[PATCH v2 08/16] iommu: introduce device fault data

[Jacob Pan <jacob.jun.pan-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>]

Device faults detected by IOMMU can be reported outside IOMMU
subsystem. This patch intends to provide a generic device
fault data such that device drivers can communicate IOMMU faults
without model specific knowledge.

The assumption is that model specific IOMMU driver can filter and
handle most of the IOMMU faults if the cause is within IOMMU driver
control. Therefore, the fault reasons can be reported are grouped
and generalized based common specifications such as PCI ATS.

Signed-off-by: Jacob Pan <jacob.jun.pan-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
---
 include/linux/iommu.h | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 4af1820..3f9b367 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -49,6 +49,7 @@ struct bus_type;
 struct device;
 struct iommu_domain;
 struct notifier_block;
+struct iommu_fault_event;
 
 /* iommu fault flags */
 #define IOMMU_FAULT_READ	0x0
@@ -56,6 +57,7 @@ struct notifier_block;
 
 typedef int (*iommu_fault_handler_t)(struct iommu_domain *,
 			struct device *, unsigned long, int, void *);
+typedef int (*iommu_dev_fault_handler_t)(struct device *, struct iommu_fault_event *);
 
 struct iommu_domain_geometry {
 	dma_addr_t aperture_start; /* First address that can be mapped    */
@@ -264,6 +266,60 @@ struct iommu_device {
 	struct device *dev;
 };
 
+enum iommu_model {
+	IOMMU_MODEL_INTEL = 1,
+	IOMMU_MODEL_AMD,
+	IOMMU_MODEL_SMMU3,
+};
+
+/*  Generic fault types, can be expanded IRQ remapping fault */
+enum iommu_fault_type {
+	IOMMU_FAULT_DMA_UNRECOV = 1,	/* unrecoverable fault */
+	IOMMU_FAULT_PAGE_REQ,		/* page request fault */
+};
+
+enum iommu_fault_reason {
+	IOMMU_FAULT_REASON_CTX = 1,
+	IOMMU_FAULT_REASON_ACCESS,
+	IOMMU_FAULT_REASON_INVALIDATE,
+	IOMMU_FAULT_REASON_UNKNOWN,
+};
+
+/**
+ * struct iommu_fault_event - Generic per device fault data
+ *
+ * - PCI and non-PCI devices
+ * - Recoverable faults (e.g. page request), information based on PCI ATS
+ * and PASID spec.
+ * - Un-recoverable faults of device interest
+ * - DMA remapping and IRQ remapping faults
+
+ * @type contains fault type.
+ * @reason fault reasons if relevant outside IOMMU driver, IOMMU driver internal
+ *         faults are not reported
+ * @paddr: tells the offending page address
+ * @pasid: contains process address space ID, used in shared virtual memory(SVM)
+ * @rid: requestor ID
+ * @page_req_group_id: page request group index
+ * @last_req: last request in a page request group
+ * @pasid_valid: indicates if the PRQ has a valid PASID
+ * @prot: page access protection flag, e.g. IOMMU_READ, IOMMU_WRITE
+ * @private_data: uniquely identify device-specific private data for an
+ *                individual page request
+ */
+struct iommu_fault_event {
+	enum iommu_fault_type type;
+	enum iommu_fault_reason reason;
+	u64 paddr;
+	u32 pasid;
+	u32 rid:16;
+	u32 page_req_group_id : 9;
+	u32 last_req : 1;
+	u32 pasid_valid : 1;
+	u32 prot;
+	u32 private_data;
+};
+
 int  iommu_device_register(struct iommu_device *iommu);
 void iommu_device_unregister(struct iommu_device *iommu);
 int  iommu_device_sysfs_add(struct iommu_device *iommu,
@@ -425,6 +481,18 @@ struct iommu_fwspec {
 	u32			ids[1];
 };
 
+/**
+ * struct iommu_fault_param - per-device IOMMU runtime data
+ * @dev_fault_handler: Callback function to handle IOMMU faults at device level
+ * @pasid_tbl_bound: Device PASID table is bound to a guest
+ *
+ */
+struct iommu_fault_param {
+	iommu_dev_fault_handler_t dev_fault_handler;
+	bool pasid_tbl_bound:1;
+	bool pasid_tbl_shadowed:1;
+};
+
 int iommu_fwspec_init(struct device *dev, struct fwnode_handle *iommu_fwnode,
 		      const struct iommu_ops *ops);
 void iommu_fwspec_free(struct device *dev);
@@ -437,6 +505,7 @@ struct iommu_ops {};
 struct iommu_group {};
 struct iommu_fwspec {};
 struct iommu_device {};
+struct iommu_fault_param {};
 
 static inline bool iommu_present(struct bus_type *bus)
 {
-- 
2.7.4