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SubjectRe: [PATCH 1/5] x86: validate against acpi motherboard resources
On Fri, 15 Feb 2008, Yinghai Lu wrote:
> From: Robert Hancock <hancockr@shaw.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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