Re: [PATCH] reserve RAM below PHYSICAL_START

Andi Kleen
2008-03-03T12:17:56Z

Andrea Arcangeli <andrea@qumranet.com> writes:

> Hello,
>
> this patch allows to prevent linux from using the ram below
> PHYSICAL_START.
>
> The "reserved RAM" can be mapped by virtualization software with to
> create a 1:1 mapping between guest physical (bus) address and host
> physical (bus) address.

Wouldn't it be easier if your virtualization software just marked
that area reserved or unmapped in its e820 map?

Of if you don't want that you can get the same result with mem=...
arguments (e.g commonly used by crash dumping)

Even if that was all not possible for some reason having CONFIG for this would
seem unfortunate for me -- i don't think users really want specially
compiled kernels for specific hypervisors. With paravirt Linux
is trying to get away from that. Some runtime setup method
would be much better.

-Andi