[Qemu-devel] Thanx for the kqemu patches; some notes about NetBSD/OpenBSD guests

[Juergen Lock]

Hi!

 I just committed Jan's kqemu patch series to the FreeBSD kqemu port
(yes FreeBSD is another one of those `left behind' OSes where kvm
doesn't really work yet...) - and I also committed an old NetBSD/OpenBSD
guest kqemu patch,
        http://lists.gnu.org/archive/html/qemu-devel/2007-11/msg00125.html
and then played with a NetBSD guest in qemu 0.10.5 a little, where I
found out a few things:

1. A few times I even got NetBSD 5.0/i386 running with -kernel-kqemu now,
tho a few other times I also got guest processes segfaulting etc.
`Regualr' kqemu seems stable now tho.

2. NetBSD doesn't seem to particularly like qemu's acpi tables, it
apparenly doesn't find a pci bus and anything on it in that case
(like a nic our audio card; `pcictl pci0 list' says Device not configured.)

3. When I disable acpi either via the boot menu or via -no-acpi it still
has trouble assigning pci irqs correctly (like, uses irq 12 instead of 11
for the nic) - this seems to have something to do with the emulated
io-apic that it still picks up in that case - if I disable that by
building a new bios that has this patch reverted,
        pc-bios/bios-pq/0003_kvm-bios-generate-mptable-unconditionally.patch
the irqs at least get assigned correctly.  (Maybe the bios should only
pass an mptable for a single cpu when there also is acpi?)

4. most of qemu's emulated nics NetBSD still doesn't like, I had most
luck with pcnet.

(5. vbox has troubles with NetBSD too, it only boots here when I enable
svm _and_ npt.  Luckily that's also when a vm runs the fastest, but of
course npt/ept are also still pretty rare...)

 Oh, if anyone wants dmesg.s of the various with/without acpi/io-apic
combinations I can post those too, the patched bios I just put at:
        
http://people.freebsd.org/~nox/qemu/pc-bios-0.10.5-no-default-mptable/bios.bin
(I had to end up building it on a Linux guest, our assembler said things
like
        rombios32start.S:56: Error: `0(%ebx)' is not a valid 16 bit base/index 
expression
.)

 Thanx,
        Juergen