Commit 5d7d82d3 authored by Shannon Nelson's avatar Shannon Nelson Committed by Michael S. Tsirkin
Browse files

virtio: allow caller to override device DMA mask in vp_modern 



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: default avatarShannon Nelson <shannon.nelson@amd.com>
Acked-by: default avatarJason Wang <jasowang@redhat.com>
Message-Id: <20230519215632.12343-3-shannon.nelson@amd.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent a37c0191

drivers/virtio/virtio_pci_modern_dev.c

+2 −1
Original line number Diff line number Diff line
@@ -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));

include/linux/virtio_pci_modern.h

+3 −0
Original line number Diff line number Diff line
@@ -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;

};



/*