Am 18.11.2020 um 22:59 schrieb Shay Agroskin: > 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. > > Fixes: 1738cd3ed342 ("net: ena: Add a driver for Amazon Elastic Network > Adapters (ENA)") > Signed-off-by: Mike Cui <mike...@amazon.com> > Signed-off-by: Arthur Kiyanovski <akiy...@amazon.com> > Signed-off-by: Shay Agroskin <shay...@amazon.com> > --- > drivers/net/ethernet/amazon/ena/ena_netdev.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c > b/drivers/net/ethernet/amazon/ena/ena_netdev.c > index 574c2b5ba21e..854a22e692bf 100644 > --- a/drivers/net/ethernet/amazon/ena/ena_netdev.c > +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c > @@ -4146,6 +4146,19 @@ static int ena_probe(struct pci_dev *pdev, const > struct pci_device_id *ent) > return rc; > } > > + rc = pci_set_dma_mask(pdev, DMA_BIT_MASK(ENA_MAX_PHYS_ADDR_SIZE_BITS)); > + if (rc) { > + dev_err(&pdev->dev, "pci_set_dma_mask failed %d\n", rc); > + goto err_disable_device; > + } > + > + rc = pci_set_consistent_dma_mask(pdev, > DMA_BIT_MASK(ENA_MAX_PHYS_ADDR_SIZE_BITS)); > + if (rc) { > + dev_err(&pdev->dev, "err_pci_set_consistent_dma_mask failed > %d\n", > + rc); > + goto err_disable_device; > + } > + > pci_set_master(pdev); > > ena_dev = vzalloc(sizeof(*ena_dev)); >
The old pci_ dma wrappers are being phased out and shouldn't be used in new code. See e.g. e059c6f340f6 ("tulip: switch from 'pci_' to 'dma_' API"). So better use: dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(ENA_MAX_PHYS_ADDR_SIZE_BITS));