Xen devel - Feb 2009 - Reserving a specific range of physical memory for a guest.

Hi,
I am trying to reserve a specific range of physical memory for a special VM
(That memory can only be allocated to this special VM). I need the memory to be
physically contiguous and the size can be around 1GB. I am planning to get the
VM memory requirements (start address and size) from the BIOS e820 tables. For
now I am looking at what xen modifications I need to make this happen? After
navigating the source extensively, I am thinking this can be achieved by
creating a separate e820 entry for that region, and assign that physical memory
to a dummy domain "dom_spec_vm" similar to dom_io, similar to the way
non RAM memory is assigned to dom_io in arch_init_memory. Following this I want
to intercept populate_physmap function and bypass the heap allocator for my
special VM, and I will assign  it the memory I  previously assigned to
dom_spec_vm.
However I am not sure if this will work and how complex it will be? I am yet to
identify other areas that need to be changed. Also I am assuming that the
xen/dom heap will not contain this physical memory, it will be treated just as a
hole in RAM memory correct?
Please let me know if there is a better way to do this? Also can I do this
without bypassing the heap, but reserving certain zones instead?
Please advice.
Thanks,
Annu.


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If you create your domain early enough after boot, perhaps you could just
allocate a contiguous 1GB from the heap without any problem?

 -- Keir

On 11/02/2009 23:18, "Dasari, Annapurna"
<annapurna.dasari@intel.com> wrote:
> However I am not sure if this will work and how complex it will be? I am
yet
> to identify other areas that need to be changed. Also I am assuming that
the
> xen/dom heap will not contain this physical memory, it will be treated just
as
> a hole in RAM memory correct?
> Please let me know if there is a better way to do this? Also can I do this
> without bypassing the heap, but reserving certain zones instead?


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