Re: [PATCH 1/1] x86/pci: Skip early E820 check for ECAM region

From: Bjorn Helgaas
Date: Thu Apr 18 2024 - 13:10:21 EST


On Wed, Apr 17, 2024 at 08:10:28PM -0700, Kuppuswamy Sathyanarayanan wrote:
>
> On 4/17/24 1:40 PM, Bjorn Helgaas wrote:
> > From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> >
> > Arul, Mateusz, Imcarneiro91, and Aman reported a regression caused by
> > 07eab0901ede ("efi/x86: Remove EfiMemoryMappedIO from E820 map"). On the
> > Lenovo Legion 9i laptop, that commit removes the area containing ECAM from
> > E820, which means the early E820 validation started failing, which meant we
> > didn't enable ECAM in the "early MCFG" path
> ...

> LGTM
>
> Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>

Thanks for taking a look!

> > - if (!early && !acpi_disabled) {
> > + if (early) {
> > +
> > + /*
> > + * Don't try to do this check unless configuration type 1
> > + * is available. How about type 2?
>
> I don't understand why above question is included in the comment. Do
> you think it is better to drop that part of the comment?

The "How about type 2?" questio was added by bb63b4219976 ("x86 pci:
remove checking type for mmconfig probe"). I only moved it and fixed
the capitalization and formatting.

> > - /* Don't try to do this check unless configuration
> > - type 1 is available. how about type 2 ?*/
> > - if (raw_pci_ops)
> > - return is_mmconf_reserved(e820__mapped_all, cfg, dev,
> > - "E820 entry");
> > -
> > return false;
> > }