Comment 4 for bug 174140

I was experiencing a similar problem with a hvm windows XP domU.

Specifying a smaller pool of memory for my dom0 appears to have made it go away for now.

ie. in my grub configuration I added a dom0_mem parameter to the end of my kernel line:

title Xen 3.1 / Ubuntu 7.10, kernel 2.6.22-14-xen
root (hd0,0)
kernel /xen-3.1.gz com2=115200 console=com2l dom0_mem=524288
module /vmlinuz-2.6.22-14-xen root=/dev/mapper/store-chalmers--root ro console=tty0 console=xvc xencons=xvc swiotlb=64
module /initrd.img-2.6.22-14-xen
quiet

Hasn't failed yet, although I have not done exhaustive testing. Just thought I'd share a potential workaround.