linux-kernel - Re: [PATCH] x86/efi: Always map boot service regions into new EFI page tables

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Date:	Sun, 13 Mar 2016 21:58:47 +0000
From:	Matt Fleming <matt@...eblueprint.co.uk>
To:	Scott Ashcroft <scott.ashcroft@...k21.com>
Cc:	Ingo Molnar <mingo@...nel.org>, "H . Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ard Biesheuvel <ard.biesheuvel@...aro.org>,
	linux-kernel@...r.kernel.org, linux-efi@...r.kernel.org,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Matthew Garrett <mjg59@...f.ucam.org>,
	Borislav Petkov <bp@...en8.de>,
	Ben Hutchings <ben@...adent.org.uk>,
	Raphael Hertzog <hertzog@...ian.org>,
	Roger Shimizu <rogershimizu@...il.com>,
	Alexis Murzeau <amurzeau@...il.com>
Subject: Re: [PATCH] x86/efi: Always map boot service regions into new EFI
 page tables

(Fixing Maarten's email address which I botched originally)

On Sun, 13 Mar, at 05:09:35PM, Scott Ashcroft wrote:
> On Fri, 2016-03-11 at 11:19 +0000, Matt Fleming wrote:
> > Some machines have EFI regions in page zero (physical address
> > 0x00000000) and historically that region has been added to the e820
> > map via trim_bios_range(), and ultimately mapped into the kernel page
> > tables. It was not mapped via efi_map_regions() as one would expect.
> > 
> > Alexis reports that with the new separate EFI page tables some boot
> > services regions, such as page zero, are not mapped. This triggers an
> > oops during the SetVirtualAddressMap() runtime call.
> 
> 
> I'm still seeing a failure to boot even with this patch.
> 
> http://www.qzxyz.com/IMG_20160313_164601.jpgSorry for the dodgy photo but the screen has almost a mirror finish.
> 
> Attached is the dmesg from 4.4 with efi=debug memblock=debug

Well, crap. Can you enable CONFIG_EFI_PGT_DUMP and send the dmesg
because it would be good to know how things are mapped before this
patch.

I'd be surprised if the issue you're seeing is related to the one that
Alexis reported. Having corrupt page table structures is a whole new
bag of scary.

Does $(grep pdpe1gb /proc/cpuinfo) show any output on your machine?