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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 AF23FC433DF for ; Fri, 15 May 2020 16:56:02 +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 7B71F206C0 for ; Fri, 15 May 2020 16:56:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=yandex-team.ru header.i=@yandex-team.ru header.b="koGGR1SK" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7B71F206C0 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=yandex-team.ru Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:36680 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jZdcv-00011v-N3 for qemu-devel@archiver.kernel.org; Fri, 15 May 2020 12:56:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:39632) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jZdcA-0000Rj-Dt; Fri, 15 May 2020 12:55:14 -0400 Received: from forwardcorp1o.mail.yandex.net ([95.108.205.193]:54502) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jZdc6-0008T0-JB; Fri, 15 May 2020 12:55:12 -0400 Received: from mxbackcorp2j.mail.yandex.net (mxbackcorp2j.mail.yandex.net [IPv6:2a02:6b8:0:1619::119]) by forwardcorp1o.mail.yandex.net (Yandex) with ESMTP id 7F64D2E1601; Fri, 15 May 2020 19:55:03 +0300 (MSK) Received: from vla5-58875c36c028.qloud-c.yandex.net (vla5-58875c36c028.qloud-c.yandex.net [2a02:6b8:c18:340b:0:640:5887:5c36]) by mxbackcorp2j.mail.yandex.net (mxbackcorp/Yandex) with ESMTP id cinVDSHVo7-sxp0jiQ4; Fri, 15 May 2020 19:55:03 +0300 Precedence: bulk DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex-team.ru; s=default; t=1589561703; bh=3CGiU4Gj12+ohYxtA8wNze8x9w6+K4D4Kp4PKfczGqQ=; h=In-Reply-To:Message-ID:Subject:To:From:References:Date:Cc; b=koGGR1SKgQcri5SFt2f94E/HJe5M5sI9pd/yLehmrFUQAIA/dMEKcA5GEBQg/PaQ4 vh3ZCX2KSbaz0n5Eh4PJcvqZWPAJ4d4B7PZ7R3bwLzL7nqZwTiAn48Aqm3tjsyMuu7 CO4IO2PigZJv/yww6iqGHJ+qiSnN3yAt2hDYKZlo= Authentication-Results: mxbackcorp2j.mail.yandex.net; dkim=pass header.i=@yandex-team.ru Received: from dynamic-vpn.dhcp.yndx.net (dynamic-vpn.dhcp.yndx.net [2a02:6b8:b081:313::1:5]) by vla5-58875c36c028.qloud-c.yandex.net (smtpcorp/Yandex) with ESMTPSA id cUtBCfJT05-sxXup6jc; Fri, 15 May 2020 19:54:59 +0300 (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client certificate not present) Date: Fri, 15 May 2020 19:54:57 +0300 From: Dima Stepanov To: Jason Wang Subject: Re: [PATCH v2 5/5] vhost: add device started check in migration set log Message-ID: <20200515165449.GA1627@dimastep-nix> References: <20200511092541.GA27558@dimastep-nix> <20200512093521.GA5363@dimastep-nix> <20200512235934-mutt-send-email-mst@kernel.org> <20200513094703.GA15906@dimastep-nix> <722839b2-9412-b768-3ce6-d1b697d6d5dd@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <722839b2-9412-b768-3ce6-d1b697d6d5dd@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) Received-SPF: pass client-ip=95.108.205.193; envelope-from=dimastep@yandex-team.ru; helo=forwardcorp1o.mail.yandex.net X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/15 12:55:04 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: fam@euphon.net, kwolf@redhat.com, yc-core@yandex-team.ru, qemu-block@nongnu.org, "Michael S. Tsirkin" , qemu-devel@nongnu.org, dgilbert@redhat.com, arei.gonglei@huawei.com, fengli@smartx.com, stefanha@redhat.com, marcandre.lureau@redhat.com, pbonzini@redhat.com, raphael.norwitz@nutanix.com, mreitz@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, May 14, 2020 at 03:34:24PM +0800, Jason Wang wrote: > > On 2020/5/13 下午5:47, Dima Stepanov wrote: > >>> case CHR_EVENT_CLOSED: > >>> /* a close event may happen during a read/write, but vhost > >>> * code assumes the vhost_dev remains setup, so delay the > >>> * stop & clear to idle. > >>> * FIXME: better handle failure in vhost code, remove bh > >>> */ > >>> if (s->watch) { > >>> AioContext *ctx = qemu_get_current_aio_context(); > >>> > >>> g_source_remove(s->watch); > >>> s->watch = 0; > >>> qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, NULL, NULL, > >>> NULL, NULL, false); > >>> > >>> aio_bh_schedule_oneshot(ctx, chr_closed_bh, opaque); > >>> } > >>> break; > >>> > >>>I think it's time we dropped the FIXME and moved the handling to common > >>>code. Jason? Marc-André? > >>I agree. Just to confirm, do you prefer bh or doing changes like what is > >>done in this series? It looks to me bh can have more easier codes. > >Could it be a good idea just to make disconnect in the char device but > >postphone clean up in the vhost-user-blk (or any other vhost-user > >device) itself? So we are moving the postphone logic and decision from > >the char device to vhost-user device. One of the idea i have is as > >follows: > > - Put ourself in the INITIALIZATION state > > - Start these vhost-user "handshake" commands > > - If we got a disconnect error, perform disconnect, but don't clean up > > device (it will be clean up on the roll back). I can be done by > > checking the state in vhost_user_..._disconnect routine or smth like it > > > Any issue you saw just using the aio bh as Michael posted above. > > Then we don't need to deal with the silent vhost_dev_stop() and we will have > codes that is much more easier to understand. I've implemented this solution inside hw/block/vhost-user-blk.c:vhost_user_blk_event() in the similar way by using the s->connected field. Looks good and more correct fix ). I have two questions here before i'll rework the fixes: 1. Is it okay to make the similar fix inside vhost_user_blk_event() or we are looking for more generic vhost-user solution? What do you think? 2. For migration we require an additional information that for the vhost-user device it isn't an error, because i'm trigerring the following assert error: Core was generated by `x86_64-softmmu/qemu-system-x86_64 -nodefaults -no-user-config -M q35,sata=false'. Program terminated with signal SIGABRT, Aborted. #0 0x00007fb56e729428 in raise () from /lib/x86_64-linux-gnu/libc.so.6 [Current thread is 1 (Thread 0x7fb486ef5700 (LWP 527734))] (gdb) bt #0 0x00007fb56e729428 in raise () from /lib/x86_64-linux-gnu/libc.so.6 #1 0x00007fb56e72b02a in abort () from /lib/x86_64-linux-gnu/libc.so.6 #2 0x00005648ea376ee6 in vhost_log_global_start (listener=0x5648ece4eb08) at ./hw/virtio/vhost.c:857 #3 0x00005648ea2dde7e in memory_global_dirty_log_start () at ./memory.c:2611 #4 0x00005648ea2e68e7 in ram_init_bitmaps (rs=0x7fb4740008c0) at ./migration/ram.c:2305 #5 0x00005648ea2e698b in ram_init_all (rsp=0x5648eb1f0f20 ) at ./migration/ram.c:2323 #6 0x00005648ea2e6cc5 in ram_save_setup (f=0x5648ec609e00, opaque=0x5648eb1f0f20 ) at ./migration/ram.c:2436 #7 0x00005648ea67b7d3 in qemu_savevm_state_setup (f=0x5648ec609e00) at migration/savevm.c:1176 #8 0x00005648ea674511 in migration_thread (opaque=0x5648ec031ff0) at migration/migration.c:3416 #9 0x00005648ea85d65d in qemu_thread_start (args=0x5648ec6057f0) at util/qemu-thread-posix.c:519 #10 0x00007fb56eac56ba in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0 #11 0x00007fb56e7fb41d in clone () from /lib/x86_64-linux-gnu/libc.so.6 (gdb) frame 2 #2 0x00005648ea376ee6 in vhost_log_global_start (listener=0x5648ece4eb08) at ./hw/virtio/vhost.c:857 857 abort(); (gdb) list 852 { 853 int r; 854 855 r = vhost_migration_log(listener, true); 856 if (r < 0) { 857 abort(); 858 } 859 } 860 861 static void vhost_log_global_stop(MemoryListener *listener) Since bh postphone the clean up, we can't use the ->started field. Do we have any mechanism to get the device type/state in the common vhost_migration_log() routine? So for example for the vhost-user/disconnect device we will be able to return 0. Or should we implement it and introduce it in this patch set? Thanks, Dima. > > Thank > > > > - vhost-user command returns error back to the _start() routine > > - Rollback in one place in the start() routine, by calling this > > postphoned clean up for the disconnect > > >