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.

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Jean-Philippe Brucker 2019-06-03 15:57:49 +01:00 committed by Joerg Roedel
parent 0c830e6b32
commit bf3255b3cf
3 changed files with 146 additions and 2 deletions

View file

@ -115,4 +115,39 @@ struct iommu_fault {
struct iommu_fault_page_request prm;
};
};
/**
* enum iommu_page_response_code - Return status of fault handlers
* @IOMMU_PAGE_RESP_SUCCESS: Fault has been handled and the page tables
* populated, retry the access. This is "Success" in PCI PRI.
* @IOMMU_PAGE_RESP_FAILURE: General error. Drop all subsequent faults from
* this device if possible. This is "Response Failure" in PCI PRI.
* @IOMMU_PAGE_RESP_INVALID: Could not handle this fault, don't retry the
* access. This is "Invalid Request" in PCI PRI.
*/
enum iommu_page_response_code {
IOMMU_PAGE_RESP_SUCCESS = 0,
IOMMU_PAGE_RESP_INVALID,
IOMMU_PAGE_RESP_FAILURE,
};
/**
* struct iommu_page_response - Generic page response information
* @version: API version of this structure
* @flags: encodes whether the corresponding fields are valid
* (IOMMU_FAULT_PAGE_RESPONSE_* values)
* @pasid: Process Address Space ID
* @grpid: Page Request Group Index
* @code: response code from &enum iommu_page_response_code
*/
struct iommu_page_response {
#define IOMMU_PAGE_RESP_VERSION_1 1
__u32 version;
#define IOMMU_PAGE_RESP_PASID_VALID (1 << 0)
__u32 flags;
__u32 pasid;
__u32 grpid;
__u32 code;
};
#endif /* _UAPI_IOMMU_H */