Re: [Qemu-devel] Multiple pci buses

[BALATON Zoltan <balaton@eik.bme.hu>]

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On Mon, 17 Mar 2014, Andreas Färber wrote:
> In earlier times QEMU did not properly support multiple PCI bus domains.
> Some code in
> http://git.qemu.org/?p=qemu.git;a=blob;f=hw/pci-host/uninorth.c;h=e72fe2a70b954bf5675ad0c8735fea6bad665be6;hb=HEAD
> is #if 0'ed out that you should take a look at.

I've seen these #if 0'ed parts but just enabling them does not seem to be 
enough. I don't know enough about how should all this work and found no 
documentation or examples to follow so I hope someone can explain what it 
takes to create two pci buses (so devices added to the first get 
0:dev:func and those added to the second get 1:dev:func addresses) and 
these busses have their Cfg/IO/MMIO space mapped to different addresses. 
The patch I came up with so far did not work. The pci buses and memory map 
from the dumps I've seen should look like this:

0000:00:0b.0 Host bridge [0600]: Apple Computer Inc. UniNorth AGP [106b:0020]
0000:00:10.0 VGA compatible controller [0300]: ATI Technologies Inc Radeon R200 QL [Radeon 8500 LE] [1002:514c]

0001:10:0b.0 Host bridge [0600]: Apple Computer Inc. UniNorth PCI [106b:001f]
0001:10:0d.0 PCI bridge [0604]: Digital Equipment Corporation DECchip 21154 [1011:0026] (rev 05)
0001:11:07.0 Unassigned class [ff00]: Apple Computer Inc. KeyLargo Mac I/O [106b:0022] (rev 02)

corresponding to this openfirmware tree:

ff8721c0: /pci@f0000000
ff898cd0:   /uni-north-agp@b
ff898f40:   /ATY,Rage128Ps@10
ff873268: /pci@f2000000
ff8742d8:   /pci-bridge@d
ff876368:     /mac-io@7

and the memory mapping is:

80000000-8fffffff : /pci@f2000000
    80000000-800fffff : PCI Bus 0001:11
      80000000-8007ffff : 0001:11:07.0
        80000000-8007ffff : 0.80000000:mac-io

90000000-9fffffff : /pci@f0000000
    90000000-9000ffff : 0000:00:10.0
      90000000-9000ffff : radeonfb mmio

f1000000-f1ffffff : /pci@f0000000
f3000000-f3ffffff : /pci@f2000000

> I had investigated that some time ago based on a G4 in our office and
> might be able to revive some patches... Please keep me CC'ed.

If you have any info/patches for this they are very welcome.

Regards,
BALATON Zoltan