virtio_ring: introduce dma sync api for virtqueue

These API has been introduced:

* virtqueue_dma_need_sync
* virtqueue_dma_sync_single_range_for_cpu
* virtqueue_dma_sync_single_range_for_device

These APIs can be used together with the premapped mechanism to sync the
DMA address.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Message-Id: <20230810123057.43407-12-xuanzhuo@linux.alibaba.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 916479c9c72cb04935317abcb9b324c438a8a472..81ecb29c88f1c2f8a71651b84840499e68417a81 100644 (file)
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -3175,4 +3175,80 @@ int virtqueue_dma_mapping_error(struct virtqueue *_vq, dma_addr_t addr)
 }
 EXPORT_SYMBOL_GPL(virtqueue_dma_mapping_error);
 
+/**
+ * virtqueue_dma_need_sync - check a dma address needs sync
+ * @_vq: the struct virtqueue we're talking about.
+ * @addr: DMA address
+ *
+ * Check if the dma address mapped by the virtqueue_dma_map_* APIs needs to be
+ * synchronized
+ *
+ * return bool
+ */
+bool virtqueue_dma_need_sync(struct virtqueue *_vq, dma_addr_t addr)
+{
+       struct vring_virtqueue *vq = to_vvq(_vq);
+
+       if (!vq->use_dma_api)
+               return false;
+
+       return dma_need_sync(vring_dma_dev(vq), addr);
+}
+EXPORT_SYMBOL_GPL(virtqueue_dma_need_sync);
+
+/**
+ * virtqueue_dma_sync_single_range_for_cpu - dma sync for cpu
+ * @_vq: the struct virtqueue we're talking about.
+ * @addr: DMA address
+ * @offset: DMA address offset
+ * @size: buf size for sync
+ * @dir: DMA direction
+ *
+ * Before calling this function, use virtqueue_dma_need_sync() to confirm that
+ * the DMA address really needs to be synchronized
+ *
+ */
+void virtqueue_dma_sync_single_range_for_cpu(struct virtqueue *_vq,
+                                            dma_addr_t addr,
+                                            unsigned long offset, size_t size,
+                                            enum dma_data_direction dir)
+{
+       struct vring_virtqueue *vq = to_vvq(_vq);
+       struct device *dev = vring_dma_dev(vq);
+
+       if (!vq->use_dma_api)
+               return;
+
+       dma_sync_single_range_for_cpu(dev, addr, offset, size,
+                                     DMA_BIDIRECTIONAL);
+}
+EXPORT_SYMBOL_GPL(virtqueue_dma_sync_single_range_for_cpu);
+
+/**
+ * virtqueue_dma_sync_single_range_for_device - dma sync for device
+ * @_vq: the struct virtqueue we're talking about.
+ * @addr: DMA address
+ * @offset: DMA address offset
+ * @size: buf size for sync
+ * @dir: DMA direction
+ *
+ * Before calling this function, use virtqueue_dma_need_sync() to confirm that
+ * the DMA address really needs to be synchronized
+ */
+void virtqueue_dma_sync_single_range_for_device(struct virtqueue *_vq,
+                                               dma_addr_t addr,
+                                               unsigned long offset, size_t size,
+                                               enum dma_data_direction dir)
+{
+       struct vring_virtqueue *vq = to_vvq(_vq);
+       struct device *dev = vring_dma_dev(vq);
+
+       if (!vq->use_dma_api)
+               return;
+
+       dma_sync_single_range_for_device(dev, addr, offset, size,
+                                        DMA_BIDIRECTIONAL);
+}
+EXPORT_SYMBOL_GPL(virtqueue_dma_sync_single_range_for_device);
+
 MODULE_LICENSE("GPL");

diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 79e3c74391e0be4dea5200a1604f1a4ed9b0a591..1311a7fbe67526382c4439916cd3e20026e8dc80 100644 (file)
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -220,4 +220,12 @@ void virtqueue_dma_unmap_single_attrs(struct virtqueue *_vq, dma_addr_t addr,
                                      size_t size, enum dma_data_direction dir,
                                      unsigned long attrs);
 int virtqueue_dma_mapping_error(struct virtqueue *_vq, dma_addr_t addr);
+
+bool virtqueue_dma_need_sync(struct virtqueue *_vq, dma_addr_t addr);
+void virtqueue_dma_sync_single_range_for_cpu(struct virtqueue *_vq, dma_addr_t addr,
+                                            unsigned long offset, size_t size,
+                                            enum dma_data_direction dir);
+void virtqueue_dma_sync_single_range_for_device(struct virtqueue *_vq, dma_addr_t addr,
+                                               unsigned long offset, size_t size,
+                                               enum dma_data_direction dir);
 #endif /* _LINUX_VIRTIO_H */