[Qemu-devel] Q35, Mac OS X, and the War On Entropy

[Gabriel L. Somlo]

Hi,

I'm working on getting OS X to run on KVM, and the latest
q35-qemu tree from GitHub, plus additionally applied commit
40862309a9d733cb0e878c79f477de003897b5d2 from mainline works
great, with the following command line:

bin/qemu-system-x86_64 -enable-kvm -m 2048 -cpu core2duo \
  -M q35 -L seabios-mac/out -kernel ./chameleon_2.0_boot \
  -usb -device usb-kbd -device usb-mouse \
  -device isa-applesmc,osk="..." \
  -device ide-drive,bus=ide.0,drive=MacHDD \
  -drive id=MacHDD,if=none,snapshot=on,file=./mac_10.6.img


However, current mainline QEMU git master does not. I need a
slightly modified command line to even start (had to add
"-L share/qemu" as a fallback bios path to avoid "could not
open option rom ..." errors):

bin/qemu-system-x86_64 -enable-kvm -m 2048 -cpu core2duo \
  -M q35 -L seabios-mac/out -L share/qemu -kernel ./chameleon_2.0_boot \
  -usb -device usb-kbd -device usb-mouse \
  -device isa-applesmc,osk="..." \
  -device ide-drive,bus=ide.0,drive=MacHDD \
  -drive id=MacHDD,if=none,snapshot=on,file=./mac_10.6.img

This seems to be equivalent: 

bin/qemu-system-x86_64 -enable-kvm -m 2048 -cpu core2duo \
  -M q35 -bios bios-mac.bin -kernel ./chameleon_2.0_boot \
  -usb -device usb-kbd -device usb-mouse \
  -device isa-applesmc,osk="..." \
  -device ide-drive,bus=ide.0,drive=MacHDD \
  -drive id=MacHDD,if=none,snapshot=on,file=./mac_10.6.img

(I use the latest SeaBIOS git plus this patch:
http://www.contrib.andrew.cmu.edu/~somlo/OSXKVM/seabios-mac-20121206.patch
for all examples, working *and* non-working).

With mainline and -M q35, OS X gives me:

"Waiting for boot volume with UUID ..."

and

"Still waiting for root device"

I don't know if there's a way to do a bisect across the two different
trees, and I couldn't find a working "-M q35" state in mainline to begin
bisecting from there. I get the above errors immediately after commits
df2d8b3ed4d2b6406335d274f9537d78ac4e3c0c,
a1c9304683161a68c1fc1d9c3bc174ec8e26a61a, and
21bcfdd9a43041720f9370831c694bcb2e11eea4
where -M q35 was added to mainline...

BTW, leaving out "-M q35" in mainline still seems to work fine (if I
explicitly add "-device ahci,id=ide" instead...

Between the working GitHub -M q35 and the non-working mainline -M q35,
"dev: ich9-ahci" from "info qtree" looks identical, save for the
"dev: ide-drive" version under ide.0 (1.3.50 on github vs. 1.2.50 in
mainline). Not sure if that's even relevant...

Any advice as to what else I could do to narrow it down further would be
appreciated !

Thanks,
--Gabriel