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: Halil Pasic <pasic@linux.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>

diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index 2c66941..42832a1 100644 (file)
--- a/drivers/s390/virtio/virtio_ccw.c
+++ b/drivers/s390/virtio/virtio_ccw.c
@@ -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;

diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 673fe3e..15f906e 100644 (file)
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -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