[PATCH v2 3/4] cxl/core: Add region info to cxl_general_media and cxl_dram events

[alison.schofield@intel.com]

From: Alison Schofield <alison.schofield@intel.com>

User space may need to know which region, if any, maps the DPAs
(device physical addresses) reported in a cxl_general_media or
cxl_dram event. Since the mapping can change, the kernel provides
this information at the time the event occurs. This informs user
space that at event <timestamp> this <region> mapped this <DPA>
to this <HPA>.

Add the same region info that is included in the cxl_poison trace
event: the DPA->HPA translation, region name, and region uuid.
Introduce and use new helpers that lookup that region info using
the struct cxl_memdev and a DPA.

The new fields are inserted in the trace event and no existing
fields are modified. If the DPA is not mapped, user will see:
hpa=ULLONG_MAX, region="", and uuid=0

This work must be protected by dpa_rwsem & region_rwsem since
it is looking up region mappings.

Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/cxl/core/core.h   |  6 +++++
 drivers/cxl/core/mbox.c   | 17 ++++++++++---
 drivers/cxl/core/region.c |  8 ++++++
 drivers/cxl/core/trace.h  | 52 +++++++++++++++++++++++++++++++++++----
 4 files changed, 74 insertions(+), 9 deletions(-)

diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
index 625394486459..2fd8d9797f36 100644
--- a/drivers/cxl/core/core.h
+++ b/drivers/cxl/core/core.h
@@ -30,8 +30,14 @@ int cxl_get_poison_by_endpoint(struct cxl_port *port);
 struct cxl_region *cxl_dpa_to_region(const struct cxl_memdev *cxlmd, u64 dpa);
 u64 cxl_trace_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd,
 		  u64 dpa);
+const char *cxl_trace_to_region_name(const struct cxl_memdev *cxlmd, u64 dpa);
 
 #else
+static inline
+const char *cxl_trace_to_region_name(const struct cxl_memdev *cxlmd, u64 dpa)
+{
+	return "";
+}
 static inline u64
 cxl_trace_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd, u64 dpa)
 {
diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
index 9adda4795eb7..3c1c37d5fcb0 100644
--- a/drivers/cxl/core/mbox.c
+++ b/drivers/cxl/core/mbox.c
@@ -842,14 +842,23 @@ void cxl_event_trace_record(const struct cxl_memdev *cxlmd,
 			    enum cxl_event_type event_type,
 			    const uuid_t *uuid, union cxl_event *evt)
 {
+	if (event_type == CXL_CPER_EVENT_MEM_MODULE) {
+		trace_cxl_memory_module(cxlmd, type, &evt->mem_module);
+		return;
+	}
+	if (event_type == CXL_CPER_EVENT_GENERIC) {
+		trace_cxl_generic_event(cxlmd, type, uuid, &evt->generic);
+		return;
+	}
+
+	/* Protect trace events that do DPA->HPA translations */
+	guard(rwsem_read)(&cxl_region_rwsem);
+	guard(rwsem_read)(&cxl_dpa_rwsem);
+
 	if (event_type == CXL_CPER_EVENT_GEN_MEDIA)
 		trace_cxl_general_media(cxlmd, type, &evt->gen_media);
 	else if (event_type == CXL_CPER_EVENT_DRAM)
 		trace_cxl_dram(cxlmd, type, &evt->dram);
-	else if (event_type == CXL_CPER_EVENT_MEM_MODULE)
-		trace_cxl_memory_module(cxlmd, type, &evt->mem_module);
-	else
-		trace_cxl_generic_event(cxlmd, type, uuid, &evt->generic);
 }
 EXPORT_SYMBOL_NS_GPL(cxl_event_trace_record, CXL);
 
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 45eb9c560fd6..a5b1eaee1e58 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -2723,6 +2723,14 @@ struct cxl_region *cxl_dpa_to_region(const struct cxl_memdev *cxlmd, u64 dpa)
 	return ctx.cxlr;
 }
 
+const char *cxl_trace_to_region_name(const struct cxl_memdev *cxlmd, u64 dpa)
+{
+	struct cxl_region *cxlr = cxl_dpa_to_region(cxlmd, dpa);
+
+	/* trace __string() assignment requires "", not NULL */
+	return cxlr ? dev_name(&cxlr->dev) : "";
+}
+
 static bool cxl_is_hpa_in_range(u64 hpa, struct cxl_region *cxlr, int pos)
 {
 	struct cxl_region_params *p = &cxlr->params;
diff --git a/drivers/cxl/core/trace.h b/drivers/cxl/core/trace.h
index 161bdb5734b0..2e24364b2b8d 100644
--- a/drivers/cxl/core/trace.h
+++ b/drivers/cxl/core/trace.h
@@ -14,6 +14,28 @@
 #include <cxlmem.h>
 #include "core.h"
 
+#ifndef __CXL_EVENTS_DECLARE_ONCE_ONLY
+#define __CXL_EVENTS_DECLARE_ONCE_ONLY
+static inline
+void store_region_info(const struct cxl_memdev *cxlmd, u64 dpa, uuid_t *uuid,
+		       u64 *hpa)
+{
+	struct cxl_region *cxlr;
+
+	cxlr = cxl_dpa_to_region(cxlmd, dpa);
+	if (cxlr) {
+		uuid_copy(uuid, &cxlr->params.uuid);
+		*hpa = cxl_trace_hpa(cxlr, cxlmd, dpa);
+	} else {
+		uuid_copy(uuid, &uuid_null);
+		*hpa = ULLONG_MAX;
+	}
+}
+#endif /* __CXL_EVENTS_DECLARE_ONCE_ONLY */
+
+#define rec_pa_to_dpa(record)						\
+	(le64_to_cpu(rec->phys_addr) & CXL_DPA_MASK)
+
 #define CXL_RAS_UC_CACHE_DATA_PARITY	BIT(0)
 #define CXL_RAS_UC_CACHE_ADDR_PARITY	BIT(1)
 #define CXL_RAS_UC_CACHE_BE_PARITY	BIT(2)
@@ -330,10 +352,14 @@ TRACE_EVENT(cxl_general_media,
 		__field(u8, channel)
 		__field(u32, device)
 		__array(u8, comp_id, CXL_EVENT_GEN_MED_COMP_ID_SIZE)
-		__field(u16, validity_flags)
 		/* Following are out of order to pack trace record */
+		__field(u64, hpa)
+		__field_struct(uuid_t, region_uuid)
+		__field(u16, validity_flags)
 		__field(u8, rank)
 		__field(u8, dpa_flags)
+		__string(region_name,
+			 cxl_trace_to_region_name(cxlmd, rec_pa_to_dpa(record)))
 	),
 
 	TP_fast_assign(
@@ -354,18 +380,24 @@ TRACE_EVENT(cxl_general_media,
 		memcpy(__entry->comp_id, &rec->component_id,
 			CXL_EVENT_GEN_MED_COMP_ID_SIZE);
 		__entry->validity_flags = get_unaligned_le16(&rec->validity_flags);
+		__assign_str(region_name,
+			     cxl_trace_to_region_name(cxlmd, __entry->dpa));
+		store_region_info(cxlmd, __entry->dpa, &__entry->region_uuid,
+				  &__entry->hpa);
 	),
 
 	CXL_EVT_TP_printk("dpa=%llx dpa_flags='%s' " \
 		"descriptor='%s' type='%s' transaction_type='%s' channel=%u rank=%u " \
-		"device=%x comp_id=%s validity_flags='%s'",
+		"device=%x comp_id=%s validity_flags='%s' " \
+		"hpa=%llx region=%s region_uuid=%pUb",
 		__entry->dpa, show_dpa_flags(__entry->dpa_flags),
 		show_event_desc_flags(__entry->descriptor),
 		show_mem_event_type(__entry->type),
 		show_trans_type(__entry->transaction_type),
 		__entry->channel, __entry->rank, __entry->device,
 		__print_hex(__entry->comp_id, CXL_EVENT_GEN_MED_COMP_ID_SIZE),
-		show_valid_flags(__entry->validity_flags)
+		show_valid_flags(__entry->validity_flags),
+		__entry->hpa, __get_str(region_name), &__entry->region_uuid
 	)
 );
 
@@ -417,10 +449,14 @@ TRACE_EVENT(cxl_dram,
 		__field(u32, nibble_mask)
 		__field(u32, row)
 		__array(u8, cor_mask, CXL_EVENT_DER_CORRECTION_MASK_SIZE)
+		__field(u64, hpa)
+		__field_struct(uuid_t, region_uuid)
 		__field(u8, rank)	/* Out of order to pack trace record */
 		__field(u8, bank_group)	/* Out of order to pack trace record */
 		__field(u8, bank)	/* Out of order to pack trace record */
 		__field(u8, dpa_flags)	/* Out of order to pack trace record */
+		__string(region_name,
+			 cxl_trace_to_region_name(cxlmd, rec_pa_to_dpa(record)))
 	),
 
 	TP_fast_assign(
@@ -444,12 +480,17 @@ TRACE_EVENT(cxl_dram,
 		__entry->column = get_unaligned_le16(rec->column);
 		memcpy(__entry->cor_mask, &rec->correction_mask,
 			CXL_EVENT_DER_CORRECTION_MASK_SIZE);
+		__assign_str(region_name,
+			     cxl_trace_to_region_name(cxlmd, __entry->dpa));
+		store_region_info(cxlmd, __entry->dpa, &__entry->region_uuid,
+				  &__entry->hpa);
 	),
 
 	CXL_EVT_TP_printk("dpa=%llx dpa_flags='%s' descriptor='%s' type='%s' " \
 		"transaction_type='%s' channel=%u rank=%u nibble_mask=%x " \
 		"bank_group=%u bank=%u row=%u column=%u cor_mask=%s " \
-		"validity_flags='%s'",
+		"validity_flags='%s' " \
+		"hpa=%llx region=%s region_uuid=%pUb",
 		__entry->dpa, show_dpa_flags(__entry->dpa_flags),
 		show_event_desc_flags(__entry->descriptor),
 		show_mem_event_type(__entry->type),
@@ -458,7 +499,8 @@ TRACE_EVENT(cxl_dram,
 		__entry->bank_group, __entry->bank,
 		__entry->row, __entry->column,
 		__print_hex(__entry->cor_mask, CXL_EVENT_DER_CORRECTION_MASK_SIZE),
-		show_dram_valid_flags(__entry->validity_flags)
+		show_dram_valid_flags(__entry->validity_flags),
+		__entry->hpa, __get_str(region_name), &__entry->region_uuid
 	)
 );
 
-- 
2.37.3