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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,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 94365C43603 for ; Mon, 9 Dec 2019 17:23:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 653C52073D for ; Mon, 9 Dec 2019 17:23:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="ZtJwfcJ6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726538AbfLIRXu (ORCPT ); Mon, 9 Dec 2019 12:23:50 -0500 Received: from smtp-fw-2101.amazon.com ([72.21.196.25]:63542 "EHLO smtp-fw-2101.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726265AbfLIRXu (ORCPT ); Mon, 9 Dec 2019 12:23:50 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1575912229; x=1607448229; h=from:to:cc:subject:date:message-id:references: in-reply-to:content-transfer-encoding:mime-version; bh=/o/DIuVt0siT0/xDHQSqGb+p+hsUxtlaap2ta8gFs3c=; b=ZtJwfcJ6q9uQaK7W3CuLy9rooxW6Lj2cG5JwBehMS74EoCelKy14v8cV WCrrclUrTOjHX+WCeydmnEcdZaSlxMyWaXL8RybjQpgeunI3BTnJZV8M+ gBy6WzOGI8zJhJhTpKkB4/8LVcc7qX5t0LfAosTg5ndmQrUJ5ivpwb1PP g=; IronPort-SDR: hUDG+2m+V51DMKrCpX/G/TdEZw/vlZOyeUKcewJhYdAI+7Eurg8b2SUBXrdD1VZAEKboO9MI7O f64BC+pBLA6w== X-IronPort-AV: E=Sophos;i="5.69,296,1571702400"; d="scan'208";a="7775052" Received: from iad6-co-svc-p1-lb1-vlan2.amazon.com (HELO email-inbound-relay-2c-168cbb73.us-west-2.amazon.com) ([10.124.125.2]) by smtp-border-fw-out-2101.iad2.amazon.com with ESMTP; 09 Dec 2019 17:23:43 +0000 Received: from EX13MTAUEA001.ant.amazon.com (pdx4-ws-svc-p6-lb7-vlan2.pdx.amazon.com [10.170.41.162]) by email-inbound-relay-2c-168cbb73.us-west-2.amazon.com (Postfix) with ESMTPS id 67D19A1DB8; Mon, 9 Dec 2019 17:23:41 +0000 (UTC) Received: from EX13D32EUC002.ant.amazon.com (10.43.164.94) by EX13MTAUEA001.ant.amazon.com (10.43.61.82) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Mon, 9 Dec 2019 17:23:40 +0000 Received: from EX13D32EUC003.ant.amazon.com (10.43.164.24) by EX13D32EUC002.ant.amazon.com (10.43.164.94) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Mon, 9 Dec 2019 17:23:40 +0000 Received: from EX13D32EUC003.ant.amazon.com ([10.43.164.24]) by EX13D32EUC003.ant.amazon.com ([10.43.164.24]) with mapi id 15.00.1367.000; Mon, 9 Dec 2019 17:23:39 +0000 From: "Durrant, Paul" To: =?iso-8859-1?Q?Roger_Pau_Monn=E9?= CC: "linux-kernel@vger.kernel.org" , "xen-devel@lists.xenproject.org" , "Juergen Gross" , Stefano Stabellini , "Boris Ostrovsky" Subject: RE: [Xen-devel] [PATCH 2/4] xenbus: limit when state is forced to closed Thread-Topic: [Xen-devel] [PATCH 2/4] xenbus: limit when state is forced to closed Thread-Index: AQHVq3SCoU35oX1INEGjFwMD1PQM5aexs7UAgAAEsBCAAAg3gIAAAevggAAghQCAAAFgMIAACyOAgAAHopCAABsYgIAAAH5A Date: Mon, 9 Dec 2019 17:23:39 +0000 Message-ID: <5851d5c9424d4df088af96b24dca1906@EX13D32EUC003.ant.amazon.com> References: <20191205140123.3817-1-pdurrant@amazon.com> <20191205140123.3817-3-pdurrant@amazon.com> <20191209113926.GS980@Air-de-Roger> <19b5c2fa36b842e58bbdddd602c4e672@EX13D32EUC003.ant.amazon.com> <20191209122537.GV980@Air-de-Roger> <54e3cd3a42d8418d9a36388315deab13@EX13D32EUC003.ant.amazon.com> <20191209142852.GW980@Air-de-Roger> <20191209151339.GZ980@Air-de-Roger> <20191209171757.GC980@Air-de-Roger> In-Reply-To: <20191209171757.GC980@Air-de-Roger> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.43.164.211] Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > -----Original Message----- > From: Roger Pau Monn=E9 > Sent: 09 December 2019 17:18 > To: Durrant, Paul > Cc: linux-kernel@vger.kernel.org; xen-devel@lists.xenproject.org; Juergen > Gross ; Stefano Stabellini ; > Boris Ostrovsky > Subject: Re: [Xen-devel] [PATCH 2/4] xenbus: limit when state is forced t= o > closed >=20 > On Mon, Dec 09, 2019 at 04:26:15PM +0000, Durrant, Paul wrote: > > > > If you want unbind to actually do a proper unplug then that's extra > work > > > and not really something I want to tackle (and re-bind would still > need to > > > be toolstack initiated as something would have to re-create the > xenstore > > > area). > > > > > > Why do you say the xenstore area would need to be recreated? > > > > > > Setting state to closed shouldn't cause any cleanup of the xenstore > > > area, as that should already happen for example when using pvgrub > > > since in that case grub itself disconnects and already causes a > > > transition to closed and a re-attachment afterwards by the guest > > > kernel. > > > > > > > For some reason, when I originally tested, the xenstore area > disappeared. I checked again and it did not this time. I just ended up > with a frontend stuck in state 5 (because it is the system disk and won't > go offline) trying to talk to a non-existent backend. Upon re-bind the > backend goes into state 5 (because it sees the 5 in the frontend) and > leaves the guest wedged. >=20 > Likely blkfront should go back to init state, but anyway, that's not > something that needs fixing as part of this series. >=20 Ok, cool. I am wondering though whether we ought to suppress bind/unbind for drivers = that don't whitelist themselves (through the new xenbus_driver flag that I'= ll add). It's somewhat misleading that the nodes are there but don't necess= arily work. Paul