grant table issue

grant table issue

[Xin Zhao]

Hi,

I am trying to export a memory page of dom0 to a domU in readonly mode. 
In dom0, I grant access permission to that domU. In domU, I did
 HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map, res->nr_pages);

All these functions returned successfully. But when I tried to access 
data in the mapped memory page, all data I got is 0. 

Is there any restriction that preventing dom0 pages from being export to 
other domains? If so, is there any way to relax this restriction?

xin

Re: grant table issue

[Keir Fraser]

On 9 Jun 2006, at 09:47, Xin Zhao wrote:

> I am trying to export a memory page of dom0 to a domU in readonly 
> mode. In dom0, I grant access permission to that domU. In domU, I did
> HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map, res->nr_pages);
>
> All these functions returned successfully. But when I tried to access 
> data in the mapped memory page, all data I got is 0.
> Is there any restriction that preventing dom0 pages from being export 
> to other domains? If so, is there any way to relax this restriction?

No, there are no such restrictions.

  -- Keir

Grant Table Issue

[ashoka xen]

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Hello

I am facing a problem in using grant tables. DomU allocates a page and
passes grant reference to Dom0. When Dom0 tries to map the shared page, it
gives following error:

(XEN) grant_table.c:264:d0 Bad flags (1) or dom (1). (expected dom 0)

Here DomU (id 1) shared a page for read-write access and Dom0 tried to map
it using GNTMAP_host_map, read-write access. CPU is x86, PAE enabled, tried
Xen-3.1.3 and Xen-3.1.4. - same error for both.

If same code is written in two modules - one for DomU and other for Dom0.
First a module is inserted into DomU and later other module is inserted into
Dom0, the code works fine.

When searched for similar problem, I found following link:

http://lists.xensource.com/archives/html/xen-ppc-devel/2006-06/msg00234.html

Is this a similar problem ?

Regards,
Ashoka

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Re: Grant Table Issue

[ashoka xen]

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Sorry for trouble. It was my mistake.
gnttab_grant_foreign_access requires Dom0's domain id
whereas gnttab_set_map_op requires DomU's domain id.

Regards,
Ashoka


On Thu, May 29, 2008 at 3:31 PM, ashoka xen <ashoka.xen@gmail.com> wrote:

> Hello
>
> I am facing a problem in using grant tables. DomU allocates a page and
> passes grant reference to Dom0. When Dom0 tries to map the shared page, it
> gives following error:
>
> (XEN) grant_table.c:264:d0 Bad flags (1) or dom (1). (expected dom 0)
>
> Here DomU (id 1) shared a page for read-write access and Dom0 tried to map
> it using GNTMAP_host_map, read-write access. CPU is x86, PAE enabled, tried
> Xen-3.1.3 and Xen-3.1.4. - same error for both.
>
> If same code is written in two modules - one for DomU and other for Dom0.
> First a module is inserted into DomU and later other module is inserted into
> Dom0, the code works fine.
>
> When searched for similar problem, I found following link:
>
>
> http://lists.xensource.com/archives/html/xen-ppc-devel/2006-06/msg00234.html
>
> Is this a similar problem ?
>
> Regards,
> Ashoka
>

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