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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>
This commit is contained in:
Halil Pasic 2019-04-26 20:32:37 +02:00 committed by Michael S. Tsirkin
parent 3279beac54
commit f35f54f11f
2 changed files with 15 additions and 24 deletions
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22
drivers/s390/virtio/virtio_ccw.c
View File

@ -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 @@ static u64 virtio_ccw_get_features(struct virtio_device *vdev)
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;

17
include/linux/virtio.h
View File

@ -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