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x86: Use xen_vcpuop_clockevent, xen_clocksource and xen wallclock.

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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>
This commit is contained in:
Stefano Stabellini
2010-05-14 12:48:19 +01:00
committed by Jeremy Fitzhardinge
parent 99ad198c49
commit 409771d258
5 changed files with 66 additions and 22 deletions
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3
include/xen/interface/features.h
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@ -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
#define XENFEAT_NR_SUBMAPS 1
#endif /* __XEN_PUBLIC_FEATURES_H__ */