[PATCH 5.15 022/177] virtio_ring: Fix querying of maximum DMA mapping size for virtio device

Greg Kroah-Hartman
2021-12-20T15:05:38Z

From: Will Deacon <will@kernel.org>

commit 817fc978b5a29b039db0418a91072b31c9aab152 upstream.

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.

Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Signed-off-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20211201112018.25276-1-will@kernel.org
Acked-by: Jason Wang <jasowang@redhat.com>
Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Fixes: e6d6dd6c875e ("virtio: Introduce virtio_max_dma_size()")
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/virtio/virtio_ring.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -268,7 +268,7 @@ size_t virtio_max_dma_size(struct virtio
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;
}