[PATCH 12/23] iommu/vt-d: Add prq_report trace event

[Lu Baolu <baolu.lu@linux.intel.com>]

This adds a new trace event to track the page fault request report.
This event will provide almost all information defined in a page
request descriptor.

A sample output:
| prq_report: dmar0/0000:00:0a.0 seq# 1: rid=0x50 addr=0x559ef6f97 r---- pasid=0x2 index=0x1
| prq_report: dmar0/0000:00:0a.0 seq# 2: rid=0x50 addr=0x559ef6f9c rw--l pasid=0x2 index=0x1
| prq_report: dmar0/0000:00:0a.0 seq# 3: rid=0x50 addr=0x559ef6f98 r---- pasid=0x2 index=0x1
| prq_report: dmar0/0000:00:0a.0 seq# 4: rid=0x50 addr=0x559ef6f9d rw--l pasid=0x2 index=0x1
| prq_report: dmar0/0000:00:0a.0 seq# 5: rid=0x50 addr=0x559ef6f99 r---- pasid=0x2 index=0x1
| prq_report: dmar0/0000:00:0a.0 seq# 6: rid=0x50 addr=0x559ef6f9e rw--l pasid=0x2 index=0x1
| prq_report: dmar0/0000:00:0a.0 seq# 7: rid=0x50 addr=0x559ef6f9a r---- pasid=0x2 index=0x1
| prq_report: dmar0/0000:00:0a.0 seq# 8: rid=0x50 addr=0x559ef6f9f rw--l pasid=0x2 index=0x1

This will be helpful for I/O page fault related debugging.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20210520031531.712333-1-baolu.lu@linux.intel.com
---
 include/linux/intel-iommu.h        | 29 +++++++++++++++++++++++
 include/trace/events/intel_iommu.h | 37 ++++++++++++++++++++++++++++++
 drivers/iommu/intel/svm.c          |  7 ++++++
 3 files changed, 73 insertions(+)

diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index 222520d149c1..98b04fa9373e 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -778,6 +778,7 @@ struct intel_svm_dev {
 	struct device *dev;
 	struct intel_iommu *iommu;
 	struct iommu_sva sva;
+	unsigned long prq_seq_number;
 	u32 pasid;
 	int users;
 	u16 did;
@@ -828,4 +829,32 @@ static inline int iommu_calculate_max_sagaw(struct intel_iommu *iommu)
 #define intel_iommu_enabled (0)
 #endif
 
+static inline const char *decode_prq_descriptor(char *str, size_t size,
+		u64 dw0, u64 dw1, u64 dw2, u64 dw3)
+{
+	char *buf = str;
+	int bytes;
+
+	bytes = snprintf(buf, size,
+			 "rid=0x%llx addr=0x%llx %c%c%c%c%c pasid=0x%llx index=0x%llx",
+			 FIELD_GET(GENMASK_ULL(31, 16), dw0),
+			 FIELD_GET(GENMASK_ULL(63, 12), dw1),
+			 dw1 & BIT_ULL(0) ? 'r' : '-',
+			 dw1 & BIT_ULL(1) ? 'w' : '-',
+			 dw0 & BIT_ULL(52) ? 'x' : '-',
+			 dw0 & BIT_ULL(53) ? 'p' : '-',
+			 dw1 & BIT_ULL(2) ? 'l' : '-',
+			 FIELD_GET(GENMASK_ULL(51, 32), dw0),
+			 FIELD_GET(GENMASK_ULL(11, 3), dw1));
+
+	/* Private Data */
+	if (dw0 & BIT_ULL(9)) {
+		size -= bytes;
+		buf += bytes;
+		snprintf(buf, size, " private=0x%llx/0x%llx\n", dw2, dw3);
+	}
+
+	return str;
+}
+
 #endif
diff --git a/include/trace/events/intel_iommu.h b/include/trace/events/intel_iommu.h
index d233f2916584..e5c1ca6d16ee 100644
--- a/include/trace/events/intel_iommu.h
+++ b/include/trace/events/intel_iommu.h
@@ -15,6 +15,8 @@
 #include <linux/tracepoint.h>
 #include <linux/intel-iommu.h>
 
+#define MSG_MAX		256
+
 TRACE_EVENT(qi_submit,
 	TP_PROTO(struct intel_iommu *iommu, u64 qw0, u64 qw1, u64 qw2, u64 qw3),
 
@@ -51,6 +53,41 @@ TRACE_EVENT(qi_submit,
 		__entry->qw0, __entry->qw1, __entry->qw2, __entry->qw3
 	)
 );
+
+TRACE_EVENT(prq_report,
+	TP_PROTO(struct intel_iommu *iommu, struct device *dev,
+		 u64 dw0, u64 dw1, u64 dw2, u64 dw3,
+		 unsigned long seq),
+
+	TP_ARGS(iommu, dev, dw0, dw1, dw2, dw3, seq),
+
+	TP_STRUCT__entry(
+		__field(u64, dw0)
+		__field(u64, dw1)
+		__field(u64, dw2)
+		__field(u64, dw3)
+		__field(unsigned long, seq)
+		__string(iommu, iommu->name)
+		__string(dev, dev_name(dev))
+		__dynamic_array(char, buff, MSG_MAX)
+	),
+
+	TP_fast_assign(
+		__entry->dw0 = dw0;
+		__entry->dw1 = dw1;
+		__entry->dw2 = dw2;
+		__entry->dw3 = dw3;
+		__entry->seq = seq;
+		__assign_str(iommu, iommu->name);
+		__assign_str(dev, dev_name(dev));
+	),
+
+	TP_printk("%s/%s seq# %ld: %s",
+		__get_str(iommu), __get_str(dev), __entry->seq,
+		decode_prq_descriptor(__get_str(buff), MSG_MAX, __entry->dw0,
+				      __entry->dw1, __entry->dw2, __entry->dw3)
+	)
+);
 #endif /* _TRACE_INTEL_IOMMU_H */
 
 /* This part must be outside protection */
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index ade157b64ce7..d3d028c6a727 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -21,6 +21,7 @@
 #include <linux/ioasid.h>
 #include <asm/page.h>
 #include <asm/fpu/api.h>
+#include <trace/events/intel_iommu.h>
 
 #include "pasid.h"
 #include "../iommu-sva-lib.h"
@@ -976,12 +977,18 @@ static irqreturn_t prq_event_thread(int irq, void *d)
 				goto bad_req;
 		}
 
+		sdev->prq_seq_number++;
+
 		/*
 		 * If prq is to be handled outside iommu driver via receiver of
 		 * the fault notifiers, we skip the page response here.
 		 */
 		if (intel_svm_prq_report(sdev->dev, req))
 			handle_bad_prq_event(iommu, req, QI_RESP_INVALID);
+
+		trace_prq_report(iommu, sdev->dev, req->qw_0, req->qw_1,
+				 req->priv_data[0], req->priv_data[1],
+				 sdev->prq_seq_number);
 prq_advance:
 		head = (head + sizeof(*req)) & PRQ_RING_MASK;
 	}
-- 
2.25.1

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