Re: [PATCH v13 04/14] x86/mm: use INVLPGB for kernel TLB flushes

[Borislav Petkov]

On Sun, Feb 23, 2025 at 02:48:54PM -0500, Rik van Riel wrote:
> Use broadcast TLB invalidation for kernel addresses when available.
> 
> Remove the need to send IPIs for kernel TLB flushes.
> 
> Signed-off-by: Rik van Riel <riel@xxxxxxxxxxx>
> Reviewed-by: Nadav Amit <nadav.amit@xxxxxxxxx>
> Tested-by: Manali Shukla <Manali.Shukla@xxxxxxx>
> Tested-by: Brendan Jackman <jackmanb@xxxxxxxxxx>
> Tested-by: Michael Kelley <mhklinux@xxxxxxxxxxx>

What's the point of keeping those Tested-by tags if you still keep changing
the patchset?

> ---
>  arch/x86/mm/tlb.c | 34 ++++++++++++++++++++++++++++++++--
>  1 file changed, 32 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
> index dbcb5c968ff9..59396a3c6e9c 100644
> --- a/arch/x86/mm/tlb.c
> +++ b/arch/x86/mm/tlb.c
> @@ -1077,6 +1077,20 @@ void flush_tlb_all(void)
>  	on_each_cpu(do_flush_tlb_all, NULL, 1);
>  }
>  
> +static bool invlpgb_kernel_range_flush(struct flush_tlb_info *info)
> +{
> +	unsigned long addr;
> +	unsigned long nr;

Oh, c'mon:

	unsigned long addr, nr;

> +
> +	for (addr = info->start; addr < info->end; addr += nr << PAGE_SHIFT) {
> +		nr = (info->end - addr) >> PAGE_SHIFT;
> +		nr = clamp_val(nr, 1, invlpgb_count_max);
> +		invlpgb_flush_addr_nosync(addr, nr);
> +	}
> +	__tlbsync();
> +	return true;

Unused retval - that function looks like it wants to be void.

-- 
Regards/Gruss,
    Boris.

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