From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Keir Fraser <Keir.Fraser@cl.cam.ac.uk>
Cc: Tim Deegan <Tim.Deegan@xensource.com>,
Ian Pratt <Ian.Pratt@cl.cam.ac.uk>,
xen-devel@lists.xensource.com,
Levin Johnson <levin.johnson@lycos.com>,
Ian Campbell <Ian.Campbell@XenSource.com>
Subject: Re: PV guest + shadow paging
Date: Wed, 24 Oct 2007 11:59:07 -0700 [thread overview]
Message-ID: <471F95FB.8000309@goop.org> (raw)
In-Reply-To: <C344D781.17557%Keir.Fraser@cl.cam.ac.uk>
Keir Fraser wrote:
> On 24/10/07 11:00, "Jeremy Fitzhardinge" <jeremy@goop.org> wrote:
>
>
>> Tim Deegan wrote:
>>
>>> The joy of NPT(VMI?)/EPT is that you don't need shadow pagetables at
>>> all. :)
>>>
>>>
>> Sure, but from a guest interface perspective they look the same.
>>
>
> Would you want to take advantage of NPT/EPT once you've pv'ed your mmu
> interfaces?
>
I think so. NPT/EPT would seem to have all the advantages of shadow
paging and direct paging without the disadvantages. We would avoid
taking faults/hypercalls on pagetable updates, and have the secondary
benefit of not needing to worry about page permissions on pagetables,
making it easier to use superpages for the kernel and in general.
Perhaps the initial implementations will be sufficiently poor that it
isn't worth doing now, but I think it will in time.
J
next prev parent reply other threads:[~2007-10-24 18:59 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-28 15:58 PV guest + shadow paging Levin Johnson
2007-07-29 21:38 ` Ian Pratt
2007-07-30 6:34 ` Ian Campbell
2007-07-30 8:15 ` Tim Deegan
2007-10-22 11:01 ` tgh
2007-10-22 11:20 ` Tim Deegan
2007-10-22 12:01 ` Samuel Thibault
2007-10-23 15:13 ` Mark Williamson
2007-10-24 4:32 ` Jeremy Fitzhardinge
2007-10-24 8:21 ` Tim Deegan
2007-10-24 10:00 ` Jeremy Fitzhardinge
2007-10-24 10:05 ` Keir Fraser
2007-10-24 18:59 ` Jeremy Fitzhardinge [this message]
2007-10-24 20:39 ` Nakajima, Jun
2007-10-24 21:47 ` Jeremy Fitzhardinge
-- strict thread matches above, loose matches on Subject: below --
2007-07-27 19:12 Levin Johnson
2007-07-27 15:54 Levin Johnson
2007-07-26 22:32 Levin Johnson
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