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>

1 files changed, 6 insertions, 0 deletions

diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c
index d07479c340f5..1d789d56877c 100644
--- a/arch/x86/xen/suspend.c
+++ b/arch/x86/xen/suspend.c
@@ -28,8 +28,14 @@ void xen_pre_suspend(void)
 
 void xen_hvm_post_suspend(int suspend_cancelled)
 {
+        int cpu;
         xen_hvm_init_shared_info();
         xen_callback_vector();
+        if (xen_feature(XENFEAT_hvm_safe_pvclock)) {
+                for_each_online_cpu(cpu) {
+                        xen_setup_runstate_info(cpu);
+                }
+        }
 }
 
 void xen_post_suspend(int suspend_cancelled)