[kvm-unit-tests RFC 4/4] spe: Test Profiling Buffer Events

[Eric Auger <eric.auger@redhat.com>]

Setup the infrastructure to check the occurence of events.
The test checks the Buffer Full event occurs when no space
is available. The PPI is handled and we check the syndrome register
against the expected event.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
---
 arm/spe.c         | 141 +++++++++++++++++++++++++++++++++++++++++++++-
 arm/unittests.cfg |   8 +++
 2 files changed, 148 insertions(+), 1 deletion(-)

diff --git a/arm/spe.c b/arm/spe.c
index 7996f79..2f5ee35 100644
--- a/arm/spe.c
+++ b/arm/spe.c
@@ -19,6 +19,7 @@
 #include "alloc_page.h"
 #include <bitops.h>
 #include "alloc.h"
+#include <asm/gic.h>
 
 struct spe {
 	int min_interval;
@@ -36,13 +37,37 @@ struct spe {
 	bool unique_record_size;
 };
 
+enum spe_event_exception_class {
+	EC_STAGE1_DATA_ABORT =  0x24,
+	EC_STAGE2_DATA_ABORT = 0x25,
+	EC_OTHER = 0,
+};
+
+struct spe_event {
+	enum spe_event_exception_class ec;
+	bool dl;	/* data lost */
+	bool ea;	/* external abort */
+	bool s;		/* service */
+	bool coll;	/* collision */
+	union {
+		bool buffer_filled; /* ec = other */
+	} mss;
+};
+
 static struct spe spe;
 
+struct spe_stats {
+	struct spe_event observed;
+	bool unexpected;
+};
+static struct spe_stats spe_stats;
+
 #ifdef __arm__
 
 static bool spe_probe(void) { return false; }
 static void test_spe_introspection(void) { }
 static void test_spe_buffer(void) { }
+static void test_spe_events(void) { }
 
 #else
 
@@ -95,6 +120,16 @@ static void test_spe_buffer(void) { }
 #define PMSCR_EL1_TS			0x20
 #define PMSCR_EL1_PCT			0x40
 
+#define PMBSR_EL1_COLL			0x10000
+#define PMBSR_EL1_S			0x20000
+#define PMBSR_EL1_EA			0x40000
+#define PMBSR_EL1_DL			0x80000
+#define PMBSR_EL1_EC_SHIFT		26
+#define PMBSR_EL1_EC_MASK		0x3F
+#define PMBSR_EL1_MISS_MASK		0xFFFF
+
+#define SPE_PPI 21
+
 static int min_interval(uint8_t idr_bits)
 {
 	switch (idr_bits) {
@@ -119,6 +154,44 @@ static int min_interval(uint8_t idr_bits)
 	}
 }
 
+static int decode_syndrome_register(uint64_t sr, struct spe_event *event, bool verbose)
+{
+	if (!sr)
+		return 0;
+
+	if (sr & PMBSR_EL1_S)
+		event->s = true;
+	if (sr & PMBSR_EL1_COLL)
+		event->coll = true;
+	if (sr & PMBSR_EL1_EA)
+		event->ea = true;
+	if (sr & PMBSR_EL1_DL)
+		event->dl = true;
+	if (verbose)
+		report_info("PMBSR_EL1: Service=%d Collision=%d External Fault=%d DataLost=%d",
+			    event->s, event->coll, event->ea, event->dl);
+
+	switch ((sr >> PMBSR_EL1_EC_SHIFT) & PMBSR_EL1_EC_MASK) {
+	case EC_OTHER:
+		event->ec = EC_OTHER;
+		event->mss.buffer_filled = sr & 0x1;
+		if (verbose)
+			report_info("PMBSR_EL1: EC = OTHER buffer filled=%d", event->mss.buffer_filled);
+		break;
+	case EC_STAGE1_DATA_ABORT:
+		event->ec = EC_STAGE1_DATA_ABORT;
+		report_info("PMBSR_EL1: EC = stage 1 data abort");
+		break;
+	case EC_STAGE2_DATA_ABORT:
+		event->ec = EC_STAGE2_DATA_ABORT;
+		report_info("PMBSR_EL1: EC = stage 2 data abort");
+		break;
+	default:
+		return -1;
+	}
+	return 0;
+}
+
 static bool spe_probe(void)
 {
 	uint64_t pmbidr_el1, pmsidr_el1;
@@ -224,6 +297,13 @@ static void reset(void)
 
 	/* Make sure the syndrome register is void */
 	write_sysreg_s(0, PMBSR_EL1);
+
+	memset(&spe_stats, 0, sizeof(spe_stats));
+}
+
+inline bool event_match(struct spe_event *observed, struct spe_event *expected)
+{
+	return !memcmp(observed, expected, sizeof(struct spe_event));
 }
 
 static inline void drain(void)
@@ -235,6 +315,7 @@ static inline void drain(void)
 
 static void test_spe_buffer(void)
 {
+	struct spe_event observed = {}, expected = {};
 	uint64_t pmbsr_el1, val1, val2;
 	void *addr = malloc(10 * PAGE_SIZE);
 
@@ -290,7 +371,61 @@ static void test_spe_buffer(void)
 		report_info("This corresponds to %ld record(s) of %d bytes",
 			    val2 / spe.maxsize, spe.maxsize);
 	pmbsr_el1 = read_sysreg_s(PMBSR_EL1);
-	report(!pmbsr_el1, "PMBSR_EL1: no event");
+	report(!(decode_syndrome_register(pmbsr_el1, &observed, true)) &&
+	       event_match(&observed, &expected), "PMBSR_EL1: no event");
+
+	free(addr);
+}
+
+static void irq_handler(struct pt_regs *regs)
+{
+	uint32_t irqstat, irqnr;
+
+	irqstat = gic_read_iar();
+	irqnr = gic_iar_irqnr(irqstat);
+
+	if (irqnr == SPE_PPI) {
+		uint64_t pmbsr_el1 = read_sysreg_s(PMBSR_EL1);
+
+		if (decode_syndrome_register(pmbsr_el1, &spe_stats.observed, true))
+			spe_stats.unexpected = true;
+		report_info("SPE IRQ! SR=0x%lx", pmbsr_el1);
+		write_sysreg_s(0, PMBSR_EL1);
+	} else {
+		spe_stats.unexpected = true;
+	}
+	gic_write_eoir(irqstat);
+}
+
+static inline bool has_event_occurred(struct spe_event *expected)
+{
+	return (!spe_stats.unexpected && event_match(&spe_stats.observed, expected));
+}
+
+static void test_spe_events(void)
+{
+	struct spe_event expected = {.ec = EC_OTHER, .mss.buffer_filled = true, .s = true};
+	void *addr = malloc(10 * PAGE_SIZE);
+
+	gic_enable_defaults();
+	install_irq_handler(EL1H_IRQ, irq_handler);
+	local_irq_enable();
+	gic_enable_irq(SPE_PPI);
+
+	reset();
+
+	/* Willingly set pmblimitr tp pmdptr */
+	spe.pmblimitr_el1 = spe.pmbptr_el1;
+
+	mem_access_loop(addr, 100000, spe.pmblimitr_el1 | PMBLIMITR_EL1_E);
+	drain();
+	report(has_event_occurred(&expected), "PMBSR_EL1: buffer full event");
+
+	/* redo it once */
+
+	mem_access_loop(addr, 100000, spe.pmblimitr_el1 | PMBLIMITR_EL1_E);
+	drain();
+	report(has_event_occurred(&expected), "PMBSR_EL1: buffer full event");
 
 	free(addr);
 }
@@ -317,6 +452,10 @@ int main(int argc, char *argv[])
 		report_prefix_push(argv[1]);
 		test_spe_buffer();
 		report_prefix_pop();
+	} else if (strcmp(argv[1], "spe-events") == 0) {
+		report_prefix_push(argv[1]);
+		test_spe_events();
+		report_prefix_pop();
 	} else {
 		report_abort("Unknown sub-test '%s'", argv[1]);
 	}
diff --git a/arm/unittests.cfg b/arm/unittests.cfg
index bb0e84c..b2b07be 100644
--- a/arm/unittests.cfg
+++ b/arm/unittests.cfg
@@ -150,6 +150,14 @@ extra_params = -append 'spe-buffer'
 accel = kvm
 arch = arm64
 
+[spe-events]
+file = spe.flat
+groups = spe
+arch = arm64
+extra_params = -append 'spe-events'
+accel = kvm
+arch = arm64
+
 # Test GIC emulation
 [gicv2-ipi]
 file = gic.flat
-- 
2.21.3