Hello,
On Wed, 16 Apr 2025, Philippe Mathieu-Daudé wrote:
adding more PPC developers.
Maybe they are more likely to be found on qemu-ppc list and adding Howard
who may have some guide on this.
On 16/4/25 10:42, André from Negmaster wrote:
First of all many thanks for your work on PPC emulation.
I would like to request SCSI/PCI passthrough to MacOS9 if possible.
I spent the last two days trying to get this working to no avail. To me it
seems QEMU can't do that. The PPC documentation is missing information
about passthrough. I would like to see some more information there. Because
i am still not sure if it would work or not. I passed all hurdles, like
IOMMU groups, IRQ issues etc...but still no SCSI card or scanner in the
system profiler.
There's not enough information here to give more than generic advice
(details such as which qemu-system-ppc -machine, MacOS version, SCSI card,
etc. may be needed to see what you tried). In general it should work. Some
people successfully passed through video cards, usb and network cards for
qemu-system-ppc so QEMU can do that but this may not be plug and play
especially with MacOS if it needs an FCode ROM to be run as OpenBIOS does
not do that by default and may not be able to run it even if you try
manually. We needed patches for video card ROMs before.
There are two ways to pass through a SCSI device: passing through the SCSI
card and letting the host handle SCSI and only pass through the SCSI
device. For the latter you need an emulated SCSI card that's recognised by
the guest. Most guides talk about virtio-scsi but I don't think MacOS has
a driver for that and don't know if any of the emulated SCSI adapters
would work. Classic Macs have an ESP SCSI adapter AFAIK and dc390 seems to
be a PCI version of that so maybe that could work but if MacOS needs
anything in device-tree that would be added by an FCode ROM then it's
again the same problem as with a passed through card. If you don't want to
dig deeper and change anything in OpenBIOS and QEMU to make it work what
you could do is try all the emulated SCSI devices and try to find MacOS
drivers for them and see if any of those works then if you get a SCSI
adapter in the guest you could try passing through the device only. For
passing through the card I'd check first if it has an FCode ROM and then
try to run that in OpenBIOS manually (I forgot how to do that but sombody
may remember or dig up old messages on this) and then maybe patch OpenBIOS
to work with that.
So it may not be easy to set up and may require fixing some issues here
and there but generally it's possible and was done for some cards before
so there's no theretical limit that would prevent it from working.
Regards,
BALATON Zoltan
