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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 E681EC47089 for ; Fri, 28 May 2021 02:06:01 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 77A5961358 for ; Fri, 28 May 2021 02:06:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 77A5961358 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:33788 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lmRsu-0000P9-GR for qemu-devel@archiver.kernel.org; Thu, 27 May 2021 22:06:00 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:38526) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lmRrw-0007VY-3n; Thu, 27 May 2021 22:05:00 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:2486) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lmRrr-0006hR-BA; Thu, 27 May 2021 22:04:59 -0400 Received: from dggeml704-chm.china.huawei.com (unknown [172.30.72.55]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4FrnvH2SB0zWnmb; Fri, 28 May 2021 10:00:11 +0800 (CST) Received: from dggema765-chm.china.huawei.com (10.1.198.207) by dggeml704-chm.china.huawei.com (10.3.17.142) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Fri, 28 May 2021 10:04:47 +0800 Received: from [10.174.185.210] (10.174.185.210) by dggema765-chm.china.huawei.com (10.1.198.207) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Fri, 28 May 2021 10:04:46 +0800 Subject: Re: [PATCH] vfio: Fix unregister SaveVMHandler in vfio_migration_finalize To: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , "Alex Williamson" , Kirti Wankhede , "open list:All patches CC here" References: <20210527123101.289-1-jiangkunkun@huawei.com> From: Kunkun Jiang Message-ID: Date: Fri, 28 May 2021 10:04:35 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Originating-IP: [10.174.185.210] X-ClientProxiedBy: dggeme720-chm.china.huawei.com (10.1.199.116) To dggema765-chm.china.huawei.com (10.1.198.207) X-CFilter-Loop: Reflected Received-SPF: pass client-ip=45.249.212.187; envelope-from=jiangkunkun@huawei.com; helo=szxga01-in.huawei.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Juan Quintela , "Dr. David Alan Gilbert" , qemu-stable@nongnu.org, ganqixin@huawei.com, Zenghui Yu , wanghaibin.wang@huawei.com, Keqian Zhu Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi Philippe, On 2021/5/27 21:44, Philippe Mathieu-Daudé wrote: > On 5/27/21 2:31 PM, Kunkun Jiang wrote: >> In the vfio_migration_init(), the SaveVMHandler is registered for >> VFIO device. But it lacks the operation of 'unregister'. It will >> lead to 'Segmentation fault (core dumped)' in >> qemu_savevm_state_setup(), if performing live migration after a >> VFIO device is hot deleted. >> >> Fixes: 7c2f5f75f94 (vfio: Register SaveVMHandlers for VFIO device) >> Reported-by: Qixin Gan >> Signed-off-by: Kunkun Jiang > Cc: qemu-stable@nongnu.org > >> --- >> hw/vfio/migration.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c >> index 201642d75e..ef397ebe6c 100644 >> --- a/hw/vfio/migration.c >> +++ b/hw/vfio/migration.c >> @@ -892,6 +892,7 @@ void vfio_migration_finalize(VFIODevice *vbasedev) >> >> remove_migration_state_change_notifier(&migration->migration_state); >> qemu_del_vm_change_state_handler(migration->vm_state); >> + unregister_savevm(VMSTATE_IF(vbasedev->dev), "vfio", vbasedev); > Hmm what about devices using "%s/vfio" id? The unregister_savevm() needs 'VMSTATEIf *obj'. If we pass a non-null 'obj' to unregister_svevm(), it will handle the devices using "%s/vfio" id with the following code: >     if (obj) { >         char *oid = vmstate_if_get_id(obj); >         if (oid) { >             pstrcpy(id, sizeof(id), oid); >             pstrcat(id, sizeof(id), "/"); >             g_free(oid); >         } >     } >     pstrcat(id, sizeof(id), idstr); By the way, I'm puzzled that register_savevm_live() and unregister_savevm() handle devices using "%s/vfio" id differently. So I learned the commit history of register_savevm_live() and unregister_savevm(). In the beginning, both them need 'DeviceState *dev', which are replaced with VMStateIf in 3cad405babb. Later in ce62df5378b, the 'dev' was removed, because no caller of register_savevm_live() need to pass a non-null 'dev' at that time. So now the vfio devices need to handle the 'id' first and then call register_savevm_live(). I am wondering whether we need to add 'VMSTATEIf *obj' in register_savevm_live(). What do you think of this? Thanks, Kunkun Jiang > >> vfio_migration_exit(vbasedev); >> } >> >> > .