[PATCH v5 virtio 02/11] virtio: allow caller to override device DMA mask in vp_modern
From: Shannon Nelson <hidden>
Date: 2023-05-03 18:13:06
Also in:
virtualization
Subsystem:
the rest, virtio core · Maintainers:
Linus Torvalds, "Michael S. Tsirkin", Jason Wang
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 <redacted> --- 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