[PATCH v3 09/12] selftests: KVM: Add support for aarch64 to system_counter_offset_test

[Andrew Jones]

On Mon, Jul 19, 2021 at 06:49:46PM +0000, Oliver Upton wrote:
> 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 at 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
> 
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>

Reviewed-by: Andrew Jones <drjones at redhat.com>