From mboxrd@z Thu Jan  1 00:00:00 1970
From: Sheng Yang <sheng@linux.intel.com>
Subject: Re: [PATCH 1/3] KVM: x86: Relax accept conditions of kvm_apic_accept_pic_intr
Date: Fri, 17 Oct 2008 13:11:10 +0800
Message-ID: <200810171311.11309.sheng@linux.intel.com>
References: <20081015142748.385784583@mchn012c.ww002.siemens.net> <20081015142748.606503565@mchn012c.ww002.siemens.net>
Mime-Version: 1.0
Content-Type: text/plain;
  charset="utf-8"
Content-Transfer-Encoding: 7bit
Cc: Jan Kiszka <jan.kiszka@siemens.com>, avi@redhat.com,
	jiajun.xu@intel.com
To: kvm@vger.kernel.org
Return-path: <kvm-owner@vger.kernel.org>
Received: from mga09.intel.com ([134.134.136.24]:54751 "EHLO mga09.intel.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1750991AbYJQFMx (ORCPT <rfc822;kvm@vger.kernel.org>);
	Fri, 17 Oct 2008 01:12:53 -0400
In-Reply-To: <20081015142748.606503565@mchn012c.ww002.siemens.net>
Content-Disposition: inline
Sender: kvm-owner@vger.kernel.org
List-ID: <kvm.vger.kernel.org>

On Wednesday 15 October 2008 22:27:49 Jan Kiszka wrote:
> Aligning in-kernel kvm_apic_accept_pic_intr with its user space mate,
> this patch relaxes the conditions under which PIC IRQs are accepted
> by LVT0. This reflects reality and allows to reuse the service for the
> NMI watchdog use case.
>
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> ---
>  arch/x86/kvm/lapic.c |   13 ++++---------
>  1 file changed, 4 insertions(+), 9 deletions(-)
>
> Index: b/arch/x86/kvm/lapic.c
> ===================================================================
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -1072,16 +1072,11 @@ int kvm_apic_has_interrupt(struct kvm_vc
>  int kvm_apic_accept_pic_intr(struct kvm_vcpu *vcpu)
>  {
>  	u32 lvt0 = apic_get_reg(vcpu->arch.apic, APIC_LVT0);
> -	int r = 0;
>
> -	if (vcpu->vcpu_id == 0) {
> -		if (!apic_hw_enabled(vcpu->arch.apic))
> -			r = 1;
> -		if ((lvt0 & APIC_LVT_MASKED) == 0 &&
> -		    GET_APIC_DELIVERY_MODE(lvt0) == APIC_MODE_EXTINT)
> -			r = 1;
> -	}
> -	return r;
> +	if (!apic_hw_enabled(vcpu->arch.apic) ||
> +	    (lvt0 & APIC_LVT_MASKED) == 0)
> +		return 1;
> +	return 0;
>  }
>
>  void kvm_inject_apic_timer_irqs(struct kvm_vcpu *vcpu)
>
(sorry for late review...)

Thanks to find out the root cause of BSOD!

But I am a little concern about this change. As you know, PIC only connect to 
cpu0. So I think it's not proper to make it generic. 

Maybe you can use kvm_apic_accept_pic_intr(vcpu0) in later patch?

--
regards
Yang, Sheng