*
* This code is licensed under the GNU LGPL.
*/
+
#include "qemu/osdep.h"
-#include "hw/hw.h"
#include "qemu/timer.h"
#include "hw/ptimer.h"
+#include "migration/vmstate.h"
#include "qemu/host-utils.h"
#include "sysemu/replay.h"
#include "sysemu/qtest.h"
#include "block/aio.h"
+#include "sysemu/cpus.h"
#define DELTA_ADJUST 1
#define DELTA_NO_ADJUST -1
int64_t last_event;
int64_t next_event;
uint8_t policy_mask;
- QEMUBH *bh;
QEMUTimer *timer;
+ ptimer_cb callback;
+ void *callback_opaque;
+ /*
+ * These track whether we're in a transaction block, and if we
+ * need to do a timer reload when the block finishes. They don't
+ * need to be migrated because migration can never happen in the
+ * middle of a transaction block.
+ */
+ bool in_transaction;
+ bool need_reload;
};
/* Use a bottom-half routine to avoid reentrancy issues. */
static void ptimer_trigger(ptimer_state *s)
{
- if (s->bh) {
- replay_bh_schedule_event(s->bh);
- }
+ s->callback(s->callback_opaque);
}
static void ptimer_reload(ptimer_state *s, int delta_adjust)
{
- uint32_t period_frac = s->period_frac;
- uint64_t period = s->period;
- uint64_t delta = s->delta;
+ uint32_t period_frac;
+ uint64_t period;
+ uint64_t delta;
+ bool suppress_trigger = false;
- if (delta == 0 && !(s->policy_mask & PTIMER_POLICY_NO_IMMEDIATE_TRIGGER)) {
+ /*
+ * Note that if delta_adjust is 0 then we must be here because of
+ * a count register write or timer start, not because of timer expiry.
+ * In that case the policy might require us to suppress the timer trigger
+ * that we would otherwise generate for a zero delta.
+ */
+ if (delta_adjust == 0 &&
+ (s->policy_mask & PTIMER_POLICY_TRIGGER_ONLY_ON_DECREMENT)) {
+ suppress_trigger = true;
+ }
+ if (s->delta == 0 && !(s->policy_mask & PTIMER_POLICY_NO_IMMEDIATE_TRIGGER)
+ && !suppress_trigger) {
ptimer_trigger(s);
}
+ /*
+ * Note that ptimer_trigger() might call the device callback function,
+ * which can then modify timer state, so we must not cache any fields
+ * from ptimer_state until after we have called it.
+ */
+ delta = s->delta;
+ period = s->period;
+ period_frac = s->period_frac;
+
if (delta == 0 && !(s->policy_mask & PTIMER_POLICY_NO_IMMEDIATE_RELOAD)) {
delta = s->delta = s->limit;
}
ptimer_state *s = (ptimer_state *)opaque;
bool trigger = true;
+ /*
+ * We perform all the tick actions within a begin/commit block
+ * because the callback function that ptimer_trigger() calls
+ * might make calls into the ptimer APIs that provoke another
+ * trigger, and we want that to cause the callback function
+ * to be called iteratively, not recursively.
+ */
+ ptimer_transaction_begin(s);
+
if (s->enabled == 2) {
s->delta = 0;
s->enabled = 0;
if (trigger) {
ptimer_trigger(s);
}
+
+ ptimer_transaction_commit(s);
}
uint64_t ptimer_get_count(ptimer_state *s)
void ptimer_set_count(ptimer_state *s, uint64_t count)
{
+ assert(s->in_transaction);
s->delta = count;
if (s->enabled) {
- s->next_event = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
- ptimer_reload(s, 0);
+ s->need_reload = true;
}
}
{
bool was_disabled = !s->enabled;
+ assert(s->in_transaction);
+
if (was_disabled && s->period == 0) {
if (!qtest_enabled()) {
fprintf(stderr, "Timer with period zero, disabling\n");
}
s->enabled = oneshot ? 2 : 1;
if (was_disabled) {
- s->next_event = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
- ptimer_reload(s, 0);
+ s->need_reload = true;
}
}
is immediately restarted. */
void ptimer_stop(ptimer_state *s)
{
+ assert(s->in_transaction);
+
if (!s->enabled)
return;
s->delta = ptimer_get_count(s);
timer_del(s->timer);
s->enabled = 0;
+ s->need_reload = false;
}
/* Set counter increment interval in nanoseconds. */
void ptimer_set_period(ptimer_state *s, int64_t period)
{
+ assert(s->in_transaction);
s->delta = ptimer_get_count(s);
s->period = period;
s->period_frac = 0;
if (s->enabled) {
- s->next_event = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
- ptimer_reload(s, 0);
+ s->need_reload = true;
}
}
/* Set counter frequency in Hz. */
void ptimer_set_freq(ptimer_state *s, uint32_t freq)
{
+ assert(s->in_transaction);
s->delta = ptimer_get_count(s);
s->period = 1000000000ll / freq;
s->period_frac = (1000000000ll << 32) / freq;
if (s->enabled) {
- s->next_event = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
- ptimer_reload(s, 0);
+ s->need_reload = true;
}
}
count = limit. */
void ptimer_set_limit(ptimer_state *s, uint64_t limit, int reload)
{
+ assert(s->in_transaction);
s->limit = limit;
if (reload)
s->delta = limit;
if (s->enabled && reload) {
- s->next_event = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
- ptimer_reload(s, 0);
+ s->need_reload = true;
}
}
return s->limit;
}
+void ptimer_transaction_begin(ptimer_state *s)
+{
+ assert(!s->in_transaction);
+ s->in_transaction = true;
+ s->need_reload = false;
+}
+
+void ptimer_transaction_commit(ptimer_state *s)
+{
+ assert(s->in_transaction);
+ /*
+ * We must loop here because ptimer_reload() can call the callback
+ * function, which might then update ptimer state in a way that
+ * means we need to do another reload and possibly another callback.
+ * A disabled timer never needs reloading (and if we don't check
+ * this then we loop forever if ptimer_reload() disables the timer).
+ */
+ while (s->need_reload && s->enabled) {
+ s->need_reload = false;
+ s->next_event = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+ ptimer_reload(s, 0);
+ }
+ /* Now we've finished reload we can leave the transaction block. */
+ s->in_transaction = false;
+}
+
const VMStateDescription vmstate_ptimer = {
.name = "ptimer",
.version_id = 1,
}
};
-ptimer_state *ptimer_init(QEMUBH *bh, uint8_t policy_mask)
+ptimer_state *ptimer_init(ptimer_cb callback, void *callback_opaque,
+ uint8_t policy_mask)
{
ptimer_state *s;
- s = (ptimer_state *)g_malloc0(sizeof(ptimer_state));
- s->bh = bh;
+ /* The callback function is mandatory. */
+ assert(callback);
+
+ s = g_new0(ptimer_state, 1);
s->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, ptimer_tick, s);
s->policy_mask = policy_mask;
+ s->callback = callback;
+ s->callback_opaque = callback_opaque;
+
+ /*
+ * These two policies are incompatible -- trigger-on-decrement implies
+ * a timer trigger when the count becomes 0, but no-immediate-trigger
+ * implies a trigger when the count stops being 0.
+ */
+ assert(!((policy_mask & PTIMER_POLICY_TRIGGER_ONLY_ON_DECREMENT) &&
+ (policy_mask & PTIMER_POLICY_NO_IMMEDIATE_TRIGGER)));
return s;
}
void ptimer_free(ptimer_state *s)
{
- qemu_bh_delete(s->bh);
timer_free(s->timer);
g_free(s);
}
projects / qemu.git / blobdiff