import xen 32 bit paravirtual kernel from /n/sources/xen.

1 files changed, 136 insertions, 0 deletions

diff --git a/sys/src/9/xen/xentimer.c b/sys/src/9/xen/xentimer.c
new file mode 100644
index 000000000..2a57cc5b9
--- /dev/null
+++ b/sys/src/9/xen/xentimer.c
@@ -0,0 +1,136 @@
+#include "u.h"
+#include "../port/lib.h"
+#include "mem.h"
+#include "dat.h"
+#include "fns.h"
+#include "io.h"
+
+static vcpu_time_info_t shadow[MAX_VIRT_CPUS];		// XXX should be in Mach
+static ulong wallclock;
+static ulong wallclocksystime;
+
+/*
+ * Return a consistent set of time parameters.
+ */
+static vcpu_time_info_t *
+getshadow(void)
+{
+	vcpu_time_info_t *s, *t;
+
+	t = &HYPERVISOR_shared_info->vcpu_info[m->machno].time;
+	s = &shadow[m->machno];		// XXX place in mach struct
+	while(t->version != s->version) {
+		if (t->version&1)
+			continue;
+		s->version = t->version;
+		s->tsc_timestamp = t->tsc_timestamp;
+		s->system_time = t->system_time;
+		s->tsc_to_system_mul = t->tsc_to_system_mul;
+		s->tsc_shift = t->tsc_shift;
+	}
+	return s;
+}
+
+
+/* just get it from the shared info */
+void
+guesscpuhz(int) // XXX no arg!
+{
+	vcpu_time_info_t *t;
+
+	t = getshadow();
+	m->cpuhz = (1000000000LL << 32) / t->tsc_to_system_mul;
+	if(t->tsc_shift < 0)
+		m->cpuhz <<= -t->tsc_shift;
+	else
+		m->cpuhz >>= t->tsc_shift;
+	m->cpumhz = m->cpuhz / 1000000L;
+}
+
+void
+xentimerset(uvlong next)
+{
+	uvlong soon;
+
+	soon = fastticks(0) + 100000;
+	if (next < soon)
+		next = soon;
+	HYPERVISOR_set_timer_op(next);
+}
+
+void
+xentimerclock(Ureg* ureg, void*)
+{
+
+	timerintr(ureg, 0);
+}
+
+void
+xentimerenable(void)
+{
+	intrenable(VIRQ_TIMER, xentimerclock, nil, 0, "Xen Timer");
+}
+
+uvlong
+xentimerread(uvlong *hz)
+{
+	uvlong x;
+	uvlong delta, sdelta;
+	vcpu_time_info_t *t;
+
+	t = getshadow();
+	cycles(&x);
+	delta = x - t->tsc_timestamp;
+	if (t->tsc_shift < 0)
+		delta >>= -t->tsc_shift;
+	else
+		delta <<= t->tsc_shift;
+	mul64fract(&sdelta, delta, t->tsc_to_system_mul);
+	x = t->system_time + sdelta;
+	if (HYPERVISOR_shared_info->wc_sec != wallclock) {
+		wallclock = HYPERVISOR_shared_info->wc_sec;
+		wallclocksystime = x;
+	}
+	if (hz)
+		*hz = 1000000000;
+	return x;
+}
+
+ulong
+xenwallclock()
+{
+	ulong elapsed;
+
+	elapsed = (ulong)((xentimerread(0) - wallclocksystime)/1000000000);
+	return wallclock + elapsed;
+}
+
+void
+microdelay(int microsecs)
+{
+	uvlong targ, hz;
+
+	targ = xentimerread(&hz);
+	targ += microsecs * hz / 1000000;
+	while(xentimerread(0) < targ)
+		continue;
+}
+
+void
+delay(int millisecs)
+{
+	microdelay(millisecs * 1000);
+}
+
+/*  
+ *  performance measurement ticks.  must be low overhead.
+ *  doesn't have to count over a second.
+ */
+ulong
+perfticks(void)
+{
+	uvlong x;
+
+	cycles(&x);
+	return x;
+}