Amos Waterland wrote:
It would be nice to boot the exact same Linux kernel binary image on
bare hardware and as a Xen dom0 on that same hardware.  At present we
cannot do this: you stop seeing output early in the boot process.

I spent some time using OF output routines to track down the problem,
and it turns out that CONFIG_XEN_DISABLE_SERIAL=y disables all standard
serial device drivers.  So when you boot a kernel compiled with
CONFIG_XEN on bare hardware you stop seeing any output after the RTC is
probed, but the real problem occurs much later when Linux panics because
it can't open an initial console.

The below patch (not for submission) allows the same Linux kernel image to
boot as a dom0 and on bare JS20 hardware.  Note that this patch applies on
top of the "refresh xen_maple_defconfig" patch sent earlier.

The reason it is not for submission is that while it boots on bare JS21
hardware, it fails to boot as a dom0 on the same hardware.  The console
spews a lot of garbage characters and external networking never comes up.

So CONFIG_XEN_DISABLE_SERIAL probably needs turn on some intelligent
runtime probing of whether we are running on bare hardware or on Xen.
If the former, do nothing, if the latter, remove the serial devices from
the list of available consoles.  No?

On our js20 (kpblade4, for those at watson) where I managed to install SLES10 I was able to boot the xen kernel with the modification indicated by Amos using the sles10 rootfs from disk. A few things failed, but overall it was better than expected. I built the linux kernel with the following configuration.

CONFIG_CMDLINE="root=/dev/hda3 ip="

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