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 1F644C4321E for ; Tue, 1 Nov 2022 17:28:22 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1opsbn-0005nD-Vl; Tue, 01 Nov 2022 10:51:23 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1opsbl-0005n1-7P for qemu-devel@nongnu.org; Tue, 01 Nov 2022 10:51:17 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1opsbh-000167-Qj for qemu-devel@nongnu.org; Tue, 01 Nov 2022 10:51:15 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1667314272; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=uhD8YOUFjzZgF0lGF9T3GeD5xc/Q0yRByxtlcei+N7s=; b=RxmfAAYteFrS+zwkJ3pQbQXEO1YdN2mro1rC7dPSH0JhMlGuR+uMx+QpwBF5OGy8vGTsSJ mO//ZnrZQiYVxd8WBwGA8qdwPStGL/c4knFCapRkJZZ6CdzklJPoX8MX0NRu+W9HekVWVr MLY+0OPVmDReui2WXrWcxjkJM4OxLO0= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-511-GhVJZDJgOrGmRBv7Sw7C6A-1; Tue, 01 Nov 2022 10:51:09 -0400 X-MC-Unique: GhVJZDJgOrGmRBv7Sw7C6A-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4537A1C08984; Tue, 1 Nov 2022 14:51:09 +0000 (UTC) Received: from redhat.com (unknown [10.33.36.145]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3964B492B18; Tue, 1 Nov 2022 14:51:05 +0000 (UTC) Date: Tue, 1 Nov 2022 14:51:02 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: "manish.mishra" Cc: qemu-devel@nongnu.org, peterx@redhat.com Subject: Re: [PATCH] migration: check magic value for deciding the mapping of channels Message-ID: References: <20221101143029.14246-1-manish.mishra@nutanix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20221101143029.14246-1-manish.mishra@nutanix.com> User-Agent: Mutt/2.2.7 (2022-08-07) X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -38 X-Spam_score: -3.9 X-Spam_bar: --- X-Spam_report: (-3.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.051, 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_H2=-0.001, 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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Sender: "Qemu-devel" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org+qemu-devel=archiver.kernel.org@nongnu.org On Tue, Nov 01, 2022 at 02:30:29PM +0000, manish.mishra wrote: > Current logic assumes that channel connections on the destination side are > always established in the same order as the source and the first one will > always be the default channel followed by the multifid or post-copy > preemption channel. This may not be always true, as even if a channel has a > connection established on the source side it can be in the pending state on > the destination side and a newer connection can be established first. > Basically causing out of order mapping of channels on the destination side. > Currently, all channels except post-copy preempt send a magic number, this > patch uses that magic number to decide the type of channel. This logic is > applicable only for precopy(multifd) live migration, as mentioned, the > post-copy preempt channel does not send any magic number. Also, this patch > uses MSG_PEEK to check the magic number of channels so that current > data/control stream management remains un-effected. > > Signed-off-by: manish.mishra > --- > include/io/channel.h | 25 +++++++++++++++++++++++++ > io/channel-socket.c | 27 +++++++++++++++++++++++++++ > io/channel.c | 39 +++++++++++++++++++++++++++++++++++++++ > migration/migration.c | 33 +++++++++++++++++++++------------ > migration/multifd.c | 12 ++++-------- > migration/multifd.h | 2 +- > migration/postcopy-ram.c | 5 +---- > migration/postcopy-ram.h | 2 +- > 8 files changed, 119 insertions(+), 26 deletions(-) > > diff --git a/include/io/channel.h b/include/io/channel.h > index c680ee7480..74177aeeea 100644 > --- a/include/io/channel.h > +++ b/include/io/channel.h > @@ -115,6 +115,10 @@ struct QIOChannelClass { > int **fds, > size_t *nfds, > Error **errp); > + ssize_t (*io_read_peek)(QIOChannel *ioc, > + void *buf, > + size_t nbytes, > + Error **errp); > int (*io_close)(QIOChannel *ioc, > Error **errp); > GSource * (*io_create_watch)(QIOChannel *ioc, > @@ -475,6 +479,27 @@ int qio_channel_write_all(QIOChannel *ioc, > size_t buflen, > Error **errp); > > +/** > + * qio_channel_read_peek_all: > + * @ioc: the channel object > + * @buf: the memory region to read in data > + * @nbytes: the number of bytes to read > + * @errp: pointer to a NULL-initialized error object > + * > + * Read given @nbytes data from peek of channel into > + * memory region @buf. > + * > + * The function will be blocked until read size is > + * equal to requested size. > + * > + * Returns: 1 if all bytes were read, 0 if end-of-file > + * occurs without data, or -1 on error > + */ > +int qio_channel_read_peek_all(QIOChannel *ioc, > + void* buf, > + size_t nbytes, > + Error **errp); > + > /** > * qio_channel_set_blocking: > * @ioc: the channel object > diff --git a/io/channel-socket.c b/io/channel-socket.c > index b76dca9cc1..b99f5dfda6 100644 > --- a/io/channel-socket.c > +++ b/io/channel-socket.c > @@ -705,6 +705,32 @@ static ssize_t qio_channel_socket_writev(QIOChannel *ioc, > } > #endif /* WIN32 */ > > +static ssize_t qio_channel_socket_read_peek(QIOChannel *ioc, > + void *buf, > + size_t nbytes, > + Error **errp) > +{ > + QIOChannelSocket *sioc = QIO_CHANNEL_SOCKET(ioc); > + ssize_t bytes = 0; > + > +retry: > + bytes = recv(sioc->fd, buf, nbytes, MSG_PEEK); > + > + if (bytes < 0) { > + if (errno == EINTR) { > + goto retry; > + } > + if (errno == EAGAIN) { > + return QIO_CHANNEL_ERR_BLOCK; > + } > + > + error_setg_errno(errp, errno, > + "Unable to read from peek of socket"); > + return -1; > + } > + > + return bytes; > +} > > #ifdef QEMU_MSG_ZEROCOPY > static int qio_channel_socket_flush(QIOChannel *ioc, > @@ -902,6 +928,7 @@ static void qio_channel_socket_class_init(ObjectClass *klass, > > ioc_klass->io_writev = qio_channel_socket_writev; > ioc_klass->io_readv = qio_channel_socket_readv; > + ioc_klass->io_read_peek = qio_channel_socket_read_peek; > ioc_klass->io_set_blocking = qio_channel_socket_set_blocking; > ioc_klass->io_close = qio_channel_socket_close; > ioc_klass->io_shutdown = qio_channel_socket_shutdown; > diff --git a/io/channel.c b/io/channel.c > index 0640941ac5..a2d9b96f3f 100644 > --- a/io/channel.c > +++ b/io/channel.c > @@ -346,6 +346,45 @@ int qio_channel_write_all(QIOChannel *ioc, > return qio_channel_writev_all(ioc, &iov, 1, errp); > } > > +int qio_channel_read_peek_all(QIOChannel *ioc, > + void* buf, > + size_t nbytes, > + Error **errp) > +{ > + QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc); > + ssize_t bytes = 0; > + > + if (!klass->io_read_peek) { > + error_setg(errp, "Channel does not support read peek"); > + return -1; > + } There's no io_read_peek for QIOChannelTLS, so we'll hit this error... > diff --git a/migration/migration.c b/migration/migration.c > index 739bb683f3..f4b6f278a9 100644 > --- a/migration/migration.c > +++ b/migration/migration.c > @@ -733,31 +733,40 @@ void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp) > { > MigrationIncomingState *mis = migration_incoming_get_current(); > Error *local_err = NULL; > - bool start_migration; > QEMUFile *f; > + bool default_channel = true; > + uint32_t channel_magic = 0; > + int ret = 0; > > - if (!mis->from_src_file) { > - /* The first connection (multifd may have multiple) */ > + if (migrate_use_multifd() && !migration_in_postcopy()) { > + ret = qio_channel_read_peek_all(ioc, (void *)&channel_magic, > + sizeof(channel_magic), &local_err); > + > + if (ret != 1) { > + error_propagate(errp, local_err); > + return; > + } ....and thus this will fail for TLS channels AFAICT. > + > + default_channel = (channel_magic == cpu_to_be32(QEMU_VM_FILE_MAGIC)); > + } else { > + default_channel = !mis->from_src_file; > + } With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|