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 for kexec@lists.infradead.org; Mon, 26 May 2014 01:53:27 +0000
Date: Mon, 26 May 2014 09:52:56 +0800
From: Dave Young <dyoung@redhat.com>
Subject: Re: [PATCH] x86: do not enable efi boot for sgi uv machine
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To: Vivek Goyal <vgoyal@redhat.com>
Cc: horms@verge.net.au, kexec@lists.infradead.org, Borislav Petkov <bp@suse.de>, matt.fleming@intel.com

On Fri, May 23, 2014 at 11:54:27AM -0400, Vivek Goyal wrote:
> On Fri, May 23, 2014 at 09:47:08AM -0400, Dave Young wrote:
> > Hi,
> > 
> > Vivek, replying with webmail, sorry for the formatting issue.
> > 
> > Another way is export the mapping scheme in sysfs. So if kernel boot
> > with efi=old_map we can detect it as well. OTOH in future there's probably
> > other quirk system.
> > 
> > So kexec-tools can switch to use old way if kernel use ioremap.
> 
> Exporting type of mapping being used in current kernel and automatically
> deciding that whether to boot with efi or noefi sounds reasonable to me.
> I am assuming that once type of mapping got fixed in first kernel boot
> it can't be changed in subsequent kernel boots?

Right, 2nd kernel will continue to use the original mapping because we can
only call the firmware function once to enter virtual mode. 

Thanks
Dave

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