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Re: [Xen-devel] Read-only locking of Guest Memory pages

From: Srujan Kotikela <ksrujandas@xxxxxxxxx>

Date: Thu, 16 Jun 2011 07:38:13 -0500

Delivery-date: Thu, 16 Jun 2011 05:41:48 -0700

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List-id: Xen developer discussion <xen-devel.lists.xensource.com>

Also isn't it true that xen maintains these page tables as read only? Correct me, if I am wrong.

--
Srujan D. Kotikela

On Wed, Jun 15, 2011 at 5:05 AM, Tim Deegan <Tim.Deegan@xxxxxxxxxx> wrote:

At 11:38 -0500 on 14 Jun (1308051493), Srujan Kotikela wrote:
> Hi Tim,
>
> I am trying to implement a secure architecture where a process' (selected)
> memory pages have to be set as read-only. The process will send the virtual
> address of pages required (through a custom hypercall) to be set read-only.
> I need to compute the physical address of the pages and set them read-only.

Thanks. In that case I suspect the memory event hypercalls are what you
need. They allow access rights on guest frames to be set from a tool in
dom0. They only work on EPT, though.

Tim.

> On Tue, Jun 14, 2011 at 3:14 AM, Tim Deegan <Tim.Deegan@xxxxxxxxxx> wrote:
>
> > Hi,
> >
> > At 14:52 -0500 on 13 Jun (1307976734), Srujan Kotikela wrote:
> > > Does Xen provide any mechanism to set read-only access/lock on guest's
> > > pages?
> >
> > Yes, Xen has lots of code that makes guest memory read-only for various
> > reasons, and one of them might be suitable. What's your overall goal?
> >
> > (BTW, you might want to read
> > http://wiki.xensource.com/xenwiki/AskingXenDevelQuestions)
> >
> > Cheers,
> >
> > Tim.
> >
> > --
> > Tim Deegan <Tim.Deegan@xxxxxxxxxx>
> > Principal Software Engineer, Xen Platform Team
> > Citrix Systems UK Ltd. (Company #02937203, SL9 0BG)
> >

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--

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

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