Re: [PATCH] hw/qdev-core: Add compatibility for (non)-transitional devs

[Jean-Louis Dupond <jean-louis@dupond.be>]

On 19/10/2021 17:27, Eduardo Habkost wrote:
> On Tue, Oct 12, 2021 at 10:24:28AM +0200, Jean-Louis Dupond wrote:
>> hw_compat modes only take into account their base name.
> What do you mean by "base name"?
virtio-net-pci (without the (non-)transitional extension.
>> But if a device is created with (non)-transitional, then the compat
>> values are not used, causing migrating issues.
>>
>> This commit adds their (non)-transitional entries with the same settings
>> as the base entry.
>
> Wouldn't it be easier to fix the incorrect compat_props arrays to
> use "virtio-*-pci-base" instead?
>
> If a piece of code is supposed to affect/support both
> non-transitional and transitional subclasses, that's why
> VirtioPCIDeviceTypeInfo.base_name exists.
>
Thats easier indeed :)
>> Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1999141
>>
>> Signed-off-by: Jean-Louis Dupond <jean-louis@dupond.be>
>> ---
>>   include/hw/qdev-core.h | 34 ++++++++++++++++++++++++++++++++++
>>   1 file changed, 34 insertions(+)
>>
>> diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
>> index 4ff19c714b..5726825c2d 100644
>> --- a/include/hw/qdev-core.h
>> +++ b/include/hw/qdev-core.h
>> @@ -293,6 +293,30 @@ typedef struct GlobalProperty {
>>       bool optional;
>>   } GlobalProperty;
>>   
>> +
>> +/**
>> + * Helper to add (non)transitional compat properties
>> + */
>> +static inline void
>> +compat_props_add_transitional(GPtrArray *arr, GlobalProperty *prop)
>> +{
>> +    GlobalProperty *transitional = g_new0(typeof(*transitional), 1);
>> +    transitional->driver = g_strdup_printf("%s-transitional", prop->driver);
>> +    transitional->property = g_strdup(prop->property);
>> +    transitional->value = g_strdup(prop->value);
>> +    transitional->used = prop->used;
>> +    transitional->optional = prop->optional;
>> +    g_ptr_array_add(arr, (void *)transitional);
>> +
>> +    GlobalProperty *non_transitional = g_new0(typeof(*non_transitional), 1);
>> +    non_transitional->driver = g_strdup_printf("%s-non-transitional", prop->driver);
>> +    non_transitional->property = g_strdup(prop->property);
>> +    non_transitional->value = g_strdup(prop->value);
>> +    non_transitional->used = prop->used;
>> +    non_transitional->optional = prop->optional;
>> +    g_ptr_array_add(arr, (void *)non_transitional);
>> +}
>> +
>>   static inline void
>>   compat_props_add(GPtrArray *arr,
>>                    GlobalProperty props[], size_t nelem)
>> @@ -300,6 +324,16 @@ compat_props_add(GPtrArray *arr,
>>       int i;
>>       for (i = 0; i < nelem; i++) {
>>           g_ptr_array_add(arr, (void *)&props[i]);
>> +        if (g_str_equal(props[i].driver, "vhost-user-blk-pci") ||
>> +            g_str_equal(props[i].driver, "virtio-scsi-pci") ||
>> +            g_str_equal(props[i].driver, "virtio-blk-pci") ||
>> +            g_str_equal(props[i].driver, "virtio-balloon-pci") ||
>> +            g_str_equal(props[i].driver, "virtio-serial-pci") ||
>> +            g_str_equal(props[i].driver, "virtio-9p-pci") ||
>> +            g_str_equal(props[i].driver, "virtio-net-pci") ||
>> +            g_str_equal(props[i].driver, "virtio-rng-pci")) {
>> +            compat_props_add_transitional(arr, &props[i]);
>> +        }
>>       }
>>   }
>>   
>> -- 
>> 2.33.0
>>
>>