iommu/vt-d: Fix RID2PASID setup/teardown failure

The IOMMU driver shares the pasid table for PCI alias devices. When the RID2PASID entry of the shared pasid table has been filled by the first device, the subsequent device will encounter the "DMAR: Setup RID2PASID failed" failure as the pasid entry has already been marked as present. As the result, the IOMMU probing process will be aborted. On the contrary, when any alias device is hot-removed from the system, for example, by writing to /sys/bus/pci/devices/.../remove, the shared RID2PASID will be cleared without any notifications to other devices. As the result, any DMAs from those rest devices are blocked. Sharing pasid table among PCI alias devices could save two memory pages for devices underneath the PCIe-to-PCI bridges. Anyway, considering that those devices are rare on modern platforms that support VT-d in scalable mode and the saved memory is negligible, it's reasonable to remove this part of immature code to make the driver feasible and stable.

Lu Baolu committed 4 years ago

Commit 4140d771 parent 316f92a4 files · +3 −94Browse files

Showing the changes to include/linux (1 of 4 files). Show all

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include/linux/intel-iommu.h+0−3

 struct device_domain_info {
 	struct list_head link;	/* link to domain siblings */
 	struct list_head global; /* link to global list */
-	struct list_head table;	/* link to pasid table */
 	u32 segment;		/* PCI segment number */
 	u8 bus;			/* PCI bus number */
 	u8 devfn;		/* PCI devfn number */
 void *alloc_pgtable_page(int node);
 void free_pgtable_page(void *vaddr);
 struct intel_iommu *domain_get_iommu(struct dmar_domain *domain);
-int for_each_device_domain(int (*fn)(struct device_domain_info *info,
-				     void *data), void *data);
 void iommu_flush_write_buffer(struct intel_iommu *iommu);
 int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct device *dev);
 struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devfn);