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

[Dov Murik]

On 07/10/2021 19:28, Dov Murik wrote:
> 
> 
> 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.
> 

I sent another series [1] with this fix (and a similar fix in
launch_start); it can be added as part of this housekeeping series.

[1] 
20211011173026.2454294-1-dovmurik@linux.ibm.com/">https://lore.kernel.org/qemu-devel/20211011173026.2454294-1-dovmurik@linux.ibm.com/

-Dov

> -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 *
>>