Commit 5b02218c authored Nov 23, 2020 by Shay Agroskin Committed by Greg Kroah-Hartman Dec 02, 2020

net: ena: set initial DMA width to avoid intel iommu issue



[ Upstream commit 09323b3bca95181c0da79daebc8b0603e500f573 ]

The ENA driver uses the readless mechanism, which uses DMA, to find
out what the DMA mask is supposed to be.

If DMA is used without setting the dma_mask first, it causes the
Intel IOMMU driver to think that ENA is a 32-bit device and therefore
disables IOMMU passthrough permanently.

This patch sets the dma_mask to be ENA_MAX_PHYS_ADDR_SIZE_BITS=48
before readless initialization in
ena_device_init()->ena_com_mmio_reg_read_request_init(),
which is large enough to workaround the intel_iommu issue.

DMA mask is set again to the correct value after it's received from the
device after readless is initialized.

The patch also changes the driver to use dma_set_mask_and_coherent()
function instead of the two pci_set_dma_mask() and
pci_set_consistent_dma_mask() ones. Both methods achieve the same
effect.

Fixes: 1738cd3e ("net: ena: Add a driver for Amazon Elastic Network Adapters (ENA)")
Signed-off-by: Mike Cui <mikecui@amazon.com>
Signed-off-by: Arthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: Shay Agroskin <shayagr@amazon.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 24071f8d

drivers/net/ethernet/amazon/ena/ena_netdev.c

+8 −9

Original line number	Original line	Diff line number	Diff line
	@@ -2433,16 +2433,9 @@ static int ena_device_init(struct ena_com_dev ena_dev, struct pci_dev pdev,
	goto err_mmio_read_less;		goto err_mmio_read_less;
	}		}

	rc = pci_set_dma_mask(pdev, DMA_BIT_MASK(dma_width));		rc = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(dma_width));
	if (rc) {		if (rc) {
	dev_err(dev, "pci_set_dma_mask failed 0x%x\n", rc);		dev_err(dev, "dma_set_mask_and_coherent failed %d\n", rc);
	goto err_mmio_read_less;
	}

	rc = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(dma_width));
	if (rc) {
	dev_err(dev, "err_pci_set_consistent_dma_mask failed 0x%x\n",
	rc);
	goto err_mmio_read_less;		goto err_mmio_read_less;
	}		}

	@@ -3183,6 +3176,12 @@ static int ena_probe(struct pci_dev pdev, const struct pci_device_id ent)
	return rc;		return rc;
	}		}

			rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(ENA_MAX_PHYS_ADDR_SIZE_BITS));
			if (rc) {
			dev_err(&pdev->dev, "dma_set_mask_and_coherent failed %d\n", rc);
			goto err_disable_device;
			}

	pci_set_master(pdev);		pci_set_master(pdev);

	ena_dev = vzalloc(sizeof(*ena_dev));		ena_dev = vzalloc(sizeof(*ena_dev));