From fae0ba2157340635fd99912c0c3b7a28c355c588 Mon Sep 17 00:00:00 2001 From: Nadav Amit Date: Mon, 18 Aug 2014 22:42:13 +0300 Subject: [PATCH] KVM: x86: Clear apic tsc-deadline after deadline Intel SDM 10.5.4.1 says "When the timer generates an interrupt, it disarms itself and clears the IA32_TSC_DEADLINE MSR". This patch clears the MSR upon timer interrupt delivery which delivered on deadline mode. Since the MSR may be reconfigured while an interrupt is pending, causing the new value to be overriden, pending timer interrupts are checked before setting a new deadline. Signed-off-by: Nadav Amit Signed-off-by: Paolo Bonzini --- arch/x86/kvm/lapic.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 08e8a899e005..666c086c82d4 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -1352,6 +1352,9 @@ void kvm_set_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu, u64 data) return; hrtimer_cancel(&apic->lapic_timer.timer); + /* Inject here so clearing tscdeadline won't override new value */ + if (apic_has_pending_timer(vcpu)) + kvm_inject_apic_timer_irqs(vcpu); apic->lapic_timer.tscdeadline = data; start_apic_timer(apic); } @@ -1639,6 +1642,8 @@ void kvm_inject_apic_timer_irqs(struct kvm_vcpu *vcpu) if (atomic_read(&apic->lapic_timer.pending) > 0) { kvm_apic_local_deliver(apic, APIC_LVTT); + if (apic_lvtt_tscdeadline(apic)) + apic->lapic_timer.tscdeadline = 0; atomic_set(&apic->lapic_timer.pending, 0); } } -- 2.20.1