ibmvtpm byteswapping inconsistency

Ashley Lai ashleydlai at gmail.com
Fri Jan 27 09:58:15 AEDT 2017


Adding Vicky from IBM.


On 01/26/2017 04:05 PM, Jason Gunthorpe wrote:
> On Thu, Jan 26, 2017 at 09:22:48PM +0100, Michal Such??nek wrote:
>
>> This is repeated a few times in the driver so I added memset to quiet
>> gcc and make behavior deterministic in case the unused fields get some
>> meaning in the future.
> Yep, reserved certainly needs to be zeroed.. Can you send a patch?
> memset is overkill...
>
>> However, in tpm_ibmvtpm_send the structure is initialized as
>>
>> 	struct ibmvtpm_crq crq;
>>          __be64 *word = (__be64 *)&crq;
>> ...
>>          crq.valid = (u8)IBMVTPM_VALID_CMD;
>>          crq.msg = (u8)VTPM_TPM_COMMAND;
>>          crq.len = cpu_to_be16(count);
>>          crq.data = cpu_to_be32(ibmvtpm->rtce_dma_handle);
>>
>> and submitted with
>>
>> 	rc = ibmvtpm_send_crq(ibmvtpm->vdev, be64_to_cpu(word[0]),
>>                                be64_to_cpu(word[1]));
>> meaning it is swapped twice.
> No idea, Nayna may know.
>
> My guess is that '__be64 *word' should be 'u64 *word'...
>
> Jason



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