From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCHv4 15/15] Pass boot device list to firmware. Date: Thu, 18 Nov 2010 13:38:31 +0200 Message-ID: <20101118113831.GD31261@redhat.com> References: <1289749181-12070-1-git-send-email-gleb@redhat.com> <1289749181-12070-16-git-send-email-gleb@redhat.com> <20101115084242.GG7948@redhat.com> <20101116141112.GS7948@redhat.com> <20101116190246.GA27851@redhat.com> <20101118101827.GC7948@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Blue Swirl , qemu-devel@nongnu.org, kvm@vger.kernel.org, armbru@redhat.com, alex.williamson@redhat.com, kevin@koconnor.net To: Gleb Natapov Return-path: Received: from mx1.redhat.com ([209.132.183.28]:22801 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751016Ab0KRLir (ORCPT ); Thu, 18 Nov 2010 06:38:47 -0500 Content-Disposition: inline In-Reply-To: <20101118101827.GC7948@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Thu, Nov 18, 2010 at 12:18:27PM +0200, Gleb Natapov wrote: > On Wed, Nov 17, 2010 at 09:54:27PM +0000, Blue Swirl wrote: > > 2010/11/16 Gleb Natapov : > > > On Tue, Nov 16, 2010 at 06:30:19PM +0000, Blue Swirl wrote: > > >> >> Perhaps the FW path should use device class names if no name = is specified. > > >> > What do you mean by "device class name". We can do something l= ike this: > > >> > if (dev->child_bus.lh_first) > > >> > =A0 =A0 =A0 =A0return dev->child_bus.lh_first->info->name; > > >> > > > >> > i.e if there is child bus use its bus name as fw name. This wi= ll make > > >> > all pci devices to have "pci" as fw name automatically. The pr= oblem is > > >> > that theoretically same device can provide different buses. > > >> > > >> I meant PCI class name, like "display" for display controllers, > > >> "network" for NICs etc. > > >> > > > That is what my pci bus related patch is doing already. > > > > > >> >> I'll try Sparc32 to see how this fits there. > > >> > > >> Except bootindex is not implemented for SCSI. > > > Will look into adding it. > >=20 > > Thanks. The bootindex on Sparc32 looks like this: > > bootindex /esp@0000000078800000/disk@1,0 > > /ethernet@ffffffffffffffff/ethernet-phy@0 > >=20 > For arches other then x86 there is a lot of work left to be done :) > For starter exotic sparc buses should get their own get_fw_dev_path() > implementation. >=20 > > I don't think I got Lance setup right. > >=20 > > OF paths for the devices would be: > > /iommu@0,10000000/sbus@0,10001000/espdma@5,8400000/esp@5,8800000/sd= @1,0 > > /iommu@0,10000000/sbus@0,10001000/ledma@5,8400010/le@5,8c00000 > If qdev hierarchy does not correspond to real HW there is no much we = can > do expect for fixing qdev. That's bad. This raises a concern: if these paths expose qdev internals, any attempt to fix this will break migration. > >=20 > > The logic for ESP is that ESP (registers at 0x78800000, slot offset > > 0x880000) is handled by the DMA controller (registers at 0x78400000= , > > slot offset 0x840000), they are in a SBus slot #5, and SBus (regist= ers > > at 0x10001000) is in turn handled by IOMMU (registers at 0x10000000= ). > > Lance should be handled the same way. > >=20 > > This hierarchy is partly known by QEMU because DMA accesses use thi= s > > flow, but not otherwise. There is no concept of SBus slots, DMA tal= ks > > to IOMMU directly. Though in this case both ESP, Lance and their DM= A > > controllers are on board devices in a MACIO chip. It may be possibl= e > > to add the hierarchy information at each stage. > >=20 > > It should also be possible for BIOS to determine the device just fr= om > > the physical address if we ignored OF compatibility. > It would be nice to be OF compatible at least at some level. Of cours= e OF > spec is not strict enough to have two different implementations produ= ce > exactly same device path that can be compared by strcpy. Can we appl= y > the series now? At least for x86 it provides useful paths and work ca= n > be continue for other arches by interested parties. >=20 > -- > Gleb. Something I only now realized is that we commit to never changing the paths for any architecture that supports migration. --=20 MST