linux/include/xen/interface/features.h
Stefano Stabellini 409771d258 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>
2010-07-26 23:13:25 -07:00

53 lines
1.6 KiB
C

/******************************************************************************
* features.h
*
* Feature flags, reported by XENVER_get_features.
*
* Copyright (c) 2006, Keir Fraser <keir@xensource.com>
*/
#ifndef __XEN_PUBLIC_FEATURES_H__
#define __XEN_PUBLIC_FEATURES_H__
/*
* If set, the guest does not need to write-protect its pagetables, and can
* update them via direct writes.
*/
#define XENFEAT_writable_page_tables 0
/*
* If set, the guest does not need to write-protect its segment descriptor
* tables, and can update them via direct writes.
*/
#define XENFEAT_writable_descriptor_tables 1
/*
* If set, translation between the guest's 'pseudo-physical' address space
* and the host's machine address space are handled by the hypervisor. In this
* mode the guest does not need to perform phys-to/from-machine translations
* when performing page table operations.
*/
#define XENFEAT_auto_translated_physmap 2
/* If set, the guest is running in supervisor mode (e.g., x86 ring 0). */
#define XENFEAT_supervisor_mode_kernel 3
/*
* If set, the guest does not need to allocate x86 PAE page directories
* below 4GB. This flag is usually implied by auto_translated_physmap.
*/
#define XENFEAT_pae_pgdir_above_4gb 4
/* x86: Does this Xen host support the MMU_PT_UPDATE_PRESERVE_AD hypercall? */
#define XENFEAT_mmu_pt_update_preserve_ad 5
/* 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__ */