iommu: Add recoverable fault reporting

Some IOMMU hardware features, for example PCI PRI and Arm SMMU Stall, enable recoverable I/O page faults. Allow IOMMU drivers to report PRI Page Requests and Stall events through the new fault reporting API. The consumer of the fault can be either an I/O page fault handler in the host, or a guest OS. Once handled, the fault must be completed by sending a page response back to the IOMMU. Add an iommu_page_response() function to complete a page fault. There are two ways to extend the userspace API: * Add a field to iommu_page_response and a flag to iommu_page_response::flags describing the validity of this field. * Introduce a new iommu_page_response_X structure with a different version number. The kernel must then support both versions.

Jean-Philippe Brucker committed 7 years ago

Commit bf3255b1 parent 0c830e63 files · +146 −2Browse files

Showing the changes to include/uapi/linux (1 of 3 files). Show all

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include/uapi/linux/iommu.h+35−0

@@ -115,4 +115,39 @@ struct iommu_fault { · 114 unmodified lines
115	115	struct iommu_fault_page_request prm;
116	116	};
117	117	};
	118	+
	119	+/**
	120	+ * enum iommu_page_response_code - Return status of fault handlers
	121	+ * @IOMMU_PAGE_RESP_SUCCESS: Fault has been handled and the page tables
	122	+ * populated, retry the access. This is "Success" in PCI PRI.
	123	+ * @IOMMU_PAGE_RESP_FAILURE: General error. Drop all subsequent faults from
	124	+ * this device if possible. This is "Response Failure" in PCI PRI.
	125	+ * @IOMMU_PAGE_RESP_INVALID: Could not handle this fault, don't retry the
	126	+ * access. This is "Invalid Request" in PCI PRI.
	127	+ */
	128	+enum iommu_page_response_code {
	129	+ IOMMU_PAGE_RESP_SUCCESS = 0,
	130	+ IOMMU_PAGE_RESP_INVALID,
	131	+ IOMMU_PAGE_RESP_FAILURE,
	132	+};
	133	+
	134	+/**
	135	+ * struct iommu_page_response - Generic page response information
	136	+ * @version: API version of this structure
	137	+ * @flags: encodes whether the corresponding fields are valid
	138	+ * (IOMMU_FAULT_PAGE_RESPONSE_* values)
	139	+ * @pasid: Process Address Space ID
	140	+ * @grpid: Page Request Group Index
	141	+ * @code: response code from &enum iommu_page_response_code
	142	+ */
	143	+struct iommu_page_response {
	144	+#define IOMMU_PAGE_RESP_VERSION_1 1
	145	+ __u32 version;
	146	+#define IOMMU_PAGE_RESP_PASID_VALID (1 << 0)
	147	+ __u32 flags;
	148	+ __u32 pasid;
	149	+ __u32 grpid;
	150	+ __u32 code;
	151	+};
	152	+
118	153	#endif /* _UAPI_IOMMU_H */