Re: [Part2 PATCH v5.1 12.4/31] crypto: ccp: Implement SEV_PLATFORM_STATUS ioctl command

[Brijesh Singh]

On 10/11/2017 03:45 PM, Brijesh Singh wrote:
> On 10/11/2017 03:28 PM, Borislav Petkov wrote:
> > On Wed, Oct 11, 2017 at 03:10:49PM -0500, Brijesh Singh wrote:
> > > The current 'struct sev_data_status' matches with the firmware names 
> > > and the
> > > bit fields. Only thing I did was the fields with no name is called as
> > > "reservedX"
> >
> > Ok, I see it. So what you actually wanna do is:
> >
> > struct sev_data_status {
> > ÂÂÂÂÂÂÂÂ u8 api_major;ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ /* Out */
> > ÂÂÂÂÂÂÂÂ u8 api_minor;ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ /* Out */
> > ÂÂÂÂÂÂÂÂ u8 state;ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ /* Out */
> > ÂÂÂÂÂÂÂÂ u8 flags;ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ /* Out */
> > ÂÂÂÂÂÂÂÂ u32 config;ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ /* Out */
> > ÂÂÂÂÂÂÂÂ u32 guest_count;ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ /* Out */
> > } __packed;
>
> OK, if userspace is going to pick bits apart then how about this:
>
>  Âstruct sev_data_status {
>  ÂÂÂÂÂÂÂÂ u8 api_major;ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ /* Out */
>  ÂÂÂÂÂÂÂÂ u8 api_minor;ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ /* Out */
>  ÂÂÂÂÂÂÂÂ u8 state;ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ /* Out */
>  ÂÂÂÂÂÂÂÂ u32 flags;ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ /* Out */
>  ÂÂÂÂÂÂÂÂ u8 build;ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ /* Out */
>  ÂÂÂÂÂÂÂÂ u32 guest_count;ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ /* Out */
>  Â} __packed;


BTW, I kept the build name because KVM driver prints some debug 
information like this:

pr_info_once("SEV: api_major %d api_minor %d build %d\n",
              status->api_major, status->api_minor, status->build);

Of course, I can modify it to access bit field if we decide to go with 
your recommended structure - thanks