[kvm-unit-tests PATCH 3/4] x86/pmu: Test adaptive PEBS without any adaptive counters

[Sean Christopherson <seanjc@google.com>]

If adaptive PEBS is supported, verify that only basic PEBS records are
generated for counters without their ADAPTIVE flag set.  Per the SDM,
adaptive records are generated if and only if both the per-counter flag
*and* the global enable(s) in MSR_PEBS_DATA_CFG are set.

  IA32_PERFEVTSELx.Adaptive_Record[34]: If this bit is set and
  IA32_PEBS_ENABLE.PEBS_EN_PMCx is set for the corresponding GP counter,
  an overflow of PMCx results in generation of an adaptive PEBS record
  with state information based on the selections made in MSR_PEBS_DATA_CFG.
  If this bit is not set, a basic record is generated.

and

  IA32_FIXED_CTR_CTRL.FCx_Adaptive_Record: If this bit is set and
  IA32_PEBS_ENABLE.PEBS_EN_FIXEDx is set for the corresponding Fixed
  counter, an overflow of FixedCtrx results in generation of an adaptive
  PEBS record with state information based on the selections made in
  MSR_PEBS_DATA_CFG. If this bit is not set, a basic record is generated.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 x86/pmu_pebs.c | 74 ++++++++++++++++++++++++++------------------------
 1 file changed, 38 insertions(+), 36 deletions(-)

diff --git a/x86/pmu_pebs.c b/x86/pmu_pebs.c
index dff1ed26..0e8d60c3 100644
--- a/x86/pmu_pebs.c
+++ b/x86/pmu_pebs.c
@@ -89,11 +89,11 @@ static u64 counter_start_values[] = {
 	0xffffffffffff,
 };
 
-static unsigned int get_adaptive_pebs_record_size(u64 pebs_data_cfg)
+static unsigned int get_pebs_record_size(u64 pebs_data_cfg, bool use_adaptive)
 {
 	unsigned int sz = sizeof(struct pebs_basic);
 
-	if (!has_baseline)
+	if (!use_adaptive)
 		return sz;
 
 	if (pebs_data_cfg & PEBS_DATACFG_MEMINFO)
@@ -199,10 +199,10 @@ static void free_buffers(void)
 		free_page(pebs_buffer);
 }
 
-static void pebs_enable(u64 bitmask, u64 pebs_data_cfg)
+static void pebs_enable(u64 bitmask, u64 pebs_data_cfg, bool use_adaptive)
 {
 	static struct debug_store *ds;
-	u64 baseline_extra_ctrl = 0, fixed_ctr_ctrl = 0;
+	u64 adaptive_ctrl = 0, fixed_ctr_ctrl = 0;
 	unsigned int idx;
 
 	if (has_baseline)
@@ -212,15 +212,15 @@ static void pebs_enable(u64 bitmask, u64 pebs_data_cfg)
 	ds->pebs_index = ds->pebs_buffer_base = (unsigned long)pebs_buffer;
 	ds->pebs_absolute_maximum = (unsigned long)pebs_buffer + PAGE_SIZE;
 	ds->pebs_interrupt_threshold = ds->pebs_buffer_base +
-		get_adaptive_pebs_record_size(pebs_data_cfg);
+		get_pebs_record_size(pebs_data_cfg, use_adaptive);
 
 	for (idx = 0; idx < pmu.nr_fixed_counters; idx++) {
 		if (!(BIT_ULL(FIXED_CNT_INDEX + idx) & bitmask))
 			continue;
-		if (has_baseline)
-			baseline_extra_ctrl = BIT(FIXED_CNT_INDEX + idx * 4);
+		if (use_adaptive)
+			adaptive_ctrl = BIT(FIXED_CNT_INDEX + idx * 4);
 		wrmsr(MSR_PERF_FIXED_CTRx(idx), ctr_start_val);
-		fixed_ctr_ctrl |= (0xbULL << (idx * 4) | baseline_extra_ctrl);
+		fixed_ctr_ctrl |= (0xbULL << (idx * 4) | adaptive_ctrl);
 	}
 	if (fixed_ctr_ctrl)
 		wrmsr(MSR_CORE_PERF_FIXED_CTR_CTRL, fixed_ctr_ctrl);
@@ -228,10 +228,10 @@ static void pebs_enable(u64 bitmask, u64 pebs_data_cfg)
 	for (idx = 0; idx < max_nr_gp_events; idx++) {
 		if (!(BIT_ULL(idx) & bitmask))
 			continue;
-		if (has_baseline)
-			baseline_extra_ctrl = ICL_EVENTSEL_ADAPTIVE;
+		if (use_adaptive)
+			adaptive_ctrl = ICL_EVENTSEL_ADAPTIVE;
 		wrmsr(MSR_GP_EVENT_SELECTx(idx), EVNTSEL_EN | EVNTSEL_OS | EVNTSEL_USR |
-						 intel_arch_events[idx] | baseline_extra_ctrl);
+						 intel_arch_events[idx] | adaptive_ctrl);
 		wrmsr(MSR_GP_COUNTERx(idx), ctr_start_val);
 	}
 
@@ -268,11 +268,11 @@ static void pebs_disable(unsigned int idx)
 	wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0);
 }
 
-static void check_pebs_records(u64 bitmask, u64 pebs_data_cfg)
+static void check_pebs_records(u64 bitmask, u64 pebs_data_cfg, bool use_adaptive)
 {
 	struct pebs_basic *pebs_rec = (struct pebs_basic *)pebs_buffer;
 	struct debug_store *ds = (struct debug_store *)ds_bufer;
-	unsigned int pebs_record_size = get_adaptive_pebs_record_size(pebs_data_cfg);
+	unsigned int pebs_record_size;
 	unsigned int count = 0;
 	bool expected, pebs_idx_match, pebs_size_match, data_cfg_match;
 	void *cur_record;
@@ -293,12 +293,9 @@ static void check_pebs_records(u64 bitmask, u64 pebs_data_cfg)
 	do {
 		pebs_rec = (struct pebs_basic *)cur_record;
 		pebs_record_size = pebs_rec->format_size >> RECORD_SIZE_OFFSET;
-		pebs_idx_match =
-			pebs_rec->applicable_counters & bitmask;
-		pebs_size_match =
-			pebs_record_size == get_adaptive_pebs_record_size(pebs_data_cfg);
-		data_cfg_match =
-			(pebs_rec->format_size & GENMASK_ULL(47, 0)) == pebs_data_cfg;
+		pebs_idx_match = pebs_rec->applicable_counters & bitmask;
+		pebs_size_match = pebs_record_size == get_pebs_record_size(pebs_data_cfg, use_adaptive);
+		data_cfg_match = (pebs_rec->format_size & GENMASK_ULL(47, 0)) == pebs_data_cfg;
 		expected = pebs_idx_match && pebs_size_match && data_cfg_match;
 		report(expected,
 		       "PEBS record (written seq %d) is verified (including size, counters and cfg).", count);
@@ -311,56 +308,57 @@ static void check_pebs_records(u64 bitmask, u64 pebs_data_cfg)
 			printf("FAIL: The applicable_counters (0x%lx) doesn't match with pmc_bitmask (0x%lx).\n",
 			       pebs_rec->applicable_counters, bitmask);
 		if (!pebs_size_match)
-			printf("FAIL: The pebs_record_size (%d) doesn't match with MSR_PEBS_DATA_CFG (%d).\n",
-			       pebs_record_size, get_adaptive_pebs_record_size(pebs_data_cfg));
+			printf("FAIL: The pebs_record_size (%d) doesn't match with expected record size (%d).\n",
+			       pebs_record_size, get_pebs_record_size(pebs_data_cfg, use_adaptive));
 		if (!data_cfg_match)
-			printf("FAIL: The pebs_data_cfg (0x%lx) doesn't match with MSR_PEBS_DATA_CFG (0x%lx).\n",
-			       pebs_rec->format_size & 0xffffffffffff, pebs_data_cfg);
+			printf("FAIL: The pebs_data_cfg (0x%lx) doesn't match with the effective MSR_PEBS_DATA_CFG (0x%lx).\n",
+			       pebs_rec->format_size & 0xffffffffffff, use_adaptive ? pebs_data_cfg : 0);
 	}
 }
 
-static void check_one_counter(enum pmc_type type,
-			      unsigned int idx, u64 pebs_data_cfg)
+static void check_one_counter(enum pmc_type type, unsigned int idx,
+			      u64 pebs_data_cfg, bool use_adaptive)
 {
 	int pebs_bit = BIT_ULL(type == FIXED ? FIXED_CNT_INDEX + idx : idx);
 
 	report_prefix_pushf("%s counter %d (0x%lx)",
 			    type == FIXED ? "Extended Fixed" : "GP", idx, ctr_start_val);
 	reset_pebs();
-	pebs_enable(pebs_bit, pebs_data_cfg);
+	pebs_enable(pebs_bit, pebs_data_cfg, use_adaptive);
 	workload();
 	pebs_disable(idx);
-	check_pebs_records(pebs_bit, pebs_data_cfg);
+	check_pebs_records(pebs_bit, pebs_data_cfg, use_adaptive);
 	report_prefix_pop();
 }
 
 /* more than one PEBS records will be generated. */
-static void check_multiple_counters(u64 bitmask, u64 pebs_data_cfg)
+static void check_multiple_counters(u64 bitmask, u64 pebs_data_cfg,
+				    bool use_adaptive)
 {
 	reset_pebs();
-	pebs_enable(bitmask, pebs_data_cfg);
+	pebs_enable(bitmask, pebs_data_cfg, use_adaptive);
 	workload2();
 	pebs_disable(0);
-	check_pebs_records(bitmask, pebs_data_cfg);
+	check_pebs_records(bitmask, pebs_data_cfg, use_adaptive);
 }
 
-static void check_pebs_counters(u64 pebs_data_cfg)
+static void check_pebs_counters(u64 pebs_data_cfg, bool use_adaptive)
 {
 	unsigned int idx;
 	u64 bitmask = 0;
 
 	for (idx = 0; has_baseline && idx < pmu.nr_fixed_counters; idx++)
-		check_one_counter(FIXED, idx, pebs_data_cfg);
+		check_one_counter(FIXED, idx, pebs_data_cfg, use_adaptive);
 
 	for (idx = 0; idx < max_nr_gp_events; idx++)
-		check_one_counter(GP, idx, pebs_data_cfg);
+		check_one_counter(GP, idx, pebs_data_cfg, use_adaptive);
 
 	for (idx = 0; has_baseline && idx < pmu.nr_fixed_counters; idx++)
 		bitmask |= BIT_ULL(FIXED_CNT_INDEX + idx);
 	for (idx = 0; idx < max_nr_gp_events; idx += 2)
 		bitmask |= BIT_ULL(idx);
 	report_prefix_pushf("Multiple (0x%lx)", bitmask);
-	check_multiple_counters(bitmask, pebs_data_cfg);
+	check_multiple_counters(bitmask, pebs_data_cfg, use_adaptive);
 	report_prefix_pop();
 }
 
@@ -408,7 +406,7 @@ int main(int ac, char **av)
 
 	for (i = 0; i < ARRAY_SIZE(counter_start_values); i++) {
 		ctr_start_val = counter_start_values[i];
-		check_pebs_counters(0);
+		check_pebs_counters(0, false);
 		if (!has_baseline)
 			continue;
 
@@ -419,7 +417,11 @@ int main(int ac, char **av)
 				pebs_data_cfg |= ((MAX_NUM_LBR_ENTRY -1) << PEBS_DATACFG_LBR_SHIFT);
 
 			report_prefix_pushf("Adaptive (0x%lx)", pebs_data_cfg);
-			check_pebs_counters(pebs_data_cfg);
+			check_pebs_counters(pebs_data_cfg, true);
+			report_prefix_pop();
+
+			report_prefix_pushf("Ignored Adaptive (0x%lx)", pebs_data_cfg);
+			check_pebs_counters(pebs_data_cfg, false);
 			report_prefix_pop();
 		}
 	}
-- 
2.44.0.278.ge034bb2e1d-goog