Re: [PATCH v17 02/10] x86: kdump: make the lower bound of crash kernel reservation consistent

[Borislav Petkov]

On Fri, Dec 10, 2021 at 02:55:25PM +0800, Zhen Lei wrote:
> From: Chen Zhou <chenzhou10@xxxxxxxxxx>
> 
> The lower bounds of crash kernel reservation and crash kernel low
> reservation are different, use the consistent value CRASH_ALIGN.

A big WHY is missing here to explain why the lower bound of the
allocation range needs to be 16M and why was 0 wrong?

> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 5cc60996eac56d6..6424ee4f23da2cf 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -441,7 +441,8 @@ static int __init reserve_crashkernel_low(void)
>  			return 0;
>  	}
>  
> -	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
> +	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
> +			CRASH_ADDR_LOW_MAX);

You don't have to break this line.

Thx.

-- 
Regards/Gruss,
    Boris.

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