x86: Use xen_vcpuop_clockevent, xen_clocksource and xen wallclock.
Use xen_vcpuop_clockevent instead of hpet and APIC timers as main
clockevent device on all vcpus, use the xen wallclock time as wallclock
instead of rtc and use xen_clocksource as clocksource.
The pv clock algorithm needs to work correctly for the xen_clocksource
and xen wallclock to be usable, only modern Xen versions offer a
reliable pv clock in HVM guests (XENFEAT_hvm_safe_pvclock).
Using the hpet as clocksource means a VMEXIT every time we read/write to
the hpet mmio addresses, pvclock give us a better rating without
VMEXITs. Same goes for the xen wallclock and xen_vcpuop_clockevent
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Don Dutile <ddutile@redhat.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index b3c6c59..4780e55 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -20,6 +20,7 @@
#include <asm/xen/hypercall.h>
#include <xen/events.h>
+#include <xen/features.h>
#include <xen/interface/xen.h>
#include <xen/interface/vcpu.h>
@@ -160,7 +161,7 @@
* nanoseconds, which is nanoseconds the VCPU spent in RUNNING+BLOCKED
* states.
*/
-unsigned long long xen_sched_clock(void)
+static unsigned long long xen_sched_clock(void)
{
struct vcpu_runstate_info state;
cycle_t now;
@@ -195,7 +196,7 @@
/* Get the TSC speed from Xen */
-unsigned long xen_tsc_khz(void)
+static unsigned long xen_tsc_khz(void)
{
struct pvclock_vcpu_time_info *info =
&HYPERVISOR_shared_info->vcpu_info[0].time;
@@ -230,7 +231,7 @@
put_cpu_var(xen_vcpu);
}
-unsigned long xen_get_wallclock(void)
+static unsigned long xen_get_wallclock(void)
{
struct timespec ts;
@@ -238,7 +239,7 @@
return ts.tv_sec;
}
-int xen_set_wallclock(unsigned long now)
+static int xen_set_wallclock(unsigned long now)
{
/* do nothing for domU */
return -1;
@@ -473,7 +474,11 @@
}
}
-__init void xen_time_init(void)
+static const struct pv_time_ops xen_time_ops __initdata = {
+ .sched_clock = xen_sched_clock,
+};
+
+static __init void xen_time_init(void)
{
int cpu = smp_processor_id();
struct timespec tp;
@@ -497,3 +502,46 @@
xen_setup_timer(cpu);
xen_setup_cpu_clockevents();
}
+
+__init void xen_init_time_ops(void)
+{
+ pv_time_ops = xen_time_ops;
+
+ x86_init.timers.timer_init = xen_time_init;
+ x86_init.timers.setup_percpu_clockev = x86_init_noop;
+ x86_cpuinit.setup_percpu_clockev = x86_init_noop;
+
+ x86_platform.calibrate_tsc = xen_tsc_khz;
+ x86_platform.get_wallclock = xen_get_wallclock;
+ x86_platform.set_wallclock = xen_set_wallclock;
+}
+
+static void xen_hvm_setup_cpu_clockevents(void)
+{
+ int cpu = smp_processor_id();
+ xen_setup_runstate_info(cpu);
+ xen_setup_timer(cpu);
+ xen_setup_cpu_clockevents();
+}
+
+__init void xen_hvm_init_time_ops(void)
+{
+ /* vector callback is needed otherwise we cannot receive interrupts
+ * on cpu > 0 */
+ if (!xen_have_vector_callback && num_present_cpus() > 1)
+ return;
+ if (!xen_feature(XENFEAT_hvm_safe_pvclock)) {
+ printk(KERN_INFO "Xen doesn't support pvclock on HVM,"
+ "disable pv timer\n");
+ return;
+ }
+
+ pv_time_ops = xen_time_ops;
+ x86_init.timers.setup_percpu_clockev = xen_time_init;
+ x86_cpuinit.setup_percpu_clockev = xen_hvm_setup_cpu_clockevents;
+
+ x86_platform.calibrate_tsc = xen_tsc_khz;
+ x86_platform.get_wallclock = xen_get_wallclock;
+ x86_platform.set_wallclock = xen_set_wallclock;
+}
+