vbox: replace alarm_timer thread with trigger_once

Instead of using the alarm_timer thread we use our own timer thread
that uses a kernel semaphore on Nova. On all other platforms a timer
connection and trigger_once is used.

Fixes #1727.

repos/ports/src/virtualbox/accloff/sup.cc

@@ -16,6 +16,7 @@
 /* Genode includes */
 #include <base/printf.h>
 #include <base/semaphore.h>
+#include <timer_session/connection.h>
 
 /* VirtualBox includes */
 #include <VBox/vmm/vm.h>
@@ -101,6 +102,27 @@ uint64_t genode_cpu_hz() {
 }
 
 
+void genode_update_tsc(void (*update_func)(void), unsigned long update_us)
+{
+	using namespace Genode;
+
+	Timer::Connection timer;
+	Signal_context    sig_ctx;
+	Signal_receiver   sig_rec;
+	Signal_context_capability sig_cap = sig_rec.manage(&sig_ctx);
+
+	timer.sigh(sig_cap);
+	timer.trigger_once(update_us);
+
+	for (;;) {
+		Signal s = sig_rec.wait_for_signal();
+		update_func();
+
+		timer.trigger_once(update_us);
+	}
+}
+
+
 bool Vmm_memory::revoke_from_vm(Region *r)
 {
 	PWRN("%s unimplemented", __func__);

repos/ports/src/virtualbox/spec/nova/sup.cc

@@ -19,6 +19,7 @@
 #include <rom_session/connection.h>
 #include <timer_session/connection.h>
 #include <os/attached_rom_dataspace.h>
+#include <trace/timestamp.h>
 
 #include <vmm/vcpu_thread.h>
 #include <vmm/vcpu_dispatcher.h>
@@ -189,6 +190,32 @@ uint64_t genode_cpu_hz()
 }
 
 
+void genode_update_tsc(void (*update_func)(void), unsigned long update_us)
+{
+	using namespace Genode;
+	using namespace Nova;
+
+	enum { TSC_FACTOR = 1000ULL };
+
+	Genode::addr_t sem = Thread_base::myself()->tid().exc_pt_sel + Nova::SM_SEL_EC;
+	unsigned long tsc_khz = (genode_cpu_hz() / 1000) / TSC_FACTOR;
+
+	Trace::Timestamp us_64 = update_us;
+
+	for (;;) {
+		update_func();
+
+		Trace::Timestamp now = Trace::timestamp();
+
+		/* block until timeout fires or it gets canceled */
+		unsigned long long tsc_absolute = now + us_64 * tsc_khz;
+		Genode::uint8_t res = sm_ctrl(sem, SEMAPHORE_DOWN, tsc_absolute);
+		if (res != Nova::NOVA_OK && res != Nova::NOVA_TIMEOUT)
+			nova_die();
+	}
+}
+
+
 bool Vmm_memory::revoke_from_vm(Region *r)
 {
 	Assert(r);

repos/ports/src/virtualbox/sup.cc

@@ -39,8 +39,7 @@ struct Attached_gip : Genode::Attached_ram_dataspace
 
 
 enum {
-	UPDATE_HZ  = 100,                     /* Hz */
-	/* Note: UPDATE_MS < 10ms is not supported by alarm timer, take care !*/
+	UPDATE_HZ  = 1000,
 	UPDATE_MS  = 1000 / UPDATE_HZ,
 	UPDATE_NS  = UPDATE_MS * 1000 * 1000,
 };
@@ -49,9 +48,11 @@ enum {
 PSUPGLOBALINFOPAGE g_pSUPGlobalInfoPage;
 
 
-class Periodic_GIP : public Genode::Alarm {
+struct Periodic_gip : public Genode::Thread<4096>
+{
+	Periodic_gip() : Thread("periodic_gip") { start(); }
 
-	bool on_alarm(unsigned) override
+	static void update()
 	{
 		/**
 		 * We're using rdtsc here since timer_session->elapsed_ms produces
@@ -98,11 +99,10 @@ class Periodic_GIP : public Genode::Alarm {
 		 * read struct SUPGIPCPU description for more details.
 		 */
 		ASMAtomicIncU32(&cpu->u32TransactionId);
-
-		return true;
 	}
-};
 
+	void entry() override { genode_update_tsc(update, UPDATE_MS * 1000); }
+};
 
 
 int SUPR3Init(PSUPDRVSESSION *ppSession)
@@ -149,8 +149,7 @@ int SUPR3Init(PSUPDRVSESSION *ppSession)
 	cpu->idApic                  = 0;
 
 	/* schedule periodic call of GIP update function */
-	static Periodic_GIP alarm;
-	Genode::Timeout_thread::alarm_timer()->schedule(&alarm, UPDATE_MS);
+	static Periodic_gip periodic_gip;
 
 	initialized = true;
 

repos/ports/src/virtualbox/sup.h

@@ -35,6 +35,7 @@ bool create_emt_vcpu(pthread_t * pthread, size_t stack,
 
 
 uint64_t genode_cpu_hz();
+void genode_update_tsc(void (*update_func)(void), unsigned long update_us);
 
 Genode::Cpu_session * get_vcpu_cpu_session();