[PATCH v2 09/12] selftests: KVM: Add support for aarch64 to system_counter_offset_test

Oliver Upton
2021-07-16T21:26:55Z

KVM/arm64 now allows userspace to adjust the guest virtual counter-timer
via a vCPU device attribute. Test that changes to the virtual
counter-timer offset result in the correct view being presented to the
guest.

Signed-off-by: Oliver Upton <oupton@google.com>
---
tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/include/aarch64/processor.h | 12 +++++
.../kvm/system_counter_offset_test.c | 54 ++++++++++++++++++-
3 files changed, 66 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 7bf2e5fb1d5a..d89908108c97 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -96,6 +96,7 @@ TEST_GEN_PROGS_aarch64 += kvm_page_table_test
TEST_GEN_PROGS_aarch64 += set_memory_region_test
TEST_GEN_PROGS_aarch64 += steal_time
TEST_GEN_PROGS_aarch64 += kvm_binary_stats_test
+TEST_GEN_PROGS_aarch64 += system_counter_offset_test

TEST_GEN_PROGS_s390x = s390x/memop
TEST_GEN_PROGS_s390x += s390x/resets
diff --git a/tools/testing/selftests/kvm/include/aarch64/processor.h b/tools/testing/selftests/kvm/include/aarch64/processor.h
index 27dc5c2e56b9..3168cdbae6ee 100644
--- a/tools/testing/selftests/kvm/include/aarch64/processor.h
+++ b/tools/testing/selftests/kvm/include/aarch64/processor.h
@@ -129,4 +129,16 @@ void vm_install_sync_handler(struct kvm_vm *vm,

#define isb() asm volatile("isb" : : : "memory")

+static inline uint64_t read_cntvct_ordered(void)
+{
+ uint64_t r;
+
+ __asm__ __volatile__("isb\n\t"
+ "mrs %0, cntvct_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 7e9015770759..88ad997f5b69 100644
--- a/tools/testing/selftests/kvm/system_counter_offset_test.c
+++ b/tools/testing/selftests/kvm/system_counter_offset_test.c
@@ -53,7 +53,59 @@ static uint64_t host_read_guest_system_counter(struct test_case *test)
return rdtsc() + test->tsc_offset;
}

-#else /* __x86_64__ */
+#elif __aarch64__ /* __x86_64__ */
+
+enum arch_counter {
+ VIRTUAL,
+};
+
+struct test_case {
+ enum arch_counter counter;
+ uint64_t offset;
+};
+
+static struct test_case test_cases[] = {
+ { .counter = VIRTUAL, .offset = 0 },
+ { .counter = VIRTUAL, .offset = 180 * NSEC_PER_SEC },
+ { .counter = VIRTUAL, .offset = -180 * NSEC_PER_SEC },
+};
+
+static void check_preconditions(struct kvm_vm *vm)
+{
+ if (!_vcpu_has_device_attr(vm, VCPU_ID, KVM_ARM_VCPU_TIMER_CTRL,
+ KVM_ARM_VCPU_TIMER_OFFSET_VTIMER))
+ return;
+
+ print_skip("KVM_ARM_VCPU_TIMER_OFFSET_VTIMER not supported; skipping test");
+ exit(KSFT_SKIP);
+}
+
+static void setup_system_counter(struct kvm_vm *vm, struct test_case *test)
+{
+ vcpu_access_device_attr(vm, VCPU_ID, KVM_ARM_VCPU_TIMER_CTRL,
+ KVM_ARM_VCPU_TIMER_OFFSET_VTIMER, &test->offset,
+ true);
+}
+
+static uint64_t guest_read_system_counter(struct test_case *test)
+{
+ switch (test->counter) {
+ case VIRTUAL:
+ return read_cntvct_ordered();
+ default:
+ GUEST_ASSERT(0);
+ }
+
+ /* unreachable */
+ return 0;
+}
+
+static uint64_t host_read_guest_system_counter(struct test_case *test)
+{
+ return read_cntvct_ordered() - test->offset;
+}
+
+#else /* __aarch64__ */

#error test not implemented for this architecture!

--
2.32.0.402.g57bb445576-goog