Re: [PATCH 2/4] x86/amd_nb: add support for newer PCI topologies

From: Borislav Petkov
Date: Mon Nov 05 2018 - 16:42:43 EST


On Mon, Nov 05, 2018 at 08:33:34PM +0000, Woods, Brian wrote:
> I think having them togeter is cleaner. If you aren't finding any
> misc IDs, I highly doubt you'll find any root IDs. There shouldn't
> be much of a difference in how fast the function exits, either way.
> If you want it the other way though, I don't mind changing it.

Yes please. Because this is the usual kernel coding style of calling a
function (or a loop which has some result in this case) and testing that
result immediately after the function call.

> Would
>
> /*
> * If there are more PCI root devices than data fabric/
> * system management network interfaces, then the (N)
> * PCI roots per DF/SMN interface are functionally the
> * same (for DF/SMN access) and N-1 are redundant. The
> * N-1 PCI roots should be skipped per DF/SMN interface
> * so the DF/SMN interfaces get mapped to the correct
> * PCI root.

You say "correct" as there is a special one. But the text before it says
they're "functionally the same" wrt DF/SMN access so it sounds to me
like we wanna map the first one we find and ignore the others.

I.e., we wanna say

"... so the DF/SMN interfaces get mapped to the *first* PCI root and the
others N-1 ignored."

Or am I misreading this?

Thx.

--
Regards/Gruss,
Boris.

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