Messages in this thread | | | Subject | Re: l1tf: Kernel suggests I throw away third of my memory. I'd rather not | From | Dave Hansen <> | Date | Wed, 17 Oct 2018 15:21:00 -0700 |
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On 10/17/2018 04:32 AM, Pavel Machek wrote: >> Well, that depends. Do you care about PROT_NONE attacks as well? If not >> then no-swap would help you. But even then no-swap is rather theoretical >> attack on a physical host unless you allow an arbitrary swapout to a >> malicious user (e.g. allow a user controlled memcg hard limit that would >> cause excessive local swapouts). > PROT_NONE attack.. aha, so kernel stores not only information about > swapped-out pages but also about file-backed pages that are currently > not present? Hmm. That makes it more complex :-(.
There are also migration PTE entries that are "swap-like". They can exist even if you swapoff -a.
Can we do better? Sure. I think we'd all be happy to review patches that improve the situation if folks have simple ideas for improvement.
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