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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id F4154C433F5 for ; Wed, 2 Mar 2022 18:37:26 +0000 (UTC) Received: from localhost ([::1]:59440 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nPTqo-0007LF-5D for qemu-devel@archiver.kernel.org; Wed, 02 Mar 2022 13:37:26 -0500 Received: from eggs.gnu.org ([209.51.188.92]:36760) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nPTkd-0001Th-D0 for qemu-devel@nongnu.org; Wed, 02 Mar 2022 13:31:03 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:39105) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nPTkb-0000KD-LD for qemu-devel@nongnu.org; Wed, 02 Mar 2022 13:31:03 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1646245861; 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=a8gHke2pCSAMiwh/6LHB8vvYNMwQN7z8KlGxyLEWOVA=; b=PGZ0TAh9Sktfni6jzz/afo1yiaN9MYJto0/w7cnq8fS37iVXNE/mQPx0dqmG0DpRoa2D9x rzL7HWqmL2OOoYYm1VeEHpwVUBMeZw8f97kfV/O3KVv4wqPF5caGDb+TECDrGVWuJTMF+1 7c1up7pYeHRzaua4GT2xOKQcQVCMNFc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-609-5RVStdfBNoqyOClMsgLmQQ-1; Wed, 02 Mar 2022 13:30:57 -0500 X-MC-Unique: 5RVStdfBNoqyOClMsgLmQQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A2DF384A5F3; Wed, 2 Mar 2022 18:30:56 +0000 (UTC) Received: from dgilbert-t580.localhost (unknown [10.33.36.30]) by smtp.corp.redhat.com (Postfix) with ESMTP id EC6A0105916D; Wed, 2 Mar 2022 18:30:54 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, f.ebner@proxmox.com, hreitz@redhat.com, jinpu.wang@ionos.com, peter.maydell@linaro.org, peterx@redhat.com, s.reiter@proxmox.com Subject: [PULL 14/18] migration: Enlarge postcopy recovery to capture !-EIO too Date: Wed, 2 Mar 2022 18:29:32 +0000 Message-Id: <20220302182936.227719-15-dgilbert@redhat.com> In-Reply-To: <20220302182936.227719-1-dgilbert@redhat.com> References: <20220302182936.227719-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII" Received-SPF: pass client-ip=170.10.129.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: quintela@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Peter Xu We used to have quite a few places making sure -EIO happened and that's the only way to trigger postcopy recovery. That's based on the assumption that we'll only return -EIO for channel issues. It'll work in 99.99% cases but logically that won't cover some corner cases. One example is e.g. ram_block_from_stream() could fail with an interrupted network, then -EINVAL will be returned instead of -EIO. I remembered Dave Gilbert pointed that out before, but somehow this is overlooked. Neither did I encounter anything outside the -EIO error. However we'd better touch that up before it triggers a rare VM data loss during live migrating. To cover as much those cases as possible, remove the -EIO restriction on triggering the postcopy recovery, because even if it's not a channel failure, we can't do anything better than halting QEMU anyway - the corpse of the process may even be used by a good hand to dig out useful memory regions, or the admin could simply kill the process later on. Reviewed-by: Dr. David Alan Gilbert Signed-off-by: Peter Xu Message-Id: <20220301083925.33483-11-peterx@redhat.com> Signed-off-by: Dr. David Alan Gilbert --- migration/migration.c | 4 ++-- migration/postcopy-ram.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/migration/migration.c b/migration/migration.c index bcc385b94b..306e2ac60e 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -2865,7 +2865,7 @@ retry: out: res = qemu_file_get_error(rp); if (res) { - if (res == -EIO && migration_in_postcopy()) { + if (res && migration_in_postcopy()) { /* * Maybe there is something we can do: it looks like a * network down issue, and we pause for a recovery. @@ -3466,7 +3466,7 @@ static MigThrError migration_detect_error(MigrationState *s) error_free(local_error); } - if (state == MIGRATION_STATUS_POSTCOPY_ACTIVE && ret == -EIO) { + if (state == MIGRATION_STATUS_POSTCOPY_ACTIVE && ret) { /* * For postcopy, we allow the network to be down for a * while. After that, it can be continued by a diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c index d08d396c63..b0d12d5053 100644 --- a/migration/postcopy-ram.c +++ b/migration/postcopy-ram.c @@ -1039,7 +1039,7 @@ retry: msg.arg.pagefault.address); if (ret) { /* May be network failure, try to wait for recovery */ - if (ret == -EIO && postcopy_pause_fault_thread(mis)) { + if (postcopy_pause_fault_thread(mis)) { /* We got reconnected somehow, try to continue */ goto retry; } else { -- 2.35.1