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=-5.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 80484C433E2 for ; Sun, 19 Jul 2020 01:50:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5874222B4B for ; Sun, 19 Jul 2020 01:50:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="E2fwWQu2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726256AbgGSBuw (ORCPT ); Sat, 18 Jul 2020 21:50:52 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:50630 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726359AbgGSBuw (ORCPT ); Sat, 18 Jul 2020 21:50:52 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 06J1gVUj104805; Sun, 19 Jul 2020 01:49:54 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2020-01-29; bh=EaYL3Q9q6QNFTsvFEQW1LskL6r73jcbI3lEAanfcPTk=; b=E2fwWQu2Q5dkhtuwVH5Y2Z2unfGCUoCMV6BXjJKvXnmibNWZcABC11FQYejv+oyjHLBN vrCAM6xBhwmK0c4Eo5V/E3ai6h9XLmBBywUUBX9U1y6dkiPLqgXW6uJqCFiQTZ7q7/wJ sLuE1aPoSPEL2prhFotkVJZFdjR/zINp5hdp0h7a7UNAvVPR6lS+Cxxs0T/bxiaBtpbc lbuJaZH2oyM8kOSWfMQlBZRnQodmyksJRBR3rKOvs1jfKcvjcYGhsgMh3fcJMcmOq1mH G7bLP72vcVlBMIUipDMLYu4iNnu21ffwfzh9zrFCro+tL5JubkUUXrDQtZ85qOvxs2Qr Ow== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2130.oracle.com with ESMTP id 32brgr258a-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Sun, 19 Jul 2020 01:49:54 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 06J1loiU070561; Sun, 19 Jul 2020 01:47:54 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserp3030.oracle.com with ESMTP id 32canj2wcp-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sun, 19 Jul 2020 01:47:54 +0000 Received: from abhmp0019.oracle.com (abhmp0019.oracle.com [141.146.116.25]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 06J1lAXW028549; Sun, 19 Jul 2020 01:47:14 GMT Received: from [10.39.198.189] (/10.39.198.189) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Sun, 19 Jul 2020 01:47:09 +0000 Subject: Re: [PATCH v2 01/11] xen/manage: keep track of the on-going suspend mode To: Anchal Agarwal Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, x86@kernel.org, jgross@suse.com, linux-pm@vger.kernel.org, linux-mm@kvack.org, kamatam@amazon.com, sstabellini@kernel.org, konrad.wilk@oracle.com, roger.pau@citrix.com, axboe@kernel.dk, davem@davemloft.net, rjw@rjwysocki.net, len.brown@intel.com, pavel@ucw.cz, peterz@infradead.org, eduval@amazon.com, sblbir@amazon.com, xen-devel@lists.xenproject.org, vkuznets@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, dwmw@amazon.co.uk, benh@kernel.crashing.org References: <20200702182136.GA3511@dev-dsk-anchalag-2a-9c2d1d96.us-west-2.amazon.com> <50298859-0d0e-6eb0-029b-30df2a4ecd63@oracle.com> <20200715204943.GB17938@dev-dsk-anchalag-2a-9c2d1d96.us-west-2.amazon.com> <0ca3c501-e69a-d2c9-a24c-f83afd4bdb8c@oracle.com> <20200717191009.GA3387@dev-dsk-anchalag-2a-9c2d1d96.us-west-2.amazon.com> From: Boris Ostrovsky Autocrypt: addr=boris.ostrovsky@oracle.com; keydata= xsFNBFH8CgsBEAC0KiOi9siOvlXatK2xX99e/J3OvApoYWjieVQ9232Eb7GzCWrItCzP8FUV PQg8rMsSd0OzIvvjbEAvaWLlbs8wa3MtVLysHY/DfqRK9Zvr/RgrsYC6ukOB7igy2PGqZd+M MDnSmVzik0sPvB6xPV7QyFsykEgpnHbvdZAUy/vyys8xgT0PVYR5hyvhyf6VIfGuvqIsvJw5 C8+P71CHI+U/IhsKrLrsiYHpAhQkw+Zvyeml6XSi5w4LXDbF+3oholKYCkPwxmGdK8MUIdkM d7iYdKqiP4W6FKQou/lC3jvOceGupEoDV9botSWEIIlKdtm6C4GfL45RD8V4B9iy24JHPlom woVWc0xBZboQguhauQqrBFooHO3roEeM1pxXjLUbDtH4t3SAI3gt4dpSyT3EvzhyNQVVIxj2 FXnIChrYxR6S0ijSqUKO0cAduenhBrpYbz9qFcB/GyxD+ZWY7OgQKHUZMWapx5bHGQ8bUZz2 SfjZwK+GETGhfkvNMf6zXbZkDq4kKB/ywaKvVPodS1Poa44+B9sxbUp1jMfFtlOJ3AYB0WDS Op3d7F2ry20CIf1Ifh0nIxkQPkTX7aX5rI92oZeu5u038dHUu/dO2EcuCjl1eDMGm5PLHDSP 0QUw5xzk1Y8MG1JQ56PtqReO33inBXG63yTIikJmUXFTw6lLJwARAQABzTNCb3JpcyBPc3Ry b3Zza3kgKFdvcmspIDxib3Jpcy5vc3Ryb3Zza3lAb3JhY2xlLmNvbT7CwXgEEwECACIFAlH8 CgsCGwMGCwkIBwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEIredpCGysGyasEP/j5xApopUf4g 9Fl3UxZuBx+oduuw3JHqgbGZ2siA3EA4bKwtKq8eT7ekpApn4c0HA8TWTDtgZtLSV5IdH+9z JimBDrhLkDI3Zsx2CafL4pMJvpUavhc5mEU8myp4dWCuIylHiWG65agvUeFZYK4P33fGqoaS VGx3tsQIAr7MsQxilMfRiTEoYH0WWthhE0YVQzV6kx4wj4yLGYPPBtFqnrapKKC8yFTpgjaK jImqWhU9CSUAXdNEs/oKVR1XlkDpMCFDl88vKAuJwugnixjbPFTVPyoC7+4Bm/FnL3iwlJVE qIGQRspt09r+datFzPqSbp5Fo/9m4JSvgtPp2X2+gIGgLPWp2ft1NXHHVWP19sPgEsEJXSr9 tskM8ScxEkqAUuDs6+x/ISX8wa5Pvmo65drN+JWA8EqKOHQG6LUsUdJolFM2i4Z0k40BnFU/ kjTARjrXW94LwokVy4x+ZYgImrnKWeKac6fMfMwH2aKpCQLlVxdO4qvJkv92SzZz4538az1T m+3ekJAimou89cXwXHCFb5WqJcyjDfdQF857vTn1z4qu7udYCuuV/4xDEhslUq1+GcNDjAhB nNYPzD+SvhWEsrjuXv+fDONdJtmLUpKs4Jtak3smGGhZsqpcNv8nQzUGDQZjuCSmDqW8vn2o hWwveNeRTkxh+2x1Qb3GT46uzsFNBFH8CgsBEADGC/yx5ctcLQlB9hbq7KNqCDyZNoYu1HAB Hal3MuxPfoGKObEktawQPQaSTB5vNlDxKihezLnlT/PKjcXC2R1OjSDinlu5XNGc6mnky03q yymUPyiMtWhBBftezTRxWRslPaFWlg/h/Y1iDuOcklhpr7K1h1jRPCrf1yIoxbIpDbffnuyz kuto4AahRvBU4Js4sU7f/btU+h+e0AcLVzIhTVPIz7PM+Gk2LNzZ3/on4dnEc/qd+ZZFlOQ4 KDN/hPqlwA/YJsKzAPX51L6Vv344pqTm6Z0f9M7YALB/11FO2nBB7zw7HAUYqJeHutCwxm7i BDNt0g9fhviNcJzagqJ1R7aPjtjBoYvKkbwNu5sWDpQ4idnsnck4YT6ctzN4I+6lfkU8zMzC gM2R4qqUXmxFIS4Bee+gnJi0Pc3KcBYBZsDK44FtM//5Cp9DrxRQOh19kNHBlxkmEb8kL/pw XIDcEq8MXzPBbxwHKJ3QRWRe5jPNpf8HCjnZz0XyJV0/4M1JvOua7IZftOttQ6KnM4m6WNIZ 2ydg7dBhDa6iv1oKdL7wdp/rCulVWn8R7+3cRK95SnWiJ0qKDlMbIN8oGMhHdin8cSRYdmHK kTnvSGJNlkis5a+048o0C6jI3LozQYD/W9wq7MvgChgVQw1iEOB4u/3FXDEGulRVko6xCBU4 SQARAQABwsFfBBgBAgAJBQJR/AoLAhsMAAoJEIredpCGysGyfvMQAIywR6jTqix6/fL0Ip8G jpt3uk//QNxGJE3ZkUNLX6N786vnEJvc1beCu6EwqD1ezG9fJKMl7F3SEgpYaiKEcHfoKGdh 30B3Hsq44vOoxR6zxw2B/giADjhmWTP5tWQ9548N4VhIZMYQMQCkdqaueSL+8asp8tBNP+TJ PAIIANYvJaD8xA7sYUXGTzOXDh2THWSvmEWWmzok8er/u6ZKdS1YmZkUy8cfzrll/9hiGCTj u3qcaOM6i/m4hqtvsI1cOORMVwjJF4+IkC5ZBoeRs/xW5zIBdSUoC8L+OCyj5JETWTt40+lu qoqAF/AEGsNZTrwHJYu9rbHH260C0KYCNqmxDdcROUqIzJdzDKOrDmebkEVnxVeLJBIhYZUd t3Iq9hdjpU50TA6sQ3mZxzBdfRgg+vaj2DsJqI5Xla9QGKD+xNT6v14cZuIMZzO7w0DoojM4 ByrabFsOQxGvE0w9Dch2BDSI2Xyk1zjPKxG1VNBQVx3flH37QDWpL2zlJikW29Ws86PHdthh Fm5PY8YtX576DchSP6qJC57/eAAe/9ztZdVAdesQwGb9hZHJc75B+VNm4xrh/PJO6c1THqdQ 19WVJ+7rDx3PhVncGlbAOiiiE3NOFPJ1OQYxPKtpBUukAlOTnkKE6QcA4zckFepUkfmBV1wM Jg6OxFYd01z+a+oL Message-ID: <5464f384-d4b4-73f0-d39e-60ba9800d804@oracle.com> Date: Sat, 18 Jul 2020 21:47:04 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200717191009.GA3387@dev-dsk-anchalag-2a-9c2d1d96.us-west-2.amazon.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9686 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=100 suspectscore=0 malwarescore=0 phishscore=0 spamscore=100 mlxscore=100 bulkscore=0 adultscore=0 mlxlogscore=-1000 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007190011 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9686 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=100 malwarescore=0 bulkscore=0 spamscore=100 impostorscore=0 suspectscore=0 adultscore=0 clxscore=1015 mlxlogscore=-1000 priorityscore=1501 phishscore=0 lowpriorityscore=0 mlxscore=100 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007190010 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org (Roger, question for you at the very end) On 7/17/20 3:10 PM, Anchal Agarwal wrote: > On Wed, Jul 15, 2020 at 05:18:08PM -0400, Boris Ostrovsky wrote: >> CAUTION: This email originated from outside of the organization. Do no= t click links or open attachments unless you can confirm the sender and k= now the content is safe. >> >> >> >> On 7/15/20 4:49 PM, Anchal Agarwal wrote: >>> On Mon, Jul 13, 2020 at 11:52:01AM -0400, Boris Ostrovsky wrote: >>>> CAUTION: This email originated from outside of the organization. Do = not click links or open attachments unless you can confirm the sender and= know the content is safe. >>>> >>>> >>>> >>>> On 7/2/20 2:21 PM, Anchal Agarwal wrote: >>>>> + >>>>> +bool xen_is_xen_suspend(void) >>>> Weren't you going to call this pv suspend? (And also --- is this sus= pend >>>> or hibernation? Your commit messages and cover letter talk about fix= ing >>>> hibernation). >>>> >>>> >>> This is for hibernation is for pvhvm/hvm/pv-on-hvm guests as you may = call it. >>> The method is just there to check if "xen suspend" is in progress. >>> I do not see "xen_suspend" differentiating between pv or hvm >>> domain until later in the code hence, I abstracted it to xen_is_xen_s= uspend. >> >> I meant "pv suspend" in the sense that this is paravirtual suspend, no= t >> suspend for paravirtual guests. Just like pv drivers are for both pv a= nd >> hvm guests. >> >> >> And then --- should it be pv suspend or pv hibernation? >> >> > Ok so I think I am lot confused by this question. Here is what this > function for, function xen_is_xen_suspend() just tells us whether=20 > the guest is in "SHUTDOWN_SUSPEND" state or not. This check is needed > for correct invocation of syscore_ops callbacks registered for guest's > hibernation and for xenbus to invoke respective callbacks[suspend/resum= e > vs freeze/thaw/restore]. > Since "shutting_down" state is defined static and is not directly avail= able > to other parts of the code, the function solves the purpose. > > I am having hard time understanding why this should be called pv > suspend/hibernation unless you are suggesting something else? > Am I missing your point here?=20 I think I understand now what you are trying to say --- it's whether we are going to use xen_suspend() routine, right? If that's the case then sure, you can use "xen_suspend" term. (I'd probably still change xen_is_xen_suspend() to is_xen_suspend()) >>>>> +{ >>>>> + return suspend_mode =3D=3D XEN_SUSPEND; >>>>> +} >>>>> + >>>> +static int xen_setup_pm_notifier(void) >>>> +{ >>>> + if (!xen_hvm_domain()) >>>> + return -ENODEV; >>>> >>>> I forgot --- what did we decide about non-x86 (i.e. ARM)? >>> It would be great to support that however, its out of >>> scope for this patch set. >>> I=E2=80=99ll be happy to discuss it separately. >> >> I wasn't implying that this *should* work on ARM but rather whether th= is >> will break ARM somehow (because xen_hvm_domain() is true there). >> >> > Ok makes sense. TBH, I haven't tested this part of code on ARM and the = series > was only support x86 guests hibernation. > Moreover, this notifier is there to distinguish between 2 PM > events PM SUSPEND and PM hibernation. Now since we only care about PM > HIBERNATION I may just remove this code and rely on "SHUTDOWN_SUSPEND" = state. > However, I may have to fix other patches in the series where this check= may > appear and cater it only for x86 right? I don't know what would happen if ARM guest tries to handle hibernation callbacks. The only ones that you are introducing are in block and net fronts and that's arch-independent. You do add a bunch of x86-specific code though (syscore ops), would something similar be needed for ARM? >>>> And PVH dom0. >>> That's another good use case to make it work with however, I still >>> think that should be tested/worked upon separately as the feature its= elf >>> (PVH Dom0) is very new. >> >> Same question here --- will this break PVH dom0? >> > I haven't tested it as a part of this series. Is that a blocker here? I suspect dom0 will not do well now as far as hibernation goes, in which case you are not breaking anything. Roger? -boris