From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: QEMU PIC indirection patch for in-kernel APIC work Date: Wed, 04 Apr 2007 13:19:10 -0500 Message-ID: <4613EC1E.1080004@us.ibm.com> References: <4610A6A9.BA47.005A.0@novell.com> <46134B74.1080004@qumranet.com> <4613B438.60107@codemonkey.ws> <46139F39.BA47.005A.0@novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Gregory Haskins Return-path: In-Reply-To: <46139F39.BA47.005A.0-Et1tbQHTxzrQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Gregory Haskins wrote: >>>> On Wed, Apr 4, 2007 at 10:20 AM, in message <4613B438.60107-rdkfGonbjUSkNkDKm+mE6A@public.gmane.org>, >>>> > Anthony Liguori wrote: > >> The devices are already written to take a set_irq function. Instead of >> hijacking the emulated PIC device, I think it would be better if in >> pc.c, we just conditionally created our PIC device that reflected to the >> hypervisor and passed the appropriate function to the emulated hardware. >> >> > > When I first starting looking at the code, I was hoping to do exactly that. But unfortunately it appears as though many devices call pic_set_irq() directly which is why I used the approach I did. Take a look at qemu/hw/rt18139.c for an example. > Yeah, I was thinking of serial.c specifically. I just looked again and things are not quite as clean as I had thought. PPC has a set_irq hook but it also has it's own pic_set_irq function. I suspect the cleanest thing to do would be to register an irq handler that takes an callback/opaque. Probably switch pic_set_irq calls to qemu_set_irq or something. But this is definitely a topic to bring up on qemu-devel as it touches all architectures. Regards, Anthony Liguori > >> Otherwise, to support all the other architectures, there's going to be a >> lot of modifications. >> > > Fully agree, which is why I waited for review before putting in all that work ;) > > -Greg > > ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV