To add a bit of vendor flexibility with various virtio based devices,
allow the caller to specify a different DMA mask. This adds a dma_mask
field to struct virtio_pci_modern_device. If defined by the driver,
this mask will be used in a call to dma_set_mask_and_coherent() instead
of the traditional DMA_BIT_MASK(64). This allows limiting the DMA space
on vendor devices with address limitations.
Signed-off-by: Shannon Nelson <shannon.nelson@xxxxxxx>
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
---
drivers/virtio/virtio_pci_modern_dev.c | 3 ++-
include/linux/virtio_pci_modern.h | 3 +++
2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c
index 9b2d6614de67..aad7d9296e77 100644
--- a/drivers/virtio/virtio_pci_modern_dev.c
+++ b/drivers/virtio/virtio_pci_modern_dev.c
@@ -268,7 +268,8 @@ int vp_modern_probe(struct virtio_pci_modern_device *mdev)
return -EINVAL;
}
- err = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(64));
+ err = dma_set_mask_and_coherent(&pci_dev->dev,
+ mdev->dma_mask ? : DMA_BIT_MASK(64));
if (err)
err = dma_set_mask_and_coherent(&pci_dev->dev,
DMA_BIT_MASK(32));
diff --git a/include/linux/virtio_pci_modern.h b/include/linux/virtio_pci_modern.h
index e7b1db1dd0bb..067ac1d789bc 100644
--- a/include/linux/virtio_pci_modern.h
+++ b/include/linux/virtio_pci_modern.h
@@ -41,6 +41,9 @@ struct virtio_pci_modern_device {
/* optional check for vendor virtio device, returns dev_id or -ERRNO */
int (*device_id_check)(struct pci_dev *pdev);
+
+ /* optional mask for devices with limited DMA space */
+ u64 dma_mask;
};
/*
--
2.17.1
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