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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 E75CAC76190 for ; Mon, 22 Jul 2019 15:36:22 +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 CAC142190D for ; Mon, 22 Jul 2019 15:36:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CAC142190D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.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 8D87AD1A; Mon, 22 Jul 2019 15:36:22 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 14C5ECC9; Mon, 22 Jul 2019 15:36:21 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id B18EE102; Mon, 22 Jul 2019 15:36:12 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5751D28; Mon, 22 Jul 2019 08:36:12 -0700 (PDT) Received: from [10.1.197.57] (e110467-lin.cambridge.arm.com [10.1.197.57]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 351A73F694; Mon, 22 Jul 2019 08:36:11 -0700 (PDT) Subject: Re: [PATCH 2/2] virtio/virtio_ring: Fix the dma_max_mapping_size call To: Eric Auger , eric.auger.pro@gmail.com, hch@lst.de, m.szyprowski@samsung.com, mst@redhat.com, jasowang@redhat.com, virtualization@lists.linux-foundation.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org References: <20190722145509.1284-1-eric.auger@redhat.com> <20190722145509.1284-3-eric.auger@redhat.com> From: Robin Murphy Message-ID: Date: Mon, 22 Jul 2019 16:36:09 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190722145509.1284-3-eric.auger@redhat.com> Content-Language: en-GB 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-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org On 22/07/2019 15:55, Eric Auger wrote: > Do not call dma_max_mapping_size for devices that have no DMA > mask set, otherwise we can hit a NULL pointer dereference. > > This occurs when a virtio-blk-pci device is protected with > a virtual IOMMU. > > Fixes: e6d6dd6c875e ("virtio: Introduce virtio_max_dma_size()") > Signed-off-by: Eric Auger > Suggested-by: Christoph Hellwig > --- > drivers/virtio/virtio_ring.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > 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. Robin. > max_segment_size = dma_max_mapping_size(&vdev->dev); > > return max_segment_size; > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu