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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 45012C4321D for ; Fri, 17 Aug 2018 07:09:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E576621878 for ; Fri, 17 Aug 2018 07:09:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E576621878 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726549AbeHQKLX (ORCPT ); Fri, 17 Aug 2018 06:11:23 -0400 Received: from verein.lst.de ([213.95.11.211]:34231 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726094AbeHQKLX (ORCPT ); Fri, 17 Aug 2018 06:11:23 -0400 Received: by newverein.lst.de (Postfix, from userid 2407) id BC35768EF0; Fri, 17 Aug 2018 09:10:09 +0200 (CEST) Date: Fri, 17 Aug 2018 09:10:09 +0200 From: Christoph Hellwig To: Michal Wnukowski Cc: Linus Torvalds , keith.busch@linux.intel.com, Jens Axboe , Sagi Grimberg , Linux Kernel Mailing List , linux-nvme , Keith Busch , yigitfiliz@google.com, Christoph Hellwig Subject: Re: [PATCH] Bugfix for handling of shadow doorbell buffer. Message-ID: <20180817071009.GB11383@lst.de> References: <20180814221735.62804-1-wnukowski@google.com> <20180814225716.GA3224@localhost.localdomain> 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) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 14, 2018 at 06:35:16PM -0700, Michal Wnukowski wrote: > > The other side in this case is not actual controller hardware, but > virtual one (the regular hardware should rely on normal MMIO > doorbells). There could very much be real hardware there. We've made it clear in the spec that while a typical use case is a virtualized controller there is nothing peventing hardware implementations. There have been previous hardware prototypes to use very similar tricks, e.g.: https://www.usenix.org/node/179878