qdev: Introduce lost tick policy property
Potentially tick-generating timer devices will gain a common property:
lock_tick_policy. It allows to encode 4 different ways how to deal with
tick events the guest did not process in time:
discard - ignore lost ticks (e.g. if the guest compensates for them
already)
delay - replay all lost ticks in a row once the guest accepts them
again
merge - if multiple ticks are lost, all of them are merged into one
which is replayed once the guest accepts it again
slew - lost ticks are gradually replayed at a higher frequency than
the original tick
Not all timer device will need to support all modes. However, all need
to accept the configuration via this common property.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/hw/qdev-properties.c b/hw/qdev-properties.c
index c98219a..028bee7 100644
--- a/hw/qdev-properties.c
+++ b/hw/qdev-properties.c
@@ -885,6 +885,55 @@
.set = set_generic,
};
+
+/* --- lost tick policy --- */
+
+static const struct {
+ const char *name;
+ LostTickPolicy code;
+} lost_tick_policy_table[] = {
+ { .name = "discard", .code = LOST_TICK_DISCARD },
+ { .name = "delay", .code = LOST_TICK_DELAY },
+ { .name = "merge", .code = LOST_TICK_MERGE },
+ { .name = "slew", .code = LOST_TICK_SLEW },
+};
+
+static int parse_lost_tick_policy(DeviceState *dev, Property *prop,
+ const char *str)
+{
+ LostTickPolicy *ptr = qdev_get_prop_ptr(dev, prop);
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(lost_tick_policy_table); i++) {
+ if (!strcasecmp(str, lost_tick_policy_table[i].name)) {
+ *ptr = lost_tick_policy_table[i].code;
+ break;
+ }
+ }
+ if (i == ARRAY_SIZE(lost_tick_policy_table)) {
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static int print_lost_tick_policy(DeviceState *dev, Property *prop, char *dest,
+ size_t len)
+{
+ LostTickPolicy *ptr = qdev_get_prop_ptr(dev, prop);
+
+ return snprintf(dest, len, "%s", lost_tick_policy_table[*ptr].name);
+}
+
+PropertyInfo qdev_prop_losttickpolicy = {
+ .name = "lost_tick_policy",
+ .type = PROP_TYPE_LOSTTICKPOLICY,
+ .size = sizeof(LostTickPolicy),
+ .parse = parse_lost_tick_policy,
+ .print = print_lost_tick_policy,
+ .get = get_generic,
+ .set = set_generic,
+};
+
/* --- pci address --- */
/*
@@ -1127,6 +1176,12 @@
qdev_prop_set(dev, name, value, PROP_TYPE_MACADDR);
}
+void qdev_prop_set_losttickpolicy(DeviceState *dev, const char *name,
+ LostTickPolicy *value)
+{
+ qdev_prop_set(dev, name, value, PROP_TYPE_LOSTTICKPOLICY);
+}
+
void qdev_prop_set_ptr(DeviceState *dev, const char *name, void *value)
{
qdev_prop_set(dev, name, &value, PROP_TYPE_PTR);