[ipxe-devel] eepro100 vs qemu

Michael Brown mbrown at fensystems.co.uk
Tue Mar 15 02:13:06 UTC 2011

On Tuesday 15 Mar 2011 01:25:51 Michael Brown wrote:
> On Monday 14 Mar 2011 19:57:35 Alex Williamson wrote:
> > Ok, sorry for the distraction, I think I can explain it now.  Last week
> > I was testing large (8G) guests.  Today I was trying to figure out how
> > the pcnet32 image ever worked because I couldn't make the old gpxe or
> > the new ipxe image work.  Eventually I discovered that it worked if I
> > used a smaller guest memory size (512M).  I then used that to test all
> > the images under qemu, followed by kvm.  Unfortunately nothing boots
> > under kvm with a 512M guest.  In fact, I can only boot these ROMs if the
> > guest has 3.6G or more (note that qemu/kvm currently has a 512MB I/O
> > hole, so this means there's memory bounding the hole on both sides).
> >
> > This was introduced with the commit above, 132c3917.  So we've still got
> > a blocker for refreshing the current ROMs.  Thanks,
> Thanks for this.  I can reproduce a PMM failure using the current qemu git
> tree with -enable-kvm.

I think this should be fixed now.  It was a rather nasty bug, in which different 
rounding granularities resulted in writing over the BIOS's PMM data 


I have no idea why this shows up only with KVM enabled.  It should affect KVM 
and non-KVM equally, unless SeaBIOS behaves differently when KVM is enabled.

Thanks for tracking this down.


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