From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [regression] KVM: hangs and "irq timeout" booting HURD unless
 -no-kvm-irqchip passed
Date: Tue, 8 Feb 2011 15:44:19 -0200
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Cc: Gleb Natapov <gleb@redhat.com>,
	Jonathan Nieder <jrnieder@gmail.com>, kvm@vger.kernel.org,
	Michael Tokarev <mjt@tls.msk.ru>,
	Guillem Jover <guillem@debian.org>
To: Avi Kivity <avi@redhat.com>
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On Tue, Feb 08, 2011 at 04:57:16PM +0200, Avi Kivity wrote:
> On 02/08/2011 04:47 PM, Gleb Natapov wrote:
> >On Tue, Feb 08, 2011 at 04:43:33PM +0200, Avi Kivity wrote:
> >>  On 02/08/2011 04:22 PM, Marcelo Tosatti wrote:
> >>  >I don't think the isr_ack logic is overly complex that it should be
> >>  >removed. For some cases it is still beneficial, see example case on
> >>  >commit e48258009d941, which is not handled by kick coalescing of
> >>  >kvm_vcpu_kick.
> >>
> >>  On the other hand, I think it can be done differently.  For example
> >>  LVT0 is probably programmed to mask interrupts; we can simply look
> >>  at it and not kick if that's the case.  We can use notifiers from
> >>  the lapic to the pic to avoid looking at lapic data.
> >>
> >I believe this is what my patch is doing. Look at pic_unlock(). The code
> >search for vcpu to kick by calling kvm_apic_accept_pic_intr() function
> >(which checks that LVT is masked).
> 
> It does indeed.
> 
> >If no vcpu is found we kicks bsp.
> >Why? I removed that.
> 
> The code that looks for a vcpu that has LVT0 unmasked is newer than
> the isr_ack code (see cfe149e91b82).  So it looks like the isr_ack
> code is indeed unnecessary now.

Right. Patch looks fine.