On 20/02/18 23:19, Jacob Pan wrote:

On Mon, 12 Feb 2018 18:33:24 +0000
Jean-Philippe Brucker [off-list ref] wrote:

quoted

 
+/**
+ * enum page_response_code - Return status of fault handlers,
telling the IOMMU
+ * driver how to proceed with the fault.
+ *
+ * @IOMMU_FAULT_STATUS_HANDLED: Stop processing the fault, and do
not send a
+ *	reply to the device.
+ * @IOMMU_FAULT_STATUS_CONTINUE: Fault was not handled. Call the
next handler,
+ *	or terminate.
+ * @IOMMU_FAULT_STATUS_SUCCESS: Fault has been handled and the page
tables
+ *	populated, retry the access. This is "Success" in PCI PRI.
+ * @IOMMU_FAULT_STATUS_FAILURE: General error. Drop all subsequent
faults from
+ *	this device if possible. This is "Response Failure" in PCI
PRI.
+ * @IOMMU_FAULT_STATUS_INVALID: Could not handle this fault, don't
retry the
+ *	access. This is "Invalid Request" in PCI PRI.
+ */
+enum page_response_code {
+	IOMMU_PAGE_RESP_HANDLED = 0,
+	IOMMU_PAGE_RESP_CONTINUE,
+	IOMMU_PAGE_RESP_SUCCESS,
+	IOMMU_PAGE_RESP_INVALID,
+	IOMMU_PAGE_RESP_FAILURE,
+};

it seems to me two things are mixed here:
1. driver handler response status (HANDLED, CONTINUE)
2. PCI standard page response code (the rest)
Can we leave them separate? then we don't have to convert this enum
to/from PCI ATS page response code.

Except when the producer is a platform device instead of PCI :) But I get
your point. I liked combining them into one enum because it may simplify
some device drivers. I can separate HANDLED/CONTINUE and have drivers
always call page_response().

Thanks,
Jean