Commit d7b4e328 authored by Maxime Coquelin's avatar Maxime Coquelin Committed by Michael S. Tsirkin
Browse files

vduse: implement DMA sync callbacks 



Since commit 295525e2 ("virtio_net: merge dma
operations when filling mergeable buffers"), VDUSE device
require support for DMA's .sync_single_for_cpu() operation
as the memory is non-coherent between the device and CPU
because of the use of a bounce buffer.

This patch implements both .sync_single_for_cpu() and
.sync_single_for_device() callbacks, and also skip bounce
buffer copies during DMA map and unmap operations if the
DMA_ATTR_SKIP_CPU_SYNC attribute is set to avoid extra
copies of the same buffer.

Signed-off-by: default avatarMaxime Coquelin <maxime.coquelin@redhat.com>
Message-Id: <20240219170606.587290-1-maxime.coquelin@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 749a4016

drivers/vdpa/vdpa_user/iova_domain.c

+24 −3
Original line number Diff line number Diff line
@@ -373,6 +373,26 @@ static void vduse_domain_free_iova(struct iova_domain *iovad, 
	free_iova_fast(iovad, iova >> shift, iova_len);

}



void vduse_domain_sync_single_for_device(struct vduse_iova_domain *domain,

				      dma_addr_t dma_addr, size_t size,

				      enum dma_data_direction dir)

{

	read_lock(&domain->bounce_lock);

	if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)

		vduse_domain_bounce(domain, dma_addr, size, DMA_TO_DEVICE);

	read_unlock(&domain->bounce_lock);

}



void vduse_domain_sync_single_for_cpu(struct vduse_iova_domain *domain,

				      dma_addr_t dma_addr, size_t size,

				      enum dma_data_direction dir)

{

	read_lock(&domain->bounce_lock);

	if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL)

		vduse_domain_bounce(domain, dma_addr, size, DMA_FROM_DEVICE);

	read_unlock(&domain->bounce_lock);

}



dma_addr_t vduse_domain_map_page(struct vduse_iova_domain *domain,

				 struct page *page, unsigned long offset,

				 size_t size, enum dma_data_direction dir,
@@ -393,7 +413,8 @@ dma_addr_t vduse_domain_map_page(struct vduse_iova_domain *domain, 
	if (vduse_domain_map_bounce_page(domain, (u64)iova, (u64)size, pa))

		goto err_unlock;



	if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)

	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&

	    (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))

		vduse_domain_bounce(domain, iova, size, DMA_TO_DEVICE);



	read_unlock(&domain->bounce_lock);
@@ -411,9 +432,9 @@ void vduse_domain_unmap_page(struct vduse_iova_domain *domain, 
			     enum dma_data_direction dir, unsigned long attrs)

{

	struct iova_domain *iovad = &domain->stream_iovad;



	read_lock(&domain->bounce_lock);

	if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL)

	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&

	    (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))

		vduse_domain_bounce(domain, dma_addr, size, DMA_FROM_DEVICE);



	vduse_domain_unmap_bounce_page(domain, (u64)dma_addr, (u64)size);

drivers/vdpa/vdpa_user/iova_domain.h

+8 −0
Original line number Diff line number Diff line
@@ -44,6 +44,14 @@ int vduse_domain_set_map(struct vduse_iova_domain *domain, 
void vduse_domain_clear_map(struct vduse_iova_domain *domain,

			    struct vhost_iotlb *iotlb);



void vduse_domain_sync_single_for_device(struct vduse_iova_domain *domain,

				      dma_addr_t dma_addr, size_t size,

				      enum dma_data_direction dir);



void vduse_domain_sync_single_for_cpu(struct vduse_iova_domain *domain,

				      dma_addr_t dma_addr, size_t size,

				      enum dma_data_direction dir);



dma_addr_t vduse_domain_map_page(struct vduse_iova_domain *domain,

				 struct page *page, unsigned long offset,

				 size_t size, enum dma_data_direction dir,

drivers/vdpa/vdpa_user/vduse_dev.c

+22 −0
Original line number Diff line number Diff line
@@ -798,6 +798,26 @@ static const struct vdpa_config_ops vduse_vdpa_config_ops = { 
	.free			= vduse_vdpa_free,

};



static void vduse_dev_sync_single_for_device(struct device *dev,

					     dma_addr_t dma_addr, size_t size,

					     enum dma_data_direction dir)

{

	struct vduse_dev *vdev = dev_to_vduse(dev);

	struct vduse_iova_domain *domain = vdev->domain;



	vduse_domain_sync_single_for_device(domain, dma_addr, size, dir);

}



static void vduse_dev_sync_single_for_cpu(struct device *dev,

					     dma_addr_t dma_addr, size_t size,

					     enum dma_data_direction dir)

{

	struct vduse_dev *vdev = dev_to_vduse(dev);

	struct vduse_iova_domain *domain = vdev->domain;



	vduse_domain_sync_single_for_cpu(domain, dma_addr, size, dir);

}



static dma_addr_t vduse_dev_map_page(struct device *dev, struct page *page,

				     unsigned long offset, size_t size,

				     enum dma_data_direction dir,
@@ -858,6 +878,8 @@ static size_t vduse_dev_max_mapping_size(struct device *dev) 
}



static const struct dma_map_ops vduse_dev_dma_ops = {

	.sync_single_for_device = vduse_dev_sync_single_for_device,

	.sync_single_for_cpu = vduse_dev_sync_single_for_cpu,

	.map_page = vduse_dev_map_page,

	.unmap_page = vduse_dev_unmap_page,

	.alloc = vduse_dev_alloc_coherent,