[v3,0/4] s390: Ultravisor device

Message

Steffen Eiden March 4, 2022, 2:11 p.m. UTC

This series adds an Ultravisor(UV) device letting the userspace send some
Ultravisor calls to the UV. Currently two calls are supported.
Query Ultravisor Information (QUI) and
Receive Attestation Measurement (Attest[ation]).

The UV device is implemented as a miscdevice accepting only IOCTLs.
The IOCTL cmd specifies the UV call and the IOCTL arg the request
and response data depending on the UV call.
The device driver writes the UV response in the ioctl argument data.

The 'uvdevice' does no checks on the request beside faulty userspace
addresses, if sizes are in a sane range before allocating in kernel space,
and other tests that prevent the system from corruption.
Especially, no checks are made, that will be performed by the UV anyway
(E.g. 'invalid command' in case of attestation on unsupported hardware).
These errors are reported back to Userspace using the UV return code
field.

The first two patches introduce the new device as a module configured to be
compiled directly into the kernel (y) similar to the s390 SCLP and CHSH
miscdevice modules. Patch 3&4 introduce Kselftests which verify error
paths of the ioctl.

v2->v3:
   The main change is that QUI is now introduced after Attestation as we
   might not want pick it. Also the Kselftest patch is splitted into
   Attestation and QUI so that they can be picked without requiring
   QUI support of the uvdevice.

  * dropped the Kconfig dependency
  * reorganized the series:
    - Patch 1 now covers the introduction of the uvdevice and Attestation
    - Patch 2 adds QUI to uvdevice
    - Patch 3/4 add Kselftests for Attestation and QUI
  * fixed some nits
  * added some comments

v1->v2:
  * ioctl returns -ENOIOCTLCMD in case of a invalid ioctl command
  * streamlined reserved field test
  * default Kconfig is y instead of m
  * improved selftest documentation

Steffen Eiden (4):
  drivers/s390/char: Add Ultravisor io device
  drivers/s390/char: Add Query Ultravisor Information to uvdevice
  selftests: drivers/s390x: Add uvdevice tests
  selftests: drivers/s390x: Add uvdevice  QUI tests

 MAINTAINERS                                   |   3 +
 arch/s390/include/asm/uv.h                    |  23 +-
 arch/s390/include/uapi/asm/uvdevice.h         |  53 +++
 drivers/s390/char/Kconfig                     |  10 +
 drivers/s390/char/Makefile                    |   1 +
 drivers/s390/char/uvdevice.c                  | 320 ++++++++++++++++++
 tools/testing/selftests/Makefile              |   1 +
 tools/testing/selftests/drivers/.gitignore    |   1 +
 .../selftests/drivers/s390x/uvdevice/Makefile |  22 ++
 .../selftests/drivers/s390x/uvdevice/config   |   1 +
 .../drivers/s390x/uvdevice/test_uvdevice.c    | 281 +++++++++++++++
 11 files changed, 715 insertions(+), 1 deletion(-)
 create mode 100644 arch/s390/include/uapi/asm/uvdevice.h
 create mode 100644 drivers/s390/char/uvdevice.c
 create mode 100644 tools/testing/selftests/drivers/s390x/uvdevice/Makefile
 create mode 100644 tools/testing/selftests/drivers/s390x/uvdevice/config
 create mode 100644 tools/testing/selftests/drivers/s390x/uvdevice/test_uvdevice.c

Comments

Janosch Frank March 16, 2022, 9:04 a.m. UTC | #1

On 3/4/22 15:11, Steffen Eiden wrote:
> This series adds an Ultravisor(UV) device letting the userspace send some
> Ultravisor calls to the UV. Currently two calls are supported.
> Query Ultravisor Information (QUI) and
> Receive Attestation Measurement (Attest[ation]).
> 
> The UV device is implemented as a miscdevice accepting only IOCTLs.
> The IOCTL cmd specifies the UV call and the IOCTL arg the request
> and response data depending on the UV call.
> The device driver writes the UV response in the ioctl argument data.
> 
> The 'uvdevice' does no checks on the request beside faulty userspace
> addresses, if sizes are in a sane range before allocating in kernel space,
> and other tests that prevent the system from corruption.
> Especially, no checks are made, that will be performed by the UV anyway
> (E.g. 'invalid command' in case of attestation on unsupported hardware).
> These errors are reported back to Userspace using the UV return code
> field.
> 
> The first two patches introduce the new device as a module configured to be
> compiled directly into the kernel (y) similar to the s390 SCLP and CHSH
> miscdevice modules. Patch 3&4 introduce Kselftests which verify error
> paths of the ioctl.

Please fixup the commit message in the first patch and then push patches 
#1 and #3 to devel so we get CI coverage.

For now I'd opt to not include the qui patches but please put them on a 
branch. They might prove to be useful at a later time.

> 
> v2->v3:
>     The main change is that QUI is now introduced after Attestation as we
>     might not want pick it. Also the Kselftest patch is splitted into
>     Attestation and QUI so that they can be picked without requiring
>     QUI support of the uvdevice.
> 
>    * dropped the Kconfig dependency
>    * reorganized the series:
>      - Patch 1 now covers the introduction of the uvdevice and Attestation
>      - Patch 2 adds QUI to uvdevice
>      - Patch 3/4 add Kselftests for Attestation and QUI
>    * fixed some nits
>    * added some comments
> 
> v1->v2:
>    * ioctl returns -ENOIOCTLCMD in case of a invalid ioctl command
>    * streamlined reserved field test
>    * default Kconfig is y instead of m
>    * improved selftest documentation
> 
> Steffen Eiden (4):
>    drivers/s390/char: Add Ultravisor io device
>    drivers/s390/char: Add Query Ultravisor Information to uvdevice
>    selftests: drivers/s390x: Add uvdevice tests
>    selftests: drivers/s390x: Add uvdevice  QUI tests
> 
>   MAINTAINERS                                   |   3 +
>   arch/s390/include/asm/uv.h                    |  23 +-
>   arch/s390/include/uapi/asm/uvdevice.h         |  53 +++
>   drivers/s390/char/Kconfig                     |  10 +
>   drivers/s390/char/Makefile                    |   1 +
>   drivers/s390/char/uvdevice.c                  | 320 ++++++++++++++++++
>   tools/testing/selftests/Makefile              |   1 +
>   tools/testing/selftests/drivers/.gitignore    |   1 +
>   .../selftests/drivers/s390x/uvdevice/Makefile |  22 ++
>   .../selftests/drivers/s390x/uvdevice/config   |   1 +
>   .../drivers/s390x/uvdevice/test_uvdevice.c    | 281 +++++++++++++++
>   11 files changed, 715 insertions(+), 1 deletion(-)
>   create mode 100644 arch/s390/include/uapi/asm/uvdevice.h
>   create mode 100644 drivers/s390/char/uvdevice.c
>   create mode 100644 tools/testing/selftests/drivers/s390x/uvdevice/Makefile
>   create mode 100644 tools/testing/selftests/drivers/s390x/uvdevice/config
>   create mode 100644 tools/testing/selftests/drivers/s390x/uvdevice/test_uvdevice.c
>