[PATCH RFC 0/2] KVM: x86: Support using the VMX preemption timer for APIC Timer periodic/oneshot mode

From: Wanpeng Li
Date: Tue Oct 11 2016 - 08:17:47 EST


Most windows guests which I have on hand currently still utilize APIC Timer
periodic/oneshot mode instead of APIC Timer tsc-deadline mode:
- windows 2008 server r2
- windows 2012 server r2
- windows 7
- windows 10

This patchset adds the support using the VMX preemption timer for APIC Timer
periodic/oneshot mode.

I add a print in oneshot mode testcase of kvm-unit-tests/apic.flat and observed
that w/ patch the latency is ~2% of w/o patch. I think maybe something is still
not right in the patchset, in addition, tmcct in apic_get_tmcct() maybe is not
calculated correctly. Your comments to improve the patchset is a great appreciated.

Wanpeng Li (2):
KVM: lapic: Extract start_sw_period() to handle oneshot/periodic mode
KVM: x86: Support using the vmx preemption timer for APIC Timer periodic/one mode

arch/x86/kvm/lapic.c | 162 ++++++++++++++++++++++++++++++---------------------
1 file changed, 95 insertions(+), 67 deletions(-)

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1.9.1