[PATCH v6 0/5] ARM: arm64: Add SMCCC TRNG entropy service

Andre Przywara
2021-01-06T10:36:03Z

Hi,

a fix to v5, now *really* fixing the wrong priority of SMCCC vs. RNDR
in arch_get_random_seed_long_early(). Apologies for messing this up
in v5 and thanks to broonie for being on the watch!

Will, Catalin: it would be much appreciated if you could consider taking
patch 1/5. This contains the common definitions, and is a prerequisite
for every other patch, although they are somewhat independent and likely
will need to go through different subsystems.

Cheers,
Andre
==============================

The ARM architected TRNG firmware interface, described in ARM spec
DEN0098[1], defines an ARM SMCCC based interface to a true random number
generator, provided by firmware.

This series collects all the patches implementing this in various
places: as a user feeding into the ARCH_RANDOM pool, both for ARM and
arm64, and as a service provider for KVM guests.

Patch 1 introduces the interface definition used by all three entities.
Patch 2 prepares the Arm SMCCC firmware driver to probe for the
interface. This patch is needed to avoid a later dependency on *two*
patches (there might be a better solution to this problem).

Patch 3 implements the ARM part, patch 4 is the arm64 version.
The final patch 5 adds support to provide random numbers to KVM guests.

This was tested on:
- QEMU -kernel (no SMCCC, regression test)
- Juno w/ prototype of the h/w Trusted RNG support
- mainline KVM (SMCCC, but no TRNG: regression test)
- ARM and arm64 KVM guests, using the KVM service in patch 5/5

Based on v5.11-rc2, please let me know if I should rebase it on
something else. A git repo is accessible at:
https://gitlab.arm.com/linux-arm/linux-ap/-/commits/smccc-trng/v6/

Cheers,
Andre

[1] https://developer.arm.com/documentation/den0098/latest/

Changelog v5 ... v6:
- *really* fixing order of SMCCC vs. RNDR call in the *_early() version

Changelog v4 ... v5:
- change order of SMCCC call vs. RNDR call in arch_get_random_seed_long_early
- adding Sudeep's R-b: tags

Changelog v3 ... v4:
- include cache.h to always have __ro_after_init defined
- change order of SMCCC call vs. RNDR call in arm64's archrandom.h
- adding LinusW's R-b: tags

Changelog v2 ... v3:
- ARM: fix compilation with randconfig
- arm64: use SMCCC call also in arch_get_random_seed_long_early()
- KVM: comment on return value usage
- KVM: use more interesting UUID (enjoy, Marc!)
- KVM: use bitmaps instead of open coded long arrays
- KVM: drop direct usage of arch_get_random() interface

Changelog "v1" ... v2:
- trigger ARCH_RANDOM initialisation from the SMCCC firmware driver
- use a single bool in smccc.c to hold the initialisation state for arm64
- handle endianess correctly in the KVM provider

Andre Przywara (2):
firmware: smccc: Introduce SMCCC TRNG framework
arm64: Add support for SMCCC TRNG entropy source

Ard Biesheuvel (3):
firmware: smccc: Add SMCCC TRNG function call IDs
ARM: implement support for SMCCC TRNG entropy source
KVM: arm64: implement the TRNG hypervisor call

arch/arm/Kconfig | 4 ++
arch/arm/include/asm/archrandom.h | 74 +++++++++++++++++++++++++
arch/arm64/include/asm/archrandom.h | 82 ++++++++++++++++++++++++----
arch/arm64/include/asm/kvm_host.h | 2 +
arch/arm64/kvm/Makefile | 2 +-
arch/arm64/kvm/hypercalls.c | 6 ++
arch/arm64/kvm/trng.c | 85 +++++++++++++++++++++++++++++
drivers/firmware/smccc/smccc.c | 6 ++
include/linux/arm-smccc.h | 31 +++++++++++
9 files changed, 281 insertions(+), 11 deletions(-)
create mode 100644 arch/arm/include/asm/archrandom.h
create mode 100644 arch/arm64/kvm/trng.c

--
2.17.1

*** BLURB HERE ***

Andre Przywara (2):
firmware: smccc: Introduce SMCCC TRNG framework
arm64: Add support for SMCCC TRNG entropy source

Ard Biesheuvel (3):
firmware: smccc: Add SMCCC TRNG function call IDs
ARM: implement support for SMCCC TRNG entropy source
KVM: arm64: implement the TRNG hypervisor call

arch/arm/Kconfig | 4 ++
arch/arm/include/asm/archrandom.h | 74 +++++++++++++++++++++++++
arch/arm64/include/asm/archrandom.h | 82 ++++++++++++++++++++++++----
arch/arm64/include/asm/kvm_host.h | 2 +
arch/arm64/kvm/Makefile | 2 +-
arch/arm64/kvm/hypercalls.c | 6 ++
arch/arm64/kvm/trng.c | 85 +++++++++++++++++++++++++++++
drivers/firmware/smccc/smccc.c | 6 ++
include/linux/arm-smccc.h | 31 +++++++++++
9 files changed, 281 insertions(+), 11 deletions(-)
create mode 100644 arch/arm/include/asm/archrandom.h
create mode 100644 arch/arm64/kvm/trng.c

--
2.17.1