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 BEF1C46866; Tue, 3 Jun 2025 14:31:07 +0200 (CEST) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 3F78B4069F; Tue, 3 Jun 2025 14:31:07 +0200 (CEST) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by mails.dpdk.org (Postfix) with ESMTP id 719F840697 for ; Tue, 3 Jun 2025 14:31:06 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1748953865; 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:autocrypt:autocrypt; bh=jaj49fMrX89uO9cccUruDn5lyiKDr4dgeFZTFg1Jb44=; b=XuEQdAT3HjAwskp626o7FvM6D/BPXAAkSSHz6z/Jfk21k4VXCZ4WzVxjDzRCc+ecVME7dL OLo84s9Tx6yf8d7NMgv7RORV1HbYDlJCeToLqScZ7GGVGsqyOWFB60CXir4BiH0sv32pWa 2kMRZ33iZr6+RxmIQnVTwpWRib2QLro= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-567-N8iUhVrhM9ae5TuLzzLs0A-1; Tue, 03 Jun 2025 08:31:04 -0400 X-MC-Unique: N8iUhVrhM9ae5TuLzzLs0A-1 X-Mimecast-MFC-AGG-ID: N8iUhVrhM9ae5TuLzzLs0A_1748953863 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 0769F1800570; Tue, 3 Jun 2025 12:31:02 +0000 (UTC) Received: from [10.45.242.7] (unknown [10.45.242.7]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 0CDF219560A3; Tue, 3 Jun 2025 12:30:55 +0000 (UTC) Message-ID: <6ee82aef-dbb1-4e5f-8a53-6a956161c1db@redhat.com> Date: Tue, 3 Jun 2025 14:30:51 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 1/1] vhost: handle virtqueue locking for memory hotplug To: Danylo Vodopianov , thomas@monjalon.net, aman.deep.singh@intel.com, yuying.zhang@intel.com, orika@nvidia.com, mcoqueli@redhat.com, ckm@napatech.com, matan@mellanox.com, david.marchand@redhat.com, mko-plv@napatech.com, sil-plv@napatech.com Cc: stephen@networkplumber.org, dev@dpdk.org, Chenbo Xia References: <20250602084025.1881768-2-dvo-plv@napatech.com> <20250602085005.1882499-1-dvo-plv@napatech.com> <20250602085005.1882499-2-dvo-plv@napatech.com> From: Maxime Coquelin Autocrypt: addr=maxime.coquelin@redhat.com; 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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 Hello Danylo, On 6/2/25 10:50 AM, Danylo Vodopianov wrote: > For vDPA devices, virtqueues are not locked once the device has been > configured. In the > commit 5e8fcc60b59d ("vhost: enhance virtqueue access lock asserts"), > the asserts were enhanced to trigger rte_panic functionality, preventing > access to virtqueues without locking. However, this change introduced > an issue where the memory hotplug mechanism, added in the > commit 127f9c6f7b78 ("vhost: handle memory hotplug with vDPA devices"), > no longer works. Since it expects for all queues are locked. > > During the initialization of a vDPA device, the driver sets the > VIRTIO_DEV_VDPA_CONFIGURED flag, which prevents the > vhost_user_lock_all_queue_pairs function from locking the > virtqueues. This leads to the error: the VIRTIO_DEV_VDPA_CONFIGURED > flag allows the use of the hotplug mechanism, but it fails > because the virtqueues are not locked, while it expects to be locked > for VHOST_USER_SET_MEM_TABLE in the table VHOST_MESSAGE_HANDLERS. > > This patch addresses the issue by enhancing the conditional statement > to include a new condition. Specifically, when the device receives the > VHOST_USER_SET_MEM_TABLE request, the virtqueues are locked to update > the basic configurations and hotplug the guest memory. > > This fix does not impact access lock when vDPA driver is configured > for other unnecessary message handlers. > > Manual memory configuring with "--socket-mem" option allows to avoid > hotplug mechanism using. s/using/use/ It needs a fixes tag, and stable@dpdk.org should be cc'ed, so that it gets backported to LTS branches. > > Signed-off-by: Danylo Vodopianov > --- > lib/vhost/vhost_user.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c > index ec950acf97..16d03e1033 100644 > --- a/lib/vhost/vhost_user.c > +++ b/lib/vhost/vhost_user.c > @@ -3178,7 +3178,13 @@ vhost_user_msg_handler(int vid, int fd) > * would cause a dead lock. > */ > if (msg_handler != NULL && msg_handler->lock_all_qps) { > - if (!(dev->flags & VIRTIO_DEV_VDPA_CONFIGURED)) { > + /* Lock all queue pairs if the device is not configured for vDPA, > + * or if it is configured for vDPA but the request is VHOST_USER_SET_MEM_TABLE. > + * This ensures proper queue locking for memory table updates and guest > + * memory hotplug. > + */ > + if (!(dev->flags & VIRTIO_DEV_VDPA_CONFIGURED) || > + request == VHOST_USER_SET_MEM_TABLE) { It looks like a workaround, and I'm afraid it could cause regression with some vDPA devices, or that it would not be enough and we would have to add other requests as exception. Wouldn't it better to modify VHOST_USER_ASSERT_LOCK() so that it takes into account the VIRTIO_DEV_VDPA_CONFIGURED flag? Thanks, Maxime > vhost_user_lock_all_queue_pairs(dev); > unlock_required = 1; > }