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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 156BEC352A1 for ; Tue, 6 Dec 2022 14:20:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=0kqoRf+XjnNXwhswsLJCrkOPC8aiO2DP0YqepNTsM5Q=; b=AKvd10fdS8PqhUdVpIoC6aRGOW pp0MI4p/spsfPfJ5XM8PkG6v9EaEL9uWGJqSsuRoJhNRwviYpx1PyWdpBOUAXuubppdRseuHOwwdK Wk1gd98u3ASucHHSGV6hC0qVTJaZrbrjqAyVTXXUTcn23LjnvwUC1sqDQphCFVDDL8akV/1F6GvN0 2Il4WTc8VgfWAoxMDSByc0h316aycx5KDREsjEfmikd5xbk/IXrKDpwRRyAFUSTrPKNNP2olIanKS kaFHsYlhQcdGiVxHbCoWyonAivdjVA1aeZz/pt6C87Wah2HFMZK9GAUTDVeKtdC7aBfNVWop8kR1C ZF6saDrg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1p2YoE-00ATzi-BV; Tue, 06 Dec 2022 14:20:34 +0000 Received: from mail-pj1-x102d.google.com ([2607:f8b0:4864:20::102d]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1p2YoA-00ATwx-LR for linux-nvme@lists.infradead.org; Tue, 06 Dec 2022 14:20:32 +0000 Received: by mail-pj1-x102d.google.com with SMTP id cm20so14576165pjb.1 for ; Tue, 06 Dec 2022 06:20:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=0kqoRf+XjnNXwhswsLJCrkOPC8aiO2DP0YqepNTsM5Q=; b=PoQVjmSy5xTwYFliGZR9OOSDBYM5gBvnpPzZAXulgAt+dJ3Yv8FA4gQGPA91tTC39N LGXjgSMxpNAMzBSzlnp2xg1KYYV/JyCxcLAYFBX2GZBMB0c6RiEu0J9jayvnlM8zlPWG TdNJ79c/8kWJX+0OpcsbH1BvWcP0DQJsxGigdO6dHgXKsTvh4pKLxnIP4dNArwZavnr0 HBz6rREOxYExVSGE1TnP+BVjoIYmJJDAMTGM+K96jzrzY+42XewZ26j/jzggHCY5vxlf 6X+Jvmcwo02YE8V2CwVpCFdPv6KPxJ0YwyCtTTBQptMnF+3oJt9+Bpi5mqqdqf2hToqR FWGQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=0kqoRf+XjnNXwhswsLJCrkOPC8aiO2DP0YqepNTsM5Q=; b=d1Lwv/icTaoimPq7Nb8teebFOHJ1K1w0osq6R4CG1sWVZvCvR18C9QtOOFVI7imQd5 oI7AesOILWMojpttpB7o2nw3PrKOWugZE11VkKEiJLhUhwAoY1tBu0cuZ+11lCCcwPgw ZmacHOkmW3rwyXzkeFm0S3VHGgFR3XRXc13uXdgm3DLTZy6HgP7ClfWpkf/5ewqo9Zxc IU4pzc1z4ipa2AXKBnew/Us47xL0gtt1mbXms5lmfN9J64LeD+PsmLFIQ2gO0i9PLHHx JnXrR9btfuuUUwuyECDe1rM/DQByIxeXu/5lJTMf8qZQ9IVc/ZPEKZVTZU86Y+CPUxdB AlvA== X-Gm-Message-State: ANoB5pk/j4ldgwG95ONGC5cncCssCcv2w/1ogTEBlDBFTd8X9ZmUQyYg kkQJiMg2E7gbr+LfijXr5kwsbw== X-Google-Smtp-Source: AA0mqf5gHYWwo38iLmYp9F1iuP/OVjscdmaIJjaPvl1VQQ29+QjauKFugs2/SKKCFzZz6Vg4bd1Tjw== X-Received: by 2002:a17:902:b184:b0:189:1d01:a4ae with SMTP id s4-20020a170902b18400b001891d01a4aemr71127865plr.93.1670336428643; Tue, 06 Dec 2022 06:20:28 -0800 (PST) Received: from ziepe.ca ([206.223.160.26]) by smtp.gmail.com with ESMTPSA id 17-20020a170902e9d100b0018997f6fc88sm12648048plk.34.2022.12.06.06.20.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Dec 2022 06:20:27 -0800 (PST) Received: from jgg by wakko with local (Exim 4.95) (envelope-from ) id 1p2Yo6-004c0g-KS; Tue, 06 Dec 2022 10:20:26 -0400 Date: Tue, 6 Dec 2022 10:20:26 -0400 From: Jason Gunthorpe To: Christoph Hellwig Cc: Lei Rao , kbusch@kernel.org, axboe@fb.com, kch@nvidia.com, sagi@grimberg.me, alex.williamson@redhat.com, cohuck@redhat.com, yishaih@nvidia.com, shameerali.kolothum.thodi@huawei.com, kevin.tian@intel.com, mjrosato@linux.ibm.com, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, kvm@vger.kernel.org, eddie.dong@intel.com, yadong.li@intel.com, yi.l.liu@intel.com, Konrad.wilk@oracle.com, stephen@eideticom.com, hang.yuan@intel.com Subject: Re: [RFC PATCH 5/5] nvme-vfio: Add a document for the NVMe device Message-ID: References: <20221206055816.292304-1-lei.rao@intel.com> <20221206055816.292304-6-lei.rao@intel.com> <20221206062604.GB6595@lst.de> <20221206130901.GB24358@lst.de> <20221206140002.GB27689@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221206140002.GB27689@lst.de> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221206_062030_940700_31A8BE41 X-CRM114-Status: GOOD ( 17.34 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Tue, Dec 06, 2022 at 03:00:02PM +0100, Christoph Hellwig wrote: > > >From what I understood this series basically allows two Intel devices > > to pass a big opaque blob of data. Intel didn't document what is in > > that blob, so I assume it captures everything you mention above. > > Which would be just as bad, because it then changes the IDs under > the live OS on a restore. This is not something that can be done > behind the back of the hypervisors / control plane OS. Sorry, what live OS? In the VFIO restore model there is no "live OS" on resume. The load/resume cycle is as destructive as reset to the vfio device. When qemu operates vfio the destination CPU will not be running until the load/resume of all the VFIO devices is completed. So from the VM perspective it sees a complete no change, so long as the data blob causes the destination vfio device to fully match the source, including all IDs, etc. Jason