[PATCH vhost v3 15/19] virtio_ring: introduce dma map api for page

Xuan Zhuo
2024-02-29T07:21:13Z

The virtio-net sq will use these APIs to map the scatterlist.
For scatterlist, the page dma APIs are more appropriate.

dma_addr_t virtqueue_dma_map_page_attrs(struct virtqueue *_vq, struct page *page,
size_t offset, size_t size,
enum dma_data_direction dir,
unsigned long attrs);
void virtqueue_dma_unmap_page_attrs(struct virtqueue *_vq, dma_addr_t addr,
size_t size, enum dma_data_direction dir,
unsigned long attrs);

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
drivers/virtio/virtio_ring.c | 52 ++++++++++++++++++++++++++++++++++++
include/linux/virtio.h | 7 +++++
2 files changed, 59 insertions(+)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 63084487c171..df7633155558 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -3117,6 +3117,58 @@ void virtqueue_dma_unmap_single_attrs(struct virtqueue *_vq, dma_addr_t addr,
}
EXPORT_SYMBOL_GPL(virtqueue_dma_unmap_single_attrs);

+/**
+ * virtqueue_dma_map_page_attrs - map DMA for _vq
+ * @_vq: the struct virtqueue we're talking about.
+ * @page: the page to do dma
+ * @offset: the offset inside the page
+ * @size: the size of the page to do dma
+ * @dir: DMA direction
+ * @attrs: DMA Attrs
+ *
+ * The caller calls this to do dma mapping in advance. The DMA address can be
+ * passed to this _vq when it is in pre-mapped mode.
+ *
+ * return DMA address. Caller should check that by virtqueue_dma_mapping_error().
+ */
+dma_addr_t virtqueue_dma_map_page_attrs(struct virtqueue *_vq, struct page *page,
+ size_t offset, size_t size,
+ enum dma_data_direction dir,
+ unsigned long attrs)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ if (!vq->use_dma_api)
+ return page_to_phys(page) + offset;
+
+ return dma_map_page_attrs(vring_dma_dev(vq), page, offset, size, dir, attrs);
+}
+EXPORT_SYMBOL_GPL(virtqueue_dma_map_page_attrs);
+
+/**
+ * virtqueue_dma_unmap_page_attrs - unmap DMA for _vq
+ * @_vq: the struct virtqueue we're talking about.
+ * @addr: the dma address to unmap
+ * @size: the size of the buffer
+ * @dir: DMA direction
+ * @attrs: DMA Attrs
+ *
+ * Unmap the address that is mapped by the virtqueue_dma_map_* APIs.
+ *
+ */
+void virtqueue_dma_unmap_page_attrs(struct virtqueue *_vq, dma_addr_t addr,
+ size_t size, enum dma_data_direction dir,
+ unsigned long attrs)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ if (!vq->use_dma_api)
+ return;
+
+ dma_unmap_page_attrs(vring_dma_dev(vq), addr, size, dir, attrs);
+}
+EXPORT_SYMBOL_GPL(virtqueue_dma_unmap_page_attrs);
+
/**
* virtqueue_dma_mapping_error - check dma address
* @_vq: the struct virtqueue we're talking about.
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 2167893313f6..b81b93b3eb27 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -224,6 +224,13 @@ dma_addr_t virtqueue_dma_map_single_attrs(struct virtqueue *_vq, void *ptr, size
void virtqueue_dma_unmap_single_attrs(struct virtqueue *_vq, dma_addr_t addr,
size_t size, enum dma_data_direction dir,
unsigned long attrs);
+dma_addr_t virtqueue_dma_map_page_attrs(struct virtqueue *_vq, struct page *page,
+ size_t offset, size_t size,
+ enum dma_data_direction dir,
+ unsigned long attrs);
+void virtqueue_dma_unmap_page_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);
--
2.32.0.3.g01195cf9f