From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keir Fraser Subject: Re: [PATCH] x86: rework hypercall argument translation area setup Date: Thu, 21 Feb 2013 12:57:17 +0000 Message-ID: References: <5126206902000078000BFE26@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5126206902000078000BFE26@nat28.tlf.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich Cc: xen-devel List-Id: xen-devel@lists.xenproject.org On 21/02/2013 12:26, "Jan Beulich" wrote: >> Well, fine in principle. This manual setup/teardown of l2/l1 pagetables in >> the perdomain area is getting a bit tiresome though isn't it? Isn't there >> some setup helper that could be abstracted out for all users, and perhaps >> even some automated teardown-and-freeing on domain destroy? I just sighed >> when I saw more skanky pagetable manipulation for what is a conceptually >> simple change. > > I tried to spot pieces worth folding into helper functions, but > didn't really find anything worthwhile (the purposes of the > mappings are just too different). Perhaps we could have a > map_pages_to_guest(), taking care of all intermediate page > table levels? I can't see much else, and the main problem is that > of tracking pages used for page tables here anyway. Well, possibly even that might be an improvement. > Are we concerned about the performance of guest GDT/LDT page > (un)mappings? LDT must often change on guest process context switch? So I would think yes we do. -- Keir