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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,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 5A665C43381 for ; Thu, 28 Feb 2019 23:20:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 204932075B for ; Thu, 28 Feb 2019 23:20:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551396014; bh=XB3UiBzB3HqFLT6vnRpMzyXAIPdB2LC8DyZLwc/27ik=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=whefQ0WGCexrIEwdH0q1vp9LSExIrzepw5pIyvhsPxrKVNVCKX9OIfAevViy7htam bmrnIc2SuanqxNigXV1dNWQYQ0UbJo6xwVhQJPkljp5VsJ6kMLGw9eppY4zmE8W0mr SAGBRys3l4Da5zyCZrlLQPto8liT8VHt4zQWSCK4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729353AbfB1XUK (ORCPT ); Thu, 28 Feb 2019 18:20:10 -0500 Received: from mga06.intel.com ([134.134.136.31]:4373 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727988AbfB1XUK (ORCPT ); Thu, 28 Feb 2019 18:20:10 -0500 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 28 Feb 2019 15:20:07 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,425,1544515200"; d="scan'208";a="138087648" Received: from unknown (HELO localhost.localdomain) ([10.232.112.69]) by orsmga002.jf.intel.com with ESMTP; 28 Feb 2019 15:20:06 -0800 Date: Thu, 28 Feb 2019 16:20:22 -0700 From: Keith Busch To: Austin.Bolen@dell.com Cc: hch@infradead.org, Alex_Gagniuc@Dellteam.com, torvalds@linux-foundation.org, keith.busch@intel.com, sagi@grimberg.me, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, axboe@fb.com, mr.nuke.me@gmail.com, hch@lst.de, jonathan.derrick@intel.com Subject: Re: [PATCH] nvme-pci: Prevent mmio reads if pci channel offline Message-ID: <20190228232020.GB22003@localhost.localdomain> References: <20190225155501.GI10237@localhost.localdomain> <940d608e1a044a54abcb9d65923951f3@ausx13mps317.AMER.DELL.COM> <443262761d0e41fbb46a46dab28759c2@AUSX13MPC131.AMER.DELL.COM> <20190228141655.GA18319@infradead.org> <883e2fad8f6e4791bfee2ec08992da39@AUSX13MPC131.AMER.DELL.COM> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <883e2fad8f6e4791bfee2ec08992da39@AUSX13MPC131.AMER.DELL.COM> User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 28, 2019 at 11:10:11PM +0000, Austin.Bolen@dell.com wrote: > I'd also note that in PCIe, things that intentionally take the link down > like SBR or Link Disable suppress surprise down error reporting. But > NSSR doesn't have this requirement to suppress surprise down reporting. > I think that's a gap on the part of the NVMe spec. SBR and Link Disable are done from the down stream port, though, so the host can still communicate with the function that took the link down. That's entirely different than taking the link down from the end device, so I'm not sure how NVMe can fix that. But I can't even recall why NVMe defined NSSR to require PCIe LTSSM Detect. That seems entirely unnecessary and is just asking for trouble.