hv: timer: add periodic timer setup support

and add MIN_TIMER_PERIOD_US for limit periodic timer frequency.
Now it's set to 500 us.

Signed-off-by: Li, Fei1 <fei1.li@intel.com>

hypervisor/arch/x86/guest/vlapic.c

@@ -1576,7 +1576,7 @@ vlapic_reset(struct vlapic *vlapic)
 
 	vlapic->svr_last = lapic->svr;
 
-	initialize_timer(&vlapic->timer, NULL, NULL, 0);
+	initialize_timer(&vlapic->timer, NULL, NULL, 0, 0, 0);
 }
 
 void
@@ -1974,7 +1974,7 @@ vlapic_wrmsr(struct vcpu *vcpu, uint32_t msr, uint64_t val)
 
 			initialize_timer(&vlapic->timer,
 					tsc_periodic_time, (void *)vcpu,
-					val);
+					val, TICK_MODE_ONESHOT, 0);
 
 			if (add_timer(&vlapic->timer) != 0) {
 				pr_err("failed to add timer on VM %d",

hypervisor/arch/x86/timer.c

@@ -37,6 +37,7 @@
 #define MAX_TIMER_ACTIONS	32
 #define TIMER_IRQ		(NR_MAX_IRQS - 1)
 #define CAL_MS			10
+#define MIN_TIMER_PERIOD_US	500
 
 uint64_t tsc_hz = 1000000000;
 
@@ -228,6 +229,12 @@ int timer_softirq(int pcpu_id)
 
 		run_timer(timer);
 
+		if (timer->mode == TICK_MODE_PERIODIC) {
+			timer->fire_tsc += max(timer->period_in_cycle,
+					US_TO_TICKS(MIN_TIMER_PERIOD_US));
+			add_timer(timer);
+		}
+
 		/* search next one */
 		timer = find_expired_timer(cpu_timer, rdtsc());
 	}

hypervisor/debug/console.c

@@ -221,23 +221,21 @@ static int console_timer_callback(__unused void *data)
 	/* Kick HV-Shell and Uart-Console tasks */
 	console_handler();
 
-	/* Restart the timer */
-	console_setup_timer();
-
 	return 0;
 }
 
 void console_setup_timer(void)
 {
 	static struct timer console_timer;
-	uint64_t fire_tsc;
+	uint64_t period_in_cycle, fire_tsc;
 
-	fire_tsc = rdtsc() + CYCLES_PER_MS * CONSOLE_KICK_TIMER_TIMEOUT;
+	period_in_cycle = CYCLES_PER_MS * CONSOLE_KICK_TIMER_TIMEOUT;
+	fire_tsc = rdtsc() + period_in_cycle;
 	initialize_timer(&console_timer,
 			console_timer_callback, NULL,
-			fire_tsc);
+			fire_tsc, TICK_MODE_PERIODIC, period_in_cycle);
 
-	/* Start an one-shot timer */
+	/* Start an periodic timer */
 	if (add_timer(&console_timer) != 0)
 		pr_err("Failed to add console kick timer");
 }

hypervisor/include/arch/x86/timer.h

@@ -33,9 +33,17 @@
 
 typedef int (*timer_handle_t)(void *);
 
+enum tick_mode {
+	TICK_MODE_ONESHOT = 0,
+	TICK_MODE_PERIODIC,
+};
+
+
 struct timer {
 	struct list_head node;		/* link all timers */
+	int mode;			/* timer mode: one-shot or periodic */
 	uint64_t fire_tsc;		/* tsc deadline to interrupt */
+	uint64_t period_in_cycle;	/* period of the periodic timer in unit of TSC cycles */
 	timer_handle_t func;		/* callback if time reached */
 	void *priv_data;		/* func private data */
 };
@@ -43,12 +51,16 @@ struct timer {
 static inline void initialize_timer(struct timer *timer,
 				timer_handle_t func,
 				void *priv_data,
-				uint64_t fire_tsc)
+				uint64_t fire_tsc,
+				int mode,
+				uint64_t period_in_cycle)
 {
 	if (timer) {
 		timer->func = func;
 		timer->priv_data = priv_data;
 		timer->fire_tsc = fire_tsc;
+		timer->mode = mode;
+		timer->period_in_cycle = period_in_cycle;
 	}
 }