From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:33199) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Qcgo9-0002Zq-IS for qemu-devel@nongnu.org; Fri, 01 Jul 2011 12:43:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Qcgo8-0000PY-1C for qemu-devel@nongnu.org; Fri, 01 Jul 2011 12:43:09 -0400 Received: from ch1ehsobe001.messaging.microsoft.com ([216.32.181.181]:5847 helo=CH1EHSOBE011.bigfish.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Qcgo6-0000P9-Pk for qemu-devel@nongnu.org; Fri, 01 Jul 2011 12:43:07 -0400 Date: Fri, 1 Jul 2011 11:43:01 -0500 From: Scott Wood Message-ID: <20110701114301.08d0154b@schlenkerla.am.freescale.net> In-Reply-To: <4E0DB945.4070203@codemonkey.ws> References: <9F6FE96B71CF29479FF1CDC8046E1503165EEB@039-SN1MPN1-003.039d.mgd.msft.net> <1309481894.14501.230.camel@pasglop> <4E0DB945.4070203@codemonkey.ws> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] device assignment for embedded Power List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Wood Scott-B07421 , "qemu-devel@nongnu.org" , Alexander Graf , "blauwirbel@gmail.com" , Yoder Stuart-B08248 , "alex.williamson@redhat.com" , "paul@codesourcery.com" , "joerg.roedel@amd.com" , "dwg@au1.ibm.com" , "armbru@redhat.com" On Fri, 1 Jul 2011 07:10:45 -0500 Anthony Liguori wrote: > I agree in principle but I think it should be done in a slightly > different way. > > I think we ought to support composing a device by passthrough. For > instance, something like: > > [physical-device "mydev"] > region[0].file = "/dev/mem" > region[0].guest_address = "0x42232000" > region[0].file_offset = "0x23423400" > region[0].size = "4096" > irq[0].guest_irq = "10" > irq[0].host_irq = "10" > > This should be independent of anything to do with device tree. This > would be useful for x86 too to assign platform devices (like the HPET). That's fine, as long as there's something layered on top of it for the case where we do want to reference something in the device tree. However, we'll need to address the question of what it means to say "irq 10" -- outside of PC-land there often isn't a global IRQ numberspace that isn't a fiction created by some software layer. Addressing this is one of the device tree's strengths. -Scott