From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Jan Beulich" <jbeulich@novell.com>
Subject: Re: feature flags use
Date: Fri, 10 Nov 2006 15:59:27 +0100
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	<C17A3E57.449F%keir@xensource.com>
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To: xen-devel@lists.xensource.com, Keir Fraser <keir@xensource.com>
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>That flag is treated oddly. Actually we detect if the kernel uses Elf notes
>or whether it has the string PAE=yes[extended]. In either case we notify the
>hypervisor via *vm_assist*! This then decides whether or not we advertise
>the XENFEAT flag to the domU.

I was talking about XENFEAT_pae_pgdir_above_4gb - this flag appears to be
be useless.
Also, regardless of whether you advertise support for the feature to a domU,
the code inside Xen doesn't treat the two cases (kernel with and without this
flag set) differently.

>Anyway, what feature flag do you want to add? Is this to distinguish PV PAE
>guest from PV 64-bit guest?

At this point I was thinking about that hypervisor_virt_start change that the
kernel needs to advertise it can deal with.

Jan