Check if the RMI support is sufficient for using in KVM. Specifically, we currently only support creating realm VMs when KVM is running in VHE mode. Signed-off-by: Steven Price --- Changes since v13: * Most of the init has been moved out of the 'kvm' directory so this is much more basic now. Changes since v12: * Drop check for 4k page size. Changes since v11: * Reword slightly the comments on the realm states. Changes since v10: * kvm_is_realm() no longer has a NULL check. * Rename from "rme" to "rmi" when referring to the RMM interface. * Check for RME (hardware) support before probing for RMI support. Changes since v8: * No need to guard kvm_init_rme() behind 'in_hyp_mode'. Changes since v6: * Improved message for an unsupported RMI ABI version. Changes since v5: * Reword "unsupported" message from "host supports" to "we want" to clarify that 'we' are the 'host'. Changes since v2: * Drop return value from kvm_init_rme(), it was always 0. * Rely on the RMM return value to identify whether the RSI ABI is compatible. --- arch/arm64/include/asm/kvm_host.h | 4 ++++ arch/arm64/include/asm/kvm_rmi.h | 17 +++++++++++++++++ arch/arm64/include/asm/virt.h | 1 + arch/arm64/kvm/Kconfig | 1 + arch/arm64/kvm/Makefile | 2 +- arch/arm64/kvm/arm.c | 5 +++++ arch/arm64/kvm/rmi.c | 24 ++++++++++++++++++++++++ 7 files changed, 53 insertions(+), 1 deletion(-) create mode 100644 arch/arm64/include/asm/kvm_rmi.h create mode 100644 arch/arm64/kvm/rmi.c diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index bae2c4f92ef5..1a5e15040111 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -27,6 +27,7 @@ #include #include #include +#include #include #define __KVM_HAVE_ARCH_INTC_INITIALIZED @@ -424,6 +425,9 @@ struct kvm_arch { /* Nested virtualization info */ struct dentry *debugfs_nv_dentry; #endif + + bool is_realm; + struct realm realm; }; struct kvm_vcpu_fault_info { diff --git a/arch/arm64/include/asm/kvm_rmi.h b/arch/arm64/include/asm/kvm_rmi.h new file mode 100644 index 000000000000..57d24b244c95 --- /dev/null +++ b/arch/arm64/include/asm/kvm_rmi.h @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2023-2026 ARM Ltd. + */ + +#ifndef __ASM_KVM_RMI_H +#define __ASM_KVM_RMI_H + +/** + * struct realm - Additional per VM data for a Realm + */ +struct realm { +}; + +void kvm_init_rmi(void); + +#endif /* __ASM_KVM_RMI_H */ diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h index b546703c3ab9..92cec42952f4 100644 --- a/arch/arm64/include/asm/virt.h +++ b/arch/arm64/include/asm/virt.h @@ -87,6 +87,7 @@ void __hyp_reset_vectors(void); bool is_kvm_arm_initialised(void); DECLARE_STATIC_KEY_FALSE(kvm_protected_mode_initialized); +DECLARE_STATIC_KEY_FALSE(kvm_rmi_is_available); static inline bool is_pkvm_initialized(void) { diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig index 449154f9a485..189e8ad78b22 100644 --- a/arch/arm64/kvm/Kconfig +++ b/arch/arm64/kvm/Kconfig @@ -37,6 +37,7 @@ menuconfig KVM select SCHED_INFO select GUEST_PERF_EVENTS if PERF_EVENTS select KVM_GUEST_MEMFD + select ARM_RMM help Support hosting virtualized guest machines. diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile index 59612d2f277c..ed3cf30eb06e 100644 --- a/arch/arm64/kvm/Makefile +++ b/arch/arm64/kvm/Makefile @@ -16,7 +16,7 @@ CFLAGS_handle_exit.o += -Wno-override-init kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \ inject_fault.o va_layout.o handle_exit.o config.o \ guest.o debug.o reset.o sys_regs.o stacktrace.o \ - vgic-sys-reg-v3.o fpsimd.o pkvm.o \ + vgic-sys-reg-v3.o fpsimd.o pkvm.o rmi.o \ arch_timer.o trng.o vmid.o emulate-nested.o nested.o at.o \ vgic/vgic.o vgic/vgic-init.o \ vgic/vgic-irqfd.o vgic/vgic-v2.o \ diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 50adfff75be8..b961c22fce3d 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -42,6 +42,7 @@ #include #include #include +#include #include #include @@ -111,6 +112,8 @@ long kvm_get_cap_for_kvm_ioctl(unsigned int ioctl, long *ext) return -EINVAL; } +DEFINE_STATIC_KEY_FALSE(kvm_rmi_is_available); + DECLARE_KVM_HYP_PER_CPU(unsigned long, kvm_hyp_vector); DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_base); @@ -3019,6 +3022,8 @@ static __init int kvm_arm_init(void) in_hyp_mode = is_kernel_in_hyp_mode(); + kvm_init_rmi(); + if (cpus_have_final_cap(ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE) || cpus_have_final_cap(ARM64_WORKAROUND_1508412)) kvm_info("Guests without required CPU erratum workarounds can deadlock system!\n" \ diff --git a/arch/arm64/kvm/rmi.c b/arch/arm64/kvm/rmi.c new file mode 100644 index 000000000000..384991d69f78 --- /dev/null +++ b/arch/arm64/kvm/rmi.c @@ -0,0 +1,24 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2023-2026 ARM Ltd. + */ + +#include + +#include +#include + +void kvm_init_rmi(void) +{ + /* + * TODO: Support Realm guests in nVHE mode, this will require adding + * EL2 stub(s) for REC entry and possibly other things. + */ + if (!is_kernel_in_hyp_mode()) + return; + + if (!is_rmi_available()) + return; + + /* Future patch will enable static branch kvm_rmi_is_available */ +} -- 2.43.0