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 7FE70C433DF for ; Mon, 18 May 2020 02:51:41 +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 4512020787 for ; Mon, 18 May 2020 02:51:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="MWZRjrAA" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4512020787 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:44296 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jaVsS-0007dX-Et for qemu-devel@archiver.kernel.org; Sun, 17 May 2020 22:51:40 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:60864) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jaVru-0007Cx-Pr for qemu-devel@nongnu.org; Sun, 17 May 2020 22:51:06 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:41205 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jaVrq-0004F4-Q9 for qemu-devel@nongnu.org; Sun, 17 May 2020 22:51:05 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589770260; h=from:from:reply-to:subject:subject: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=mVM+bHcefveo2YekQP95B9G6kPgYRM8jcXvBwrJuH04=; b=MWZRjrAAMtR0u9o/+7y3AVXhkHl1r6S9DOoQplZj1Jww6Hs6emNRn7rfjpT59B2lhkqEBO /jKB1wpUZSFCeT4q99Njul1OVO8pCNUjOLC0qHJA3ugJ5M+fDgJH5++CjpKRJmCrB6cKgR QXeFPtM7nzqrUSjG/DCqezKYDXnJQ38= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-258-QvYATZQrNWiW8eXtDKDjFg-1; Sun, 17 May 2020 22:50:58 -0400 X-MC-Unique: QvYATZQrNWiW8eXtDKDjFg-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id AD21C10082EB; Mon, 18 May 2020 02:50:56 +0000 (UTC) Received: from [10.72.13.232] (ovpn-13-232.pek2.redhat.com [10.72.13.232]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9999F397; Mon, 18 May 2020 02:50:41 +0000 (UTC) Subject: Re: [PATCH v2 5/5] vhost: add device started check in migration set log To: Dima Stepanov 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> <20200515165449.GA1627@dimastep-nix> From: Jason Wang Message-ID: <553370a5-926b-d9c4-a8ec-8bdc07c94e6e@redhat.com> Date: Mon, 18 May 2020 10:50:39 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200515165449.GA1627@dimastep-nix> Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=205.139.110.120; envelope-from=jasowang@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/17 22:51:00 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_PASS=-0.001 autolearn=_AUTOLEARN 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: 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 2020/5/16 上午12:54, Dima Stepanov wrote: > 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? I think I agree with Michael, it's better to have a generic vhost-user solution. But if it turns out to be not easy, we can start from fixing vhost-user-blk. > 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? This requires more thought, I will reply in Feng's mail. Thanks > > 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 >>>