From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [Qemu-devel] KVM call minutes 2013-01-29 - Port I/O Date: Wed, 30 Jan 2013 18:08:17 +0100 Message-ID: <51095381.9080503@redhat.com> References: <871ud4gfoa.fsf@elfo.elfo> <5109065B.4060803@suse.de> <51094024.20803@redhat.com> <87vcae8wbk.fsf@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Gerd Hoffmann , =?ISO-8859-1?Q?Andreas_F=E4rber?= , Juan Quintela , KVM devel mailing list , qemu-devel , Alexander Graf , Benjamin Herrenschmidt , qemu-ppc , =?ISO-8859-1?Q?Herv=E9_Poussineau?= , David Gibson , Alon Levy , "Michael S. Tsirkin" To: Anthony Liguori Return-path: Received: from mail-qe0-f54.google.com ([209.85.128.54]:41855 "EHLO mail-qe0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754304Ab3A3RI0 (ORCPT ); Wed, 30 Jan 2013 12:08:26 -0500 Received: by mail-qe0-f54.google.com with SMTP id 1so833153qeb.27 for ; Wed, 30 Jan 2013 09:08:26 -0800 (PST) In-Reply-To: <87vcae8wbk.fsf@codemonkey.ws> Sender: kvm-owner@vger.kernel.org List-ID: Il 30/01/2013 17:33, Anthony Liguori ha scritto: > Gerd Hoffmann writes: > >> Hi, >> >>> hw/qxl.c: portio_list_add(qxl_vga_port_list, >>> pci_address_space_io(dev), 0x3b0); >>> hw/vga.c: portio_list_add(vga_port_list, address_space_io, 0x3b0); >> >> That reminds me I should solve this in a more elegant way. >> >> qxl takes over the vga io ports. The reason it does this is because qxl >> switches into vga mode in case the vga ports are accessed while not in >> vga mode. After doing the check (and possibly switching mode) the vga >> handler is called to actually handle it. > > The best way to handle this would be to remodel how we do VGA. > > Make VGACommonState a proper QOM object and use it as the base class for > QXL, CirrusVGA, QEMUVGA (std-vga), and VMwareVGA. I think QXL should have-a VGA rather than being one. It completely bypasses the VGA infrastructure if not in VGA mode. > The VGA accessors should be exposed as a memory region but the sub class > ought to be responsible for actually adding it to a subregion. > >> >> That twist makes it a bit hard to convert vga ... >> >> Anyone knows how one would do that with the memory api instead? I think >> taking over the ports is easy as the memory regions have priorities so I >> can simply register a region with higher priority. I have no clue how to >> forward the access to the vga code though. Avi had a prototype patch series for IOMMU regions. You could add one between the QXL device and the VGA. It doesn't have to do a translation, but trying to translate a VGA address already means that you must go to VGA mode. Paolo > > That should be possible with priorities, but I think it's wrong. There > aren't two VGA devices. QXL is-a VGA device and the best way to > override behavior of base VGA device is through polymorphism. > > This isn't really a memory API issue, it's a modeling issue. > > Regards, > > Anthony Liguori > >> Anyone has clues / suggestions? >> >> thanks, >> Gerd > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >