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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 5CFACC76194 for ; Thu, 25 Jul 2019 11:54:02 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3DB272238C for ; Thu, 25 Jul 2019 11:54:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3DB272238C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 19201AF0; Thu, 25 Jul 2019 11:54:02 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id BFCAC910; Thu, 25 Jul 2019 11:54:01 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 6A7B1775; Thu, 25 Jul 2019 11:54:01 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7331D300CA39; Thu, 25 Jul 2019 11:54:00 +0000 (UTC) Received: from [10.36.116.102] (ovpn-116-102.ams2.redhat.com [10.36.116.102]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 45E2960C05; Thu, 25 Jul 2019 11:53:51 +0000 (UTC) Subject: Re: [PATCH 2/2] virtio/virtio_ring: Fix the dma_max_mapping_size call To: Christoph Hellwig , Robin Murphy References: <20190722145509.1284-1-eric.auger@redhat.com> <20190722145509.1284-3-eric.auger@redhat.com> <20190723153851.GE720@lst.de> From: Auger Eric Message-ID: Date: Thu, 25 Jul 2019 13:53:49 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190723153851.GE720@lst.de> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.42]); Thu, 25 Jul 2019 11:54:00 +0000 (UTC) Cc: mst@redhat.com, jasowang@redhat.com, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, iommu@lists.linux-foundation.org, eric.auger.pro@gmail.com X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org Hi, On 7/23/19 5:38 PM, Christoph Hellwig wrote: > On Mon, Jul 22, 2019 at 04:36:09PM +0100, Robin Murphy wrote: >>> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c >>> index c8be1c4f5b55..37c143971211 100644 >>> --- a/drivers/virtio/virtio_ring.c >>> +++ b/drivers/virtio/virtio_ring.c >>> @@ -262,7 +262,7 @@ size_t virtio_max_dma_size(struct virtio_device *vdev) >>> { >>> size_t max_segment_size = SIZE_MAX; >>> - if (vring_use_dma_api(vdev)) >>> + if (vring_use_dma_api(vdev) && vdev->dev.dma_mask) >> >> Hmm, might it make sense to roll that check up into vring_use_dma_api() >> itself? After all, if the device has no mask then it's likely that other >> DMA API ops wouldn't really work as expected either. > > Makes sense to me. > I am confused: if vring_use_dma_api() returns false if the dma_mask is unset (ie. vring_use_dma_api() returns false), the virtio-blk-pci device will not be able to get translated addresses and won't work properly. The patch above allows the dma api to be used and only influences the max_segment_size and it works properly. So is it normal the dma_mask is unset in my case? Thanks Eric _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu