Commit f35f54f1 authored by Halil Pasic's avatar Halil Pasic Committed by Michael S. Tsirkin
Browse files

virtio/s390: DMA support for virtio-ccw 



Currently virtio-ccw devices do not work if the device has
VIRTIO_F_IOMMU_PLATFORM. In future we do want to support DMA API with
virtio-ccw.

Let us do the plumbing, so the feature VIRTIO_F_IOMMU_PLATFORM works
with virtio-ccw.

Let us also switch from legacy avail/used accessors to the DMA aware
ones (even if it isn't strictly necessary), and remove the legacy
accessors (we were the last users).

Signed-off-by: default avatarHalil Pasic <pasic@linux.ibm.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: default avatarCornelia Huck <cohuck@redhat.com>
parent 3279beac

drivers/s390/virtio/virtio_ccw.c

+15 −7
Original line number Diff line number Diff line
@@ -66,6 +66,7 @@ struct virtio_ccw_device { 
	bool device_lost;

	unsigned int config_ready;

	void *airq_info;

	u64 dma_mask;

};



struct vq_info_block_legacy {
@@ -539,8 +540,8 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev, 
		info->info_block->s.desc = queue;

		info->info_block->s.index = i;

		info->info_block->s.num = info->num;

		info->info_block->s.avail = (__u64)virtqueue_get_avail(vq);

		info->info_block->s.used = (__u64)virtqueue_get_used(vq);

		info->info_block->s.avail = (__u64)virtqueue_get_avail_addr(vq);

		info->info_block->s.used = (__u64)virtqueue_get_used_addr(vq);

		ccw->count = sizeof(info->info_block->s);

	}

	ccw->cmd_code = CCW_CMD_SET_VQ;
@@ -772,10 +773,8 @@ out_free: 
static void ccw_transport_features(struct virtio_device *vdev)

{

	/*

	 * Packed ring isn't enabled on virtio_ccw for now,

	 * because virtio_ccw uses some legacy accessors,

	 * e.g. virtqueue_get_avail() and virtqueue_get_used()

	 * which aren't available in packed ring currently.

	 * There shouldn't be anything that precludes supporting packed.

	 * TODO: Remove the limitation after having another look into this.

	 */

	__virtio_clear_bit(vdev, VIRTIO_F_RING_PACKED);

}
@@ -1258,6 +1257,16 @@ static int virtio_ccw_online(struct ccw_device *cdev) 
		ret = -ENOMEM;

		goto out_free;

	}



	vcdev->vdev.dev.parent = &cdev->dev;

	cdev->dev.dma_mask = &vcdev->dma_mask;

	/* we are fine with common virtio infrastructure using 64 bit DMA */

	ret = dma_set_mask_and_coherent(&cdev->dev, DMA_BIT_MASK(64));

	if (ret) {

		dev_warn(&cdev->dev, "Failed to enable 64-bit DMA.\n");

		goto out_free;

	}



	vcdev->config_block = kzalloc(sizeof(*vcdev->config_block),

				   GFP_DMA | GFP_KERNEL);

	if (!vcdev->config_block) {
@@ -1272,7 +1281,6 @@ static int virtio_ccw_online(struct ccw_device *cdev) 


	vcdev->is_thinint = virtio_ccw_use_airq; /* at least try */



	vcdev->vdev.dev.parent = &cdev->dev;

	vcdev->vdev.dev.release = virtio_ccw_release_dev;

	vcdev->vdev.config = &virtio_ccw_config_ops;

	vcdev->cdev = cdev;

include/linux/virtio.h

+0 −17
Original line number Diff line number Diff line
@@ -90,23 +90,6 @@ dma_addr_t virtqueue_get_desc_addr(struct virtqueue *vq); 
dma_addr_t virtqueue_get_avail_addr(struct virtqueue *vq);

dma_addr_t virtqueue_get_used_addr(struct virtqueue *vq);



/*

 * Legacy accessors -- in almost all cases, these are the wrong functions

 * to use.

 */

static inline void *virtqueue_get_desc(struct virtqueue *vq)

{

	return virtqueue_get_vring(vq)->desc;

}

static inline void *virtqueue_get_avail(struct virtqueue *vq)

{

	return virtqueue_get_vring(vq)->avail;

}

static inline void *virtqueue_get_used(struct virtqueue *vq)

{

	return virtqueue_get_vring(vq)->used;

}



/**

 * virtio_device - representation of a device using virtio

 * @index: unique position on the virtio bus

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