[PATCH v2 1/1] efi_driver: don't bind internal block devices

[Heinrich Schuchardt]

On 9/9/22 15:59, AKASHI Takahiro wrote:
> On Fri, Sep 09, 2022 at 03:00:57PM +0200, Heinrich Schuchardt wrote:
>> UEFI block devices can either mirror U-Boot's internal devices or be
>> provided by an EFI application like iPXE.
>>
>> When ConnectController() is invoked for the EFI_BLOCK_IO_PROTOCOL
>> interface for such an application provided device we create a virtual
>> U-Boot block device of type "efi_blk".
>>
>> Currently we do not call ConnectController() when handles for U-Boot's
>> internal block devices are created. If an EFI application calls
>> ConnectController() for a handle relating to an internal block device,
>> we erroneously create an extra "efi_blk" block device.
>>
>> E.g. the UEFI shell has a command 'connect -r' which calls
>> ConnectController() for all handles.
> 
> Not exactly.
> ConnectController() will be called against handles which hold
> DevicePathProtocol.
> 
>> In the Supported() method of our EFI_DRIVER_BINDING_PROTOCOL return
>> EFI_ALREADY_STARTED when dealing with an U-Boot internal device.
> 
> No. EFI_ALREADY_STARTED is not the right return value
> for "ordinary block devices" since this driver does not manage
> those devices under the current implementation.
> Return EFI_UNSUPPORTED instead.
> 
> ALREADY_STARTED is a right one for EFI-app driver.
> You must distinguish the two cases.
> That is why I said that efi_uc_supported() should have a stricter check.
> 
>> Reported-by: Etienne Carriere <etienne.carriere at linaro.org>
>> Fixes: b406eb04c360 ("efi_loader: disk: a helper function to delete efi_disk objects")
> 
> NAK.
> The bug, "erroneously create an extra "efi_blk" block device", has existed
> since you introduced efi_driver/efi_block_device.c.
> 
> Use 'Fixes: commit 05ef48a2484b ("efi_driver: EFI block driver")'.

Thanks for reviewing. I will take these changes when merging.

Best regards

Heinrich

> 
> -Takahiro Akashi
> 
>> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
>> Reviewed-by: Etienne Carriere <etienne.carriere at linaro.org>
>> Tested-by: Etienne Carriere <etienne.carriere at linaro.org>
>> Reviewed-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
>> ---
>> v2:
>> 	add a code comment
>> ---
>>   lib/efi_driver/efi_uclass.c | 9 +++++++++
>>   1 file changed, 9 insertions(+)
>>
>> diff --git a/lib/efi_driver/efi_uclass.c b/lib/efi_driver/efi_uclass.c
>> index b01ce89c84..1d7a0f57e3 100644
>> --- a/lib/efi_driver/efi_uclass.c
>> +++ b/lib/efi_driver/efi_uclass.c
>> @@ -71,6 +71,15 @@ static efi_status_t EFIAPI efi_uc_supported(
>>   	EFI_ENTRY("%p, %p, %ls", this, controller_handle,
>>   		  efi_dp_str(remaining_device_path));
>>   
>> +	/*
>> +	 * U-Boot internal devices install protocols interfaces without calling
>> +	 * ConnectController(). Hence we should not bind an extra driver.
>> +	 */
>> +	if (controller_handle->dev) {
>> +		ret = EFI_ALREADY_STARTED;
>> +		goto out;
>> +	}
>> +
>>   	ret = EFI_CALL(systab.boottime->open_protocol(
>>   			controller_handle, bp->ops->protocol,
>>   			&interface, this->driver_binding_handle,
>> -- 
>> 2.37.2
>>