From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Cooper <andrew.cooper3@citrix.com>
Subject: Re: [PATCH RFC 11/31] xen/x86: Calculate Raw featureset
Date: Tue, 22 Dec 2015 17:27:18 +0000
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To: Jan Beulich <JBeulich@suse.com>
Cc: Tim Deegan <tim@xen.org>, Ian Campbell <Ian.Campbell@citrix.com>, Xen-devel <xen-devel@lists.xen.org>
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On 22/12/15 17:14, Jan Beulich wrote:
>>>> On 16.12.15 at 22:24, <andrew.cooper3@citrix.com> wrote:
>> Calculate and expose the raw featureset to userspace.  This is for
>> informational purposes; the difference between the raw and the host
>> featuresets are the features Xen has specifically chosen not to use.
> And what use is this? Looks like dead code to me...

It is specifically needed by XenServers toolstack to safely import VMs
from older versions.  I expect the same will be true for any other
toolstack which attempted to do multi-host levelling, although libxl
doesn't need it because it doesn't even pretend do to levelling.

It turns out that it is also needed to correct the AMD SEP check in
patch 10.

~Andrew