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From: Paolo Bonzini <pbonzini@redhat.com>
To: Wanpeng Li <kernellwp@gmail.com>,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Sean Christopherson <sean.j.christopherson@intel.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	Haiwei Li <lihaiwei@tencent.com>
Subject: Re: [PATCH v2 1/5] KVM: LAPIC: Introduce interrupt delivery fastpath
Date: Thu, 23 Apr 2020 11:25:00 +0200	[thread overview]
Message-ID: <09cba36c-61d8-e660-295d-af54ceb36036@redhat.com> (raw)
In-Reply-To: <1587632507-18997-2-git-send-email-wanpengli@tencent.com>

On 23/04/20 11:01, Wanpeng Li wrote:
> +static void fast_deliver_interrupt(struct kvm_lapic *apic, int vector)
> +{
> +	struct kvm_vcpu *vcpu = apic->vcpu;
> +
> +	kvm_lapic_clear_vector(vector, apic->regs + APIC_TMR);
> +
> +	if (vcpu->arch.apicv_active) {
> +		if (kvm_x86_ops.pi_test_and_set_pir_on(vcpu, vector))
> +			return;
> +
> +		kvm_x86_ops.sync_pir_to_irr(vcpu);
> +	} else {
> +		kvm_lapic_set_irr(vector, apic);
> +		if (kvm_cpu_has_injectable_intr(vcpu)) {
> +			if (kvm_x86_ops.interrupt_allowed(vcpu)) {
> +				kvm_queue_interrupt(vcpu,
> +					kvm_cpu_get_interrupt(vcpu), false);
> +				kvm_x86_ops.set_irq(vcpu);
> +			} else
> +				kvm_x86_ops.enable_irq_window(vcpu);
> +		}
> +	}
> +}
> +

Ok, got it now.  The problem is that deliver_posted_interrupt goes through

        if (!kvm_vcpu_trigger_posted_interrupt(vcpu, false))
                kvm_vcpu_kick(vcpu);

Would it help to make the above

        if (vcpu != kvm_get_running_vcpu() &&
	    !kvm_vcpu_trigger_posted_interrupt(vcpu, false))
                kvm_vcpu_kick(vcpu);

?  If that is enough for the APICv case, it's good enough.

Paolo


  reply	other threads:[~2020-04-23  9:25 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-23  9:01 [PATCH v2 0/5] KVM: VMX: Tscdeadline timer emulation fastpath Wanpeng Li
2020-04-23  9:01 ` [PATCH v2 1/5] KVM: LAPIC: Introduce interrupt delivery fastpath Wanpeng Li
2020-04-23  9:25   ` Paolo Bonzini [this message]
2020-04-23  9:35     ` Wanpeng Li
2020-04-23  9:39       ` Paolo Bonzini
2020-04-23  9:44         ` Wanpeng Li
2020-04-23  9:52           ` Paolo Bonzini
2020-04-23  9:01 ` [PATCH v2 2/5] KVM: X86: Introduce need_cancel_enter_guest helper Wanpeng Li
2020-04-23  9:01 ` [PATCH v2 3/5] KVM: VMX: Introduce generic fastpath handler Wanpeng Li
2020-04-23  9:01 ` [PATCH v2 4/5] KVM: X86: TSCDEADLINE MSR emulation fastpath Wanpeng Li
2020-04-23  9:37   ` Paolo Bonzini
2020-04-23  9:54     ` Wanpeng Li
2020-04-23 10:28       ` Paolo Bonzini
2020-04-23  9:01 ` [PATCH v2 5/5] KVM: VMX: Handle preemption timer fastpath Wanpeng Li
2020-04-23  9:40   ` Paolo Bonzini
2020-04-23  9:56     ` Wanpeng Li
2020-04-23 10:29       ` Paolo Bonzini
2020-04-24  6:38         ` Wanpeng Li
2020-04-26  7:38   ` kbuild test robot

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