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vduse: implement DMA sync callbacks

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Since commit 295525e29a ("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: Maxime Coquelin <maxime.coquelin@redhat.com>
Message-Id: <20240219170606.587290-1-maxime.coquelin@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Maxime Coquelin 2024-02-19 18:06:06 +01:00 committed by Michael S. Tsirkin
parent 749a401683
commit d7b4e3287c
3 changed files with 54 additions and 3 deletions
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27
drivers/vdpa/vdpa_user/iova_domain.c
View file

@ -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);

8
drivers/vdpa/vdpa_user/iova_domain.h
View file

@ -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,

22
drivers/vdpa/vdpa_user/vduse_dev.c
View file

@ -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,