[HACK PATCH 18/18] KVM: arm64: selftests: Add test for probing PMUv3 sysregs

[Oliver Upton <oliver.upton@linux.dev>]

Add a test for sniffing out PMUv3 register traps.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---

Not intended to be applied, just sharing in case someone finds it
useful.

 tools/testing/selftests/kvm/Makefile          |   1 +
 .../kvm/aarch64/pmuv3_register_probe.c        | 135 ++++++++++++++++++
 2 files changed, 136 insertions(+)
 create mode 100644 tools/testing/selftests/kvm/aarch64/pmuv3_register_probe.c

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 41593d2e7de9..739542928306 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -159,6 +159,7 @@ TEST_GEN_PROGS_aarch64 += aarch64/debug-exceptions
 TEST_GEN_PROGS_aarch64 += aarch64/hypercalls
 TEST_GEN_PROGS_aarch64 += aarch64/mmio_abort
 TEST_GEN_PROGS_aarch64 += aarch64/page_fault_test
+TEST_GEN_PROGS_aarch64 += aarch64/pmuv3_register_probe
 TEST_GEN_PROGS_aarch64 += aarch64/psci_test
 TEST_GEN_PROGS_aarch64 += aarch64/set_id_regs
 TEST_GEN_PROGS_aarch64 += aarch64/smccc_filter
diff --git a/tools/testing/selftests/kvm/aarch64/pmuv3_register_probe.c b/tools/testing/selftests/kvm/aarch64/pmuv3_register_probe.c
new file mode 100644
index 000000000000..859b0162dbeb
--- /dev/null
+++ b/tools/testing/selftests/kvm/aarch64/pmuv3_register_probe.c
@@ -0,0 +1,135 @@
+#include <perf/arm_pmuv3.h>
+
+#include "vgic.h"
+#include "test_util.h"
+#include "processor.h"
+
+static bool undef_taken;
+
+#define test_read(sr)							\
+do {									\
+	u64 __val = read_sysreg(sr);					\
+									\
+	if (READ_ONCE(undef_taken))					\
+		GUEST_PRINTF("read_sysreg("#sr"): UNDEFINED\n");	\
+	else								\
+		GUEST_PRINTF("read_sysreg("#sr"): %lx\n", __val);	\
+	WRITE_ONCE(undef_taken, false);					\
+} while (0)
+
+#define test_write(val, sr)							\
+do {										\
+	write_sysreg(val, sr);							\
+										\
+	if (READ_ONCE(undef_taken))						\
+		GUEST_PRINTF("write_sysreg(%x, "#sr"): UNDEFINED\n", val);	\
+	else									\
+		GUEST_PRINTF("write_sysreg(%x, "#sr"): OK\n", val);		\
+	WRITE_ONCE(undef_taken, false);						\
+} while (0)
+
+static void guest_undef_handler(struct ex_regs *regs)
+{
+	WRITE_ONCE(undef_taken, true);
+	regs->pc += 4;
+}
+
+#define READ_PMEVCNTRN(n)	test_read(pmevcntr##n##_el0)
+static void test_read_evcntr(int n)
+{
+	PMEVN_SWITCH(n, READ_PMEVCNTRN);
+}
+
+#define READ_PMEVTYPERN(n)	test_read(pmevtyper##n##_el0);
+static void test_read_evtyper(int n)
+{
+	PMEVN_SWITCH(n, READ_PMEVTYPERN);
+}
+
+static void guest_code(void)
+{
+	test_read(pmcr_el0);
+	test_read(pmcntenset_el0);
+	test_read(pmcntenclr_el0);
+	test_read(pmovsset_el0);
+	test_read(pmovsclr_el0);
+	test_read(pmintenset_el1);
+	test_read(pmintenclr_el1);
+	test_read(pmceid0_el0);
+	test_read(pmceid1_el0);
+
+	test_read(pmccntr_el0);
+	test_read(pmccfiltr_el0);
+	test_write(0, pmswinc_el0);
+
+	test_write(0, pmselr_el0);
+	test_read(pmxevcntr_el0);
+	test_read(pmxevtyper_el0);
+
+	test_read(pmuserenr_el0);
+
+	for (int i = 0; i < 31; i++) {
+		test_read_evcntr(i);
+		test_read_evtyper(i);
+	}
+
+	GUEST_DONE();
+}
+
+static void run_test(struct kvm_vcpu *vcpu)
+{
+	struct ucall uc;
+
+	while (true) {
+		vcpu_run(vcpu);
+
+		switch (get_ucall(vcpu, &uc)) {
+		case UCALL_PRINTF:
+			REPORT_GUEST_PRINTF(uc);
+			break;
+		case UCALL_DONE:
+			return;
+		default:
+			TEST_FAIL("Unknown ucall %lu", uc.cmd);
+		}
+	}
+}
+
+int main(void)
+{
+	struct kvm_device_attr attr;
+	struct kvm_vcpu_init init;
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+	int irq = 23;
+
+	TEST_REQUIRE(kvm_has_cap(KVM_CAP_ARM_PMU_V3));
+
+	vm = vm_create(1);
+	vm_ioctl(vm, KVM_ARM_PREFERRED_TARGET, &init);
+	init.features[0] |= (1 << KVM_ARM_VCPU_PMU_V3);
+	vcpu = aarch64_vcpu_add(vm, 0, &init, guest_code);
+
+	__TEST_REQUIRE(vgic_v3_setup(vm, 1, 64) >= 0,
+		       "Failed to create vgic-v3, skipping");
+
+	vm_init_descriptor_tables(vm);
+	vcpu_init_descriptor_tables(vcpu);
+	vm_install_sync_handler(vm, VECTOR_SYNC_CURRENT, ESR_ELx_EC_UNKNOWN,
+				guest_undef_handler);
+
+	attr = (struct kvm_device_attr) {
+		.group	= KVM_ARM_VCPU_PMU_V3_CTRL,
+		.attr	= KVM_ARM_VCPU_PMU_V3_IRQ,
+		.addr	= (u64)&irq,
+	};
+	vcpu_ioctl(vcpu, KVM_SET_DEVICE_ATTR, &attr);
+
+	attr = (struct kvm_device_attr) {
+		.group	= KVM_ARM_VCPU_PMU_V3_CTRL,
+		.attr	= KVM_ARM_VCPU_PMU_V3_INIT,
+	};
+	vcpu_ioctl(vcpu, KVM_SET_DEVICE_ATTR, &attr);
+
+	run_test(vcpu);
+}
-- 
2.39.5