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References: <20220330174621.1567317-1-bgardon@google.com> <20220330174621.1567317-4-bgardon@google.com>
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From:   Jing Zhang <jingzhangos@google.com>
Date:   Wed, 30 Mar 2022 11:51:01 -0700
Message-ID: <CAAdAUtizJcjEqLv8hcjNv0ZCOAy62DXA6voEhtYeeK4EpLf6HQ@mail.gmail.com>
Subject: Re: [PATCH v3 03/11] KVM: selftests: Test reading a single stat
To:     Ben Gardon <bgardon@google.com>
Cc:     linux-kernel@vger.kernel.org, KVM <kvm@vger.kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Peter Xu <peterx@redhat.com>,
        Sean Christopherson <seanjc@google.com>,
        David Matlack <dmatlack@google.com>,
        Jim Mattson <jmattson@google.com>,
        David Dunn <daviddunn@google.com>,
        Junaid Shahid <junaids@google.com>
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On Wed, Mar 30, 2022 at 10:46 AM Ben Gardon <bgardon@google.com> wrote:
>
> Retrieve the value of a single stat by name in the binary stats test to
> ensure the kvm_util library functions work.
>
> CC: Jing Zhang <jingzhangos@google.com>
> Signed-off-by: Ben Gardon <bgardon@google.com>
> ---
>  .../selftests/kvm/include/kvm_util_base.h     |  1 +
>  .../selftests/kvm/kvm_binary_stats_test.c     |  3 ++
>  tools/testing/selftests/kvm/lib/kvm_util.c    | 53 +++++++++++++++++++
>  3 files changed, 57 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
> index 4783fd1cd4cf..78c4407f36b4 100644
> --- a/tools/testing/selftests/kvm/include/kvm_util_base.h
> +++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
> @@ -402,6 +402,7 @@ 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 dump_vm_stats(struct kvm_vm *vm);
> +uint64_t vm_get_single_stat(struct kvm_vm *vm, const char *stat_name);
>
>  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 afc4701ce8dd..97bde355f105 100644
> --- a/tools/testing/selftests/kvm/kvm_binary_stats_test.c
> +++ b/tools/testing/selftests/kvm/kvm_binary_stats_test.c
> @@ -177,6 +177,9 @@ static void vm_stats_test(struct kvm_vm *vm)
>
>         /* Dump VM stats */
>         dump_vm_stats(vm);
> +
> +       /* Read a single stat. */
> +       printf("remote_tlb_flush: %lu\n", vm_get_single_stat(vm, "remote_tlb_flush"));
>  }
>
>  static void vcpu_stats_test(struct kvm_vm *vm, int vcpu_id)
> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> index f87df68b150d..9c4574381daa 100644
> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> @@ -2705,3 +2705,56 @@ void dump_vm_stats(struct kvm_vm *vm)
>         close(stats_fd);
>  }
>
> +static int vm_get_stat_data(struct kvm_vm *vm, const char *stat_name,
> +                           uint64_t **data)
> +{
> +       struct kvm_stats_desc *stats_desc;
> +       struct kvm_stats_header *header;
> +       struct kvm_stats_desc *desc;
> +       size_t size_desc;
> +       int stats_fd;
> +       int ret = -EINVAL;
> +       int i;
> +
> +       *data = NULL;
> +
> +       stats_fd = vm_get_stats_fd(vm);
> +
> +       header = read_vm_stats_header(stats_fd);
> +
> +       stats_desc = read_vm_stats_desc(stats_fd, header);
> +
> +       size_desc = stats_desc_size(header);
> +
> +       /* Read kvm stats data one by one */
> +       for (i = 0; i < header->num_desc; ++i) {
> +               desc = (void *)stats_desc + (i * size_desc);
> +
> +               if (strcmp(desc->name, stat_name))
> +                       continue;
> +
> +               ret = read_stat_data(stats_fd, header, desc, data);
> +       }
> +
> +       free(stats_desc);
> +       free(header);
> +
> +       close(stats_fd);
> +
> +       return ret;
> +}
> +
> +uint64_t vm_get_single_stat(struct kvm_vm *vm, const char *stat_name)
> +{
> +       uint64_t *data;
> +       uint64_t value;
> +       int ret;
> +
> +       ret = vm_get_stat_data(vm, stat_name, &data);
> +       TEST_ASSERT(ret == 1, "Stat %s expected to have 1 element, but has %d",
> +                   stat_name, ret);
> +       value = *data;
> +       free(data);
> +       return value;
> +}
> +
> --
> 2.35.1.1021.g381101b075-goog
>
Reviewed-by: Jing Zhang <jingzhangos@google.com>