[PATCH v8 7/9] selftests: KVM: Test physical counter offsetting

[Oliver Upton]

Test that userspace adjustment of the guest physical counter-timer
results in the correct view within the guest.

Cc: Andrew Jones <drjones at redhat.com>
Signed-off-by: Oliver Upton <oupton at google.com>
Reviewed-by: Andrew Jones <drjones at redhat.com>
---
 .../selftests/kvm/include/aarch64/processor.h | 12 +++++++
 .../kvm/system_counter_offset_test.c          | 34 ++++++++++++++++---
 2 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/aarch64/processor.h b/tools/testing/selftests/kvm/include/aarch64/processor.h
index 4c7472823df3..57b7802cf9e2 100644
--- a/tools/testing/selftests/kvm/include/aarch64/processor.h
+++ b/tools/testing/selftests/kvm/include/aarch64/processor.h
@@ -144,4 +144,16 @@ static inline uint64_t read_cntvct_ordered(void)
 	return r;
 }
 
+static inline uint64_t read_cntpct_ordered(void)
+{
+	uint64_t r;
+
+	__asm__ __volatile__("isb\n\t"
+			     "mrs %0, cntpct_el0\n\t"
+			     "isb\n\t"
+			     : "=r"(r));
+
+	return r;
+}
+
 #endif /* SELFTEST_KVM_PROCESSOR_H */
diff --git a/tools/testing/selftests/kvm/system_counter_offset_test.c b/tools/testing/selftests/kvm/system_counter_offset_test.c
index 7ea406fdd56f..757b5b2e960e 100644
--- a/tools/testing/selftests/kvm/system_counter_offset_test.c
+++ b/tools/testing/selftests/kvm/system_counter_offset_test.c
@@ -57,6 +57,9 @@ static uint64_t host_read_guest_system_counter(struct test_case *test)
 
 enum arch_counter {
 	VIRTUAL,
+	PHYSICAL,
+	/* offset physical, read virtual */
+	PHYSICAL_READ_VIRTUAL,
 };
 
 struct test_case {
@@ -68,6 +71,12 @@ static struct test_case test_cases[] = {
 	{ .counter = VIRTUAL, .offset = 0 },
 	{ .counter = VIRTUAL, .offset = 180 * NSEC_PER_SEC },
 	{ .counter = VIRTUAL, .offset = -180 * NSEC_PER_SEC },
+	{ .counter = PHYSICAL, .offset = 0 },
+	{ .counter = PHYSICAL, .offset = 180 * NSEC_PER_SEC },
+	{ .counter = PHYSICAL, .offset = -180 * NSEC_PER_SEC },
+	{ .counter = PHYSICAL_READ_VIRTUAL, .offset = 0 },
+	{ .counter = PHYSICAL_READ_VIRTUAL, .offset = 180 * NSEC_PER_SEC },
+	{ .counter = PHYSICAL_READ_VIRTUAL, .offset = -180 * NSEC_PER_SEC },
 };
 
 static void check_preconditions(struct kvm_vm *vm)
@@ -76,32 +85,49 @@ static void check_preconditions(struct kvm_vm *vm)
 		.cap = KVM_CAP_ARM_VTIMER_OFFSET,
 	};
 
-	if (vcpu_has_reg(vm, VCPU_ID, KVM_REG_ARM_TIMER_OFFSET))
-		return;
-
 	if (!kvm_check_cap(KVM_CAP_ARM_VTIMER_OFFSET)) {
 		print_skip("KVM_REG_ARM_TIMER_OFFSET not supported");
 		exit(KSFT_SKIP);
 	}
 
 	vm_enable_cap(vm, &cap);
+
+	if (_vcpu_has_device_attr(vm, VCPU_ID, KVM_ARM_VCPU_TIMER_CTRL,
+				  KVM_ARM_VCPU_TIMER_PHYS_OFFSET)) {
+		print_skip("KVM_ARM_VCPU_TIMER_PHYS_OFFSET not supported");
+		exit(KSFT_SKIP);
+	}
 }
 
 static void setup_system_counter(struct kvm_vm *vm, struct test_case *test)
 {
+	uint64_t cntvoff, cntpoff;
 	struct kvm_one_reg reg = {
 		.id = KVM_REG_ARM_TIMER_OFFSET,
-		.addr = (__u64)&test->offset,
+		.addr = (__u64)&cntvoff,
 	};
 
+	if (test->counter == VIRTUAL) {
+		cntvoff = test->offset;
+		cntpoff = 0;
+	} else {
+		cntvoff = 0;
+		cntpoff = test->offset;
+	}
+
 	vcpu_set_reg(vm, VCPU_ID, &reg);
+	vcpu_access_device_attr(vm, VCPU_ID, KVM_ARM_VCPU_TIMER_CTRL,
+				KVM_ARM_VCPU_TIMER_PHYS_OFFSET, &cntpoff, true);
 }
 
 static uint64_t guest_read_system_counter(struct test_case *test)
 {
 	switch (test->counter) {
 	case VIRTUAL:
+	case PHYSICAL_READ_VIRTUAL:
 		return read_cntvct_ordered();
+	case PHYSICAL:
+		return read_cntpct_ordered();
 	default:
 		GUEST_ASSERT(0);
 	}
-- 
2.33.0.464.g1972c5931b-goog