[libvirt] [PATCH v1 05/15] conf: Introduce VIR_DOMAIN_LOADER_TYPE_NONE

[Michal Privoznik]

On 2/28/19 10:27 AM, Laszlo Ersek wrote:
> On 02/27/19 11:04, Michal Privoznik wrote:
>> This is going to extend virDomainLoader enum. The reason is that
>> once loader path is NULL its type makes no sense. However, since
>> value of zero corresponds to VIR_DOMAIN_LOADER_TYPE_ROM the
>> following XML would be produced:
>>
>>    <os>
>>      <loader type='rom'/>
>>      ...
>>    </os>
>>
>> To solve this, introduce VIR_DOMAIN_LOADER_TYPE_NONE which would
>> correspond to value of zero and then use post parse callback to
>> set the default loader type to 'rom' if needed.
>>
>> Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
>> ---
>>   src/conf/domain_conf.c              | 23 +++++++++++++++++++++--
>>   src/conf/domain_conf.h              |  3 ++-
>>   src/qemu/qemu_command.c             |  1 +
>>   src/qemu/qemu_domain.c              |  1 +
>>   tests/domaincapsschemadata/full.xml |  1 +
>>   5 files changed, 26 insertions(+), 3 deletions(-)
> 
> Sounds pretty complex, but I guess it makes sense. If both @type and the
> pathname content are missing, then @type will default to NONE. (This
> used not to be possible, given that pathname used to be required.) If
> @type is absent but the pathname is present, then we flip the type
> manually to ROM.

Right. The whole idea is that after all these patches the following 
domain XML should be valid:

   <os firmware='efi'>
     <loader secure='yes'/>
   </os>

This is for inactive domain. While starting the domain libvirt fills in 
path and its type. But for inactive XML tehre is no path. Therefore, 
there should be no loader type associated with it.

> 
>> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
>> index f622a4dddf..b436b91c66 100644
>> --- a/src/conf/domain_conf.c
>> +++ b/src/conf/domain_conf.c
>> @@ -1013,6 +1013,7 @@ VIR_ENUM_IMPL(virDomainMemoryAllocation, VIR_DOMAIN_MEMORY_ALLOCATION_LAST,
>>   
>>   VIR_ENUM_IMPL(virDomainLoader,
>>                 VIR_DOMAIN_LOADER_TYPE_LAST,
>> +              "none",
>>                 "rom",
>>                 "pflash",
>>   );
>> @@ -4286,6 +4287,20 @@ virDomainDefPostParseMemory(virDomainDefPtr def,
>>   }
>>   
>>   
>> +static void
>> +virDomainDefPostParseOs(virDomainDefPtr def)
>> +{
>> +    if (!def->os.loader)
>> +        return;
>> +
>> +    if (def->os.loader->path &&
>> +        def->os.loader->type == VIR_DOMAIN_LOADER_TYPE_NONE) {
>> +        /* By default, loader is type of 'rom' */
>> +        def->os.loader->type = VIR_DOMAIN_LOADER_TYPE_ROM;
>> +    }
>> +}
>> +
>> +
>>   static void
>>   virDomainDefPostParseMemtune(virDomainDefPtr def)
>>   {
>> @@ -5465,6 +5480,8 @@ virDomainDefPostParseCommon(virDomainDefPtr def,
>>       if (virDomainDefPostParseMemory(def, data->parseFlags) < 0)
>>           return -1;
>>   
>> +    virDomainDefPostParseOs(def);
>> +
>>       virDomainDefPostParseMemtune(def);
>>   
>>       if (virDomainDefRejectDuplicateControllers(def) < 0)
>> @@ -18706,7 +18723,7 @@ virDomainLoaderDefParseXML(xmlNodePtr node,
>>   
>>       if (type_str) {
>>           int type;
>> -        if ((type = virDomainLoaderTypeFromString(type_str)) < 0) {
>> +        if ((type = virDomainLoaderTypeFromString(type_str)) <= 0) {
> 
> Why is this change necessary? Hm... I assume, due to the enum
> auto-generation in libvirt, the introduction of "none" will
> automatically cause virDomainLoaderTypeFromString() to recognize "none"
> as value 0. But we want to act like "none" isn't a valid value (it's
> internal use only). Hence the same error message as before.

Exactly. virDomainLoaderTypeFromString() will take whatever string user 
provided and return matching enum value. For instance, for "rom" it 
returns VIR_DOMAIN_LOADER_TYPE_ROM, "pflash" is then mapped on 
VIR_DOMAIN_LOADER_TYPE_PFLASH. And with this patch "none" would be 
mapped to VIR_DOMAIN_LOADER_TYPE_NONE which has the value of 0. And we 
don't want to accept "none" in the domain XML, do we? Hence the change.

> 
> I reckon this is OK.
> 
> Reviewed-by: Laszlo Ersek <lersek at redhat.com>

Thanks,
Michal