Re: Change 5c371b31be3203 in stable breaks Xen

[Jeremy Fitzhardinge]

Ian Campbell wrote:
> On Tue, 2008-11-25 at 13:26 -0800, Jeremy Fitzhardinge wrote:
>   
> > I have a report of Xen breaking between 2.6.27.5 and .6.  I bisected
> > it 
> > down to change:
> >
> > commit 5c371b31be32033b0a4a993431484da8a2305369
> > Author: Yinghai Lu <yhlu.kernel@xxxxxxxxx>
> > Date:   Mon Sep 22 02:52:26 2008 -0700
> >
> >     x86: fix CONFIG_X86_RESERVE_LOW_64K=y
> >    
> >     commit 2216d199b1430d1c0affb1498a9ebdbd9c0de439 upstream
> >     
>
> Looks like 5dc64a3442b98eaa0e3730c35fcf00cf962a93e7 might be needed in
> stable too?
>   

Ah, yes, that looks like the right fix.  I'll see if it helps.

   J

>         
>         commit 5dc64a3442b98eaa0e3730c35fcf00cf962a93e7
>         Author: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
>         Date:   Fri Oct 10 11:27:38 2008 +0100
>         
>             xen: do not reserve 2 pages of padding between hypervisor and fixmap.
>             
>             When reserving space for the hypervisor the Xen paravirt backend adds
>             an extra two pages (this was carried forward from the 2.6.18-xen tree
>             which had them "for safety"). Depending on various CONFIG options this
>             can cause the boot time fixmaps to span multiple PMDs which is not
>             supported and triggers a WARN in early_ioremap_init().
>             
>             This was exposed by 2216d199b1430d1c0affb1498a9ebdbd9c0de439 which
>             moved the dmi table parsing earlier.
>                 x86: fix CONFIG_X86_RESERVE_LOW_64K=y
>             
>                 The bad_bios_dmi_table() quirk never triggered because we do DMI setup
>                 too late. Move it a bit earlier.
>             
>             There is no real reason to reserve these two extra pages and the
>             fixmap already incorporates FIX_HOLE which serves the same
>             purpose. None of the other callers of reserve_top_address do this.
>
>
>   

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