From: Lu Baolu Date: Wed, 6 May 2020 01:59:46 +0000 (+0800) Subject: iommu/vt-d: Allow PCI sub-hierarchy to use DMA domain X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=14b3526d5909f01e1d1baa05f50952788bb7418e;p=linux.git iommu/vt-d: Allow PCI sub-hierarchy to use DMA domain Before commit fa954e6831789 ("iommu/vt-d: Delegate the dma domain to upper layer"), Intel IOMMU started off with all devices in the identity domain, and took them out later if it found they couldn't access all of memory. This required devices behind a PCI bridge to use a DMA domain at the beginning because all PCI devices behind the bridge use the same source-id in their transactions and the domain couldn't be changed at run-time. Intel IOMMU driver is now aligned with the default domain framework, there's no need to keep this requirement anymore. Signed-off-by: Lu Baolu Tested-by: Daniel Drake Reviewed-by: Jon Derrick Reviewed-by: Jerry Snitselaar Link: https://lore.kernel.org/r/20200506015947.28662-3-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel --- diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 16ba7add0f72b..af309e8fa6f5f 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -2857,31 +2857,6 @@ static int device_def_domain_type(struct device *dev) if ((iommu_identity_mapping & IDENTMAP_GFX) && IS_GFX_DEVICE(pdev)) return IOMMU_DOMAIN_IDENTITY; - - /* - * 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 (!pci_is_pcie(pdev)) { - if (!pci_is_root_bus(pdev->bus)) - return IOMMU_DOMAIN_DMA; - if (pdev->class >> 8 == PCI_CLASS_BRIDGE_PCI) - return IOMMU_DOMAIN_DMA; - } else if (pci_pcie_type(pdev) == PCI_EXP_TYPE_PCI_BRIDGE) - return IOMMU_DOMAIN_DMA; } return 0;