[PATCH v9 18/20] RISC-V: perf: Add Qemu virt machine events

[Atish Patra <atish.patra@linux.dev>]

From: Atish Patra <atishp@rivosinc.com>

Qemu virt machine supports a very minimal set of legacy perf events.
Add them to the vendor table so that users can use them when
counter delegation is enabled.

Qemu is identified by its marchid. Older Qemu reports all-zero
mvendorid/marchid/mimpid, while newer Qemu reports the marchid 0x2a (42)
allocated to it in the RISC-V ISA manual [1]. Register the events for
both ids so they are available across Qemu versions.

[1] https://github.com/riscv/riscv-isa-manual/blob/main/marchid.md

Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Charlie Jenkins <thecharlesjenkins@gmail.com>
Tested-by: Charlie Jenkins <thecharlesjenkins@gmail.com>
---
 arch/riscv/include/asm/vendorid_list.h |  6 ++++++
 drivers/perf/riscv_pmu_sbi.c           | 39 ++++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)

diff --git a/arch/riscv/include/asm/vendorid_list.h b/arch/riscv/include/asm/vendorid_list.h
index 7f5030ee1fcf..beaf9236dba7 100644
--- a/arch/riscv/include/asm/vendorid_list.h
+++ b/arch/riscv/include/asm/vendorid_list.h
@@ -11,4 +11,10 @@
 #define SIFIVE_VENDOR_ID	0x489
 #define THEAD_VENDOR_ID		0x5b7
 
+#define QEMU_VIRT_VENDOR_ID		0x000
+#define QEMU_VIRT_IMPL_ID		0x000
+#define QEMU_VIRT_ARCH_ID		0x000
+/* Newer Qemu reports the spec-allocated marchid 0x2a (42) for non-vendor CPUs */
+#define QEMU_VIRT_ARCH_ID_SPEC		0x2a
+
 #endif
diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index 5eb49db8bc7c..9220c75651a5 100644
--- a/drivers/perf/riscv_pmu_sbi.c
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -26,6 +26,7 @@
 #include <asm/sbi.h>
 #include <asm/cpufeature.h>
 #include <asm/vendor_extensions.h>
+#include <asm/vendorid_list.h>
 #include <asm/vendor_extensions/andes.h>
 #include <asm/hwcap.h>
 #include <asm/csr_indirect.h>
@@ -468,7 +469,45 @@ struct riscv_vendor_pmu_events {
 	  .hw_event_map = _hw_event_map, .cache_event_map = _cache_event_map, \
 	  .attrs_events = _attrs },
 
+/* QEMU virt PMU events */
+static const struct riscv_pmu_event qemu_virt_hw_event_map[PERF_COUNT_HW_MAX] = {
+	PERF_MAP_ALL_UNSUPPORTED,
+	[PERF_COUNT_HW_CPU_CYCLES]		= {0x01, 0xFFFFFFF8},
+	[PERF_COUNT_HW_INSTRUCTIONS]		= {0x02, 0xFFFFFFF8}
+};
+
+static const struct riscv_pmu_event qemu_virt_cache_event_map[PERF_COUNT_HW_CACHE_MAX]
+						[PERF_COUNT_HW_CACHE_OP_MAX]
+						[PERF_COUNT_HW_CACHE_RESULT_MAX] = {
+	PERF_CACHE_MAP_ALL_UNSUPPORTED,
+	[C(DTLB)][C(OP_READ)][C(RESULT_MISS)]	= {0x10019, 0xFFFFFFF8},
+	[C(DTLB)][C(OP_WRITE)][C(RESULT_MISS)]	= {0x1001B, 0xFFFFFFF8},
+
+	[C(ITLB)][C(OP_READ)][C(RESULT_MISS)]	= {0x10021, 0xFFFFFFF8},
+};
+
+RVPMU_EVENT_CMASK_ATTR(cycles, cycles, 0x01, 0xFFFFFFF8);
+RVPMU_EVENT_CMASK_ATTR(instructions, instructions, 0x02, 0xFFFFFFF8);
+RVPMU_EVENT_CMASK_ATTR(dTLB-load-misses, dTLB_load_miss, 0x10019, 0xFFFFFFF8);
+RVPMU_EVENT_CMASK_ATTR(dTLB-store-misses, dTLB_store_miss, 0x1001B, 0xFFFFFFF8);
+RVPMU_EVENT_CMASK_ATTR(iTLB-load-misses, iTLB_load_miss, 0x10021, 0xFFFFFFF8);
+
+static struct attribute *qemu_virt_event_group[] = {
+	RVPMU_EVENT_ATTR_PTR(cycles),
+	RVPMU_EVENT_ATTR_PTR(instructions),
+	RVPMU_EVENT_ATTR_PTR(dTLB_load_miss),
+	RVPMU_EVENT_ATTR_PTR(dTLB_store_miss),
+	RVPMU_EVENT_ATTR_PTR(iTLB_load_miss),
+	NULL,
+};
+
 static struct riscv_vendor_pmu_events pmu_vendor_events_table[] = {
+	RISCV_VENDOR_PMU_EVENTS(QEMU_VIRT_VENDOR_ID, QEMU_VIRT_ARCH_ID, QEMU_VIRT_IMPL_ID,
+				qemu_virt_hw_event_map, qemu_virt_cache_event_map,
+				qemu_virt_event_group)
+	RISCV_VENDOR_PMU_EVENTS(QEMU_VIRT_VENDOR_ID, QEMU_VIRT_ARCH_ID_SPEC, QEMU_VIRT_IMPL_ID,
+				qemu_virt_hw_event_map, qemu_virt_cache_event_map,
+				qemu_virt_event_group)
 };
 
 static const struct riscv_pmu_event *current_pmu_hw_event_map;

-- 
2.53.0-Meta