Messages in this thread | | | Date | Fri, 3 Dec 2021 15:50:41 +0000 | Subject | Re: [PATCH] virtio_ring: Fix querying of maximum DMA mapping size for virtio device | From | Suzuki K Poulose <> |
| |
On 01/12/2021 11:20, Will Deacon wrote: > 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>
We hit a similar problem and ended up in the same patch, a bit late [0].
FWIW:
Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
[0] https://lkml.kernel.org/r/20211203121614.3380162-1-suzuki.poulose@arm.com
> --- > drivers/virtio/virtio_ring.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index 6d2614e34470..028b05d44546 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -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; > } >
| |