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 APIC Timer periodic/oneshot mode VMX preemption timer support. I test the patchset by modifying kvm-unit-test/apic.flat to test 10w times APIC timer operations (from guest writes LVTT to timer fire and return to guest). The patchset reduces ~300+ clock cycles for each APIC timer oneshot mode operation virtualization. However, the performance of periodic mode is still bad, so this version is still a RFC. Your comments to improve the patchset is a great appreciated. v2 -> v3: * remove kvm_lapic_hv_timer_in_use() check in apic_get_tmcc, replace the hritmer_get_remaining() by target_expiration - now * rename expired_period to target_expiration * introduce set_target_expiration() helper * move the checking of minimal period to set_target_expiration() * cleanup kvm_get_lapic_target_deadline_tsc() v1 -> v2: * remember the timeout when setting up the timer to get a correct TMCCT * move apic->lapic_timer.period/tscdeadline caculations to start_apic_timer() Wanpeng Li (6): KVM: LAPIC: extract start_sw_period() to handle periodic/oneshot mode KVM: LAPIC: guarantee the timer is in tsc-deadline mode when rdmsr MSR_IA32_TSCDEADLINE KVM: LAPIC: introduce set_target_expiration to set target expiration time KVM: LAPIC: introduce kvm_get_lapic_target_expiration_tsc() to get APIC Timer target deadline tsc KVM: LAPIC: rename start/cancel_hv_tscdeadline to start/cancel_hv_timer KVM: LAPIC: Add APIC Timer periodic/oneshot mode VMX preemption timer support arch/x86/kvm/lapic.c | 173 +++++++++++++++++++++++++++++++-------------------- arch/x86/kvm/lapic.h | 2 + arch/x86/kvm/x86.c | 2 +- 3 files changed, 109 insertions(+), 68 deletions(-) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
