[PATCH v13 28/48] KVM: arm64: Handle realm VCPU load

Steven Price
2026-03-18T15:56:07Z

When loading a realm VCPU much of the work is handled by the RMM so only
some of the actions are required. Rearrange kvm_arch_vcpu_load()
slightly so we can bail out early for a realm guest.

Signed-off-by: Steven Price <steven.price@arm.com>
---
arch/arm64/kvm/arm.c | 19 ++++++++++++-------
1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 43d05da7e694..304fb1f2b3ff 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -688,7 +688,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
struct kvm_s2_mmu *mmu;
int *last_ran;

- if (is_protected_kvm_enabled())
+ if (is_protected_kvm_enabled() || kvm_is_realm(vcpu->kvm))
goto nommu;

if (vcpu_has_nv(vcpu))
@@ -732,12 +732,6 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
kvm_vgic_load(vcpu);
kvm_vcpu_load_debug(vcpu);
kvm_vcpu_load_fgt(vcpu);
- if (has_vhe())
- kvm_vcpu_load_vhe(vcpu);
- kvm_arch_vcpu_load_fp(vcpu);
- kvm_vcpu_pmu_restore_guest(vcpu);
- if (kvm_arm_is_pvtime_enabled(&vcpu->arch))
- kvm_make_request(KVM_REQ_RECORD_STEAL, vcpu);

if (kvm_vcpu_should_clear_twe(vcpu))
vcpu->arch.hcr_el2 &= ~HCR_TWE;
@@ -759,6 +753,17 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
&vcpu->arch.vgic_cpu.vgic_v3);
}

+ /* No additional state needs to be loaded on Realmed VMs */
+ if (vcpu_is_rec(vcpu))
+ return;
+
+ if (has_vhe())
+ kvm_vcpu_load_vhe(vcpu);
+ kvm_arch_vcpu_load_fp(vcpu);
+ kvm_vcpu_pmu_restore_guest(vcpu);
+ if (kvm_arm_is_pvtime_enabled(&vcpu->arch))
+ kvm_make_request(KVM_REQ_RECORD_STEAL, vcpu);
+
if (!cpumask_test_cpu(cpu, vcpu->kvm->arch.supported_cpus))
vcpu_set_on_unsupported_cpu(vcpu);
}
--
2.43.0