This series is an RFC adding support for running protected VMs using KVM under the new Arm Confidential Compute Architecture (CCA). The purpose of this series is to gather feedback on the proposed changes to the architecture code for CCA. The user ABI is not in it's final form, we plan to make use of the memfd_restricted() allocator[1] and associated infrastructure which will avoid problems in the current user ABI where a malicious VMM may be able to cause a Granule Protection Fault in the kernel (which is fatal). The ABI to the RMM (the RMI) is based on the Beta 0 specification[2] and will be updated in the future when a final version of the specification is published. This series is based on v6.2-rc1. It is also available as a git repository: https://gitlab.arm.com/linux-arm/linux-cca cca-host/rfc-v1 Introduction ============ A more general introduction to Arm CCA is available on the Arm website[3], and links to the other components involved are available in the overall cover letter[4]. Arm Confidential Compute Architecture adds two new 'worlds' to the architecture: Root and Realm. A new software component known as the RMM (Realm Management Monitor) runs in Realm EL2 and is trusted by both the Normal World and VMs running within Realms. This enables mutual distrust between the Realm VMs and the Normal World. Virtual machines running within a Realm can decide on a (4k) page-by-page granularity whether to share a page with the (Normal World) host or to keep it private (protected). This protection is provided by the hardware and attempts to access a page which isn't shared by the Normal World will trigger a Granule Protection Fault. The series starts by adding handling for these; faults within user space can be handled by killing the process, faults within kernel space are considered fatal. The Normal World host can communicate with the RMM via an SMC interface known as RMI (Realm Management Interface), and Realm VMs can communicate with the RMM via another SMC interface known as RSI (Realm Services Interface). This series adds wrappers for the full set of RMI commands and uses them to manage the realm guests. The Normal World can use RMI commands to delegate pages to the Realm world and to create, manage and run Realm VMs. Once delegated the pages are inaccessible to the Normal World (unless explicitly shared by the guest). However the Normal World may destroy the Realm VM at any time to be able to reclaim (undelegate) the pages. Entry/exit of a Realm VM attempts to reuse the KVM infrastructure, but ultimately the final mechanism is different. So this series has a bunch of commits handling the differences. As much as possible is placed in a two new files: rme.c and rme-exit.c. The RMM specification provides a new mechanism for a guest to communicate with host which goes by the name "Host Call". For now this is simply hooked up to the existing support for HVC calls from a normal guest. [1] https://lore.kernel.org/r/20221202061347.1070246-1-chao.p.peng%40linux.intel.com [2] https://developer.arm.com/documentation/den0137/1-0bet0/ [3] https://www.arm.com/architecture/security-features/arm-confidential-compute-architecture [4] .. cover letter .. Joey Gouly (2): arm64: rme: allow userspace to inject aborts arm64: rme: support RSI_HOST_CALL Steven Price (25): arm64: RME: Handle Granule Protection Faults (GPFs) arm64: RME: Add SMC definitions for calling the RMM arm64: RME: Add wrappers for RMI calls arm64: RME: Check for RME support at KVM init arm64: RME: Define the user ABI arm64: RME: ioctls to create and configure realms arm64: kvm: Allow passing machine type in KVM creation arm64: RME: Keep a spare page delegated to the RMM arm64: RME: RTT handling arm64: RME: Allocate/free RECs to match vCPUs arm64: RME: Support for the VGIC in realms KVM: arm64: Support timers in realm RECs arm64: RME: Allow VMM to set RIPAS arm64: RME: Handle realm enter/exit KVM: arm64: Handle realm MMIO emulation arm64: RME: Allow populating initial contents arm64: RME: Runtime faulting of memory KVM: arm64: Handle realm VCPU load KVM: arm64: Validate register access for a Realm VM KVM: arm64: Handle Realm PSCI requests KVM: arm64: WARN on injected undef exceptions arm64: Don't expose stolen time for realm guests KVM: arm64: Allow activating realms arm64: RME: Always use 4k pages for realms HACK: Accept prototype RMI versions Suzuki K Poulose (1): arm64: rme: Allow checking SVE on VM instance Documentation/virt/kvm/api.rst | 3 + arch/arm64/include/asm/kvm_emulate.h | 29 + arch/arm64/include/asm/kvm_host.h | 7 + arch/arm64/include/asm/kvm_rme.h | 98 ++ arch/arm64/include/asm/rmi_cmds.h | 259 +++++ arch/arm64/include/asm/rmi_smc.h | 242 +++++ arch/arm64/include/asm/virt.h | 1 + arch/arm64/include/uapi/asm/kvm.h | 63 ++ arch/arm64/kvm/Kconfig | 8 + arch/arm64/kvm/Makefile | 3 +- arch/arm64/kvm/arch_timer.c | 53 +- arch/arm64/kvm/arm.c | 105 +- arch/arm64/kvm/guest.c | 50 + arch/arm64/kvm/inject_fault.c | 2 + arch/arm64/kvm/mmio.c | 7 + arch/arm64/kvm/mmu.c | 80 +- arch/arm64/kvm/psci.c | 23 + arch/arm64/kvm/reset.c | 41 + arch/arm64/kvm/rme-exit.c | 194 ++++ arch/arm64/kvm/rme.c | 1453 ++++++++++++++++++++++++++ arch/arm64/kvm/vgic/vgic-v3.c | 9 +- arch/arm64/kvm/vgic/vgic.c | 37 +- arch/arm64/mm/fault.c | 29 +- include/kvm/arm_arch_timer.h | 2 + include/uapi/linux/kvm.h | 21 +- 25 files changed, 2772 insertions(+), 47 deletions(-) create mode 100644 arch/arm64/include/asm/kvm_rme.h create mode 100644 arch/arm64/include/asm/rmi_cmds.h create mode 100644 arch/arm64/include/asm/rmi_smc.h create mode 100644 arch/arm64/kvm/rme-exit.c create mode 100644 arch/arm64/kvm/rme.c -- 2.34.1
