Re: [PATCH 0/2 RESEND v7] add reserved e820 ranges to the kdump kernel e820 table

Borislav Petkov
2018-11-26T18:04:55Z

On Mon, Nov 26, 2018 at 09:44:46AM -0800, Dave Hansen wrote:
> On 11/23/18 9:12 PM, Lianbo Jiang wrote:
> > These patches add the new I/O resource descriptor 'IORES_DESC_RESERVED'
> > for the iomem resources search interfaces, and in order to make it still
> > work after the new descriptor is added, these codes originally related
> > to 'IORES_DESC_NONE' have been updated.
>
> I'm having a really hard time figuring out what problem these patches solve.
>
> What end-user visible behavior does this set change?

Yeah, that was a long process of digging out the "why".

I'd recommend reading the previous threads and, more specifically:

https://lkml.kernel.org/r/CABhMZUUscS3jUZUSM5Y6EYJK6weo7Mjj5-EAKGvbw0qEe%2B38zw@mail.gmail.com

in short: we need to export e820 reserved ranges to the second kernel so
that it can talk to PCI devices properly. (And I'm wondering how it did
work until now...)

--
Regards/Gruss,
Boris.

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