Re: [PATCH v3 1/4] drivers/s390/char: Add Ultravisor io device

[Steffen Eiden]

Hi greg,

On 3/17/22 12:07, Steffen Eiden wrote:
> Hi greg,
>
> On 3/17/22 10:59, Greg KH wrote:
> > On Thu, Mar 17, 2022 at 09:47:06AM +0000, Steffen Eiden wrote:
> > > This patch adds a new miscdevice to expose some Ultravisor functions
> > > to userspace. Userspace can send IOCTLs to the uvdevice that will then
> > > emit a corresponding Ultravisor Call and hands the result over to
> > > userspace. The uvdevice is available if the Ultravisor Call facility is
> > > present.
> > > Userspace can call the Retrieve Attestation Measurement
> > > Ultravisor Call using IOCTLs on the uvdevice.
> > >
> > > The uvdevice will do some sanity checks first.
> > > Then, copy the request data to kernel space, build the UVCB,
> > > perform the UV call, and copy the result back to userspace.
> > >
> > > Signed-off-by: Steffen Eiden <seiden@xxxxxxxxxxxxx>
> > > Reviewed-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> >
> > Do you have a pointer to the userspace code that interacts with this
> > kernel driver?  That would be good to have to verify that the api here
> > is sane.
> There is a userspace tool currently under development, however, not yet 
> ready to be published.
> Currently, I can only point to the Kselftest in this series and the 
> kvm-unit-tests at 
> https://lore.kernel.org/linux-s390/20220203091935.2716-1-seiden@xxxxxxxxxxxxx/ 
I forgot to point out that the Attestation userspace tool will be 
open-source and included in the s390-tool package.
I can send you the current state of that tool in private if you want.

> > thanks,
> >
> > greg k-h
>
> steffen

steffen