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 D5783C352A1 for ; Tue, 6 Dec 2022 15:38:23 +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=TBw4GoLXylEeInY9aM7/58wBqzSxKE5sngF/7k3KKjM=; b=PjUndjzspvwecFyOPSz3ueY1lo n8K3Nvd1MDxeMlC2T5WLlFmvH8HpR/kUSkFeHmk9zLnoWxWvilPJ9OPTJx1kgWhuUvBfCnQDYRzZ5 kV7i69ji65vEjCO8QIScZd3PMtIRZsVRmE038w6KkOzoGz4DjDlmOA+HqSo52k7cvK1AET/FP4Tay /GMX1myRn8N0ByxOyotazIvZALbdhC7zcXjtEbTKmzgpwsqtY8YJEgzo7gf0mlKVQIVGkVQHkVDar IEtrn+ygq/k7pcQOwM9bnZBXVYzIYltuC5sVUoOFw0jZVaA4jKz7WHesj58JwAsS02T8c+1CyHC9p iNuG0UKQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1p2a1T-00Cu1U-7l; Tue, 06 Dec 2022 15:38:19 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1p2a1R-00Ctqs-48 for linux-nvme@lists.infradead.org; Tue, 06 Dec 2022 15:38:18 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 832A468B05; Tue, 6 Dec 2022 16:38:11 +0100 (CET) Date: Tue, 6 Dec 2022 16:38:11 +0100 From: Christoph Hellwig To: Jason Gunthorpe Cc: Christoph Hellwig , 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 1/5] nvme-pci: add function nvme_submit_vf_cmd to issue admin commands for VF driver. Message-ID: <20221206153811.GB2266@lst.de> References: <20221206055816.292304-1-lei.rao@intel.com> <20221206055816.292304-2-lei.rao@intel.com> <20221206061940.GA6595@lst.de> <20221206135810.GA27689@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221206_073817_353150_48ED27BD X-CRM114-Status: GOOD ( 14.72 ) 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 11:22:33AM -0400, Jason Gunthorpe wrote: > > controlled functions (which could very well be, and in some designs > > are, additional PFs and not VFs) by controlling function. > > In principle PF vs VF doesn't matter much - the question is really TLP > labeling. If the spec says RID A is the controlling RID and RID B is > the guest RID, then it doesn't matter if they have a PF/VF > relationship or PF/PF relationship. Yes. Or in fact if you use PASIDs inside a single function. > We have locking issues in Linux SW connecting different SW drivers for > things that are not a PF/VF relationship, but perhaps that can be > solved. And I think the only reasonable answer is that the entire workflow must be 100% managed from the controlling function, and the controlled function is just around for a ride, with the controlling function enabling/disabling it as needed without ever interacting with software that directly deals with the controlled function.