diff options
Diffstat (limited to 'drivers/pci')
| -rw-r--r-- | drivers/pci/intel-iommu.c | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c index f9fc4f3bfa3..360fb67a30d 100644 --- a/drivers/pci/intel-iommu.c +++ b/drivers/pci/intel-iommu.c @@ -2122,6 +2122,36 @@ static int iommu_should_identity_map(struct pci_dev *pdev, int startup) if (iommu_identity_mapping == 2) return IS_GFX_DEVICE(pdev); + /* + * We want to start off with all devices in the 1:1 domain, and + * take them out later if we find they can't access all of memory. + * + * However, we can't do this for PCI devices behind bridges, + * because all PCI devices behind the same bridge will end up + * with the same source-id on their transactions. + * + * Practically speaking, we can't change things around for these + * devices at run-time, because we can't be sure there'll be no + * DMA transactions in flight for any of their siblings. + * + * So PCI devices (unless they're on the root bus) as well as + * their parent PCI-PCI or PCIe-PCI bridges must be left _out_ of + * the 1:1 domain, just in _case_ one of their siblings turns out + * not to be able to map all of memory. + */ + if (!pdev->is_pcie) { + if (!pci_is_root_bus(pdev->bus)) + return 0; + if (pdev->class >> 8 == PCI_CLASS_BRIDGE_PCI) + return 0; + } else if (pdev->pcie_type == PCI_EXP_TYPE_PCI_BRIDGE) + return 0; + + /* + * At boot time, we don't yet know if devices will be 64-bit capable. + * Assume that they will -- if they turn out not to be, then we can + * take them out of the 1:1 domain later. + */ if (!startup) return pdev->dma_mask > DMA_BIT_MASK(32); |