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=-4.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 2F5E7C433E0 for ; Fri, 31 Jul 2020 17:48:41 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EEDC621744 for ; Fri, 31 Jul 2020 17:48:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="NVVxcC3P" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EEDC621744 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6E70D6B0099; Fri, 31 Jul 2020 13:48:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 696FC6B009A; Fri, 31 Jul 2020 13:48:40 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 587188D000B; Fri, 31 Jul 2020 13:48:40 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0133.hostedemail.com [216.40.44.133]) by kanga.kvack.org (Postfix) with ESMTP id 44E7E6B0099 for ; Fri, 31 Jul 2020 13:48:40 -0400 (EDT) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id F350C8248047 for ; Fri, 31 Jul 2020 17:48:39 +0000 (UTC) X-FDA: 77099106000.13.quill51_191092526f85 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin13.hostedemail.com (Postfix) with ESMTP id C47A818140B70 for ; Fri, 31 Jul 2020 17:48:39 +0000 (UTC) X-HE-Tag: quill51_191092526f85 X-Filterd-Recvd-Size: 4906 Received: from mail-qk1-f195.google.com (mail-qk1-f195.google.com [209.85.222.195]) by imf31.hostedemail.com (Postfix) with ESMTP for ; Fri, 31 Jul 2020 17:48:39 +0000 (UTC) Received: by mail-qk1-f195.google.com with SMTP id u64so29500580qka.12 for ; Fri, 31 Jul 2020 10:48:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=PgavFM9fv9RyVhfrzNoVsCZw1UsAPzbtBmN1LRCEpDI=; b=NVVxcC3PrAhlWdWZAWXxQH3YnlOFLgOFSt9l4fAQh5s9CGD+7SfmnH7YtjzVCrmpAL /yoy1xD/5Y3ppQ/nvRTkHrv4u9eJ2hIDdvbPZvVyBWzSnVn4Q1ZI6Ogru6RAZXtl9WNZ jHZQMgE64oC3noQpXLWf3N6gOB4ERfg3ihC16yTOCMhwlAvGABhNAPpSfLKnWw2rdN2l ATEDeLEF7WEbyWs3zItzJaX/FLJuVcoO3JorFxvMhgyU24GVw2xIRGKxJ8Bh12drH+w0 /ZR4XSjBm0Hr4fb7q1NoZQ/bqna8kQn6OutHIE+wtJzCRTc29vF8cZQKnO/JZK9zM+dl kQbA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=PgavFM9fv9RyVhfrzNoVsCZw1UsAPzbtBmN1LRCEpDI=; b=mJJ0YhMtoJad2VGFiW47zZfn8aILwuxlntuVR2eyrcH4xmg5InhsmvDgsd54K6pqNv ETxXRACv+DRjVctyZXmR9vuo6iFzG76gxZqOZgNnN8wgi37lJXnoGYDJG51RvWMl7vnA PB2kANuGCqBfryvBt+pWHmVeNeaMd/IzEEOVU+QXg1SHmD4e3HXajawHd73LVuebVB6T hIOLtaL1Ai20j3If+67+gbbRPbu6DzcxiuEkuJHbIvD/fTWB/bzSIyauQaVF+3qBeTnh VrPL67nHSV3/WvpEKOgknlVzDgxkjYbw23uk4tsD8eoGGXMDYFA3+8CXhEhC2kuDlOQ4 dhlA== X-Gm-Message-State: AOAM533TEHQV5L5DLdweA0f98STbZQTw3YOiGWZIxDjd/suZ2V7glrDn 1BpKaVraVvpQnWXdO4NS1/ELOg== X-Google-Smtp-Source: ABdhPJz0MnmxY5FGxiJd/Rlf5vNi7glj7xvlTjk3q/iCWrbWoe08wUQotvFp9C66WBoUIiITj3nu9g== X-Received: by 2002:a37:b942:: with SMTP id j63mr5170964qkf.138.1596217718437; Fri, 31 Jul 2020 10:48:38 -0700 (PDT) Received: from ziepe.ca (hlfxns017vw-156-34-48-30.dhcp-dynamic.fibreop.ns.bellaliant.net. [156.34.48.30]) by smtp.gmail.com with ESMTPSA id 22sm8910314qkd.64.2020.07.31.10.48.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 31 Jul 2020 10:48:37 -0700 (PDT) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1k1Z93-002AAS-77; Fri, 31 Jul 2020 14:48:37 -0300 Date: Fri, 31 Jul 2020 14:48:37 -0300 From: Jason Gunthorpe To: Steven Sistare Cc: Matthew Wilcox , "Eric W. Biederman" , Anthony Yznaga , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, mhocko@kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, arnd@arndb.de, keescook@chromium.org, gerg@linux-m68k.org, ktkhai@virtuozzo.com, christian.brauner@ubuntu.com, peterz@infradead.org, esyr@redhat.com, christian@kellner.me, areber@redhat.com, cyphar@cyphar.com Subject: Re: [RFC PATCH 0/5] madvise MADV_DOEXEC Message-ID: <20200731174837.GH24045@ziepe.ca> References: <20200730171251.GI23808@casper.infradead.org> <63a7404c-e4f6-a82e-257b-217585b0277f@oracle.com> <20200730174956.GK23808@casper.infradead.org> <87y2n03brx.fsf@x220.int.ebiederm.org> <689d6348-6029-5396-8de7-a26bc3c017e5@oracle.com> <20200731152736.GP23808@casper.infradead.org> <9ba26063-0098-e796-9431-8c1d0c076ffc@oracle.com> <20200731165649.GG24045@ziepe.ca> <71ddd3c1-bb59-3e63-e137-99b88ace454d@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <71ddd3c1-bb59-3e63-e137-99b88ace454d@oracle.com> X-Rspamd-Queue-Id: C47A818140B70 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam01 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: On Fri, Jul 31, 2020 at 01:15:34PM -0400, Steven Sistare wrote: > On 7/31/2020 12:56 PM, Jason Gunthorpe wrote: > > On Fri, Jul 31, 2020 at 12:11:52PM -0400, Steven Sistare wrote: > >>> Your preservation-across-exec use-case might or might not need the > >>> VMA to be mapped at the same address. > >> > >> It does. qemu registers memory with vfio which remembers the va's in kernel > >> metadata for the device. > > > > Once the memory is registered with vfio the VA doesn't matter, vfio > > will keep the iommu pointing at the same physical pages no matter > > where they are mapped. > > Yes, but there are other code paths that compute and use offsets between va and the > base va. Mapping at a different va in the new process breaks vfio; I have tried it. Maybe you could fix vfio instead of having this adventure, if vfio is the only motivation. Jason