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From: Paul Brook <paul@codesourcery.com>
Subject: Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api
Date: Thu, 21 May 2009 15:14:30 +0100
References: <20090520162130.GA22109@redhat.com>
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To: qemu-devel@nongnu.org
Cc: Carsten Otte <cotte@de.ibm.com>, kvm@vger.kernel.org, "Michael S. Tsirkin" <mst@redhat.com>, Rusty Russell <rusty@rustcorp.com.au>, virtualization@lists.linux-foundation.org, Christian Borntraeger <borntraeger@de.ibm.com>, Avi Kivity <avi@redhat.com>

On Thursday 21 May 2009, Avi Kivity wrote:
> Paul Brook wrote:
> >>> which is a trivial wrapper around stl_phys.
> >>
> >> OK, but I'm adding another level of indirection in the middle,
> >> to allow us to tie in a kvm backend.
> >
> > kvm has no business messing with the PCI device code.
>
> kvm has a fast path for irq injection.  If qemu wants to support it we
> need some abstraction here.

Fast path from where to where? Having the PCI layer bypass/re-implement the 
APIC and inject the interrupt directly into the cpu core sounds a particularly 
bad idea.

Paul