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=-11.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 67CB9C4741F for ; Thu, 5 Nov 2020 03:10:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EBE6B20715 for ; Thu, 5 Nov 2020 03:10:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="LjAR1Xma" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388516AbgKEDKs (ORCPT ); Wed, 4 Nov 2020 22:10:48 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:39474 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731175AbgKEDKq (ORCPT ); Wed, 4 Nov 2020 22:10:46 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1604545844; 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=+u0ac9KHv5wcKAFb5ZDCdLBF5wpiQCLC3Skb+q8JnJI=; b=LjAR1XmaEXJ33P9soNUmv8CHufVUaORDD6RmmlAV4gYs8qv6b41rJ2rvVRzulXOuWTVrW7 SzywyCbgYD/1bFvtirez3Gnw9CgNpTqHQJmN1NZaycLHQ/hZrN/9uxLN+0KTfBgGSBl35W LZub8RqSDy4hSLKtZd8oA8Xvy791Go0= 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-503-yd3NH94MMTu1ekabTjB6KQ-1; Wed, 04 Nov 2020 22:10:40 -0500 X-MC-Unique: yd3NH94MMTu1ekabTjB6KQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 940321007469; Thu, 5 Nov 2020 03:10:38 +0000 (UTC) Received: from [10.72.13.154] (ovpn-13-154.pek2.redhat.com [10.72.13.154]) by smtp.corp.redhat.com (Postfix) with ESMTP id D783C5B4DC; Thu, 5 Nov 2020 03:10:25 +0000 (UTC) Subject: Re: [PATCH virtio] virtio: virtio_console: fix DMA memory allocation for rproc serial To: Alexander Lobakin , Amit Shah , Arnd Bergmann , Greg Kroah-Hartman Cc: Arnaud Pouliquen , Suman Anna , Mathieu Poirier , Bjorn Andersson , Ohad Ben-Cohen , "Michael S. Tsirkin" , virtualization@lists.linux-foundation.org, linux-remoteproc@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org References: From: Jason Wang Message-ID: <004da56d-aad2-3b69-3428-02a14263289b@redhat.com> Date: Thu, 5 Nov 2020 11:10:24 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/11/4 下午11:31, Alexander Lobakin wrote: > Since commit 086d08725d34 ("remoteproc: create vdev subdevice with > specific dma memory pool"), every remoteproc has a DMA subdevice > ("remoteprocX#vdevYbuffer") for each virtio device, which inherits > DMA capabilities from the corresponding platform device. This allowed > to associate different DMA pools with each vdev, and required from > virtio drivers to perform DMA operations with the parent device > (vdev->dev.parent) instead of grandparent (vdev->dev.parent->parent). > > virtio_rpmsg_bus was already changed in the same merge cycle with > commit d999b622fcfb ("rpmsg: virtio: allocate buffer from parent"), > but virtio_console did not. In fact, operations using the grandparent > worked fine while the grandparent was the platform device, but since > commit c774ad010873 ("remoteproc: Fix and restore the parenting > hierarchy for vdev") this was changed, and now the grandparent device > is the remoteproc device without any DMA capabilities. > So, starting v5.8-rc1 the following warning is observed: > > [ 2.483925] ------------[ cut here ]------------ > [ 2.489148] WARNING: CPU: 3 PID: 101 at kernel/dma/mapping.c:427 0x80e7eee8 > [ 2.489152] Modules linked in: virtio_console(+) > [ 2.503737] virtio_rpmsg_bus rpmsg_core > [ 2.508903] > [ 2.528898] > [ 2.913043] > [ 2.914907] ---[ end trace 93ac8746beab612c ]--- > [ 2.920102] virtio-ports vport1p0: Error allocating inbufs > > kernel/dma/mapping.c:427 is: > > WARN_ON_ONCE(!dev->coherent_dma_mask); > > obviously because the grandparent now is remoteproc dev without any > DMA caps: > > [ 3.104943] Parent: remoteproc0#vdev1buffer, grandparent: remoteproc0 > > Fix this the same way as it was for virtio_rpmsg_bus, using just the > parent device (vdev->dev.parent, "remoteprocX#vdevYbuffer") for DMA > operations. > This also allows now to reserve DMA pools/buffers for rproc serial > via Device Tree. > > Fixes: c774ad010873 ("remoteproc: Fix and restore the parenting hierarchy for vdev") > Cc: stable@vger.kernel.org # 5.1+ > Signed-off-by: Alexander Lobakin > --- > drivers/char/virtio_console.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c > index a2da8f768b94..1836cc56e357 100644 > --- a/drivers/char/virtio_console.c > +++ b/drivers/char/virtio_console.c > @@ -435,12 +435,12 @@ static struct port_buffer *alloc_buf(struct virtio_device *vdev, size_t buf_size > /* > * Allocate DMA memory from ancestor. When a virtio > * device is created by remoteproc, the DMA memory is > - * associated with the grandparent device: > - * vdev => rproc => platform-dev. > + * associated with the parent device: > + * virtioY => remoteprocX#vdevYbuffer. > */ > - if (!vdev->dev.parent || !vdev->dev.parent->parent) > + buf->dev = vdev->dev.parent; > + if (!buf->dev) > goto free_buf; > - buf->dev = vdev->dev.parent->parent; I wonder it could be the right time to introduce dma_dev for virtio instead of depending on something magic via parent. (Btw I don't even notice that there's transport specific code in virtio console, it's better to avoid it) Thanks > > /* Increase device refcnt to avoid freeing it */ > get_device(buf->dev);