diff mbox series

[40/42,SRU,U] UBUNTU: SAUCE: iommu/vt-d: Allow PCI sub-hierarchy to use DMA domain

Message ID 20200526125954.237403-41-vicamo.yang@canonical.com
State New
Headers show
Series Fix can't find root device on VMD when secureboot enabled | expand

Commit Message

You-Sheng Yang May 26, 2020, 12:59 p.m. UTC 
From: Lu Baolu <baolu.lu@linux.intel.com>

BugLink: https://bugs.launchpad.net/bugs/1876707

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 <baolu.lu@linux.intel.com>
Tested-by: Daniel Drake <drake@endlessm.com>
Reviewed-by: Jon Derrick <jonathan.derrick@intel.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Link: https://lore.kernel.org/r/20200506015947.28662-3-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
(cherry picked from commit 14b3526d5909f01e1d1baa05f50952788bb7418e
iommu/next)
Signed-off-by: You-Sheng Yang <vicamo.yang@canonical.com>
---
 drivers/iommu/intel-iommu.c | 25 -------------------------
 1 file changed, 25 deletions(-)
diff mbox series

Patch

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 16ba7add0f72..af309e8fa6f5 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;