From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 49C37A00C2; Tue, 8 Mar 2022 09:39:47 +0100 (CET) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 2C0E04068B; Tue, 8 Mar 2022 09:39:47 +0100 (CET) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by mails.dpdk.org (Postfix) with ESMTP id 74EF140041 for ; Tue, 8 Mar 2022 09:39:46 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1646728786; 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=vgs+XmRU7H1nuhXuxYWy5GRuPNF09fYa9DniZ0rOO6k=; b=bAepCKiy9X/mfFtoVCEGCwkWD1Mn54bdPNPG51nhpPt8+g4LTIoJlDkHQVeNMGayxTL2Ac +K/HIQz3ZmfUC8Z5J2NV/nl7p0hac1JUglLgyrKSJa6aA1A8YAswEcwPcYy1wRpjq5OPm6 UXvvCgOuZUD+MVKrhQmnhgsDSt6kFF8= 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-594-DZD5qLFkNPS05Z_zogSwFA-1; Tue, 08 Mar 2022 03:39:41 -0500 X-MC-Unique: DZD5qLFkNPS05Z_zogSwFA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D60661800D50; Tue, 8 Mar 2022 08:39:40 +0000 (UTC) Received: from [10.39.208.21] (unknown [10.39.208.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A9216519DE; Tue, 8 Mar 2022 08:39:39 +0000 (UTC) Message-ID: <88d35cfe-dea8-4955-e8ca-723a79c4e52b@redhat.com> Date: Tue, 8 Mar 2022 09:39:38 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH] vhost: fix external message handlers To: David Marchand Cc: dev , Fan Zhang , Chenbo Xia , Christophe Fontaine References: <20220307181101.10394-1-david.marchand@redhat.com> <2db1dea9-43e3-9ffa-5dcf-f1bc9d2c7315@redhat.com> From: Maxime Coquelin In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=maxime.coquelin@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org On 3/8/22 09:37, David Marchand wrote: > On Tue, Mar 8, 2022 at 9:34 AM Maxime Coquelin > wrote: >> On 3/7/22 19:11, David Marchand wrote: >>> Following a rework, external message handlers were receiving a pointer >>> to a vhost_user message (as stated in the API), but lost the ability to >>> interact with fds attached to the message. >>> Restore the original layout and put a build check and reminders. >>> >>> Bugzilla ID: 953 >>> Fixes: 5e0099dc709e ("vhost: remove payload size limitation") >>> >>> Signed-off-by: David Marchand >>> --- >>> This patch is untested, but sending quickly to get feedback from the >>> reporter and comments from author and maintainers. >>> >>> >>> --- >>> lib/vhost/vhost_user.c | 8 ++++---- >>> lib/vhost/vhost_user.h | 7 +++++-- >>> 2 files changed, 9 insertions(+), 6 deletions(-) >>> >>> diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c >>> index 723c6890c3..589b950458 100644 >>> --- a/lib/vhost/vhost_user.c >>> +++ b/lib/vhost/vhost_user.c >>> @@ -3023,8 +3023,8 @@ vhost_user_msg_handler(int vid, int fd) >>> >>> handled = false; >>> if (dev->extern_ops.pre_msg_handle) { >>> - ret = (*dev->extern_ops.pre_msg_handle)(dev->vid, >>> - (void *)&ctx.msg); >>> + RTE_BUILD_BUG_ON(offsetof(struct vhu_msg_context, msg) != 0); >>> + ret = (*dev->extern_ops.pre_msg_handle)(dev->vid, &ctx); >>> switch (ret) { >>> case RTE_VHOST_MSG_RESULT_REPLY: >>> send_vhost_reply(dev, fd, &ctx); >>> @@ -3069,8 +3069,8 @@ vhost_user_msg_handler(int vid, int fd) >>> skip_to_post_handle: >>> if (ret != RTE_VHOST_MSG_RESULT_ERR && >>> dev->extern_ops.post_msg_handle) { >>> - ret = (*dev->extern_ops.post_msg_handle)(dev->vid, >>> - (void *)&ctx.msg); >>> + RTE_BUILD_BUG_ON(offsetof(struct vhu_msg_context, msg) != 0); >>> + ret = (*dev->extern_ops.post_msg_handle)(dev->vid, &ctx); >>> switch (ret) { >>> case RTE_VHOST_MSG_RESULT_REPLY: >>> send_vhost_reply(dev, fd, &ctx); >>> diff --git a/lib/vhost/vhost_user.h b/lib/vhost/vhost_user.h >>> index be53669f3b..555f89c97a 100644 >>> --- a/lib/vhost/vhost_user.h >>> +++ b/lib/vhost/vhost_user.h >>> @@ -152,10 +152,13 @@ typedef struct VhostUserMsg { >>> /* Nothing should be added after the payload */ >>> } __rte_packed VhostUserMsg; >>> >>> -struct vhu_msg_context { >>> +/* Note: this structure and VhostUserMsg can't be changed carelessly as >>> + * external message handlers rely on them. >>> + */ >>> +__rte_packed struct vhu_msg_context { >>> + VhostUserMsg msg; >>> int fds[VHOST_MEMORY_MAX_NREGIONS]; >>> int fd_num; >>> - VhostUserMsg msg; >>> }; >>> >>> #define VHOST_USER_HDR_SIZE offsetof(VhostUserMsg, payload.u64) >> >> We should revisit the callbacks prototype when we'll be allowed to break >> API, passing the message pointer as void * is definitely not a good >> idea. > > Indeed. > >> >> In the mean time, I agree with your fix: >> >> Reviewed-by: Maxime Coquelin >> >> We may also add Reported-by tag when applying. > > There is an issue with clang, I'll send a v2. > Ok. Fan, can you have a try and confirm it fixes the issue on your side? Thanks, Maxime