Ubuntu 11.04 (amd64 and i386) under Xen as PV on HVM guests don't load the PV drivers.

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

So  I tried to load the Ubuntu 11.04 - both x86 and amd64 with this
little guest config:

kernel = "/usr/lib/xen/boot/hvmloader"
builder='hvm'
memory=1024
maxvcpus = 2
serial='pty'
vcpus = 2
disk = [ 'file:/home/konrad/Downloads/ubuntu-11.10-desktop-amd64.iso,hdc:cdrom,r','phy:/dev/vg_guest/ubuntu1110,hda,w']
boot="dn"
vif = [ 'type=ioemu,model=e1000,mac=00:0f:4b:00:00:66, bridge=switch' ]
vnc=1
vnclisten="0.0.0.0"
usb=1
xen_platform_pci=1
usbdevice='tablet'

And found out that the i386 does not have PAE built in, so the whole Xen
subsystem is turned off (oops) - that actually looks like a bug b/c I think
the PV drivers in HVM mode ought to work in non-PAE mode.. It means that
the guest is running completly as HVM.

But then I thought - surely the x86_64 should work. So botted it up, saw
xen-platform-pci do the unplugging off the QEMU drivers, and .. then no
network nor any disk - it looks like both xen-netfront and xen-blkfront
don't get loaded? Looking in /lib/modules/*/ shows that they exist - so they
are compiled in.

Is that a known bug or should I open a BZ for that? Thanks.