linux-kernel - Re: [PATCH 1/2] x86/boot: fix KASL when memmap range manipulation is used

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Message-ID: <20190211090931.GA2501@localhost>
Date:   Mon, 11 Feb 2019 17:09:31 +0800
From:   Baoquan He <bhe@...hat.com>
To:     Julian Stecklina <js@...en8.de>
Cc:     x86@...nel.org, Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        hpa@...or.com, linux-kernel@...r.kernel.org, jschoenh@...zon.de,
        Julian Stecklina <jsteckli@...zon.de>
Subject: Re: [PATCH 1/2] x86/boot: fix KASL when memmap range manipulation is
 used

On 01/30/19 at 05:40pm, Julian Stecklina wrote:
> diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
> index 9ed9709..5657e34 100644
> --- a/arch/x86/boot/compressed/kaslr.c
> +++ b/arch/x86/boot/compressed/kaslr.c
> @@ -155,6 +155,12 @@ parse_memmap(char *p, unsigned long long *start, unsigned long long *size)
>  	case '#':
>  	case '$':
>  	case '!':
> +		/*
> +		 * % would need some more complex parsing, because regions might
> +		 * actually become usable for KASLR, but the simple way of
> +		 * ignoring anything that is mentioned in % works for now.
> +		 */

This seems to make thing more complicated even though have to. One
concern is whether we need to check the oldtype|newtype , e.g
oldtype=reserverd, newtype=RAM, is it possible to set like that?

Thanks
Baoquan

> +	case '%':
>  		*start = memparse(p + 1, &p);
>  		return 0;
>  	case '@':
> -- 
> 2.7.4
>