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Subject: Re: [PATCH] x86/mm: Do not shuffle CPU entry areas without KASLR
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To:     =?UTF-8?Q?Michal_Koutn=c3=bd?= <mkoutny@suse.com>,
        linux-kernel@vger.kernel.org, x86@kernel.org
Cc:     Dave Hansen <dave.hansen@linux.intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>
References: <20230303160645.3594-1-mkoutny@suse.com>
From:   Dave Hansen <dave.hansen@intel.com>
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On 3/3/23 08:06, Michal Koutný wrote:
> @@ -29,6 +30,12 @@ static __init void init_cea_offsets(void)
>  	unsigned int max_cea;
>  	unsigned int i, j;
>  
> +	if (!kaslr_memory_enabled()) {
> +		for_each_possible_cpu(i)
> +			per_cpu(_cea_offset, i) = i;
> +		return;
> +	}

Should this be kaslr_memory_enabled() or kaslr_enabled()?

The delta seems to be CONFIG_KASAN, and the cpu entry area randomization
works just fine with KASAN after some recent fixes.  I _think_ that
makes cpu entry area randomization more like module randomization which
would point toward kaslr_enabled().