From: Vlastimil Babka <vbabka@suse.cz>
To: Andi Kleen <ak@linux.intel.com>, Pavel Machek <pavel@ucw.cz>
Cc: mhocko@suse.com, hpa@zytor.com, torvalds@linux-foundation.org,
dave.hansen@intel.com, kernel list <linux-kernel@vger.kernel.org>,
tglx@linutronix.de, mingo@redhat.com, bp@alien8.de
Subject: Re: l1tf: Kernel suggests I throw away third of my memory. I'd rather not
Date: Wed, 17 Oct 2018 16:13:13 +0200 [thread overview]
Message-ID: <c3d8e978-6db2-6637-8a88-e6c1acc2b854@suse.cz> (raw)
In-Reply-To: <20181017140846.GB23838@tassilo.jf.intel.com>
On 10/17/18 4:08 PM, Andi Kleen wrote:
> On Wed, Oct 17, 2018 at 12:56:10PM +0200, Pavel Machek wrote:
>> Hi!
>>
>> 6a012288 suggests I throw away 1GB on RAM. On 3GB system.. that is not
>> going to be pleasant.
>
> Just rebuild your kernel with PAE? I assume your CPU supports it.
I think it is built with PAE or this would kick in:
#if CONFIG_PGTABLE_LEVELS == 2
pr_warn("Kernel not compiled for PAE. No mitigation for L1TF\n");
return;
#endif
I.e. no MAX_PA/2 messages.
> This will also give you NX, which if you're really worried
> about security is far more important than L1TF.
>
> If you don't worry about security just ignore.
>
> -Andi
>
prev parent reply other threads:[~2018-10-17 14:16 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-17 10:56 Pavel Machek
2018-10-17 11:15 ` Michal Hocko
2018-10-17 11:32 ` Pavel Machek
2018-10-17 12:17 ` Michal Hocko
2018-10-17 22:21 ` Dave Hansen
2018-10-18 7:10 ` Vlastimil Babka
2018-10-17 14:08 ` Andi Kleen
2018-10-17 14:13 ` Vlastimil Babka [this message]
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