34 assert(scheduled == qemu_co_sleep_ns__scheduled); 35 if (sleep_state->user_state_pointer) { 36 *sleep_state->user_state_pointer = NULL; 37 } 38 timer_del(sleep_state->ts); 39 aio_co_wake(sleep_state->co); 40 } 41 42 static void co_sleep_cb(void *opaque) 43 { 44 qemu_co_sleep_wake(opaque); 45 } 46 47 void coroutine_fn qemu_co_sleep_ns_wakeable(QEMUClockType type, int64_t ns, 48 QemuCoSleepState **sleep_state) 49 { 50 AioContext *ctx = qemu_get_current_aio_context(); 51 QemuCoSleepState state = { 52 .co = qemu_coroutine_self(), 53 .ts = aio_timer_new(ctx, type, SCALE_NS, co_sleep_cb, &state), 54 .user_state_pointer = sleep_state, 55 }; 56 57 const char *scheduled = qatomic_cmpxchg(&state.co->scheduled, NULL, 58 qemu_co_sleep_ns__scheduled); 59 if (scheduled) { 60 fprintf(stderr, 61 "%s: Co-routine was already scheduled in '%s'\n", 62 __func__, scheduled); 63 abort(); 64 } 65 66 if (sleep_state) { 67 *sleep_state = &state; 68 } 69 timer_mod(state.ts, qemu_clock_get_ns(type) + ns); 70 qemu_coroutine_yield(); 71 if (sleep_state) { 72 /* 73 * Note that *sleep_state is cleared during qemu_co_sleep_wake 74 * before resuming this coroutine. 75 */ 76 assert(*sleep_state == NULL); 77 } 78 timer_free(state.ts); 79 } 80