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hv: vrtc calibrate function

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For TSC's precision (20~100ppm) is lower than physical RTC (less than 20ppm),
vRTC need to be calibrated by physical RTC. A timer tiggers calibration for
vRTC every 3 hours. This can improve efficiency because physical RTC can be
read once and calibrate all vRTC.

Tracked-On: #7440
Signed-off-by: Yuanyuan Zhao <yuanyuan.zhao@linux.intel.com>
Reviewed-by: Junjie Mao <junjie.mao@intel.com>
This commit is contained in:
Yuanyuan Zhao 2022-04-25 20:03:42 +08:00 committed by acrnsi-robot
parent 08e8161f51
commit 4bad719fd3
1 changed files with 77 additions and 3 deletions
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80
hypervisor/dm/vrtc.c
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@ -50,6 +50,8 @@ struct clktime {
uint32_t dow; /* day of week (0 - 6; 0 = Sunday) */
};
static spinlock_t vrtc_rebase_lock = { .head = 0U, .tail = 0U };
#define POSIX_BASE_YEAR 1970
#define SECDAY (24 * 60 * 60)
#define SECYR (SECDAY * 365)
@ -377,10 +379,12 @@ static time_t vrtc_get_current_time(struct acrn_vrtc *vrtc)
uint64_t offset;
time_t second = VRTC_BROKEN_TIME;
spinlock_obtain(&vrtc_rebase_lock);
if (vrtc->base_rtctime > 0) {
offset = (cpu_ticks() - vrtc->base_tsc) / (get_tsc_khz() * 1000U);
second = vrtc->base_rtctime + vrtc->offset_rtctime + (time_t)offset;
}
spinlock_release(&vrtc_rebase_lock);
return second;
}
@ -565,7 +569,9 @@ static bool vrtc_write(struct acrn_vcpu *vcpu, uint16_t addr, size_t width,
*((uint8_t *)&vrtc->rtcdev + vrtc->addr) = (uint8_t)(value & mask);
current = vrtc_get_current_time(vrtc);
after = rtc_to_secs(vrtc);
spinlock_obtain(&vrtc_rebase_lock);
vrtc->offset_rtctime += after - current;
spinlock_release(&vrtc_rebase_lock);
break;
}
}
@ -574,9 +580,70 @@ static bool vrtc_write(struct acrn_vcpu *vcpu, uint16_t addr, size_t width,
return true;
}
#define CALIBRATE_PERIOD (3 * 3600 * 1000) /* By ms, totally 3 hours. */
static struct hv_timer calibrate_timer;
static time_t vrtc_get_physical_rtc_time(struct acrn_vrtc *vrtc)
{
struct rtcdev *vrtcdev = &vrtc->rtcdev;
vrtcdev->sec = cmos_get_reg_val(RTC_SEC);
vrtcdev->min = cmos_get_reg_val(RTC_MIN);
vrtcdev->hour = cmos_get_reg_val(RTC_HRS);
vrtcdev->day_of_month = cmos_get_reg_val(RTC_DAY);
vrtcdev->month = cmos_get_reg_val(RTC_MONTH);
vrtcdev->year = cmos_get_reg_val(RTC_YEAR);
vrtcdev->century = cmos_get_reg_val(RTC_CENTURY);
vrtcdev->reg_b = cmos_get_reg_val(RTC_STATUSB);
return rtc_to_secs(vrtc);
}
static void vrtc_update_basetime(time_t physical_time, time_t offset)
{
struct acrn_vm *vm;
uint32_t vm_id;
for (vm_id = 0U; vm_id < CONFIG_MAX_VM_NUM; vm_id++) {
vm = get_vm_from_vmid(vm_id);
if (is_rt_vm(vm) || is_prelaunched_vm(vm)) {
spinlock_obtain(&vrtc_rebase_lock);
vm->vrtc.base_tsc = cpu_ticks();
vm->vrtc.base_rtctime = physical_time;
vm->vrtc.offset_rtctime += offset;
spinlock_release(&vrtc_rebase_lock);
}
}
}
static void calibrate_timer_callback(__unused void *data)
{
struct acrn_vrtc temp_vrtc;
time_t physical_time = vrtc_get_physical_rtc_time(&temp_vrtc);
vrtc_update_basetime(physical_time, 0);
}
static void calibrate_setup_timer(void)
{
uint64_t period_in_cycle, fire_tsc;
period_in_cycle = TICKS_PER_MS * CALIBRATE_PERIOD;
fire_tsc = cpu_ticks() + period_in_cycle;
initialize_timer(&calibrate_timer,
calibrate_timer_callback, NULL,
fire_tsc, period_in_cycle);
/* Start an periodic timer */
if (add_timer(&calibrate_timer) != 0) {
pr_err("Failed to add calibrate timer");
}
}
static void vrtc_set_basetime(struct acrn_vrtc *vrtc)
{
struct rtcdev *vrtcdev = &vrtc->rtcdev;
time_t current;
/*
* Read base time from physical rtc.
@ -593,7 +660,10 @@ static void vrtc_set_basetime(struct acrn_vrtc *vrtc)
vrtcdev->reg_c = cmos_get_reg_val(RTC_INTR);
vrtcdev->reg_d = cmos_get_reg_val(RTC_STATUSD);
vrtc->base_rtctime = rtc_to_secs(vrtc);
current = rtc_to_secs(vrtc);
spinlock_obtain(&vrtc_rebase_lock);
vrtc->base_rtctime = current;
spinlock_release(&vrtc_rebase_lock);
}
void vrtc_init(struct acrn_vm *vm)
@ -607,6 +677,10 @@ void vrtc_init(struct acrn_vm *vm)
vm->vrtc.vm = vm;
register_pio_emulation_handler(vm, RTC_PIO_IDX, &range, vrtc_read, vrtc_write);
vrtc_set_basetime(&vm->vrtc);
vm->vrtc.base_tsc = cpu_ticks();
if (is_service_vm(vm)) {
calibrate_setup_timer();
} else {
vrtc_set_basetime(&vm->vrtc);
vm->vrtc.base_tsc = cpu_ticks();
}
}