Xen devel - Dec 2011 - mapping virtual address to corresponding shadow page in xen

hi,

How can I get corresponding shadowed page number of a virtual address in vm?

-- 
Best Regards,
Mohamad Rezaei

At 16:06 +0330 on 24 Dec (1324742798), Mohamad Rezaei
wrote:
> hi,
> 
> How can I get corresponding shadowed page number of a virtual address in
vm?
I''m afraid I don''t know what you mean. 

Please read this: http://wiki.xen.org/wiki/AskingXenDevelQuestions
and try again.

Cheers,

Tim.

My question is when I want to read a data from domain, I use
copy_from_guest. but now I want to map that address in domain (guest)
to an address inside xen (hypervisor). I need to translate that
address. somehow like this: gva -> gpfn -> gmfn -> mfn. To do this I
have started a dom0 with dom0_shadow=1 option. So I presume that vtx
is enabled for dom0.

Best Regards
Mohamad Rezaei
--------------------
Distributed Systems Research Laboratory
Computer Engineering Department
Iran University of Science and Technology



On Sat, Dec 24, 2011 at 4:19 PM, Tim Deegan <tim@xen.org>
wrote:
> At 16:06 +0330 on 24 Dec (1324742798), Mohamad Rezaei wrote:
>> hi,
>>
>> How can I get corresponding shadowed page number of a virtual address
in vm?
>
> I''m afraid I don''t know what you mean.
>
> Please read this: http://wiki.xen.org/wiki/AskingXenDevelQuestions
> and try again.
>
> Cheers,
>
> Tim.

Hi, 

At 16:26 +0330 on 24 Dec (1324744009), Mohamad Rezaei
wrote:
> My question is when I want to read a data from domain, I use
> copy_from_guest. but now I want to map that address in domain (guest)
> to an address inside xen (hypervisor). I need to translate that
> address. somehow like this: gva -> gpfn -> gmfn -> mfn. To do this
I
> have started a dom0 with dom0_shadow=1 option. So I presume that vtx
> is enabled for dom0.
Actually shadow pagetables are quite separate from VT-x (and predate it
- they were originally used for live migratoin of PV guests).  So no,
dom0_shadow=1 doesn''t turn on VT-x for dom0.

Luckily, you don''t need VT-x to map a page of dom0 memory (in fact it
wouldn''t help).

Have a look at mem_event_enable() in xen/arch/x86/mm/mem_event.c - it
does exactly wat you need, starting with VA ring_addr and ending with a
mapping in med->ring_page.

Cheers, 

Tim.