Re: [PATCH v6 17/21] RISC-V: perf: Add Qemu virt machine events
From: Atish Patra
Date: Wed Jun 24 2026 - 03:00:41 EST
On 6/21/26 11:44 PM, Charlie Jenkins wrote:
On Mon, Jun 08, 2026 at 11:01:31PM -0700, Atish Patra wrote:
From: Atish Patra <atishp@xxxxxxxxxxxx>Palmer proposed a change to this a while ago to set the archid for qemu
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.
Signed-off-by: Atish Patra <atishp@xxxxxxxxxxxx>
---
arch/riscv/include/asm/vendorid_list.h | 4 ++++
drivers/perf/riscv_pmu_sbi.c | 36 ++++++++++++++++++++++++++++++++++
2 files changed, 40 insertions(+)
diff --git a/arch/riscv/include/asm/vendorid_list.h b/arch/riscv/include/asm/vendorid_list.h
index 7f5030ee1fcf..603aa2b21c0b 100644
--- a/arch/riscv/include/asm/vendorid_list.h
+++ b/arch/riscv/include/asm/vendorid_list.h
@@ -11,4 +11,8 @@
#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
as 42 but it looks like it was never merged in qemu, but it was merged
into the riscv spec.
Here is the spec PR: https://github.com/riscv/riscv-isa-manual/pull/1213
Here is the current spec: https://github.com/riscv/riscv-isa-manual/blob/main/marchid.md
Here is the QEMU patch: https://lore.kernel.org/all/20240131182430.20174-1-palmer@xxxxxxxxxxxx/
Should we follow up with this/maybe this should be accounted for here as
an alternate id?
Ahh yes. I remember that thread now. Thanks for digging this.
Yes. We should resurrect that patch and use that archid as an alternate ID.
- Charlie
+
#endif
diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index 00b84b28117a..74acac54328e 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_ind.h>
@@ -453,7 +454,42 @@ 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)
};
static const struct riscv_pmu_event *current_pmu_hw_event_map;
--
2.53.0-Meta