linux-kernel - Re: [PATCH 1/5] x86: validate against acpi motherboard resources

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Date:	Sun, 17 Feb 2008 15:06:16 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Yinghai Lu <Yinghai.Lu@....COM>
cc:	Ingo Molnar <mingo@...e.hu>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Greg KH <greg@...ah.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/5] x86: validate against acpi motherboard resources

On Fri, 15 Feb 2008, Yinghai Lu wrote:
> From: Robert Hancock <hancockr@...w.ca>
> 
> This path adds validation of the MMCONFIG table against the ACPI reserved
> motherboard resources.  If the MMCONFIG table is found to be reserved in
> ACPI, we don't bother checking the E820 table.  The PCI Express firmware
> spec apparently tells BIOS developers that reservation in ACPI is required
> and E820 reservation is optional, so checking against ACPI first makes
> sense.  Many BIOSes don't reserve the MMCONFIG region in E820 even though
> it is perfectly functional, the existing check needlessly disables MMCONFIG
> in these cases.
> 
> In order to do this, MMCONFIG setup has been split into two phases.  If PCI
> configuration type 1 is not available then MMCONFIG is enabled early as
> before.  Otherwise, it is enabled later after the ACPI interpreter is
> enabled, since we need to be able to execute control methods in order to
> check the ACPI reserved resources.  Presently this is just triggered off
> the end of ACPI interpreter initialization.
> 
> There are a few other behavioral changes here:
> 
> - Validate all MMCONFIG configurations provided, not just the first one.
> 
> - Validate the entire required length of each configuration according to
>   the provided ending bus number is reserved, not just the minimum required
>   allocation.
> 
> - Validate that the area is reserved even if we read it from the chipset
>   directly and not from the MCFG table.  This catches the case where the
>   BIOS didn't set the location properly in the chipset and has mapped it
>   over other things it shouldn't have.
> 
> This also cleans up the MMCONFIG initialization functions so that they
> simply do nothing if MMCONFIG is not compiled in.
> 
> Based on an original patch by Rajesh Shah from Intel.

Applied. Thanks,

	 tglx
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