powerpc/powernv: Fix IOMMU group lost (763fe0ad) · Commits · 戴 / test

When we take full hotplug to recover from EEH errors, PCI buses could be involved. For the case, the child devices of involved PCI buses can't be attached to IOMMU group properly, which is caused by commit ("powerpc/powernv: Reduce multi-hit of iommu_add_device()"). When adding the PCI devices of the newly created PCI buses to the system, the IOMMU group is expected to be added in (C). (A) fails to bind the IOMMU group because bus->is_added is false. (B) fails because the device doesn't have binding IOMMU table yet. bus->is_added is set to true at end of (C) and pdev->is_added is set to true at (D). pcibios_add_pci_devices() pci_scan_bridge() pci_scan_child_bus() pci_scan_slot() pci_scan_single_device() pci_scan_device() pci_device_add() pcibios_add_device() A: Ignore device_add() B: Ignore pcibios_fixup_bus() pcibios_setup_bus_devices() pcibios_setup_device() C: Hit pcibios_finish_adding_to_bus() pci_bus_add_devices() pci_bus_add_device() D: Add device If the parent PCI bus isn't involved in hotplug, the IOMMU group is expected to be bound in (B). (A) should fail as the sysfs entries aren't populated. The patch fixes the issue by reverting commit and remove WARN_ON() in iommu_add_device() to allow calling the function even the specified device already has associated IOMMU group. Cc: <stable@vger.kernel.org> # 3.16+ Reported-by:

Thadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com> Signed-off-by:

Gavin Shan <gwshan@linux.vnet.ibm.com> Acked-by:

Wei Yang <weiyang@linux.vnet.ibm.com> Signed-off-by:

Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/kernel/iommu.c

+21 −17

Original line number	Diff line number	Diff line
		@@ -1120,37 +1120,41 @@ EXPORT_SYMBOL_GPL(iommu_release_ownership);
		int iommu_add_device(struct device *dev)
		{
		struct iommu_table *tbl;
		int ret = 0;

		if (WARN_ON(dev->iommu_group)) {
		pr_warn("iommu_tce: device %s is already in iommu group %d, skipping\n",
		dev_name(dev),
		/*
		* The sysfs entries should be populated before
		* binding IOMMU group. If sysfs entries isn't
		* ready, we simply bail.
		*/
		if (!device_is_registered(dev))
		return -ENOENT;

		if (dev->iommu_group) {
		pr_debug("%s: Skipping device %s with iommu group %d\n",
		__func__, dev_name(dev),
		iommu_group_id(dev->iommu_group));
		return -EBUSY;
		}

		tbl = get_iommu_table_base(dev);
		if (!tbl \|\| !tbl->it_group) {
		pr_debug("iommu_tce: skipping device %s with no tbl\n",
		dev_name(dev));
		pr_debug("%s: Skipping device %s with no tbl\n",
		__func__, dev_name(dev));
		return 0;
		}

		pr_debug("iommu_tce: adding %s to iommu group %d\n",
		dev_name(dev), iommu_group_id(tbl->it_group));
		pr_debug("%s: Adding %s to iommu group %d\n",
		__func__, dev_name(dev),
		iommu_group_id(tbl->it_group));

		if (PAGE_SIZE < IOMMU_PAGE_SIZE(tbl)) {
		pr_err("iommu_tce: unsupported iommu page size.");
		pr_err("%s has not been added\n", dev_name(dev));
		pr_err("%s: Invalid IOMMU page size %lx (%lx) on %s\n",
		__func__, IOMMU_PAGE_SIZE(tbl),
		PAGE_SIZE, dev_name(dev));
		return -EINVAL;
		}

		ret = iommu_group_add_device(tbl->it_group, dev);
		if (ret < 0)
		pr_err("iommu_tce: %s has not been added, ret=%d\n",
		dev_name(dev), ret);

		return ret;
		return iommu_group_add_device(tbl->it_group, dev);
		}
		EXPORT_SYMBOL_GPL(iommu_add_device);

arch/powerpc/platforms/powernv/pci-ioda.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -857,7 +857,7 @@ static void pnv_pci_ioda_dma_dev_setup(struct pnv_phb phb, struct pci_dev pdev

		pe = &phb->ioda.pe_array[pdn->pe_number];
		WARN_ON(get_dma_ops(&pdev->dev) != &dma_iommu_ops);
		set_iommu_table_base(&pdev->dev, &pe->tce32_table);
		set_iommu_table_base_and_group(&pdev->dev, &pe->tce32_table);
		}

		static int pnv_pci_ioda_dma_set_mask(struct pnv_phb *phb,

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