Subject: Re: ibmvtpm byteswapping inconsistency

From: Jason Gunthorpe <[email-masked]>
Date: Thu, 26 Jan 2017 15:05:36 -0700

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