[PATCH v4 02/14] perf: RISC-V: Improve privilege mode filtering for perf

Atish Patra posted 14 patches 2 years, 7 months ago
There is a newer version of this series
[PATCH v4 02/14] perf: RISC-V: Improve privilege mode filtering for perf
Posted by Atish Patra 2 years, 7 months ago
Currently, the host driver doesn't have any method to identify if the
requested perf event is from kvm or bare metal. As KVM runs in HS
mode, there are no separate hypervisor privilege mode to distinguish
between the attributes for guest/host.

Improve the privilege mode filtering by using the event specific
config1 field.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
---
 drivers/perf/riscv_pmu_sbi.c   | 27 ++++++++++++++++++++++-----
 include/linux/perf/riscv_pmu.h |  2 ++
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index 6b53adc..71174fa 100644
--- a/drivers/perf/riscv_pmu_sbi.c
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -301,6 +301,27 @@ int riscv_pmu_get_hpm_info(u32 *hw_ctr_width, u32 *num_hw_ctr)
 }
 EXPORT_SYMBOL_GPL(riscv_pmu_get_hpm_info);
 
+static unsigned long pmu_sbi_get_filter_flags(struct perf_event *event)
+{
+	unsigned long cflags = 0;
+	bool guest_events = false;
+
+	if (event->attr.config1 & RISCV_PMU_CONFIG1_GUEST_EVENTS)
+		guest_events = true;
+	if (event->attr.exclude_kernel)
+		cflags |= guest_events ? SBI_PMU_CFG_FLAG_SET_VSINH : SBI_PMU_CFG_FLAG_SET_SINH;
+	if (event->attr.exclude_user)
+		cflags |= guest_events ? SBI_PMU_CFG_FLAG_SET_VUINH : SBI_PMU_CFG_FLAG_SET_UINH;
+	if (guest_events && event->attr.exclude_hv)
+		cflags |= SBI_PMU_CFG_FLAG_SET_SINH;
+	if (event->attr.exclude_host)
+		cflags |= SBI_PMU_CFG_FLAG_SET_UINH | SBI_PMU_CFG_FLAG_SET_SINH;
+	if (event->attr.exclude_guest)
+		cflags |= SBI_PMU_CFG_FLAG_SET_VSINH | SBI_PMU_CFG_FLAG_SET_VUINH;
+
+	return cflags;
+}
+
 static int pmu_sbi_ctr_get_idx(struct perf_event *event)
 {
 	struct hw_perf_event *hwc = &event->hw;
@@ -311,11 +332,7 @@ static int pmu_sbi_ctr_get_idx(struct perf_event *event)
 	uint64_t cbase = 0;
 	unsigned long cflags = 0;
 
-	if (event->attr.exclude_kernel)
-		cflags |= SBI_PMU_CFG_FLAG_SET_SINH;
-	if (event->attr.exclude_user)
-		cflags |= SBI_PMU_CFG_FLAG_SET_UINH;
-
+	cflags = pmu_sbi_get_filter_flags(event);
 	/* retrieve the available counter index */
 #if defined(CONFIG_32BIT)
 	ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_CFG_MATCH, cbase,
diff --git a/include/linux/perf/riscv_pmu.h b/include/linux/perf/riscv_pmu.h
index a1c3f77..43fc892 100644
--- a/include/linux/perf/riscv_pmu.h
+++ b/include/linux/perf/riscv_pmu.h
@@ -26,6 +26,8 @@
 
 #define RISCV_PMU_STOP_FLAG_RESET 1
 
+#define RISCV_PMU_CONFIG1_GUEST_EVENTS 0x1
+
 struct cpu_hw_events {
 	/* currently enabled events */
 	int			n_events;
-- 
2.25.1