acrn-hypervisor/devicemodel/core/timer.c

148 lines
3.0 KiB
C

/*
* Copyright (C) 2018-2022 Intel Corporation.
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <stdio.h>
#include <stdbool.h>
#include <unistd.h>
#include <errno.h>
#include <sys/timerfd.h>
#include "vmmapi.h"
#include "mevent.h"
#include "timer.h"
#include "log.h"
/* We can use timerfd and epoll mechanism to emulate kinds of timers like
* PIT/RTC/WDT/PMTIMER/... in device model under Linux.
* Compare with sigevent mechanism, timerfd has a advantage that it could
* avoid race condition on resource accessing in the async sigev thread.
*
* Please note timerfd and epoll are all Linux specific. If the code need to be
* ported to other OS, we can modify the api with POSIX timers and sigevent
* mechanism.
*/
static void
timer_handler(int fd __attribute__((unused)),
enum ev_type t __attribute__((unused)),
void *arg)
{
struct acrn_timer *timer = arg;
uint64_t nexp;
ssize_t size;
void (*cb)(void *, uint64_t);
if (timer == NULL) {
return;
}
/* Consume I/O event for default EPOLLLT type.
* Here is a temporary solution, the processing could be moved to
* mevent.c once EVF_TIMER is supported.
*/
size = read(timer->fd, &nexp, sizeof(nexp));
if (size < 0) {
if (errno != EAGAIN) {
pr_err("acrn_timer read timerfd error");
}
return;
}
/* check the validity of timer expiration. */
if ((size == 0) || (nexp == 0))
return;
if ((cb = timer->callback) != NULL) {
(*cb)(timer->callback_param, nexp);
}
}
int32_t
acrn_timer_init(struct acrn_timer *timer, void (*cb)(void *, uint64_t),
void *param)
{
if ((timer == NULL) || (cb == NULL)) {
return -1;
}
timer->fd = -1;
if ((timer->clockid == CLOCK_REALTIME) ||
(timer->clockid == CLOCK_MONOTONIC)) {
timer->fd = timerfd_create(timer->clockid,
TFD_NONBLOCK | TFD_CLOEXEC);
} else {
pr_err("acrn_timer clockid is not supported.\n");
}
if (timer->fd <= 0) {
pr_err("acrn_timer create failed.\n");
return -1;
}
timer->mevp = mevent_add(timer->fd, EVF_READ, timer_handler, timer, NULL, NULL);
if (timer->mevp == NULL) {
close(timer->fd);
pr_err("acrn_timer mevent add failed.\n");
return -1;
}
timer->callback = cb;
timer->callback_param = param;
return 0;
}
void
acrn_timer_deinit(struct acrn_timer *timer)
{
if (timer == NULL) {
return;
}
if (timer->mevp != NULL) {
mevent_delete_close(timer->mevp);
timer->mevp = NULL;
}
timer->fd = -1;
timer->callback = NULL;
timer->callback_param = NULL;
}
int32_t
acrn_timer_settime(struct acrn_timer *timer, const struct itimerspec *new_value)
{
if (timer == NULL) {
errno = EINVAL;
return -1;
}
return timerfd_settime(timer->fd, 0, new_value, NULL);
}
int32_t
acrn_timer_settime_abs(struct acrn_timer *timer,
const struct itimerspec *new_value)
{
if (timer == NULL) {
errno = EINVAL;
return -1;
}
return timerfd_settime(timer->fd, TFD_TIMER_ABSTIME, new_value, NULL);
}
int32_t
acrn_timer_gettime(struct acrn_timer *timer, struct itimerspec *cur_value)
{
if (timer == NULL) {
errno = EINVAL;
return -1;
}
return timerfd_gettime(timer->fd, cur_value);
}