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=-11.3 required=3.0 tests=BAYES_00,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 C7624C4742C for ; Mon, 16 Nov 2020 12:23:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 58CA12224B for ; Mon, 16 Nov 2020 12:23:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=st.com header.i=@st.com header.b="uik4X0nC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729238AbgKPKrf (ORCPT ); Mon, 16 Nov 2020 05:47:35 -0500 Received: from mx07-00178001.pphosted.com ([185.132.182.106]:8944 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727107AbgKPKre (ORCPT ); Mon, 16 Nov 2020 05:47:34 -0500 Received: from pps.filterd (m0046668.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 0AGAbJbu017760; Mon, 16 Nov 2020 11:47:04 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=st.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=STMicroelectronics; bh=ZnFMeOsKLgn0Gfn0T/aAv7kklPoIvURiSXIZWk2Z01I=; b=uik4X0nCyvzFs6usxbIyAHGmsY18uLomUO3eqmzoq8mPdJFLaCBkMcXCWAI3K6paJQzA bLv7QazcOlv9CGhejn15zM05SJbrsFyaxlg5g/bcDdgU7i0SgZM7MYNav6KQDvR96T21 t/u1SqJ0K4/WlJBFMWNcGdtUaEBEmNogUBgDb/BhMsXTC+JN2BoTafVRop8dB/Optur7 BGr0ijplwNRfNyZRnbgsUUz3tg1zGGAc+d4fzVuJwFflBbFCq/fpFxHLCbC3t28WzF0B BOmd1PzXmyN0Dv39/rQmC1O1+RAdJU1GNj7dPdX/qG5mApkYLAntx+5R7/JsIjKEqawO Tw== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com with ESMTP id 34t5k4tbbc-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 16 Nov 2020 11:47:04 +0100 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id C9FA710002A; Mon, 16 Nov 2020 11:47:01 +0100 (CET) Received: from Webmail-eu.st.com (sfhdag3node1.st.com [10.75.127.7]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 9D869251AEB; Mon, 16 Nov 2020 11:47:01 +0100 (CET) Received: from lmecxl0889.lme.st.com (10.75.127.50) by SFHDAG3NODE1.st.com (10.75.127.7) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Mon, 16 Nov 2020 11:47:00 +0100 Subject: Re: [PATCH virtio] virtio: virtio_console: fix DMA memory allocation for rproc serial To: Christoph Hellwig , Alexander Lobakin CC: Amit Shah , Arnd Bergmann , Greg Kroah-Hartman , Suman Anna , Mathieu Poirier , Bjorn Andersson , Ohad Ben-Cohen , "Michael S. Tsirkin" , Jason Wang , "virtualization@lists.linux-foundation.org" , "linux-remoteproc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" References: <20201116091950.GA30524@infradead.org> From: Arnaud POULIQUEN Message-ID: Date: Mon, 16 Nov 2020 11:46:59 +0100 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: <20201116091950.GA30524@infradead.org> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.75.127.50] X-ClientProxiedBy: SFHDAG2NODE1.st.com (10.75.127.4) To SFHDAG3NODE1.st.com (10.75.127.7) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.312,18.0.737 definitions=2020-11-16_03:2020-11-13,2020-11-16 signatures=0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi all, On 11/16/20 10:19 AM, Christoph Hellwig wrote: > I just noticed this showing up in Linus' tree and I'm not happy. > > This whole model of the DMA subdevices in remoteproc is simply broken. > > We really need to change the virtio code pass an expicit DMA device ( > similar to what e.g. the USB and RDMA code does), instead of faking up > devices with broken adhoc inheritance of DMA properties and magic poking > into device parent relationships. For your formation I started some stuff on my side to be able to declare the virtio device in DT as a remoteproc child node. https://lkml.org/lkml/2020/4/16/1817 Quite big refactoring, but could be a way to answer... Regards, Arnaud > > Bjorn, I thought you were going to look into this a while ago? > > > On Wed, Nov 04, 2020 at 03:31:36PM +0000, 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; >> >> /* Increase device refcnt to avoid freeing it */ >> get_device(buf->dev); >> -- >> 2.29.2 >> >> > ---end quoted text--- >