From: Wanpeng Li <kernellwp@gmail.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>
Subject: [PATCH v2 1/3] KVM: LAPIC: Write 0 to TMICT should also cancel vmx-preemption timer
Date: Mon, 7 Jun 2021 00:19:43 -0700 [thread overview]
Message-ID: <1623050385-100988-1-git-send-email-wanpengli@tencent.com> (raw)
From: Wanpeng Li <wanpengli@tencent.com>
According to the SDM 10.5.4.1:
A write of 0 to the initial-count register effectively stops the local
APIC timer, in both one-shot and periodic mode.
However, the lapic timer oneshot/periodic mode which is emulated by vmx-preemption
timer doesn't stop by writing 0 to TMICT since vmx->hv_deadline_tsc is still
programmed and the guest will receive the spurious timer interrupt later. This
patch fixes it by also cancelling the vmx-preemption timer when writing 0 to
the initial-count register.
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
v1 -> v2:
* rename to cancel_apic_timer
* update patch description
arch/x86/kvm/lapic.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 8120e86..6d72d8f 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1494,6 +1494,15 @@ static void limit_periodic_timer_frequency(struct kvm_lapic *apic)
static void cancel_hv_timer(struct kvm_lapic *apic);
+static void cancel_apic_timer(struct kvm_lapic *apic)
+{
+ hrtimer_cancel(&apic->lapic_timer.timer);
+ preempt_disable();
+ if (apic->lapic_timer.hv_timer_in_use)
+ cancel_hv_timer(apic);
+ preempt_enable();
+}
+
static void apic_update_lvtt(struct kvm_lapic *apic)
{
u32 timer_mode = kvm_lapic_get_reg(apic, APIC_LVTT) &
@@ -1502,11 +1511,7 @@ static void apic_update_lvtt(struct kvm_lapic *apic)
if (apic->lapic_timer.timer_mode != timer_mode) {
if (apic_lvtt_tscdeadline(apic) != (timer_mode ==
APIC_LVT_TIMER_TSCDEADLINE)) {
- hrtimer_cancel(&apic->lapic_timer.timer);
- preempt_disable();
- if (apic->lapic_timer.hv_timer_in_use)
- cancel_hv_timer(apic);
- preempt_enable();
+ cancel_apic_timer(apic);
kvm_lapic_set_reg(apic, APIC_TMICT, 0);
apic->lapic_timer.period = 0;
apic->lapic_timer.tscdeadline = 0;
@@ -2092,7 +2097,7 @@ int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
if (apic_lvtt_tscdeadline(apic))
break;
- hrtimer_cancel(&apic->lapic_timer.timer);
+ cancel_apic_timer(apic);
kvm_lapic_set_reg(apic, APIC_TMICT, val);
start_apic_timer(apic);
break;
--
2.7.4
next reply other threads:[~2021-06-07 7:21 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-07 7:19 Wanpeng Li [this message]
2021-06-07 7:19 ` [PATCH v2 2/3] KVM: LAPIC: Reset TMCCT during vCPU reset Wanpeng Li
2021-06-08 16:27 ` Paolo Bonzini
2021-06-09 2:15 ` Wanpeng Li
2021-06-09 5:51 ` Paolo Bonzini
2021-06-09 7:18 ` Wanpeng Li
2021-06-07 7:19 ` [PATCH v2 3/3] KVM: X86: Let's harden the ipi fastpath condition edge-trigger mode Wanpeng Li
2021-06-08 16:27 ` Paolo Bonzini
2021-06-08 16:35 ` Sean Christopherson
2021-06-08 17:40 ` Paolo Bonzini
2021-06-09 2:08 ` Wanpeng Li
2021-06-08 16:27 ` [PATCH v2 1/3] KVM: LAPIC: Write 0 to TMICT should also cancel vmx-preemption timer Paolo Bonzini
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