[PATCH v2 00/16] arm64: Add SMCCC v1.1 support and CVE-2017-5715 (Spectre variant 2) mitigation

[Marc Zyngier]

ARM has recently published a SMC Calling Convention (SMCCC)
specification update[1] that provides an optimised calling convention
and optional, discoverable support for mitigating CVE-2017-5715. ARM
Trusted Firmware (ATF) has already gained such an implementation[2].

This series addresses a few things:

- It provides a KVM implementation of PSCI v1.0, which is a
  prerequisite for being able to discover SMCCC v1.1, together with a
  new userspace API to control the PSCI revision number that the guest
  sees.

- It allows KVM to advertise SMCCC v1.1, which is de-facto supported
  already (it never corrupts any of the guest registers).

- It implements KVM support for the ARCH_WORKAROUND_1 function that is
  used to mitigate CVE-2017-5715 in a guest (if such mitigation is
  available on the host).

- It implements SMCCC v1.1 and ARCH_WORKAROUND_1 discovery support in
  the kernel itself.

- It finally provides firmware callbacks for CVE-2017-5715 for both
  kernel and KVM.

This method is intended to fully replace the initial PSCI_GET_VERSION
approach. Although PSCI_GET_VERSION still works, it has an obvious
overhead and is called on some of the hottest paths. We expect
ARCH_WORKAROUND_1 to be much faster.

Patch 1 is already merged, and included here for reference. Patches on
top of arm64/for-next/core. Tested on Seattle and Juno, the latter
with ATF implementing SMCCC v1.1.

[1]: https://developer.arm.com/-/media/developer/pdf/ARM%20DEN%200070A%20Firmware%20interfaces%20for%20mitigating%20CVE-2017-5715_V1.0.pdf

Hopefully this link is a persistent one. It is otherwise linked to
from [3], which is persistent.

[2]: https://github.com/ARM-software/arm-trusted-firmware/pull/1240

[3]: https://developer.arm.com/support/security-update/frequently-asked-questions

* From v1:
  - Fixed 32bit build
  - Fix function number sign extension (Ard)
  - Inline SMCCC v1.1 primitives (cpp soup)
  - Prevent SMCCC spamming on feature probing
  - Random fixes and tidying up

Marc Zyngier (16):
  arm64: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls
  arm: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls
  arm/arm64: KVM: Consolidate the PSCI include files
  arm/arm64: KVM: Add PSCI_VERSION helper
  arm/arm64: KVM: Add smccc accessors to PSCI code
  arm/arm64: KVM: Implement PSCI 1.0 support
  arm/arm64: KVM: Add PSCI version selection API
  arm/arm64: KVM: Advertise SMCCC v1.1
  arm/arm64: KVM: Turn kvm_psci_version into a static inline
  arm64: KVM: Report SMCCC_ARCH_WORKAROUND_1 BP hardening support
  arm64: KVM: Add SMCCC_ARCH_WORKAROUND_1 fast handling
  firmware/psci: Expose PSCI conduit
  firmware/psci: Expose SMCCC version through psci_ops
  arm/arm64: smccc: Make function identifiers an unsigned quantity
  arm/arm64: smccc: Implement SMCCC v1.1 inline primitive
  arm64: Add ARM_SMCCC_ARCH_WORKAROUND_1 BP hardening support

 Documentation/virtual/kvm/api.txt      |   3 +-
 Documentation/virtual/kvm/arm/psci.txt |  30 +++++
 arch/arm/include/asm/kvm_host.h        |   3 +
 arch/arm/include/asm/kvm_psci.h        |  27 -----
 arch/arm/include/uapi/asm/kvm.h        |   6 +
 arch/arm/kvm/guest.c                   |  13 +++
 arch/arm/kvm/handle_exit.c             |   8 +-
 arch/arm64/include/asm/kvm_host.h      |   3 +
 arch/arm64/include/asm/kvm_psci.h      |  44 ++++++-
 arch/arm64/include/uapi/asm/kvm.h      |   6 +
 arch/arm64/kernel/bpi.S                |  20 ++++
 arch/arm64/kernel/cpu_errata.c         |  68 ++++++++++-
 arch/arm64/kvm/guest.c                 |  14 ++-
 arch/arm64/kvm/handle_exit.c           |   9 +-
 arch/arm64/kvm/hyp/hyp-entry.S         |  20 +++-
 arch/arm64/kvm/hyp/switch.c            |  20 ++--
 drivers/firmware/psci.c                |  49 +++++++-
 include/kvm/arm_psci.h                 |  63 ++++++++++
 include/linux/arm-smccc.h              | 181 ++++++++++++++++++++++++++++-
 include/linux/psci.h                   |  13 +++
 virt/kvm/arm/arm.c                     |   2 +-
 virt/kvm/arm/psci.c                    | 202 +++++++++++++++++++++++++++++----
 22 files changed, 721 insertions(+), 83 deletions(-)
 create mode 100644 Documentation/virtual/kvm/arm/psci.txt
 delete mode 100644 arch/arm/include/asm/kvm_psci.h
 create mode 100644 include/kvm/arm_psci.h

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2.14.2