From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Rapoport Subject: Re: [PATCH RFC] mm: add MAP_EXCLUSIVE to create exclusive user mappings Date: Sun, 27 Oct 2019 13:00:13 +0200 Message-ID: <385EB6D4-A1B0-4617-B256-181AA1C3BDE3@kernel.org> References: <1572171452-7958-1-git-send-email-rppt@kernel.org> <87d0eieb0i.fsf@mid.deneb.enyo.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <87d0eieb0i.fsf@mid.deneb.enyo.de> Sender: linux-kernel-owner@vger.kernel.org To: Florian Weimer Cc: linux-kernel@vger.kernel.org, Alexey Dobriyan , Andrew Morton , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Dave Hansen , James Bottomley , Peter Zijlstra , Steven Rostedt , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , linux-api@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, Mike Rapoport List-Id: linux-api@vger.kernel.org On October 27, 2019 12:30:21 PM GMT+02:00, Florian Weimer wrote: >* Mike Rapoport: > >> The patch below aims to allow applications to create mappins that >have >> pages visible only to the owning process=2E Such mappings could be used >to >> store secrets so that these secrets are not visible neither to other >> processes nor to the kernel=2E > >How is this expected to interact with CRIU? CRIU dumps the memory contents using a parasite code from inside the dumpe= e address space, so it would work the same way as for the other mappings=2E= Of course, at the restore time the exclusive mapping should be recreated w= ith the appropriate flags=2E >> I've only tested the basic functionality, the changes should be >verified >> against THP/migration/compaction=2E Yet, I'd appreciate early feedback= =2E > >What are the expected semantics for VM migration? Should it fail? I don't quite follow=2E If qemu would use such mappings it would be able t= o transfer them during live migration=2E --=20 Sincerely yours, Mike