Re: [PATCH v4 02/10] KVM: selftests: Read binary stats header in lib

[David Matlack]

On Mon, Apr 11, 2022 at 2:10 PM Ben Gardon <bgardon@xxxxxxxxxx> wrote:
>
> Move the code to read the binary stats header to the KVM selftests
> library. It will be re-used by other tests to check KVM behavior.
>
> No functional change intended.
>
> Signed-off-by: Ben Gardon <bgardon@xxxxxxxxxx>
> ---
>  tools/testing/selftests/kvm/include/kvm_util_base.h | 1 +
>  tools/testing/selftests/kvm/kvm_binary_stats_test.c | 4 ++--
>  tools/testing/selftests/kvm/lib/kvm_util.c          | 8 ++++++++
>  3 files changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
> index 92cef0ffb19e..5ba3132f3110 100644
> --- a/tools/testing/selftests/kvm/include/kvm_util_base.h
> +++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
> @@ -400,6 +400,7 @@ void assert_on_unhandled_exception(struct kvm_vm *vm, uint32_t vcpuid);
>
>  int vm_get_stats_fd(struct kvm_vm *vm);
>  int vcpu_get_stats_fd(struct kvm_vm *vm, uint32_t vcpuid);
> +void read_vm_stats_header(int stats_fd, struct kvm_stats_header *header);
>
>  uint32_t guest_get_vcpuid(void);
>
> diff --git a/tools/testing/selftests/kvm/kvm_binary_stats_test.c b/tools/testing/selftests/kvm/kvm_binary_stats_test.c
> index dad34d8a41fe..22c22a90f15a 100644
> --- a/tools/testing/selftests/kvm/kvm_binary_stats_test.c
> +++ b/tools/testing/selftests/kvm/kvm_binary_stats_test.c
> @@ -33,8 +33,8 @@ static void stats_test(int stats_fd)
>         struct kvm_stats_desc *pdesc;
>
>         /* Read kvm stats header */
> -       ret = read(stats_fd, &header, sizeof(header));
> -       TEST_ASSERT(ret == sizeof(header), "Read stats header");
> +       read_vm_stats_header(stats_fd, &header);

stats_test() is used to test both VM and vCPU stats. The only
difference is whether stats_fd is the VM stats fd or a vCPU stats fd.

Given that, please rename read_vm_stats_header() to something more
generic (since it can also be used for reading the vCPU stats header).
e.g. read_stats_header().

> +
>         size_desc = sizeof(*stats_desc) + header.name_size;
>
>         /* Read kvm stats id string */
> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> index 1665a220abcb..0caf28e324ed 100644
> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> @@ -2556,3 +2556,11 @@ int vcpu_get_stats_fd(struct kvm_vm *vm, uint32_t vcpuid)
>
>         return ioctl(vcpu->fd, KVM_GET_STATS_FD, NULL);
>  }
> +
> +void read_vm_stats_header(int stats_fd, struct kvm_stats_header *header)
> +{
> +       ssize_t ret;
> +
> +       ret = read(stats_fd, header, sizeof(*header));
> +       TEST_ASSERT(ret == sizeof(*header), "Read stats header");
> +}
> --
> 2.35.1.1178.g4f1659d476-goog
>