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hpet: fix and cleanup persistence of interrupt status 

There are several bugs in the handling of the ISR register:

- switching level->edge was not lowering the interrupt and
  clearing ISR

- switching on the enable bit was not raising a level-triggered
  interrupt if the timer had fired

- the timer must be kept running even if not enabled, in
  order to set the ISR flag, so writes to HPET_TN_CFG must
  not call hpet_del_timer()

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2024-07-16 11:36:44 +02:00
parent 0418f90809
commit f0ccf77078
1 changed files with 41 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

60
hw/timer/hpet.c
View File

@ -196,21 +196,31 @@ static void update_irq(struct HPETTimer *timer, int set)
}
s = timer->state;
mask = 1 << timer->tn;
if (!set || !timer_enabled(timer) || !hpet_enabled(timer->state)) {
if (set && (timer->config & HPET_TN_TYPE_LEVEL)) {
/*
* If HPET_TN_ENABLE bit is 0, "the timer will still operate and
* generate appropriate status bits, but will not cause an interrupt"
*/
s->isr |= mask;
} else {
s->isr &= ~mask;
}
if (set && timer_enabled(timer) && hpet_enabled(s)) {
if (timer_fsb_route(timer)) {
address_space_stl_le(&address_space_memory, timer->fsb >> 32,
timer->fsb & 0xffffffff, MEMTXATTRS_UNSPECIFIED,
NULL);
} else if (timer->config & HPET_TN_TYPE_LEVEL) {
qemu_irq_raise(s->irqs[route]);
} else {
qemu_irq_pulse(s->irqs[route]);
}
} else {
if (!timer_fsb_route(timer)) {
qemu_irq_lower(s->irqs[route]);
}
} else if (timer_fsb_route(timer)) {
address_space_stl_le(&address_space_memory, timer->fsb >> 32,
timer->fsb & 0xffffffff, MEMTXATTRS_UNSPECIFIED,
NULL);
} else if (timer->config & HPET_TN_TYPE_LEVEL) {
s->isr |= mask;
qemu_irq_raise(s->irqs[route]);
} else {
s->isr &= ~mask;
qemu_irq_pulse(s->irqs[route]);
}
}
@ -414,8 +424,13 @@ static void hpet_set_timer(HPETTimer *t)
static void hpet_del_timer(HPETTimer *t)
{
HPETState *s = t->state;
timer_del(t->qemu_timer);
update_irq(t, 0);
if (s->isr & (1 << t->tn)) {
/* For level-triggered interrupt, this leaves ISR set but lowers irq. */
update_irq(t, 1);
}
}
static uint64_t hpet_ram_read(void *opaque, hwaddr addr,
@ -515,20 +530,26 @@ static void hpet_ram_write(void *opaque, hwaddr addr,
switch ((addr - 0x100) % 0x20) {
case HPET_TN_CFG:
trace_hpet_ram_write_tn_cfg();
if (activating_bit(old_val, new_val, HPET_TN_FSB_ENABLE)) {
if (deactivating_bit(old_val, new_val, HPET_TN_TYPE_LEVEL)) {
/*
* Do this before changing timer->config; otherwise, if
* HPET_TN_FSB is set, update_irq will not lower the qemu_irq.
*/
update_irq(timer, 0);
}
val = hpet_fixup_reg(new_val, old_val, HPET_TN_CFG_WRITE_MASK);
timer->config = (timer->config & 0xffffffff00000000ULL) | val;
if (activating_bit(old_val, new_val, HPET_TN_ENABLE)
&& (s->isr & (1 << timer_id))) {
update_irq(timer, 1);
}
if (new_val & HPET_TN_32BIT) {
timer->cmp = (uint32_t)timer->cmp;
timer->period = (uint32_t)timer->period;
}
if (activating_bit(old_val, new_val, HPET_TN_ENABLE) &&
hpet_enabled(s)) {
if (hpet_enabled(s)) {
hpet_set_timer(timer);
} else if (deactivating_bit(old_val, new_val, HPET_TN_ENABLE)) {
hpet_del_timer(timer);
}
break;
case HPET_TN_CFG + 4: // Interrupt capabilities
@ -606,9 +627,10 @@ static void hpet_ram_write(void *opaque, hwaddr addr,
s->hpet_offset =
ticks_to_ns(s->hpet_counter) - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
for (i = 0; i < s->num_timers; i++) {
if ((&s->timer[i])->cmp != ~0ULL) {
hpet_set_timer(&s->timer[i]);
if (timer_enabled(&s->timer[i]) && (s->isr & (1 << i))) {
update_irq(&s->timer[i], 1);
}
hpet_set_timer(&s->timer[i]);
}
} else if (deactivating_bit(old_val, new_val, HPET_CFG_ENABLE)) {
/* Halt main counter and disable interrupt generation. */