virtio_ring: Fix querying of maximum DMA mapping size for virtio device
PATCH 1/1 virtio_ring: Fix querying of maximum DMA mapping size for virtio device
virtio_max_dma_size() returns the maximum DMA mapping size of the virtio device by querying dma_max_mapping_size() for the device when the DMA API is in use for the vring. Unfortunately, the device passed is initialised by register_virtio_device() and does not inherit the DMA configuration from its parent, resulting in SWIOTLB errors when bouncing is enabled and the default 256K mapping limit (IO_TLB_SEGSIZE) is not respected:
| virtio-pci 0000:00:01.0: swiotlb buffer is full (sz: 294912 bytes), total 1024 (slots), used 725 (slots)
Follow the pattern used elsewhere in the virtio_ring code when calling into the DMA layer and pass the parent device to dma_max_mapping_size() instead.
--- drivers/virtio/virtio_ring.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/virtio/virtio_ring.c +1 -1
@@ -268,7 +268,7 @@ size_t virtio_max_dma_size(struct virtio_device *vdev)size_t max_segment_size =SIZE_MAX ;if (vring_use_dma_api (vdev)) - max_segment_size =dma_max_mapping_size (&vdev->dev); + max_segment_size =dma_max_mapping_size (vdev->dev.parent);return max_segment_size; }
Signature · 1 line
2.34.0.rc2.393.gf8c9666880-goog
Quoted 15 lines · Will Deacon
virtio_max_dma_size()returns the maximum DMA mapping size of the virtio device by queryingdma_max_mapping_size()for the device when the DMA API is in use for the vring. Unfortunately, the device passed is initialised byregister_virtio_device()and does not inherit the DMA configuration from its parent, resulting in SWIOTLB errors when bouncing is enabled and the default 256K mapping limit (IO_TLB_SEGSIZE) is not respected:| virtio-pci 0000:00:01.0: swiotlb buffer is full (sz: 294912 bytes), total 1024 (slots), used 725 (slots)
Follow the pattern used elsewhere in the
virtio_ringcode when calling into the DMA layer and pass the parent device todma_max_mapping_size()instead.
Quoted 5 lines
Cc Marc Zyngier <[email protected]>Cc Quentin Perret <[email protected]>Cc "Michael S. Tsirkin" <[email protected]>Cc Jason Wang <[email protected]>Signed-off-by Will Deacon <[email protected]>
Quoted 20 lines
--- drivers/virtio/virtio_ring.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)drivers/virtio/virtio_ring.c +1
-2@@ -268,7 +268,7 @@ size_t virtio_max_dma_size(struct virtio_device *vdev)size_t max_segment_size =SIZE_MAX ;if (vring_use_dma_api (vdev)) - max_segment_size =dma_max_mapping_size (&vdev->dev); + max_segment_size =dma_max_mapping_size (vdev->dev.parent);return max_segment_size; } --2.34.0.rc2.393.gf8c9666880-goog
Quoted 14 lines · Will Deacon
virtio_max_dma_size()returns the maximum DMA mapping size of the virtio device by queryingdma_max_mapping_size()for the device when the DMA API is in use for the vring. Unfortunately, the device passed is initialised byregister_virtio_device()and does not inherit the DMA configuration from its parent, resulting in SWIOTLB errors when bouncing is enabled and the default 256K mapping limit (IO_TLB_SEGSIZE) is not respected:| virtio-pci 0000:00:01.0: swiotlb buffer is full (sz: 294912 bytes), total 1024 (slots), used 725 (slots)
Follow the pattern used elsewhere in the
virtio_ringcode when calling into the DMA layer and pass the parent device todma_max_mapping_size()instead.
Quoted 5 lines
Cc Marc Zyngier <[email protected]>Cc Quentin Perret <[email protected]>Cc "Michael S. Tsirkin" <[email protected]>Cc Jason Wang <[email protected]>Signed-off-by Will Deacon <[email protected]>
We hit a similar problem and ended up in the same patch, a bit late [0].
FWIW:
[0] https://lkml.kernel.org/r/[email protected]
Quoted 18 lines
--- drivers/virtio/virtio_ring.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)drivers/virtio/virtio_ring.c +1
-1@@ -268,7 +268,7 @@ size_t virtio_max_dma_size(struct virtio_device *vdev)size_t max_segment_size =SIZE_MAX ;if (vring_use_dma_api (vdev)) - max_segment_size =dma_max_mapping_size (&vdev->dev); + max_segment_size =dma_max_mapping_size (vdev->dev.parent);return max_segment_size; }