qemu FreeBSD/sparc64 host - a bit of debugging

[Juergen Lock]

On Mon, Jul 18, 2011 at 10:58:58PM -0400, Super Bisquit wrote:
> On Mon, Jul 18, 2011 at 2:22 PM, Juergen Lock <nox at jelal.kn-bremen.de>wrote:
> 
> > Hi!
> >
> >  I'm the FreeBSD qemu port maintainer and don't have a sparc64 box
> > myself, but Jashank Jeremy (Cc'd) now was so kind to test qemu 0.14.1
> > on a FreeBSD/sparc64 box booting a FreeBSD 8/i386 install iso using
> > i386-softmmu
> 
> 
> What's the difference- an honest question- between this and a normal qemu
> boot?
> 
Depends on what you mean by normal qemu boot...  If you are wondering
about the i386-softmmu, that's just the name of the 32bit x86 system
emulation target, the executable is called qemu.  So he ran something
like:

	qemu -cdrom FreeBSD-8.2-i386-bootonly.iso -vnc ...

> > and we found two things:
> >
> > 1. The hang people have been reporting seems to be caused by this tb:
> >
> >        IN:
> >        0x000e7a31:  in     $0xb3,%al
> >        0x000e7a33:  test   %al,%al
> >        0x000e7a35:  jne    0xe7a31
> >
> >   i.e. it (the qemu bios I suppose) is waiting for x86 ioport 0xb3
> >   to become zero.  This port is #defined in hw/apm.c as:
> >
> >        qemu-0.14.1/hw/apm.c:#define APM_STS_IOPORT  0xb3
> >
> >   but the definition seems to be used nowhere in that source file.
> >   Anyone have an idea why this port is never zero on sparc64 hosts
> >   but seems to be on others?  (endian issue?  uninitialized variable?)
> >
> Have you asked Whitehorn what it my be?
> 
 No but I can Cc him...  Actually I can Cc the freebsd-sparc64 list too.
> >
> > 2. Booting the same guest with -no-acpi gets further, bios and
> >   bootloader messages are printed until it hangs again, this
> >   time while handling a guest irq 8 which seems to be rtc.
> >
> 
> Is there a way of disabling the clock? If not, then would it be useful to
> set the emulated cpu speed?
> 
 I don't think any of these two are possible.
> >
> >  Maybe this is useful to some... :)
> >
> 
> Actually, it's quite useful to me.

 That's good to hear. :)

	Juergen