From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EE96EC43461 for ; Fri, 4 Sep 2020 19:20:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 18FD3206A5 for ; Fri, 4 Sep 2020 19:20:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 18FD3206A5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=deneb.enyo.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6D7296B0002; Fri, 4 Sep 2020 15:20:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 65FF46B0003; Fri, 4 Sep 2020 15:20:02 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5287B6B0037; Fri, 4 Sep 2020 15:20:02 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0105.hostedemail.com [216.40.44.105]) by kanga.kvack.org (Postfix) with ESMTP id 3A65E6B0002 for ; Fri, 4 Sep 2020 15:20:02 -0400 (EDT) Received: from smtpin19.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id DE9083633 for ; Fri, 4 Sep 2020 19:20:01 +0000 (UTC) X-FDA: 77226344202.19.way95_610671b270b4 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin19.hostedemail.com (Postfix) with ESMTP id 841B71AD1B5 for ; Fri, 4 Sep 2020 19:20:01 +0000 (UTC) X-HE-Tag: way95_610671b270b4 X-Filterd-Recvd-Size: 2706 Received: from albireo.enyo.de (albireo.enyo.de [37.24.231.21]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Fri, 4 Sep 2020 19:20:00 +0000 (UTC) Received: from [172.17.203.2] (helo=deneb.enyo.de) by albireo.enyo.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) id 1kEHFf-0005Q2-Bo; Fri, 04 Sep 2020 19:19:59 +0000 Received: from fw by deneb.enyo.de with local (Exim 4.92) (envelope-from ) id 1kEHFf-0003P6-8r; Fri, 04 Sep 2020 21:19:59 +0200 From: Florian Weimer To: Adalbert =?utf-8?Q?Laz=C4=83r?= Cc: linux-mm@kvack.org, linux-api@vger.kernel.org, Andrew Morton , Alexander Graf , Stefan Hajnoczi , Jerome Glisse , Paolo Bonzini , Mihai =?utf-8?Q?Don=C8=9Bu?= , Mircea Cirjaliu , Andy Lutomirski , Arnd Bergmann , Sargun Dhillon , Aleksa Sarai , Oleg Nesterov , Jann Horn , Kees Cook , Matthew Wilcox , Christian Brauner Subject: Re: [RESEND RFC PATCH 0/5] Remote mapping References: <20200904113116.20648-1-alazar@bitdefender.com> Date: Fri, 04 Sep 2020 21:19:59 +0200 In-Reply-To: <20200904113116.20648-1-alazar@bitdefender.com> ("Adalbert \=\?utf-8\?Q\?Laz\=C4\=83r\=22's\?\= message of "Fri, 4 Sep 2020 14:31:11 +0300") Message-ID: <87pn71gxi8.fsf@mid.deneb.enyo.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 841B71AD1B5 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: * Adalbert Laz=C4=83r: >>> - the control plane accepts three ioctls >>> >>> PIDFD_MEM_MAP takes a struct like >>> >>> struct pidfd_mem_map { >>> uint64_t address; >>> off_t offset; >>> off_t size; >>> int flags; >>> int padding[7]; >>> } >>> >>> After this is done, the memory access fd can be mmap-ed at range >>> [offset, >>> offset+size), and it will read memory from range [address, >>> address+size) of the target descriptor. >>> >>> PIDFD_MEM_UNMAP takes a struct like >>> >>> struct pidfd_mem_unmap { >>> off_t offset; >>> off_t size; >>> } >>> >>> and unmaps the corresponding range of course. off_t depends on preprocessor macros (_FILE_OFFSET_BITS), so these types should be uint64_t, too. I'm not sure what the advantage is of returning separate file descriptors, and nit operating directly on the pidfd.