xemu/qemu-timer.h
Jan Kiszka 21d5d12bb0 Introduce QEMU_CLOCK_HOST
Despite its name QEMU_CLOCK_REALTIME is (normally) not using
CLOCK_REALTIME / the host system time as base. In order to allow also
non-trivial RTC emulations (MC146818) to follow the host time instead of
the virtual guest time, introduce the new clock type QEMU_CLOCK_HOST. It
is unconditionally based on CLOCK_REALTIME, thus will follow system time
changes of the host.

The only limitation of its current implementation is that pending
host_clock timers may not fire early if the host time is pushed forward
beyond their expiry. So far no urgent need to overcome this limitation
was identified, so it's left as simple as it is (expiry on next alarm
timer tick).

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-10-05 09:32:45 -05:00

60 lines
2.0 KiB
C

#ifndef QEMU_TIMER_H
#define QEMU_TIMER_H
/* timers */
typedef struct QEMUClock QEMUClock;
typedef void QEMUTimerCB(void *opaque);
/* The real time clock should be used only for stuff which does not
change the virtual machine state, as it is run even if the virtual
machine is stopped. The real time clock has a frequency of 1000
Hz. */
extern QEMUClock *rt_clock;
/* The virtual clock is only run during the emulation. It is stopped
when the virtual machine is stopped. Virtual timers use a high
precision clock, usually cpu cycles (use ticks_per_sec). */
extern QEMUClock *vm_clock;
/* The host clock should be use for device models that emulate accurate
real time sources. It will continue to run when the virtual machine
is suspended, and it will reflect system time changes the host may
undergo (e.g. due to NTP). The host clock has the same precision as
the virtual clock. */
extern QEMUClock *host_clock;
int64_t qemu_get_clock(QEMUClock *clock);
QEMUTimer *qemu_new_timer(QEMUClock *clock, QEMUTimerCB *cb, void *opaque);
void qemu_free_timer(QEMUTimer *ts);
void qemu_del_timer(QEMUTimer *ts);
void qemu_mod_timer(QEMUTimer *ts, int64_t expire_time);
int qemu_timer_pending(QEMUTimer *ts);
int qemu_timer_expired(QEMUTimer *timer_head, int64_t current_time);
static inline int64_t get_ticks_per_sec(void)
{
return 1000000000LL;
}
void qemu_get_timer(QEMUFile *f, QEMUTimer *ts);
void qemu_put_timer(QEMUFile *f, QEMUTimer *ts);
/* ptimer.c */
typedef struct ptimer_state ptimer_state;
typedef void (*ptimer_cb)(void *opaque);
ptimer_state *ptimer_init(QEMUBH *bh);
void ptimer_set_period(ptimer_state *s, int64_t period);
void ptimer_set_freq(ptimer_state *s, uint32_t freq);
void ptimer_set_limit(ptimer_state *s, uint64_t limit, int reload);
uint64_t ptimer_get_count(ptimer_state *s);
void ptimer_set_count(ptimer_state *s, uint64_t count);
void ptimer_run(ptimer_state *s, int oneshot);
void ptimer_stop(ptimer_state *s);
void qemu_put_ptimer(QEMUFile *f, ptimer_state *s);
void qemu_get_ptimer(QEMUFile *f, ptimer_state *s);
#endif