linux-kernel - Re: [PATCH] Remove warning in efi_enter_virtual

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Message-ID: <20130418164457.GB6884@leaf>
Date:	Thu, 18 Apr 2013 09:44:58 -0700
From:	Josh Triplett <josh@...htriplett.org>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	Matt Fleming <matt@...sole-pimps.org>,
	Bryan O'Donoghue <bryan.odonoghue.lkml@...us-software.ie>,
	matthew.garrett@...ula.com, linux-efi@...r.kernel.org,
	x86@...nel.org, linux-kernel@...r.kernel.org,
	Darren Hart <darren.hart@...el.com>,
	Ingo Molnar <mingo@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Josh Boyer <jwboyer@...hat.com>
Subject: Re: [PATCH] Remove warning in efi_enter_virtual_mode

On Thu, Apr 18, 2013 at 09:38:04AM -0700, H. Peter Anvin wrote:
> On 04/18/2013 09:33 AM, Josh Triplett wrote:
> > On Thu, Apr 18, 2013 at 12:00:26PM +0100, Matt Fleming wrote:
> >>> No, no - we *don't* have a BGRT object at all.
> >>>
> >>> We have a completely clean memory map - but the BGRT code is causing the
> >>> is_ram() failure.
> >>  
> >> You assume that mapping of the Boot Services regions is done purely for
> >> the benefit of pulling out the bgrt image - it's not, see the above
> >> commit log - and I assumed that you had an ACPI bgrt pointer in your
> >> memory map, but you don't.
> >>
> >> Darren, Josh, have you ever seen an i386 machine with a bgrt pointer? If
> >> not, and given that we've never seen an i386 firmware that requires the
> >> above workaround from Matthew, combined with the fact that there are so
> >> few i386 implementations out there, I'm inclined to apply the patch
> >> below, because anything else is a lot more work. We can address this
> >> properly if we ever start seeing i386 machines with bgrt pointers that
> >> reference highmem.
> > 
> > The machine I developed the BGRT changes on kept the image below the 4G
> > mark, inside one of the memory regions reclaimable via
> > ExitBootServices().
> 
> Well, highmem is >= ~896M.  Do you have a machine with BGRT over the
> highmem mark?

I don't have the machine in question anymore, and I don't remember.

- Josh Triplett
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