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

From: Marc Zyngier
Date: Mon Jan 29 2018 - 12:46:18 EST


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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