From 50310600ebda74b9988467e2e6128711c7ba56fc Mon Sep 17 00:00:00 2001 From: Lu Baolu Date: Tue, 23 Jun 2020 07:13:43 +0800 Subject: [PATCH] iommu/vt-d: Enable PCI ACS for platform opt in hint PCI ACS is disabled if Intel IOMMU is off by default or intel_iommu=off is used in command line. Unfortunately, Intel IOMMU will be forced on if there're devices sitting on an external facing PCI port that is marked as untrusted (for example, thunderbolt peripherals). That means, PCI ACS is disabled while Intel IOMMU is forced on to isolate those devices. As the result, the devices of an MFD will be grouped by a single group even the ACS is supported on device. [ 0.691263] pci 0000:00:07.1: Adding to iommu group 3 [ 0.691277] pci 0000:00:07.2: Adding to iommu group 3 [ 0.691292] pci 0000:00:07.3: Adding to iommu group 3 Fix it by requesting PCI ACS when Intel IOMMU is detected with platform opt in hint. Fixes: 89a6079df791a ("iommu/vt-d: Force IOMMU on for platform opt in hint") Co-developed-by: Lalithambika Krishnakumar Signed-off-by: Lalithambika Krishnakumar Signed-off-by: Lu Baolu Reviewed-by: Mika Westerberg Cc: Mika Westerberg Cc: Ashok Raj Link: https://lore.kernel.org/r/20200622231345.29722-5-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel --- drivers/iommu/intel/dmar.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c index cc46dff98fa0..683b812c5c47 100644 --- a/drivers/iommu/intel/dmar.c +++ b/drivers/iommu/intel/dmar.c @@ -898,7 +898,8 @@ int __init detect_intel_iommu(void) if (!ret) ret = dmar_walk_dmar_table((struct acpi_table_dmar *)dmar_tbl, &validate_drhd_cb); - if (!ret && !no_iommu && !iommu_detected && !dmar_disabled) { + if (!ret && !no_iommu && !iommu_detected && + (!dmar_disabled || dmar_platform_optin())) { iommu_detected = 1; /* Make sure ACS will be enabled */ pci_request_acs();