Re: [PATCH] KVM: No disable_irq for MSI/MSI-X interrupt on device assignment

[Sheng Yang <sheng@linux.intel.com>]

On Monday 04 May 2009 16:25:55 Avi Kivity wrote:
> Sheng Yang wrote:
> > Disable interrupt at interrupt handler and enable it when guest ack is
> > for the level triggered interrupt, to prevent reinjected interrupt.
> > MSI/MSI-X don't need it.
> >
> > One possible problem is multiply same vector interrupt injected between
> > irq handler and scheduled work handler would be merged as one for
> > MSI/MSI-X. But AFAIK, the drivers handle it well.
> >
> > The patch fixed the oplin card performance issue(MSI-X performance is
> > half of MSI/INTx).
> >
> >
> >  	schedule_work(&assigned_dev->interrupt_work);
> >
> > -	disable_irq_nosync(irq);
> > -	assigned_dev->host_irq_disabled = true;
> > +	if (assigned_dev->irq_requested_type & KVM_DEV_IRQ_GUEST_INTX) {
> > +		disable_irq_nosync(irq);
> > +		assigned_dev->host_irq_disabled = true;
> > +	}
> >
> >  out:
> >  	spin_unlock_irqrestore(&assigned_dev->assigned_dev_lock, flags);
>
> I don't have the spin_lock_irqrestore() here.  The patch applies, but
> with fuzz.  Am I missing a patch?

Oh, it's Marcelo's patchset...

[patch 0/4] use smp_send_reschedule in vcpu_kick / assigned dev host intx race 
fix

-- 
regards
Yang, Sheng