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Re: [Xen-devel] [PATCH] x86-64 linux: unmap temporary mappings establish

To: "Jan Beulich" <jbeulich@xxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] x86-64 linux: unmap temporary mappings established for setup of 1:1 mappings
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Thu, 1 Jun 2006 19:21:40 +0100
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On 31 May 2006, at 14:17, Jan Beulich wrote:

The temporary mappings needed to set up the 1:1 mappings must be torn down after use; otherwise they may trigger the WARN_ON() in vmap_pte_range() (namely if the chunk allocated to hold kernel and initial page tables gets close to or exceeds 128Mb, or if a sufficiently high mem= argument causes the static allocations to grow beyond 128Mb, which in
either case means these mappings extend into the modules area).

I've applied this to -unstable, but in this patch I only see code to destroy the extended init mappings. What happens if you have a really big initrd (for example)? That will push the initial pagetables up into the modules area -- is that handled correctly now or is more fixup required?

Also your patch didn't apply to 3.0-testing. You'll need to supply a version specifically for -testing if you want it applied there.

 -- Keir


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