lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Tue, 10 Aug 2021 14:20:08 -0700 From: Andi Kleen <ak@...ux.intel.com> To: Dave Hansen <dave.hansen@...el.com>, "Kirill A. Shutemov" <kirill@...temov.name>, Borislav Petkov <bp@...en8.de>, Andy Lutomirski <luto@...nel.org>, Sean Christopherson <seanjc@...gle.com>, Andrew Morton <akpm@...ux-foundation.org>, Joerg Roedel <jroedel@...e.de> Cc: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>, David Rientjes <rientjes@...gle.com>, Vlastimil Babka <vbabka@...e.cz>, Tom Lendacky <thomas.lendacky@....com>, Thomas Gleixner <tglx@...utronix.de>, Peter Zijlstra <peterz@...radead.org>, Paolo Bonzini <pbonzini@...hat.com>, Ingo Molnar <mingo@...hat.com>, Varad Gautam <varad.gautam@...e.com>, Dario Faggioli <dfaggioli@...e.com>, x86@...nel.org, linux-mm@...ck.org, linux-coco@...ts.linux.dev, linux-kernel@...r.kernel.org, "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com> Subject: Re: [PATCH 1/5] mm: Add support for unaccepted memory > These boot blips are not the biggest issue in the world. But, it is > fully under the guest's control and I think the guest has some > responsibility to provide *some* mitigation for it. It sounds more like an exercise in preliminary optimization at this point. If it's a real problem we can still worry about it later. > 1. Do background acceptance, as opposed to relying 100% on demand-driven > acceptance. Guarantees a limited window in which blips can occur. Like Kirill wrote this was abandoned because it always allocates all memory on the host even if the guest doesn't need it. > 2. Do acceptance based on user input, like from sysfs. You can easily do that by running "memhog" at boot. No need for anything in the kernel. BTW I believe this is also configurable at the guest BIOS level. > 3. Add a command-line argument to accept everything up front, or at > least before userspace runs. Same. > 4. Add some statistic for how much unaccepted memory remains. Yes that makes sense. We should have statistic counters for all of this. Also I agree with your suggestion that we should get the slow path out of the zone locks/interrupt disable region. That should be easy enough and is an obvious improvement. -Andi
Powered by blists - more mailing lists