From ec615f43d3b61edcfdc4d8d1f672be1059573d1b Mon Sep 17 00:00:00 2001 From: Robin Murphy Date: Thu, 3 Nov 2016 17:39:07 +0000 Subject: [PATCH] iommu/arm-smmu: Don't inadvertently reject multiple SMMUv3s We now delay installing our per-bus iommu_ops until we know an SMMU has successfully probed, as they don't serve much purpose beforehand, and doing so also avoids fights between multiple IOMMU drivers in a single kernel. However, the upshot of passing the return value of bus_set_iommu() back from our probe function is that if there happens to be more than one SMMUv3 device in a system, the second and subsequent probes will wind up returning -EBUSY to the driver core and getting torn down again. Avoid re-setting ops if ours are already installed, so that any genuine failures stand out. Fixes: 08d4ca2a672b ("iommu/arm-smmu: Support non-PCI devices with SMMUv3") CC: Lorenzo Pieralisi CC: Hanjun Guo Signed-off-by: Robin Murphy Signed-off-by: Joerg Roedel --- drivers/iommu/arm-smmu-v3.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c index 15c01c3cd540..e6f9b2d745ca 100644 --- a/drivers/iommu/arm-smmu-v3.c +++ b/drivers/iommu/arm-smmu-v3.c @@ -2636,17 +2636,26 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev) /* And we're up. Go go go! */ of_iommu_set_ops(dev->of_node, &arm_smmu_ops); #ifdef CONFIG_PCI - pci_request_acs(); - ret = bus_set_iommu(&pci_bus_type, &arm_smmu_ops); - if (ret) - return ret; + if (pci_bus_type.iommu_ops != &arm_smmu_ops) { + pci_request_acs(); + ret = bus_set_iommu(&pci_bus_type, &arm_smmu_ops); + if (ret) + return ret; + } #endif #ifdef CONFIG_ARM_AMBA - ret = bus_set_iommu(&amba_bustype, &arm_smmu_ops); - if (ret) - return ret; + if (amba_bustype.iommu_ops != &arm_smmu_ops) { + ret = bus_set_iommu(&amba_bustype, &arm_smmu_ops); + if (ret) + return ret; + } #endif - return bus_set_iommu(&platform_bus_type, &arm_smmu_ops); + if (platform_bus_type.iommu_ops != &arm_smmu_ops) { + ret = bus_set_iommu(&platform_bus_type, &arm_smmu_ops); + if (ret) + return ret; + } + return 0; } static int arm_smmu_device_remove(struct platform_device *pdev) -- GitLab