Re: [PATCH V5] MdeModulePkg/DxeCore: Fixed Interface returned by CoreOpenProtocol

["Gabriel L. Somlo" <gsomlo@gmail.com>]

On Wed, Jun 28, 2017 at 09:22:50PM +0800, Star Zeng wrote:
> From: Amit Kumar <amit.ak@samsung.com>
> 
> Change since v4: Revise the patch based on V4 sent by Amit Kumar
> 1) Only return the corresponding protocol interface in *Interface
> if the return status is EFI_SUCCESS or EFI_ALREADY_STARTED.
> 2) Interface is returned unmodified for all error conditions except
> EFI_UNSUPPORTED and EFI_ALREADY_STARTED, NULL will be returned in
> *Interface when EFI_UNSUPPORTED and Attributes is not
> EFI_OPEN_PROTOCOL_TEST_PROTOCOL, the protocol interface will be
> returned in *Interface when EFI_ALREADY_STARTED.

Tested-by: Gabriel Somlo <gsomlo@gmail.com>

With this patch applied, OVMF works fine for me now.

Thanks much,
--Gabriel

> Change since v3:
> 1) Fixed issue when Attributes = EFI_OPEN_PROTOCOL_TEST_PROTOCOL
> and Inteface = NULL case. [Reported by:star.zeng at intel.com]
> 
> Change Since v2:
> 1) Modified to use EFI_ERROR to get status code
> 
> Change since v1:
> 1) Fixed typo protocal to protocol
> 2) Fixed coding style
> 
> Cc: Laszlo Ersek <lersek@redhat.com>
> Cc: Amit Kumar <amit.ak@samsung.com>
> Cc: Michael D Kinney <michael.d.kinney@intel.com>
> Cc: Liming Gao <liming.gao@intel.com>
> Cc: Gabriel Somlo <gsomlo@gmail.com>
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Amit Kumar <amit.ak@samsung.com>
> Signed-off-by: Star Zeng <star.zeng@intel.com>
> ---
>  MdeModulePkg/Core/Dxe/Hand/Handle.c | 36 +++++++++++++++++++++++-------------
>  1 file changed, 23 insertions(+), 13 deletions(-)
> 
> diff --git a/MdeModulePkg/Core/Dxe/Hand/Handle.c b/MdeModulePkg/Core/Dxe/Hand/Handle.c
> index 59b89148c8f0..3862a3876f4a 100644
> --- a/MdeModulePkg/Core/Dxe/Hand/Handle.c
> +++ b/MdeModulePkg/Core/Dxe/Hand/Handle.c
> @@ -1006,12 +1006,8 @@ CoreOpenProtocol (
>    //
>    // Check for invalid Interface
>    //
> -  if (Attributes != EFI_OPEN_PROTOCOL_TEST_PROTOCOL) {
> -    if (Interface == NULL) {
> -      return EFI_INVALID_PARAMETER;
> -    } else {
> -      *Interface = NULL;
> -    }
> +  if ((Attributes != EFI_OPEN_PROTOCOL_TEST_PROTOCOL) && (Interface == NULL)) {
> +    return EFI_INVALID_PARAMETER;
>    }
>  
>    //
> @@ -1078,12 +1074,6 @@ CoreOpenProtocol (
>      goto Done;
>    }
>  
> -  //
> -  // This is the protocol interface entry for this protocol
> -  //
> -  if (Attributes != EFI_OPEN_PROTOCOL_TEST_PROTOCOL) {
> -    *Interface = Prot->Interface;
> -  }
>    Status = EFI_SUCCESS;
>  
>    ByDriver        = FALSE;
> @@ -1177,8 +1167,28 @@ CoreOpenProtocol (
>    }
>  
>  Done:
> +
> +  if (Attributes != EFI_OPEN_PROTOCOL_TEST_PROTOCOL) {
> +    //
> +    // Keep Interface unmodified in case of any Error
> +    // except EFI_ALREADY_STARTED and EFI_UNSUPPORTED.
> +    //
> +    if (!EFI_ERROR (Status) || Status == EFI_ALREADY_STARTED) {
> +      //
> +      // EFI_ALREADY_STARTED is not an error for bus driver.
> +      // Return the corresponding protocol interface. 
> +      //
> +      *Interface = Prot->Interface;
> +    } else if (Status == EFI_UNSUPPORTED) {
> +      //
> +      // Return NULL Interface if Unsupported Protocol.
> +      //
> +      *Interface = NULL;
> +    }
> +  }
> +
>    //
> -  // Done. Release the database lock are return
> +  // Done. Release the database lock and return
>    //
>    CoreReleaseProtocolLock ();
>    return Status;
> -- 
> 2.7.0.windows.1
>