[PATCH v2 11/12] selftests: KVM: Test physical counter offsetting

Oliver Upton
2021-07-16T21:26:56Z

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

Signed-off-by: Oliver Upton <oupton@google.com>
---
.../selftests/kvm/include/aarch64/processor.h | 12 ++++++++
.../kvm/system_counter_offset_test.c | 29 ++++++++++++++++---
2 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/aarch64/processor.h b/tools/testing/selftests/kvm/include/aarch64/processor.h
index 3168cdbae6ee..7f53d90e9512 100644
--- a/tools/testing/selftests/kvm/include/aarch64/processor.h
+++ b/tools/testing/selftests/kvm/include/aarch64/processor.h
@@ -141,4 +141,16 @@ 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 88ad997f5b69..3eed9dcb7693 100644
--- a/tools/testing/selftests/kvm/system_counter_offset_test.c
+++ b/tools/testing/selftests/kvm/system_counter_offset_test.c
@@ -57,6 +57,7 @@ static uint64_t host_read_guest_system_counter(struct test_case *test)

enum arch_counter {
VIRTUAL,
+ PHYSICAL,
};

struct test_case {
@@ -68,23 +69,41 @@ 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 },
};

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))
+ KVM_ARM_VCPU_TIMER_OFFSET_VTIMER) &&
+ !_vcpu_has_device_attr(vm, VCPU_ID, KVM_ARM_VCPU_TIMER_CTRL,
+ KVM_ARM_VCPU_TIMER_OFFSET_PTIMER))
return;

- print_skip("KVM_ARM_VCPU_TIMER_OFFSET_VTIMER not supported; skipping test");
+ print_skip("KVM_ARM_VCPU_TIMER_OFFSET_{VTIMER,PTIMER} not supported; skipping test");
exit(KSFT_SKIP);
}

static void setup_system_counter(struct kvm_vm *vm, struct test_case *test)
{
+ u64 attr = 0;
+
+ switch (test->counter) {
+ case VIRTUAL:
+ attr = KVM_ARM_VCPU_TIMER_OFFSET_VTIMER;
+ break;
+ case PHYSICAL:
+ attr = KVM_ARM_VCPU_TIMER_OFFSET_PTIMER;
+ break;
+ default:
+ TEST_ASSERT(false, "unrecognized counter index %u",
+ test->counter);
+ }
+
vcpu_access_device_attr(vm, VCPU_ID, KVM_ARM_VCPU_TIMER_CTRL,
- KVM_ARM_VCPU_TIMER_OFFSET_VTIMER, &test->offset,
- true);
+ attr, &test->offset, true);
}

static uint64_t guest_read_system_counter(struct test_case *test)
@@ -92,6 +111,8 @@ static uint64_t guest_read_system_counter(struct test_case *test)
switch (test->counter) {
case VIRTUAL:
return read_cntvct_ordered();
+ case PHYSICAL:
+ return read_cntpct_ordered();
default:
GUEST_ASSERT(0);
}
--
2.32.0.402.g57bb445576-goog