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=-7.3 required=3.0 tests=BAYES_00,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 EE3CFC433B4 for ; Fri, 23 Apr 2021 12:30:42 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 901A86145F for ; Fri, 23 Apr 2021 12:30:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 901A86145F Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.116267.221913 (Exim 4.92) (envelope-from ) id 1lZuwt-00078Z-PL; Fri, 23 Apr 2021 12:30:19 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 116267.221913; Fri, 23 Apr 2021 12:30:19 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lZuwt-00078S-M0; Fri, 23 Apr 2021 12:30:19 +0000 Received: by outflank-mailman (input) for mailman id 116267; Fri, 23 Apr 2021 12:30:18 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lZuws-00078N-56 for xen-devel@lists.xen.org; Fri, 23 Apr 2021 12:30:18 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 2ec9d2ac-5a52-4bb1-bb0a-87df74ff90a7; Fri, 23 Apr 2021 12:30:16 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id D834EAE58; Fri, 23 Apr 2021 12:30:15 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 2ec9d2ac-5a52-4bb1-bb0a-87df74ff90a7 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1619181015; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=s8gxPmkATKSIBIXbUhMi1EgRjNnqEjOCcHpB6u0MUus=; b=AgJiTZynF5evAffWMnoVetR8oe+SxcBxhcFnUvVDI1qOC6IYKD6Kc/VlP1a+QL31eLoLhZ TggNIV9mnxsvOQxqtSEXUVEN019WZUtAQP/YsROdRQBufQAyXkEu0LYXNp6vjw8jxfA+/v RWyCoePINcOwE5PPOOuSeUuqILn5C0Q= Subject: Re: Fwd: [BUG] Windows is frozen after restore from snapshot To: Sergey Kovalev Cc: zaytsevgu@gmail.com, xen-devel@lists.xen.org References: <6237e102-f2cf-a66e-09b6-954ebfe28f8c@list.ru> <46f8bf3e-cd6e-e2de-94c1-c8a55fb10648@list.ru> From: Jan Beulich Message-ID: <57478641-ed64-32bd-a577-428a50c880e2@suse.com> Date: Fri, 23 Apr 2021 14:30:15 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.10.0 MIME-Version: 1.0 In-Reply-To: <46f8bf3e-cd6e-e2de-94c1-c8a55fb10648@list.ru> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 23.04.2021 12:22, Sergey Kovalev wrote: > # Abstract > > After `xl save win win.mem` and then `xl restore win.hvm win.mem` > the Windows 10 VM remain frozen for about a minute. After the > minute it becomes responsive. > > During the freeze the OS remains semi-responsive: on `Ctrl+Shift+Esc` > press the wait cursor appears (blue circle indicator). > > This is an intermittent fault been reproduced only twice. > > # Technical notes > > It have been noticed that there were no timer interrupts during > the freeze. > > zaytsevgu@gmail.com has debugged the received Xen state file and > noticed that the flag HPET_TN_PERIODIC been set after unfreeze. > > Based on that he provided two Python scripts: one to check the > value and one to patch it. > > Both "broken" state files we have been detected and patched > successfully. "Patched successfully" meaning the guest, when resumed using that state, did not stall initially? In any event, if HPET_TN_PERIODIC was set after unfreeze, it was also set upon saving state. (Or are you suggesting the flag got "magically" set?) In which case we can't go and clear it behind the OS'es back. So I suspect if there is a (rare) problem here, it is likely connected to other parts of the HPET state. Since you've taken apart saved state, could you supply the full set of values (ideally multiple ones, if you happen to have them, plus ones where the problem didn't occur, to allow someone perhaps spot a pattern)? Jan