Re: [PATCH 2/3] KVM: Add gsi_msg_pending_bitmap for MSI-X

From: Sheng Yang <sheng@linux.intel.com>
To: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>, kvm@vger.kernel.org
Subject: Re: [PATCH 2/3] KVM: Add gsi_msg_pending_bitmap for MSI-X
Date: Wed, 18 Feb 2009 09:33:39 +0800	[thread overview]
Message-ID: <200902180933.40296.sheng@linux.intel.com> (raw)
In-Reply-To: <499AFD6D.5090607@redhat.com>

On Wednesday 18 February 2009 02:09:49 Avi Kivity wrote:
> Sheng Yang wrote:
> >>> +	if (assigned_dev->irq_requested_type == KVM_ASSIGNED_DEV_MSIX) {
> >>> +		u32 gsi;
> >>> +		gsi = find_gsi_from_host_irq(assigned_dev, irq);
> >>> +		if (gsi == 0)
> >>> +			return IRQ_HANDLED;
> >>
> >> So you chose GSI == 0 as invalid because of x86 assumptions? Or is there
> >> any other reason?
> >
> > Yeah, it based on x86 and IA64 IRQ 0 can't be used by MSI-X. And only x86
> > support MSI-X now(and IA64 would follow later).
>
> gsi != irq... as used in kvm it is just a cookie and is never visible to
> the guest.  I'd prefer an illegal value here.
>
>
> Also, please repost the entire patchset so I can be sure I apply the
> latest; too many versions floating around.

OK. And please don't forget there is a patchset named "Optimize and unify 
IOAPIC/MSI delivery" before this one. :)

-- 
regards
Yang, Sheng