[PATCH] efi_loader: Allow also empty capsule to be process

[Michal Simek]

Hi,

On 7/20/23 07:49, AKASHI Takahiro wrote:
> Hi,
> 
> On Wed, Jul 19, 2023 at 08:28:41AM +0200, Michal Simek wrote:
>>
>>
>> On 7/18/23 17:41, Heinrich Schuchardt wrote:
>>> On 13.07.23 16:35, Michal Simek wrote:
>>>> Empty capsule are also allowed to be process. Without it updated images
>>>> can't change their Image Acceptance state from no to yes.
>>>
>>> Is there any documentation describing the usage of empty capsule to set
>>> the image acceptance state?
>>
>> I actually don't know about documentation. I was talking to Ilias to make
>> sure that documentation is up2date because there are missing couple of
>> things there.
> 
> Sughosh should have more to say here about A/B update.
> 
>> I am testing A/B update and if you setup oemflags to 0x8000 then capsules
>> are not automatically accepted and waiting for acceptance capsule to be
>> passed.
>> When I tested it I found out that they are not process that's why I created
>> this patch.
> 
> The path you tried to modify is only executed by "efidebug capsule update"
> or more specifically via the runtime service, UPDATE_CAPSULE.
> 
> But this API is NOT officially supported in the current capsule implementation
> (at least, in my initial intention).
> The only way to invoke capsule updates is to reboot the system.
> If you want to test A/B update, please do the reboot.

I realized that to get full flow you need to use capsule update on disk to get 
all functionalities. But it is very impractical. Actually I would expect via 
efidebug you should be able to perform all steps as capsule update performs when 
you do reboot.
I would also understand that via efidebug you are not able to apply any capsule 
but I don't think it is right that you can apply just update capsules but not 
empty capsules. I would understand none or all but not something in the middle.

Thanks,
Michal