Re: ibmvtpm byteswapping inconsistency

From: Ashley Lai
Date: Thu Jan 26 2017 - 17:58:32 EST

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); = cpu_to_be32(ibmvtpm->rtce_dma_handle);

and submitted with

rc = ibmvtpm_send_crq(ibmvtpm->vdev, be64_to_cpu(word[0]),
meaning it is swapped twice.
No idea, Nayna may know.

My guess is that '__be64 *word' should be 'u64 *word'...