Re: [PATCH 02/11] KVM: arm64: CCA: Introduce Realms
From: Steven Price
Date: Thu Nov 05 2026 - 10:22:42 EST
On 03/11/2026 11:34, Suzuki K Poulose wrote:
> Hi Steven
>
> On 02/11/2026 14:12, Steven Price wrote:
>> From: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
>>
>> Add foundational work for supporting Realms.
>> - Add a new VM flavor.
>> - At KVM init, check if the KVM can support Realms (though not
>> functional
>> yet) and will be advertised by static key kvm_rmi_is_available. This
>> will be turned on in a later patch, once we have all the bits and
>> pieces ready. For now check if we are blessed with KVM_MODE_RMM.
>> - Add realm specific tracking in kvm_arch. Since Realm and protected
>> pKVM
>> states are mutually exclusive, move them into a union.
>
> I think this patch could stop with the above items.
>
>> - Also adjust the memslot preparation checks to reflect the changes.
>>
>
> This and the VCPU features could be a separate patch or merged with the
> other patches.
Yes I think you're right - this patch has got too big. I'll split out
the kvm_init_rmi() parts to a separate patch.
>> Please note that we cannot create Realm VMs yet. This requires further
>> changes to the UABI and core RMI driver support, which will come later.
>>
>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
>> Signed-off-by: Steven Price <steven.price@xxxxxxx>
>> ---
>> arch/arm64/include/asm/kvm_emulate.h | 16 +++++++
>> arch/arm64/include/asm/kvm_host.h | 57 +++++++++++++++++-------
>> arch/arm64/include/asm/kvm_rmi.h | 61 ++++++++++++++++++++++++++
>> arch/arm64/include/asm/virt.h | 1 +
>> arch/arm64/kvm/Makefile | 2 +-
>> arch/arm64/kvm/arm.c | 24 ++++++++--
>> arch/arm64/kvm/hyp/include/nvhe/pkvm.h | 2 +-
>> arch/arm64/kvm/hyp/nvhe/switch.c | 4 +-
>> arch/arm64/kvm/hyp/nvhe/timer-sr.c | 2 +-
>> arch/arm64/kvm/mmu.c | 13 +++---
>> arch/arm64/kvm/rmi.c | 18 ++++++++
>> 11 files changed, 169 insertions(+), 31 deletions(-)
>> 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_emulate.h b/arch/arm64/
>> include/asm/kvm_emulate.h
>> index 334211b8b2ee..32021bdf2610 100644
>> --- a/arch/arm64/include/asm/kvm_emulate.h
>> +++ b/arch/arm64/include/asm/kvm_emulate.h
>> @@ -831,4 +831,20 @@ static inline void kvm_reset_vcpu_psci(struct
>> kvm_vcpu *vcpu,
>> vcpu_set_reg(vcpu, 0, reset_state->r0);
>> }
>> +static inline enum realm_state kvm_realm_state(struct kvm *kvm)
>> +{
>> + return READ_ONCE(kvm->arch.realm.state);
>> +}
>> +
>> +static inline void kvm_set_realm_state(struct kvm *kvm,
>> + enum realm_state new_state)
>> +{
>> + WRITE_ONCE(kvm->arch.realm.state, new_state);
>> +}
>> +
>> +static inline bool kvm_realm_is_created(struct kvm *kvm)
>> +{
>> + return kvm_vm_is_realm(kvm) && kvm_realm_state(kvm) !=
>> REALM_STATE_NONE;
>> +}
>> +
>
>
>> #endif /* __ARM64_KVM_EMULATE_H__ */
>> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/
>> asm/kvm_host.h
>> index ccd2dc8f73c3..7d0222047ca1 100644
>> --- a/arch/arm64/include/asm/kvm_host.h
>> +++ b/arch/arm64/include/asm/kvm_host.h
>> @@ -29,6 +29,7 @@
>> #include <asm/kvm.h>
>> #include <asm/kvm_asm.h>
>> #include <asm/kvm_hcall.h>
>> +#include <asm/kvm_rmi.h>
>> #include <asm/vncr_mapping.h>
>> #define __KVM_HAVE_ARCH_INTC_INITIALIZED
>> @@ -48,6 +49,13 @@
>> #define KVM_VCPU_MAX_FEATURES 10
>> #define KVM_VCPU_VALID_FEATURES (BIT(KVM_VCPU_MAX_FEATURES) - 1)
>>
>
>
>> +#define KVM_REALM_VCPU_VALID_FEATURES \
>> + (BIT(KVM_ARM_VCPU_POWER_OFF) | \
>> + BIT(KVM_ARM_VCPU_PSCI_0_2) | \
>> + BIT(KVM_ARM_VCPU_PTRAUTH_ADDRESS) | \
>> + BIT(KVM_ARM_VCPU_SVE) | \
>> + BIT(KVM_ARM_VCPU_PTRAUTH_GENERIC))
>> +
>
> Please could we move the ^^ to a separate patch ? See more below.
Indeed - they shouldn't really be here but should be in a later series.
>> #define KVM_REQ_SLEEP \
>> KVM_ARCH_REQ_FLAGS(0, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
>> #define KVM_REQ_IRQ_PENDING KVM_ARCH_REQ(1)
>> @@ -409,6 +417,7 @@ enum kvm_arm_vm_flavor {
>> VM_PKVM, /* Normal guests on pKVM */
>> MARKER(__VM_PROTECTED),
>> VM_PROTECTED_PKVM, /* Protected VM */
>> + VM_REALM, /* CCA */
>> VM_FLAVOR_MAX
>> };
>> @@ -502,11 +511,14 @@ struct kvm_arch {
>> /* Count the number of VNCR_EL2 TLBs */
>> atomic_t vncr_tlb_count;
>> - /*
>> - * For an untrusted host VM, 'pkvm.handle' is used to lookup
>> - * the associated pKVM instance in the hypervisor.
>> - */
>> - struct kvm_protected_vm pkvm;
>> + union {
>> + /*
>> + * For an untrusted host VM, 'pkvm.handle' is used to lookup
>> + * the associated pKVM instance in the hypervisor.
>> + */
>> + struct kvm_protected_vm pkvm;
>> + struct realm realm;
>> + };
>> #ifdef CONFIG_PTDUMP_STAGE2_DEBUGFS
>> /* Nested virtualization info */
>> @@ -1572,30 +1584,43 @@ struct kvm *kvm_arch_alloc_vm(void);
>> #define __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS_RANGE
>> -#ifdef __KVM_NVHE_HYPERVISOR__
>> +#define kvm_vm_is_protected(kvm) ((kvm)->arch.vm_flavor >=
>> __VM_PROTECTED)
>> -#define kvm_vm_is_protected(kvm) \
>> - (is_protected_kvm_enabled() && ((kvm)->arch.vm_flavor ==
>> VM_PROTECTED_PKVM))
>> +#ifdef __KVM_NVHE_HYPERVISOR__
>> /*
>> * Accessing vcpu->kvm from nVHE hyp stub is tricky, as we need to
>> convert the
>> * pointer to the hyp VA. With pKVM, the nVHE code runs with the
>> hyp_vcpu,
>> - * which is populated correctly and is gated on
>> is_protected_kvm_enabled().
>> + * which is populated correctly. Always vcpu_is_protected_pkvm(),
>> which is
>> + * gated on is_protected_kvm_enabled().
>> + */
>> +#define vcpu_is_protected(vcpu) BUILD_BUG_ON(1)
>> +#else
>> +#define vcpu_is_protected(vcpu) kvm_vm_is_protected((vcpu)->kvm)
>> +#endif
>> +
>> +#define kvm_vm_is_protected_pkvm(kvm) \
>> + (is_protected_kvm_enabled() && ((kvm)->arch.vm_flavor ==
>> VM_PROTECTED_PKVM))
>> +
>> +/*
>> + * Rely on is_protected_kvm_enabled() check in
>> kvm_vm_is_protected_pkvm() to
>> + * make sure the vcpu->kvm is always valid VA in the context
>> */
>> -#define vcpu_is_protected(vcpu) \
>> +#define vcpu_is_protected_pkvm(vcpu) \
>> ({ \
>> struct kvm *__kvm = READ_ONCE((vcpu)->kvm); \
>> \
>> - (__kvm && kvm_vm_is_protected(__kvm)); \
>> + (__kvm && kvm_vm_is_protected_pkvm(__kvm)); \
>> })
>> -#else
>> -
>> -#define kvm_vm_is_protected(kvm) ((kvm)->arch.vm_flavor >=
>> __VM_PROTECTED)
>> -#define vcpu_is_protected(vcpu) kvm_vm_is_protected((vcpu)->kvm)
>> +#define kvm_vm_is_realm(kvm) ((kvm)->arch.vm_flavor == VM_REALM)
>> +#define vcpu_is_rec(vcpu) kvm_vm_is_realm((vcpu)->kvm)
>> #define kvm_vm_hyp_is_distrusting(kvm) ((kvm)->arch.vm_flavor
>> >= __VM_DISTRUSTING_HYP)
>> -#endif /* __KVM_NVHE_HYPERVISOR__ */
>> +#define kvm_arch_has_private_mem(kvm) kvm_vm_is_realm(kvm)
>> +
>> +int kvm_arm_vcpu_finalize(struct kvm_vcpu *vcpu, int feature);
>> +bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu);
>> #define kvm_has_mte(kvm) \
>> (system_supports_mte() && \
>> diff --git a/arch/arm64/include/asm/kvm_rmi.h b/arch/arm64/include/
>> asm/kvm_rmi.h
>> new file mode 100644
>> index 000000000000..3194daaacf2b
>> --- /dev/null
>> +++ b/arch/arm64/include/asm/kvm_rmi.h
>> @@ -0,0 +1,61 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Copyright (C) 2023-2026 ARM Ltd.
>> + */
>> +
>> +#ifndef __ASM_KVM_RMI_H
>> +#define __ASM_KVM_RMI_H
>> +
>> +/**
>> + * enum realm_state - State of a Realm
>> + *
>> + * Mirrors the RMM's Realm lifecycle states where they are meaningful
>> to KVM,
>> + * with REALM_STATE_DYING being a KVM-internal state used to prevent
>> further
>> + * requests while teardown is in progress. KVM does not track
>> REALM_SYSTEM_OFF
>> + * or REALM_ZOMBIE separately as they naturally lead to teardown.
>> + */
>> +enum realm_state {
>> + /**
>> + * @REALM_STATE_NONE:
>> + * Realm has not yet been created. rmi_realm_create() has not
>> + * yet been called.
>> + */
>> + REALM_STATE_NONE,
>> + /**
>> + * @REALM_STATE_NEW:
>> + * Realm is under construction, Realm Descriptor has been
>> created,
>> + * but it is not yet activated. Memory may be populated.
>> + */
>> + REALM_STATE_NEW,
>> + /**
>> + * @REALM_STATE_ACTIVE:
>> + * Realm has been created and is eligible for execution with
>> + * rmi_rec_enter(). Memory may no longer be populated with
>> known
>> + * contents.
>> + */
>> + REALM_STATE_ACTIVE,
>> + /**
>> + * @REALM_STATE_DYING:
>> + * Realm is in the process of being destroyed or has already
>> been
>> + * destroyed.
>> + */
>> + REALM_STATE_DYING,
>> + /**
>> + * @REALM_STATE_DEAD:
>> + * Realm has been destroyed.
>> + */
>> + REALM_STATE_DEAD
>> +};
>> +
>> +/**
>> + * struct realm - Additional per VM data for a Realm
>> + *
>> + * @state: The lifetime state machine for the realm
>> + */
>> +struct realm {
>> + enum realm_state state;
>> +};
>> +
>> +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/Makefile b/arch/arm64/kvm/Makefile
>> index 7aaeeb84e788..66a719ab5b6b 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 157bf4b81202..c8599fed5902 100644
>> --- a/arch/arm64/kvm/arm.c
>> +++ b/arch/arm64/kvm/arm.c
>> @@ -42,6 +42,7 @@
>> #include <asm/kvm_nested.h>
>> #include <asm/kvm_pkvm.h>
>> #include <asm/kvm_ptrauth.h>
>> +#include <asm/kvm_rmi.h>
>> #include <asm/sections.h>
>> #include <asm/stacktrace/nvhe.h>
>> @@ -112,6 +113,8 @@ 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);
>> @@ -1732,10 +1735,19 @@ static unsigned long
>> system_supported_vcpu_features(struct kvm_vcpu *vcpu)
>> {
>> unsigned long features = KVM_VCPU_VALID_FEATURES;
>> - if (vcpu->kvm->arch.vm_flavor == VM_PROTECTED_PKVM)
>> + switch (vcpu->kvm->arch.vm_flavor) {
>> + case VM_PROTECTED_PKVM:
>> kvm_pkvm_vcpu_allowed_features(vcpu->kvm, &features);
>> + break;
>> + case VM_REALM:
>> + features = KVM_REALM_VCPU_VALID_FEATURES;
>> + break;
>> + default:
>> + break;
>> + }
>
> This could be a separate patch ?
Agreed
>> - if (!cpus_have_final_cap(ARM64_HAS_32BIT_EL1))
>> + if (vcpu_is_protected(vcpu) ||
>> + !cpus_have_final_cap(ARM64_HAS_32BIT_EL1))
>> clear_bit(KVM_ARM_VCPU_EL1_32BIT, &features);
>
> We start with the allowed features and 32_BIT_EL1 is already cleared for
> both protected VMs. So we don't need this change anymore.
Ack
>> if (!kvm_supports_guest_pmuv3()) {
>> @@ -1751,7 +1763,8 @@ static unsigned long
>> system_supported_vcpu_features(struct kvm_vcpu *vcpu)
>> clear_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, &features);
>> }
>> - if (!cpus_have_final_cap(ARM64_HAS_NESTED_VIRT))
>> + if (vcpu_is_protected(vcpu) ||
>> + !cpus_have_final_cap(ARM64_HAS_NESTED_VIRT))
>> clear_bit(KVM_ARM_VCPU_HAS_EL2, &features);
>>
>
> Same as above
>
>> return features;
>> @@ -1775,7 +1788,7 @@ static int kvm_vcpu_init_check_features(struct
>> kvm_vcpu *vcpu,
>> if (features & ~system_supported_vcpu_features(vcpu))
>> return -EINVAL;
>> - /* EL2 implements PSCI 1.1; the host must not dispatch as 0.1. */
>> + /* Both pKVM and RMM implements PSCI 1.1; the host must not
>> dispatch as 0.1. */
>> if (vcpu_is_protected(vcpu) &&
>> !test_bit(KVM_ARM_VCPU_PSCI_0_2, &features))
>
> This too can be a separate patch, where we handle VCPU for Realms
>
>> return -EINVAL;
>> @@ -2312,6 +2325,7 @@ static const struct kvm_vcpu_ops
>> *arm64_vcpu_ops[] = {
>> KVM_VCPU_OPS(VM_VHE, vhe_vcpu_ops),
>> KVM_VCPU_OPS(VM_PKVM, pkvm_vcpu_ops),
>> KVM_VCPU_OPS(VM_PROTECTED_PKVM, pkvm_vcpu_ops),
>> + [VM_REALM] = NULL,
>> };
>> static void kvm_init_vcpu_ops(struct kvm_vcpu *vcpu)
>> @@ -3269,6 +3283,8 @@ 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/hyp/include/nvhe/pkvm.h b/arch/arm64/kvm/
>> hyp/include/nvhe/pkvm.h
>> index 0261b2bc681f..ae6ced6d7b9e 100644
>> --- a/arch/arm64/kvm/hyp/include/nvhe/pkvm.h
>> +++ b/arch/arm64/kvm/hyp/include/nvhe/pkvm.h
>> @@ -84,7 +84,7 @@ pkvm_hyp_vcpu_to_hyp_vm(struct pkvm_hyp_vcpu *hyp_vcpu)
>> static inline bool pkvm_hyp_vcpu_is_protected(struct pkvm_hyp_vcpu
>> *hyp_vcpu)
>> {
>> - return vcpu_is_protected(&hyp_vcpu->vcpu);
>> + return vcpu_is_protected_pkvm(&hyp_vcpu->vcpu);
>> }
>> static inline bool pkvm_hyp_vm_is_protected(struct pkvm_hyp_vm
>> *hyp_vm)
>> diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/
>> nvhe/switch.c
>> index 89fb9dd351ad..6c03f48e6be3 100644
>> --- a/arch/arm64/kvm/hyp/nvhe/switch.c
>> +++ b/arch/arm64/kvm/hyp/nvhe/switch.c
>> @@ -238,7 +238,7 @@ static const exit_handler_fn pvm_exit_handlers[] = {
>> static const exit_handler_fn *kvm_get_exit_handler_array(struct
>> kvm_vcpu *vcpu)
>> {
>> - if (unlikely(vcpu_is_protected(vcpu)))
>> + if (unlikely(vcpu_is_protected_pkvm(vcpu)))
>> return pvm_exit_handlers;
>> return hyp_exit_handlers;
>> @@ -259,7 +259,7 @@ static inline bool fixup_guest_exit(struct
>> kvm_vcpu *vcpu, u64 *exit_code)
>> * it. The check below is based on the one in
>> * kvm_arch_vcpu_ioctl_run().
>> */
>> - if (unlikely(vcpu_is_protected(vcpu) && vcpu_mode_is_32bit(vcpu))) {
>> + if (unlikely(vcpu_is_protected_pkvm(vcpu) &&
>> vcpu_mode_is_32bit(vcpu))) {
>> /*
>> * As we have caught the guest red-handed, decide that it isn't
>> * fit for purpose anymore by making the vcpu invalid. The VMM
>> diff --git a/arch/arm64/kvm/hyp/nvhe/timer-sr.c b/arch/arm64/kvm/hyp/
>> nvhe/timer-sr.c
>> index 993065716913..17bd1ff621ab 100644
>> --- a/arch/arm64/kvm/hyp/nvhe/timer-sr.c
>> +++ b/arch/arm64/kvm/hyp/nvhe/timer-sr.c
>> @@ -48,7 +48,7 @@ void __timer_enable_traps(struct kvm_vcpu *vcpu)
>> * or running a protected VM (we don't offset anything in this
>> case).
>> */
>> clr = CNTHCTL_EL1PCEN;
>> - if (vcpu_is_protected(vcpu) ||
>> + if (vcpu_is_protected_pkvm(vcpu) ||
>> !timer_get_offset(vcpu_ptimer(vcpu)))
>> set |= CNTHCTL_EL1PCTEN;
>> else
>> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
>> index 1db10d8d6db7..34ddcb2f094a 100644
>> --- a/arch/arm64/kvm/mmu.c
>> +++ b/arch/arm64/kvm/mmu.c
>> @@ -2814,17 +2814,17 @@ int kvm_arch_prepare_memory_region(struct kvm
>> *kvm,
>> hva_t hva, reg_end;
>> int ret = 0;
>> - if (kvm_vm_is_protected(kvm)) {
>> + if (kvm_vm_is_protected(kvm) && new &&
>> + (new->flags & (KVM_MEM_LOG_DIRTY_PAGES | KVM_MEM_READONLY)))
>> + return -EPERM;
>> +
>> + if (kvm->arch.vm_flavor == VM_PROTECTED_PKVM) {
>> /* Cannot modify memslots once a pVM has run. */
>> if (pkvm_hyp_vm_is_created(kvm) &&
>> (change == KVM_MR_DELETE || change == KVM_MR_MOVE)) {
>> return -EPERM;
>> }
>> - if (new &&
>> - new->flags & (KVM_MEM_LOG_DIRTY_PAGES | KVM_MEM_READONLY)) {
>> - return -EPERM;
>> - }
>> }
>
> May be the above could be a preparatory patch or add the changes common
> for Realm and pVM when we come to do the memslot for Realms ?
Ack
>> if (change != KVM_MR_CREATE && change != KVM_MR_MOVE &&
>> @@ -3158,13 +3158,14 @@ static const struct kvm_vm_s2_ops
>> kvm_default_vm_s2_ops = {
>> };
>> #define KVM_VM_S2_OPS(flavor, ops) \
>> - [(flavor)] = &(ops)
>> + [flavor] = &(ops)
>
> Spurious, unwanted change. Please drop this ^^
Sorry about that - I actually spotted it before posting, then put the
wrong branch into "git format-patch" and didn't notice :( It is correct
in the git tree.
Thanks,
Steve
>> static const struct kvm_vm_s2_ops *arm64_vm_s2_ops[] = {
>> KVM_VM_S2_OPS(VM_VHE, kvm_default_vm_s2_ops),
>> KVM_VM_S2_OPS(VM_NVHE, kvm_default_vm_s2_ops),
>> KVM_VM_S2_OPS(VM_PKVM, pkvm_vm_s2_ops),
>> KVM_VM_S2_OPS(VM_PROTECTED_PKVM, protected_pkvm_vm_s2_ops),
>> + [VM_REALM] = NULL,
>> };
>> static int kvm_vm_init_vm_s2_ops(struct kvm *kvm)
>> diff --git a/arch/arm64/kvm/rmi.c b/arch/arm64/kvm/rmi.c
>> new file mode 100644
>> index 000000000000..5ecc8b349869
>> --- /dev/null
>> +++ b/arch/arm64/kvm/rmi.c
>> @@ -0,0 +1,18 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (C) 2023-2026 ARM Ltd.
>> + */
>> +
>> +#include <linux/kvm_host.h>
>> +
>> +#include <asm/virt.h>
>> +
>> +void kvm_init_rmi(void)
>> +{
>> + if (kvm_get_mode() != KVM_MODE_RMM)
>> + return;
>
> Even this could be delayed to the end ? and this can be an empty stub
> for now.
>> +
>> + /* TODO: Check if the RMI is available */
>> +
>> + /* Future patch will enable static branch kvm_rmi_is_available */
>
> Suzuki
>