Re: [PATCH v14 03/13] x86/mm: add INVLPGB support code

From: Borislav Petkov
Date: Fri Feb 28 2025 - 13:47:50 EST


On Tue, Feb 25, 2025 at 10:00:38PM -0500, Rik van Riel wrote:
> Add helper functions and definitions needed to use broadcast TLB
> invalidation on AMD EPYC 3 and newer CPUs.
>
> All the functions defined in invlpgb.h are used later in the series.

Uff, that's tlb.h now. As already said. :-\

Btw, this is why there's no point to write *what* the patch does - that is
visible from the diff itself. This sentence is simply not needed.

> Compile time disabling X86_FEATURE_INVLPGB when the config
> option is not set allows the compiler to omit unnecessary code.
>
> Signed-off-by: Rik van Riel <riel@xxxxxxxxxxx>
> Tested-by: Manali Shukla <Manali.Shukla@xxxxxxx>
> Tested-by: Brendan Jackman <jackmanb@xxxxxxxxxx>
> Tested-by: Michael Kelley <mhklinux@xxxxxxxxxxx>
> Acked-by: Dave Hansen <dave.hansen@xxxxxxxxx>

And I asked you already but still crickets:

What do those Tested-by tags mean if you keep changing the patches?!

https://lore.kernel.org/r/20250224123142.GFZ7xmruuyrc2Wy0r7@fat_crate.local

...

IOW, you need to drop those tags.

> +/* Flush all mappings for all PCIDs except globals. */

This comment should state that addr=0 means both rax[1] (valid PCID) and
rax[2] (valid ASID) are clear and this means: flush *any* PCID and ASID. So
that it is clear.

> +static inline void invlpgb_flush_all_nonglobals(void)
> +{
> + __invlpgb(0, 0, 0, 1, 0, 0);
> + __tlbsync();
> +}
> +
> #endif /* _ASM_X86_TLB_H */
> --

--
Regards/Gruss,
Boris.

https://people.kernel.org/tglx/notes-about-netiquette