Re: mapping guest domain memory to Dom0

[Adam Thorsen <adam.thorsen@gmail.com>]

I am using the xc_map_foreign_range() function to attempt to map
memory from a guest domain into Domain 0.  I am guessing that the
value named mfn indicates the page in the guest domain that I wish to
start mapping from.

If this assumption is correct,  how do I get a value for mfn?  Say for
instance, that I wanted to map the kernel running in the guest domain?
 How about a specific process?

-Adam Thorsen


On Wed, 2 Feb 2005 15:53:54 +0000, Mark A. Williamson
<mark.williamson@cl.cam.ac.uk> wrote:
> > >Right now, domains which need to map other domains
> > >memory are privileged and can map what they like
> >
> > Is anybody doing this?  If so, what kernel mechanisms are you using?
> > (I'm sure this question is very easy to answer for a kernel hacker)
> 
> Yes, shared memory is an important part of Xen's architecture.
> 
> The userspace xc library and the xcs control switch map another domain's
> memory to put the kernel image, etc into it.  The code for this is in
> tools/libxc/xc_private.c
> 
> The blkback.c, netback.c (and usbback.c if you are on unstable) drivers under
> drivers/xen/{blk,net,usb}back/ show how to map another domain's memory from
> kernel space (it's a bit less user friendly than the userspace interface).
> 
> HTH,
> Mark
>


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