From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anshuman Khandual Subject: [RFC 2/4] virtio: Override device's DMA OPS with virtio_direct_dma_ops selectively Date: Fri, 20 Jul 2018 09:29:39 +0530 Message-ID: <20180720035941.6844-3-khandual__1675.0254821547$1532059153$gmane$org@linux.vnet.ibm.com> References: <20180720035941.6844-1-khandual@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180720035941.6844-1-khandual@linux.vnet.ibm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org Cc: robh@kernel.org, srikar@linux.vnet.ibm.com, mst@redhat.com, benh@kernel.crashing.org, linuxram@us.ibm.com, hch@infradead.org, paulus@samba.org, mpe@ellerman.id.au, joe@perches.com, khandual@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org, elfring@users.sourceforge.net, haren@linux.vnet.ibm.com, david@gibson.dropbear.id.au List-Id: virtualization@lists.linuxfoundation.org Now that virtio core always needs all virtio devices to have DMA OPS, we need to make sure that the structure it points is the right one. In the absence of VIRTIO_F_IOMMU_PLATFORM flag QEMU expects GPA from guest kernel. In such case, virtio device must use default virtio_direct_dma_ops DMA OPS structure which transforms scatter gather buffer addresses as GPA. This DMA OPS override must happen as early as possible during virtio device initializatin sequence before virtio core starts using given device's DMA OPS callbacks for I/O transactions. This change detects device's IOMMU flag and does the override in case the flag is cleared. Signed-off-by: Anshuman Khandual --- drivers/virtio/virtio.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index 7907ad3..6b13987 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -166,6 +166,8 @@ void virtio_add_status(struct virtio_device *dev, unsigned int status) } EXPORT_SYMBOL_GPL(virtio_add_status); +const struct dma_map_ops virtio_direct_dma_ops; + int virtio_finalize_features(struct virtio_device *dev) { int ret = dev->config->finalize_features(dev); @@ -174,6 +176,9 @@ int virtio_finalize_features(struct virtio_device *dev) if (ret) return ret; + if (virtio_has_iommu_quirk(dev)) + set_dma_ops(dev->dev.parent, &virtio_direct_dma_ops); + if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) return 0; -- 2.9.3