From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([208.118.235.92]:33772)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <pbonzini@redhat.com>) id 1S36bz-0000oE-HO
	for qemu-devel@nongnu.org; Thu, 01 Mar 2012 09:04:09 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <pbonzini@redhat.com>) id 1S36bY-0000Dw-QN
	for qemu-devel@nongnu.org; Thu, 01 Mar 2012 09:04:03 -0500
Received: from mx1.redhat.com ([209.132.183.28]:16521)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <pbonzini@redhat.com>) id 1S36bY-0000Dr-Hb
	for qemu-devel@nongnu.org; Thu, 01 Mar 2012 09:03:36 -0500
Message-ID: <4F4F81AE.9080503@redhat.com>
Date: Thu, 01 Mar 2012 15:03:26 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
MIME-Version: 1.0
References: <1330536077.10387.57.camel@leeds.uk.xensource.com>
	<4F4E64B5.5080900@siemens.com>
	<1330597236.10387.70.camel@leeds.uk.xensource.com>
	<4F4F5BF5.6010206@siemens.com>
	<1330602678.10387.73.camel@leeds.uk.xensource.com>
	<4F4F71F0.4070109@redhat.com>
	<alpine.DEB.2.00.1203011403140.923@kaball-desktop>
In-Reply-To: <alpine.DEB.2.00.1203011403140.923@kaball-desktop>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Subject: Re: [Qemu-devel] [PATCH] MSI / MSIX injection for Xen HVM
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>, xen-devel <xen-devel@lists.xensource.com>, "Wei Liu (Intern)" <wei.liu2@citrix.com>, QEMU-devel <qemu-devel@nongnu.org>

Il 01/03/2012 15:06, Stefano Stabellini ha scritto:
>> > This is not a NACK, but I can't help asking.  Perhaps the fake Xen
>> > interrupt controller is a bit too simplistic?  You can add a memory
>> > region corresponding to the APICs and trap writes in that region.
>> > Writes coming from QEMU are MSIs and can be injected to the hypervisor,
>> > writes coming from the VM will be trapped by Xen before going out to QEMU.
>  
> That is a good point actually: we already have lapic emulation in Xen,
> it makes sense to have apic-msi in Xen too.
> We would still need the changes to msi_notify and msix_notify though.

Why?  The stores would just go to the Xen interrupt controller MMIO area
which then does the xc_hvm_inject_msi.

Paolo