Re: [PATCH] tpm: Return QMP error when TPM is disabled in build

[Philippe Mathieu-Daudé]

On 6/9/21 7:27 PM, Philippe Mathieu-Daudé wrote:
> On 6/9/21 6:01 PM, Marc-André Lureau wrote:
>> Hi
>>
>> On Wed, Jun 9, 2021 at 7:33 PM Philippe Mathieu-Daudé <philmd@redhat.com
>> <mailto:philmd@redhat.com>> wrote:
>>
>>     When the management layer queries a binary built using --disable-tpm
>>     for TPM devices, it gets confused by getting empty responses:
>>
>>       { "execute": "query-tpm" }
>>       {
>>           "return": [
>>           ]
>>       }
>>       { "execute": "query-tpm-types" }
>>       {
>>           "return": [
>>           ]
>>       }
>>       { "execute": "query-tpm-models" }
>>       {
>>           "return": [
>>           ]
>>       }
>>
>>     Make it clearer by returning an error, mentioning the feature is
>>     disabled:
>>
>>       { "execute": "query-tpm" }
>>       {
>>           "error": {
>>               "class": "GenericError",
>>               "desc": "this feature or command is not currently supported"
>>           }
>>       }
>>
>>     Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com
>>     <mailto:philmd@redhat.com>>
>>
>>
>> Why not make the qapi schema conditional?

Using your suggestion (and ignoring QAPI marshaling error) I'm getting:

{ "execute": "query-tpm" }
{
    "error": {
        "class": "CommandNotFound",
        "desc": "The command query-tpm has not been found"
    }
}

Is that OK from a management perspective?