Comment 7 for bug 901305

A little more in-depth comparison between Xen 4.1.1 booting and Xen 3.4.3 not booting dmesg outputs shows for one thing a few maybe minor differences in reserved memory (likely to fit differently sized acpi tables), not being used vector callback and pvops timer and it seems the working case sizes cpu arrays to 15 while the other case only seems to set for the 2 vcpus defined.
The big difference seems to be that in the not working case we get the message about "Trying to unpack rootfs image as initramfs..." right before "Freeing initrd memory: 14228k freed". While in the working case there seems to be a whole lot of acpi and pci init going on. Weirdly the time stamps of the two look to be apart by roughly the same time.
In the working case there is also an error message about xs_reset_watches failed with -38. But don't know where that comes from and whether it has meaning. And the whole big difference may just be due to some trigger getting missed. Just cannot say what is missing here.