Re: [PATCH] Reserve low memory

From: Andi Kleen
Date: Mon Oct 22 2007 - 09:53:50 EST


Or Sagi <ors@xxxxxxxxx> writes:

> Adds a CONFIG_RESERVE_LOWMEM option which reserves all memory below
> CONFIG_PHYSICAL_START address.
>
> Cleans up some of the static early-boot memory allocations (nodemap, trampoline)
> Useful in particular for running virtual machines which require a 1:1 mapping
> of the physical memory. This lets a virtual machine control a dma-capable device
> directly without hypervisor involvement.

With the infrastructure in
ftp://firstfloor.org/pub/ak/x86_64/quilt/patches/early-reserve
you can do this much cleaner (and likely safer)

And using CONFIG_* options for such things is wrong anyways. If anything
it should be run time options.

-Andi
>
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