From mboxrd@z Thu Jan  1 00:00:00 1970
From: George Dunlap <george.dunlap@eu.citrix.com>
Subject: Re: [PATCH RFC v12 14/21] pvh: read_descriptor for PVH
	guests.
Date: Fri, 13 Sep 2013 17:40:35 +0100
Message-ID: <52334003.8060700@eu.citrix.com>
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To: George Dunlap <george.dunlap@eu.citrix.com>
Cc: Keir Fraser <keir@xen.org>, Tim Deegan <tim@xen.org>, Jan Beulich <jan.beulich@suse.com>, xen-devel@lists.xen.org
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On 13/09/13 17:25, George Dunlap wrote:
> This is in preparation for enabling emulated privops for PVH guests.
>
> This one unfortunately has a bit more of an impedance mismatch:
>
> * For PV, the selector is hard-coded in by passing #name in the
>    #define.  For PVH, we have to do a switch statement.
>
> * For PV, given the desrciptor, it can read the resulting base, limit,
>    &c directly; for PVH, we have to read the values currently loaded in the vmcs.
>
> This leads to a rather awkward construct where we *both* read the
> descriptor, *and* specify a selector, and introduce an intermediate function,
> read_descriptor_sel.
>
> Unfortunately, without introducing a rather pointless switch()
> statement to the PV path similar to the one in the PVH path, there's
> no way to make this less awkward.

If anyone has any clever ideas about this one, feel free to chime in...

  -George