linux-kernel - [PATCH v2 0/5] KVM: LAPIC: Add APIC Timer periodic/oneshot mode VMX preemption timer support

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Message-Id: <1477280782-3817-1-git-send-email-wanpeng.li@hotmail.com>
Date:   Mon, 24 Oct 2016 11:46:17 +0800
From:   Wanpeng Li <kernellwp@...il.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Yunhong Jiang <yunhong.jiang@...el.com>,
        Wanpeng Li <wanpeng.li@...mail.com>
Subject: [PATCH v2 0/5] KVM: LAPIC: Add APIC Timer periodic/oneshot mode VMX preemption timer support

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 ~5600+ cycles for each APIC timer periodic mode operation 
virtualization. 

v2 -> v1:
 * replace ktime_compare by ktime_after
 * introduce advance_periodic_target_expiration() and use it in kvm_lapic_expired_hv_timer()
   and in apic_timer_fn()
 * don't zero apic->lapic_timer.target_expiration of apic_lvtt_period() when 
   !kvm_lapic_hv_timer_in_use

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
  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 | 204 ++++++++++++++++++++++++++++++++++-----------------
 arch/x86/kvm/lapic.h |   2 +
 arch/x86/kvm/x86.c   |   2 +-
 3 files changed, 140 insertions(+), 68 deletions(-)

-- 
1.9.1