path: root/include/xen
diff options
authorStefano Stabellini <stefano.stabellini@eu.citrix.com>2010-05-14 12:48:19 +0100
committerJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>2010-07-26 23:13:25 -0700
commit409771d258e9dd71c30f3c9520fd2b796ffc40f0 (patch)
tree68678275563114e9d381ae587fc80bd4d34a7e90 /include/xen
parentxen: Fix find_unbound_irq in presence of ioapic irqs. (diff)
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>
Diffstat (limited to 'include/xen')
1 files changed, 3 insertions, 0 deletions
diff --git a/include/xen/interface/features.h b/include/xen/interface/features.h
index 8ab08b91bf6f..70d2563ab166 100644
--- a/include/xen/interface/features.h
+++ b/include/xen/interface/features.h
@@ -44,6 +44,9 @@
/* x86: Does this Xen host support the HVM callback vector type? */
#define XENFEAT_hvm_callback_vector 8
+/* x86: pvclock algorithm is safe to use on HVM */
+#define XENFEAT_hvm_safe_pvclock 9
#endif /* __XEN_PUBLIC_FEATURES_H__ */