[PATCH v13 18/48] arm64: RMI: Support for the VGIC in realms

Steven Price
2026-03-18T15:55:32Z

The RMM provides emulation of a VGIC to the realm guest. With RMM v2.0
the registers are passed in the system registers so this works similar
to a normal guest, but kvm_arch_vcpu_put() need reordering to early out,
and realm guests don't support GICv2 even if the host does.

Signed-off-by: Steven Price <steven.price@arm.com>
---
Changes from v12:
* GIC registers are now passed in the system registers rather than via
rec_entry/rec_exit which removes most of the changes.
Changes from v11:
* Minor changes to align with the previous patches. Note that the VGIC
handling will change with RMM v2.0.
Changes from v10:
* Make sure we sync the VGIC v4 state, and only populate valid lrs from
the list.
Changes from v9:
* Copy gicv3_vmcr from the RMM at the same time as gicv3_hcr rather
than having to handle that as a special case.
Changes from v8:
* Propagate gicv3_hcr to from the RMM.
Changes from v5:
* Handle RMM providing fewer GIC LRs than the hardware supports.
---
arch/arm64/kvm/arm.c | 11 ++++++++---
arch/arm64/kvm/vgic/vgic-init.c | 2 +-
2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 8c50ebd9fba0..45eff4c41cde 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -770,19 +770,24 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
kvm_call_hyp_nvhe(__pkvm_vcpu_put);
}

+ kvm_timer_vcpu_put(vcpu);
+ kvm_vgic_put(vcpu);
+
+ vcpu->cpu = -1;
+
+ if (vcpu_is_rec(vcpu))
+ return;
+
kvm_vcpu_put_debug(vcpu);
kvm_arch_vcpu_put_fp(vcpu);
if (has_vhe())
kvm_vcpu_put_vhe(vcpu);
- kvm_timer_vcpu_put(vcpu);
- kvm_vgic_put(vcpu);
kvm_vcpu_pmu_restore_host(vcpu);
if (vcpu_has_nv(vcpu))
kvm_vcpu_put_hw_mmu(vcpu);
kvm_arm_vmid_clear_active();

vcpu_clear_on_unsupported_cpu(vcpu);
- vcpu->cpu = -1;
}

static void __kvm_arm_vcpu_power_off(struct kvm_vcpu *vcpu)
diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c
index 9b3091ad868c..9050e556d11f 100644
--- a/arch/arm64/kvm/vgic/vgic-init.c
+++ b/arch/arm64/kvm/vgic/vgic-init.c
@@ -82,7 +82,7 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
* the proper checks already.
*/
if (type == KVM_DEV_TYPE_ARM_VGIC_V2 &&
- !kvm_vgic_global_state.can_emulate_gicv2)
+ (!kvm_vgic_global_state.can_emulate_gicv2 || kvm_is_realm(kvm)))
return -ENODEV;

/*
--
2.43.0