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 adding kvm-unit-test/apic_timer_latency.flat to test 100 thousands times APIC timer operations. The patchset reduces ~3800+ clock cycles for each APIC timer periodic mode operation virtualization. V1 -> RFC v3: * squash patch 3 into patch 6 * fix switch sw to hv timer RFC v2 -> RFC 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() RFC v1 -> RFC 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 (5): 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 kvm_get_lapic_target_expiration_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 | 193 +++++++++++++++++++++++++++++++++------------------ arch/x86/kvm/lapic.h | 2 + arch/x86/kvm/x86.c | 2 +- 3 files changed, 129 insertions(+), 68 deletions(-) -- 1.9.1
