Re: [PATCH v4 12/23] target/i386/sev: Use g_autofree in sev_launch_get_measure()

[Dov Murik]

On 07/10/2021 19:17, Philippe Mathieu-Daudé wrote:
> Use g_autofree to remove a pair of g_free/goto.
> 
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>  target/i386/sev.c | 13 ++++---------
>  1 file changed, 4 insertions(+), 9 deletions(-)
> 
> diff --git a/target/i386/sev.c b/target/i386/sev.c
> index 3a30ba6d94a..5cbbcf0bb93 100644
> --- a/target/i386/sev.c
> +++ b/target/i386/sev.c
> @@ -685,8 +685,8 @@ sev_launch_get_measure(Notifier *notifier, void *unused)
>  {
>      SevGuestState *sev = sev_guest;
>      int ret, error;
> -    guchar *data;
> -    struct kvm_sev_launch_measure *measurement;
> +    g_autofree guchar *data = NULL;
> +    g_autofree struct kvm_sev_launch_measure *measurement = NULL;

Sorry for joining so late, but why do we allocate struct
kvm_sev_launch_measure on the heap (even before this patch)? It's only
12 bytes. Might be simpler to have a local (stack) variable and not care
about memory management.

-Dov


>  
>      if (!sev_check_state(sev, SEV_STATE_LAUNCH_UPDATE)) {
>          return;
> @@ -708,7 +708,7 @@ sev_launch_get_measure(Notifier *notifier, void *unused)
>      if (!measurement->len) {
>          error_report("%s: LAUNCH_MEASURE ret=%d fw_error=%d '%s'",
>                       __func__, ret, error, fw_error_to_str(errno));
> -        goto free_measurement;
> +        return;
>      }
>  
>      data = g_new0(guchar, measurement->len);
> @@ -720,7 +720,7 @@ sev_launch_get_measure(Notifier *notifier, void *unused)
>      if (ret) {
>          error_report("%s: LAUNCH_MEASURE ret=%d fw_error=%d '%s'",
>                       __func__, ret, error, fw_error_to_str(errno));
> -        goto free_data;
> +        return;
>      }
>  
>      sev_set_guest_state(sev, SEV_STATE_LAUNCH_SECRET);
> @@ -728,11 +728,6 @@ sev_launch_get_measure(Notifier *notifier, void *unused)
>      /* encode the measurement value and emit the event */
>      sev->measurement = g_base64_encode(data, measurement->len);
>      trace_kvm_sev_launch_measurement(sev->measurement);
> -
> -free_data:
> -    g_free(data);
> -free_measurement:
> -    g_free(measurement);
>  }
>  
>  char *
>