Re: [PATCH] ACPI: NUMA: Fix overlap when extending memblks to fill CFMWS

[fan <nifan.cxl@gmail.com>]

On Fri, Dec 22, 2023 at 04:00:25PM -0800, alison.schofield@intel.com wrote:
> From: Alison Schofield <alison.schofield@intel.com>
> 

Reviewed-by: Fan Ni <fan.ni@samsung.com>

> When the BIOS only partially describes a CFMWS Window in the SRAT
> the acpi driver uses numa_fill_memblks() to extend existing memblk(s)
> to fill the entire CFMWS Window, thereby applying the proximity domain
> to the entire CFMWS.
> 
> The calculation of the memblks to fill has an off-by-one error, that
> causes numa_init to fail when it sees the overlap:
> 
> [] ACPI: SRAT: Node 0 PXM 0 [mem 0x00000000-0x7fffffff]
> [] ACPI: SRAT: Node 0 PXM 0 [mem 0x100000000-0xffffffffff]
> [] ACPI: SRAT: Node 1 PXM 1 [mem 0x10000000000-0x1ffffffffff]
> [] node 0 [mem 0x100000000-0xffffffffff] overlaps with node 1 [mem 0x100000000-0x1ffffffffff]
> 
> Fix by making the 'end' parameter to numa_fill_memblks() exclusive.
> 
> Fixes: 8f1004679987 ("ACPI/NUMA: Apply SRAT proximity domain to entire CFMWS window")
> Reported-by: "Huang, Ying" <ying.huang@intel.com>
> Suggested-by: Dan Williams <dan.j.williams@intel.com>
> Signed-off-by: Alison Schofield <alison.schofield@intel.com>
> ---
>  drivers/acpi/numa/srat.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/numa/srat.c b/drivers/acpi/numa/srat.c
> index 12f330b0eac0..b99062f7c412 100644
> --- a/drivers/acpi/numa/srat.c
> +++ b/drivers/acpi/numa/srat.c
> @@ -308,7 +308,7 @@ static int __init acpi_parse_cfmws(union acpi_subtable_headers *header,
>  
>  	cfmws = (struct acpi_cedt_cfmws *)header;
>  	start = cfmws->base_hpa;
> -	end = cfmws->base_hpa + cfmws->window_size;
> +	end = cfmws->base_hpa + cfmws->window_size - 1;
>  
>  	/*
>  	 * The SRAT may have already described NUMA details for all,
> 
> base-commit: b85ea95d086471afb4ad062012a4d73cd328fa86
> -- 
> 2.37.3
>