[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] read-only pagetable entries


  • To: Tim Deegan <Tim.Deegan@xxxxxxxxxx>
  • From: Srujan Kotikela <ksrujandas@xxxxxxxxx>
  • Date: Mon, 20 Jun 2011 07:33:02 -0500
  • Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
  • Delivery-date: Mon, 20 Jun 2011 05:34:14 -0700
  • Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=Fi2ZJIuGPHh199np9tJVJ/H2nIwI9jsSqY2Audf1tv35m6zxZZ7hQ3Pu7KiTfpDwce 3hIjXF1FeH7KlML3f5hVKzvBaqMhoqbEcogLqpix/t2650s29JepWQJUT2Ct3f6PQaOu EXNIVkBgEEed5fQ1n98V59iTzxBmZIuMzAir0=
  • List-id: Xen developer discussion <xen-devel.lists.xensource.com>

Sorry,

Clicked reply instead of reply-to-all.

--
Srujan D. Kotikela


On Mon, Jun 20, 2011 at 7:10 AM, Tim Deegan <Tim.Deegan@xxxxxxxxxx> wrote:
Hi,

Please don't take discussions off-list.  Cc'ing xen-devel again.

At 12:58 +0100 on 20 Jun (1308574721), Srujan Kotikela wrote:
> Hi,
>
> Thanks for the prompt reply. Can you tell me how to achieve the same
> in PV guests?

In PV guests you could try turning on shadow paging and enforcing the same
read-only idea (but PV guests don't have a p2m table so that will be
messy; you might be able to hook gmfn_to_mfn?).  Or you could update the
PV pagetable interface to require the guest to make the PTE read-only
(by hooking adjust_guest_l1e or similar).  That would have much better
performance but might need changes to the guest kernel to cope with its
PTEs being read-only.

> Also is there any standard/official documentation for
> Xen's memory management?

Not really, no.  The basic ideas are laid out in the original Xen papers
and in some of the Xen books that have been published but there's no
technical documentation for the code except what's in comments and HG
log entries.

Tim.

--
Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Principal Software Engineer, Xen Platform Team
Citrix Systems UK Ltd.  (Company #02937203, SL9 0BG)

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.