Hi Markus,
On 11/29/23 19:20, Markus Armbruster wrote:
> Gavin Shan <gshan@redhat.com> writes:
>
>> QEMU will be terminated if the specified CPU type isn't supported
>> in machine_run_board_init(). The list of supported CPU type names
>> is tracked by mc->valid_cpu_types.
>
> Suggest to drop the second sentence.
>
Indeed, it's not so helpful.
>> The error handling can be used to propagate error messages, to be
>> consistent how the errors are handled for other situations in the
>> same function.
>>
>> No functional change intended.
>>
>> Suggested-by: Igor Mammedov <imammedo@redhat.com>
>> Signed-off-by: Gavin Shan <gshan@redhat.com>
>> ---
>> v8: Drop @local_err and use @errp to be compatible with
>> ERRP_GUARD() (Phil)
>> ---
>> hw/core/machine.c | 13 +++++++------
>> 1 file changed, 7 insertions(+), 6 deletions(-)
>>
>> diff --git a/hw/core/machine.c b/hw/core/machine.c
>> index 0c17398141..bde7f4af6d 100644
>> --- a/hw/core/machine.c
>> +++ b/hw/core/machine.c
>> @@ -1466,15 +1466,16 @@ void machine_run_board_init(MachineState *machine, const char *mem_path, Error *
>>
>> if (!machine_class->valid_cpu_types[i]) {
>> /* The user specified CPU is not valid */
>> - error_report("Invalid CPU type: %s", machine->cpu_type);
>> - error_printf("The valid types are: %s",
>> - machine_class->valid_cpu_types[0]);
>> + error_setg(errp, "Invalid CPU type: %s", machine->cpu_type);
>> + error_append_hint(errp, "The valid types are: %s",
>> + machine_class->valid_cpu_types[0]);
>> for (i = 1; machine_class->valid_cpu_types[i]; i++) {
>> - error_printf(", %s", machine_class->valid_cpu_types[i]);
>> + error_append_hint(errp, ", %s",
>> + machine_class->valid_cpu_types[i]);
>> }
>> - error_printf("\n");
>>
>> - exit(1);
>> + error_append_hint(&errp, "\n");
>> + return;
>> }
>> }
>
> This cleans up an anti-pattern: use of error_report() within a function that
> returns errors through an Error **errp parameter.
>
> Cleanup, not bug fix, because the only caller passes &error_abort.
>
> Suggest to start the commit message with a mention of the anti-pattern.
> Here's how I'd write it:
>
> Functions that use an Error **errp parameter to return errors should
> not also report them to the user, because reporting is the caller's
> job.
>
> machine_run_board_init() violates this principle: it calls
> error_report(), error_printf(), and exit(1) when the machine doesn't
> support the requested CPU type.
>
> Clean this up by using error_setg() and error_append_hint() instead.
> No functional change, as the only caller passes &error_fatal.
>
Thanks for the nice write-up. I will take it if v9 is needed to address
comments from other people.
> Whether you use my suggestion or not:
> Reviewed-by: Markus Armbruster <armbru@redhat.com>
>
Thanks for your review.
Thanks,
Gavin