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Re: [Xen-devel] update_va_mapping_otherdomain

To: mhines@xxxxxxxxxxxxxxxxx
Subject: Re: [Xen-devel] update_va_mapping_otherdomain
From: "Michael R. Hines" <mhines@xxxxxxxxxxxxxxxxx>
Date: Sat, 08 Sep 2007 14:27:51 -0400
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So, if I would like to use dom0 to modify a specific L1 PTE belonging
to another unprivileged domain, what's the best way to go about it?

Grant references? (on L1 page tables?)

Might I be able to get a quick pointer on the right sequence of hypercalls?

Much appreciated,
- Michael

Michael R. Hines wrote:
> ooooh, ok. I understand now.
> Thank you very much for your response. =)
> - Michael
> Keir Fraser wrote:
>> On 8/9/07 02:29, "Michael R. Hines" <mhines@xxxxxxxxxxxxxxxxx> wrote:
>>> Upon successful return from update_va_mapping (i.e. return code == zero),
>>> my problem involves the last step mentioned above. The present bit still
>>> remains unchanged (is still one), although update_va_mapping return true.
>>> What might cause such a strange problem to occur?
>> That hypercall allows you to update a *local* va mapping to map *another*
>> domain's memory page. So you've mapped the guest's page somewhere random in
>> your own address space.
>>  -- Keir
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Michael R. Hines
Live long and prosper...

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