Xuan Zhuo
2023-Feb-14 07:27 UTC
[PATCH vhost 07/10] virtio_ring: add api virtio_dma_map() for advance dma
Added virtio_dma_map() to map DMA addresses for virtual memory in
advance. The purpose is to keep memory mapped across multiple add/get
buf operations.
Added virtio_dma_unmap() for unmap DMA address.
Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
drivers/virtio/virtio_ring.c | 92 ++++++++++++++++++++++++++++++++++++
include/linux/virtio.h | 9 ++++
2 files changed, 101 insertions(+)
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index cd9364eb2345..855338609c7f 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -3172,4 +3172,96 @@ const struct vring *virtqueue_get_vring(struct virtqueue
*vq)
}
EXPORT_SYMBOL_GPL(virtqueue_get_vring);
+/**
+ * virtio_dma_map_page - get the DMA addr of the memory for virtio device
+ * @dev: virtio device
+ * @page: the page of the memory to DMA
+ * @offset: the offset of the memory inside page
+ * @length: memory length
+ * @dir: DMA direction
+ *
+ * This API is only for pre-mapped buffers, for non premapped buffers virtio
+ * core handles DMA API internally.
+ *
+ * Returns the DMA addr. DMA_MAPPING_ERROR means error.
+ */
+dma_addr_t virtio_dma_map_page(struct device *dev, struct page *page, size_t
offset,
+ unsigned int length, enum dma_data_direction dir)
+{
+ struct virtio_device *vdev = dev_to_virtio(dev);
+
+ if (!vring_use_dma_api(vdev))
+ return page_to_phys(page) + offset;
+
+ return dma_map_page(vdev->dev.parent, page, offset, length, dir);
+}
+
+/**
+ * virtio_dma_map - get the DMA addr of the memory for virtio device
+ * @dev: virtio device
+ * @addr: the addr to DMA
+ * @length: memory length
+ * @dir: DMA direction
+ *
+ * This API is only for pre-mapped buffers, for non premapped buffers virtio
+ * core handles DMA API internally.
+ *
+ * Returns the DMA addr.
+ */
+dma_addr_t virtio_dma_map(struct device *dev, void *addr, unsigned int length,
+ enum dma_data_direction dir)
+{
+ struct page *page;
+ size_t offset;
+
+ page = virt_to_page(addr);
+ offset = offset_in_page(addr);
+
+ return virtio_dma_map_page(dev, page, offset, length, dir);
+}
+EXPORT_SYMBOL_GPL(virtio_dma_map);
+
+/**
+ * virtio_dma_mapping_error - check dma address
+ * @dev: virtio device
+ * @addr: DMA address
+ *
+ * This API is only for pre-mapped buffers, for non premapped buffers virtio
+ * core handles DMA API internally.
+ *
+ * Returns 0 means dma valid. Other means invalid dma address.
+ */
+int virtio_dma_mapping_error(struct device *dev, dma_addr_t addr)
+{
+ struct virtio_device *vdev = dev_to_virtio(dev);
+
+ if (!vring_use_dma_api(vdev))
+ return 0;
+
+ return dma_mapping_error(vdev->dev.parent, addr);
+}
+EXPORT_SYMBOL_GPL(virtio_dma_mapping_error);
+
+/**
+ * virtio_dma_unmap - unmap DMA addr
+ * @dev: virtio device
+ * @dma: DMA address
+ * @length: memory length
+ * @dir: DMA direction
+ *
+ * This API is only for pre-mapped buffers, for non premapped buffers virtio
+ * core handles DMA API internally.
+ */
+void virtio_dma_unmap(struct device *dev, dma_addr_t dma, unsigned int length,
+ enum dma_data_direction dir)
+{
+ struct virtio_device *vdev = dev_to_virtio(dev);
+
+ 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 3ebb346ebb7c..b5fa71476737 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>
/**
* struct virtqueue - a queue to register buffers for sending or receiving.
@@ -216,4 +217,12 @@ 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_page(struct device *dev, struct page *page, size_t
offset,
+ unsigned int length, enum dma_data_direction dir);
+dma_addr_t virtio_dma_map(struct device *dev, void *addr, unsigned int length,
+ enum dma_data_direction dir);
+int virtio_dma_mapping_error(struct device *dev, dma_addr_t addr);
+void virtio_dma_unmap(struct device *dev, dma_addr_t dma, unsigned int length,
+ enum dma_data_direction dir);
#endif /* _LINUX_VIRTIO_H */
--
2.32.0.3.g01195cf9f
Jason Wang
2023-Feb-20 05:38 UTC
[PATCH vhost 07/10] virtio_ring: add api virtio_dma_map() for advance dma
On Tue, Feb 14, 2023 at 3:27 PM Xuan Zhuo <xuanzhuo at linux.alibaba.com> wrote:> > Added virtio_dma_map() to map DMA addresses for virtual memory in > advance. The purpose is to keep memory mapped across multiple add/get > buf operations.I wonder if instead of exporting helpers like this, it might be simple to just export dma_dev then the upper layer can use DMA API at will? (Otherwise the DMA helpers need to grow/shrink as the DMA API evolves?)> > Added virtio_dma_unmap() for unmap DMA address. > > Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com> > --- > drivers/virtio/virtio_ring.c | 92 ++++++++++++++++++++++++++++++++++++ > include/linux/virtio.h | 9 ++++ > 2 files changed, 101 insertions(+) > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index cd9364eb2345..855338609c7f 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -3172,4 +3172,96 @@ const struct vring *virtqueue_get_vring(struct virtqueue *vq) > } > EXPORT_SYMBOL_GPL(virtqueue_get_vring); > > +/** > + * virtio_dma_map_page - get the DMA addr of the memory for virtio device > + * @dev: virtio device > + * @page: the page of the memory to DMA > + * @offset: the offset of the memory inside page > + * @length: memory length > + * @dir: DMA direction > + * > + * This API is only for pre-mapped buffers, for non premapped buffers virtio > + * core handles DMA API internally. > + * > + * Returns the DMA addr. DMA_MAPPING_ERROR means error. > + */ > +dma_addr_t virtio_dma_map_page(struct device *dev, struct page *page, size_t offset, > + unsigned int length, enum dma_data_direction dir) > +{This (and the reset) needs to be done per virtqueue instead per device after b0e504e5505d184b0be248b7dcdbe50b79f03758 ("virtio_ring: per virtqueue dma device").> + struct virtio_device *vdev = dev_to_virtio(dev); > + > + if (!vring_use_dma_api(vdev)) > + return page_to_phys(page) + offset; > + > + return dma_map_page(vdev->dev.parent, page, offset, length, dir); > +}Need either inline or EXPORT_SYMBOL_GPL() here. Thanks> + > +/** > + * virtio_dma_map - get the DMA addr of the memory for virtio device > + * @dev: virtio device > + * @addr: the addr to DMA > + * @length: memory length > + * @dir: DMA direction > + * > + * This API is only for pre-mapped buffers, for non premapped buffers virtio > + * core handles DMA API internally. > + * > + * Returns the DMA addr. > + */ > +dma_addr_t virtio_dma_map(struct device *dev, void *addr, unsigned int length, > + enum dma_data_direction dir) > +{ > + struct page *page; > + size_t offset; > + > + page = virt_to_page(addr); > + offset = offset_in_page(addr); > + > + return virtio_dma_map_page(dev, page, offset, length, dir); > +} > +EXPORT_SYMBOL_GPL(virtio_dma_map); > + > +/** > + * virtio_dma_mapping_error - check dma address > + * @dev: virtio device > + * @addr: DMA address > + * > + * This API is only for pre-mapped buffers, for non premapped buffers virtio > + * core handles DMA API internally. > + * > + * Returns 0 means dma valid. Other means invalid dma address. > + */ > +int virtio_dma_mapping_error(struct device *dev, dma_addr_t addr) > +{ > + struct virtio_device *vdev = dev_to_virtio(dev); > + > + if (!vring_use_dma_api(vdev)) > + return 0; > + > + return dma_mapping_error(vdev->dev.parent, addr); > +} > +EXPORT_SYMBOL_GPL(virtio_dma_mapping_error); > + > +/** > + * virtio_dma_unmap - unmap DMA addr > + * @dev: virtio device > + * @dma: DMA address > + * @length: memory length > + * @dir: DMA direction > + * > + * This API is only for pre-mapped buffers, for non premapped buffers virtio > + * core handles DMA API internally. > + */ > +void virtio_dma_unmap(struct device *dev, dma_addr_t dma, unsigned int length, > + enum dma_data_direction dir) > +{ > + struct virtio_device *vdev = dev_to_virtio(dev); > + > + 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 3ebb346ebb7c..b5fa71476737 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> > > /** > * struct virtqueue - a queue to register buffers for sending or receiving. > @@ -216,4 +217,12 @@ 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_page(struct device *dev, struct page *page, size_t offset, > + unsigned int length, enum dma_data_direction dir); > +dma_addr_t virtio_dma_map(struct device *dev, void *addr, unsigned int length, > + enum dma_data_direction dir); > +int virtio_dma_mapping_error(struct device *dev, dma_addr_t addr); > +void virtio_dma_unmap(struct device *dev, dma_addr_t dma, unsigned int length, > + enum dma_data_direction dir); > #endif /* _LINUX_VIRTIO_H */ > -- > 2.32.0.3.g01195cf9f >