virtio: fixes, features

s390 has packed ring support.
 several fixes.
 
 Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull virtio updates from Michael Tsirkin:

 - enable packed ring support for s390

 - several fixes

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  virtio/s390: enable packed ring
  virtio/s390: DMA support for virtio-ccw
  virtio/s390: use vring_create_virtqueue
  virtio/virtio_ring: do some comment fixes
  vhost-scsi: remove incorrect memory barrier
  tools/virtio/ringtest: Remove bogus definition of BUG_ON()
  virtio_ring: Fix potential mem leak in virtqueue_add_indirect_packed

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 {
@@ -108,7 +109,6 @@ struct virtio_rev_info {
 struct virtio_ccw_vq_info {
 	struct virtqueue *vq;
 	int num;
-	void *queue;
 	union {
 		struct vq_info_block s;
 		struct vq_info_block_legacy l;
@@ -423,7 +423,6 @@ static void virtio_ccw_del_vq(struct virtqueue *vq, struct ccw1 *ccw)
 	struct virtio_ccw_device *vcdev = to_vc_device(vq->vdev);
 	struct virtio_ccw_vq_info *info = vq->priv;
 	unsigned long flags;
-	unsigned long size;
 	int ret;
 	unsigned int index = vq->index;
 
@@ -461,8 +460,6 @@ static void virtio_ccw_del_vq(struct virtqueue *vq, struct ccw1 *ccw)
 			 ret, index);
 
 	vring_del_virtqueue(vq);
-	size = PAGE_ALIGN(vring_size(info->num, KVM_VIRTIO_CCW_RING_ALIGN));
-	free_pages_exact(info->queue, size);
 	kfree(info->info_block);
 	kfree(info);
 }
@@ -494,8 +491,9 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
 	int err;
 	struct virtqueue *vq = NULL;
 	struct virtio_ccw_vq_info *info;
-	unsigned long size = 0; /* silence the compiler */
+	u64 queue;
 	unsigned long flags;
+	bool may_reduce;
 
 	/* Allocate queue. */
 	info = kzalloc(sizeof(struct virtio_ccw_vq_info), GFP_KERNEL);
@@ -516,37 +514,34 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
 		err = info->num;
 		goto out_err;
 	}
-	size = PAGE_ALIGN(vring_size(info->num, KVM_VIRTIO_CCW_RING_ALIGN));
-	info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
-	if (info->queue == NULL) {
-		dev_warn(&vcdev->cdev->dev, "no queue\n");
-		err = -ENOMEM;
-		goto out_err;
-	}
+	may_reduce = vcdev->revision > 0;
+	vq = vring_create_virtqueue(i, info->num, KVM_VIRTIO_CCW_RING_ALIGN,
+				    vdev, true, may_reduce, ctx,
+				    virtio_ccw_kvm_notify, callback, name);
 
-	vq = vring_new_virtqueue(i, info->num, KVM_VIRTIO_CCW_RING_ALIGN, vdev,
-				 true, ctx, info->queue, virtio_ccw_kvm_notify,
-				 callback, name);
 	if (!vq) {
 		/* For now, we fail if we can't get the requested size. */
 		dev_warn(&vcdev->cdev->dev, "no vq\n");
 		err = -ENOMEM;
 		goto out_err;
 	}
+	/* it may have been reduced */
+	info->num = virtqueue_get_vring_size(vq);
 
 	/* Register it with the host. */
+	queue = virtqueue_get_desc_addr(vq);
 	if (vcdev->revision == 0) {
-		info->info_block->l.queue = (__u64)info->queue;
+		info->info_block->l.queue = queue;
 		info->info_block->l.align = KVM_VIRTIO_CCW_RING_ALIGN;
 		info->info_block->l.index = i;
 		info->info_block->l.num = info->num;
 		ccw->count = sizeof(info->info_block->l);
 	} else {
-		info->info_block->s.desc = (__u64)info->queue;
+		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;
@@ -572,8 +567,6 @@ out_err:
 	if (vq)
 		vring_del_virtqueue(vq);
 	if (info) {
-		if (info->queue)
-			free_pages_exact(info->queue, size);
 		kfree(info->info_block);
 	}
 	kfree(info);
@@ -780,12 +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.
+	 * Currently nothing to do here.
 	 */
-	__virtio_clear_bit(vdev, VIRTIO_F_RING_PACKED);
 }
 
 static int virtio_ccw_finalize_features(struct virtio_device *vdev)
@@ -1266,6 +1255,16 @@ 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) {
@@ -1280,7 +1279,6 @@ 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;

drivers/vhost/scsi.c

@@ -1443,7 +1443,6 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
 			tpg->tv_tpg_vhost_count++;
 			tpg->vhost_scsi = vs;
 			vs_tpg[tpg->tport_tpgt] = tpg;
-			smp_mb__after_atomic();
 			match = true;
 		}
 		mutex_unlock(&tpg->tv_tpg_mutex);

drivers/virtio/virtio_ring.c

@@ -1004,6 +1004,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
 
 	if (unlikely(vq->vq.num_free < 1)) {
 		pr_debug("Can't add buf len 1 - avail = 0\n");
+		kfree(desc);
 		END_USE(vq);
 		return -ENOSPC;
 	}
@@ -1718,10 +1719,10 @@ static inline int virtqueue_add(struct virtqueue *_vq,
 
 /**
  * virtqueue_add_sgs - expose buffers to other end
- * @vq: the struct virtqueue we're talking about.
+ * @_vq: the struct virtqueue we're talking about.
  * @sgs: array of terminated scatterlists.
- * @out_num: the number of scatterlists readable by other side
- * @in_num: the number of scatterlists which are writable (after readable ones)
+ * @out_sgs: the number of scatterlists readable by other side
+ * @in_sgs: the number of scatterlists which are writable (after readable ones)
  * @data: the token identifying the buffer.
  * @gfp: how to do memory allocations (if necessary).
  *
@@ -1821,7 +1822,7 @@ EXPORT_SYMBOL_GPL(virtqueue_add_inbuf_ctx);
 
 /**
  * virtqueue_kick_prepare - first half of split virtqueue_kick call.
- * @vq: the struct virtqueue
+ * @_vq: the struct virtqueue
  *
  * Instead of virtqueue_kick(), you can do:
  *	if (virtqueue_kick_prepare(vq))
@@ -1841,7 +1842,7 @@ EXPORT_SYMBOL_GPL(virtqueue_kick_prepare);
 
 /**
  * virtqueue_notify - second half of split virtqueue_kick call.
- * @vq: the struct virtqueue
+ * @_vq: the struct virtqueue
  *
  * This does not need to be serialized.
  *
@@ -1885,8 +1886,9 @@ EXPORT_SYMBOL_GPL(virtqueue_kick);
 
 /**
  * virtqueue_get_buf - get the next used buffer
- * @vq: the struct virtqueue we're talking about.
+ * @_vq: the struct virtqueue we're talking about.
  * @len: the length written into the buffer
+ * @ctx: extra context for the token
  *
  * If the device wrote data into the buffer, @len will be set to the
  * amount written.  This means you don't need to clear the buffer
@@ -1916,7 +1918,7 @@ void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len)
 EXPORT_SYMBOL_GPL(virtqueue_get_buf);
 /**
  * virtqueue_disable_cb - disable callbacks
- * @vq: the struct virtqueue we're talking about.
+ * @_vq: the struct virtqueue we're talking about.
  *
  * Note that this is not necessarily synchronous, hence unreliable and only
  * useful as an optimization.
@@ -1936,7 +1938,7 @@ EXPORT_SYMBOL_GPL(virtqueue_disable_cb);
 
 /**
  * virtqueue_enable_cb_prepare - restart callbacks after disable_cb
- * @vq: the struct virtqueue we're talking about.
+ * @_vq: the struct virtqueue we're talking about.
  *
  * This re-enables callbacks; it returns current queue state
  * in an opaque unsigned value. This value should be later tested by
@@ -1957,7 +1959,7 @@ EXPORT_SYMBOL_GPL(virtqueue_enable_cb_prepare);
 
 /**
  * virtqueue_poll - query pending used buffers
- * @vq: the struct virtqueue we're talking about.
+ * @_vq: the struct virtqueue we're talking about.
  * @last_used_idx: virtqueue state (from call to virtqueue_enable_cb_prepare).
  *
  * Returns "true" if there are pending used buffers in the queue.
@@ -1976,7 +1978,7 @@ EXPORT_SYMBOL_GPL(virtqueue_poll);
 
 /**
  * virtqueue_enable_cb - restart callbacks after disable_cb.
- * @vq: the struct virtqueue we're talking about.
+ * @_vq: the struct virtqueue we're talking about.
  *
  * This re-enables callbacks; it returns "false" if there are pending
  * buffers in the queue, to detect a possible race between the driver
@@ -1995,7 +1997,7 @@ EXPORT_SYMBOL_GPL(virtqueue_enable_cb);
 
 /**
  * virtqueue_enable_cb_delayed - restart callbacks after disable_cb.
- * @vq: the struct virtqueue we're talking about.
+ * @_vq: the struct virtqueue we're talking about.
  *
  * This re-enables callbacks but hints to the other side to delay
  * interrupts until most of the available buffers have been processed;
@@ -2017,7 +2019,7 @@ EXPORT_SYMBOL_GPL(virtqueue_enable_cb_delayed);
 
 /**
  * virtqueue_detach_unused_buf - detach first unused buffer
- * @vq: the struct virtqueue we're talking about.
+ * @_vq: the struct virtqueue we're talking about.
  *
  * Returns NULL or the "data" token handed to virtqueue_add_*().
  * This is not valid on an active queue; it is useful only for device
@@ -2249,7 +2251,7 @@ EXPORT_SYMBOL_GPL(vring_transport_features);
 
 /**
  * virtqueue_get_vring_size - return the size of the virtqueue's vring
- * @vq: the struct virtqueue containing the vring of interest.
+ * @_vq: the struct virtqueue containing the vring of interest.
  *
  * Returns the size of the vring.  This is mainly used for boasting to
  * userspace.  Unlike other operations, this need not be serialized.

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

tools/virtio/ringtest/ptr_ring.c

@@ -18,7 +18,6 @@
 #define ALIGN(x, a) (((x) + (a) - 1) / (a) * (a))
 #define SIZE_MAX        (~(size_t)0)
 #define KMALLOC_MAX_SIZE SIZE_MAX
-#define BUG_ON(x) assert(x)
 
 typedef pthread_spinlock_t  spinlock_t;