Added virtio_dma_map() to map DMA addresses for virtual memory in advance. The purpose of adding this function is to check vring_use_dma_api() for virtio dma operation and get vdev->dev.parent as the parameter of dma_map_page().
Added virtio_dma_unmap() for unmap DMA address. Signed-off-by: Xuan Zhuo <[email protected]> --- drivers/virtio/virtio_ring.c | 47 ++++++++++++++++++++++++++++++++++++ include/linux/virtio.h | 9 +++++++ 2 files changed, 56 insertions(+) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index e165bc2e1344..f4a0fb85df27 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -2472,4 +2472,51 @@ const struct vring *virtqueue_get_vring(struct virtqueue *vq) } EXPORT_SYMBOL_GPL(virtqueue_get_vring); +/** + * virtio_dma_map - get the DMA addr of the memory for virtio device + * @vdev: virtio device + * @page: the page of the memory to DMA + * @offset: the offset of the memory inside page + * @length: memory length + * @dir: DMA direction + * + * Returns the DMA addr. Zero means error. + */ +dma_addr_t virtio_dma_map(struct virtio_device *vdev, + struct page *page, size_t offset, + unsigned int length, + enum dma_data_direction dir) +{ + dma_addr_t addr; + + if (!vring_use_dma_api(vdev)) + return page_to_phys(page) + offset; + + addr = dma_map_page(vdev->dev.parent, page, offset, length, dir); + + if (dma_mapping_error(vdev->dev.parent, addr)) + return 0; + + return addr; +} +EXPORT_SYMBOL_GPL(virtio_dma_map); + +/** + * virtio_dma_unmap - unmap DMA addr + * @vdev: virtio device + * @dma: DMA address + * @length: memory length + * @dir: DMA direction + */ +void virtio_dma_unmap(struct virtio_device *vdev, + dma_addr_t dma, unsigned int length, + enum dma_data_direction dir) +{ + if (!vring_use_dma_api(vdev)) + return; + + dma_unmap_page(vdev->dev.parent, dma, length, dir); +} +EXPORT_SYMBOL_GPL(virtio_dma_unmap); + MODULE_LICENSE("GPL"); diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 41edbc01ffa4..6e6c6e18ecf8 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -9,6 +9,7 @@ #include <linux/device.h> #include <linux/mod_devicetable.h> #include <linux/gfp.h> +#include <linux/dma-mapping.h> /** * virtqueue - a queue to register buffers for sending or receiving. @@ -195,4 +196,12 @@ void unregister_virtio_driver(struct virtio_driver *drv); #define module_virtio_driver(__virtio_driver) \ module_driver(__virtio_driver, register_virtio_driver, \ unregister_virtio_driver) + +dma_addr_t virtio_dma_map(struct virtio_device *vdev, + struct page *page, size_t offset, + unsigned int length, + enum dma_data_direction dir); +void virtio_dma_unmap(struct virtio_device *vdev, + dma_addr_t dma, unsigned int length, + enum dma_data_direction dir); #endif /* _LINUX_VIRTIO_H */ -- 2.31.0 _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
