Add the ioctl to activate a realm and set the static branch to enable
access to the realm functionality if the RMM is detected.

Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/kvm/rme.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
index 1c67d2ccdaa9..d8e0a447e0cc 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -1194,6 +1194,20 @@ static int kvm_init_ipa_range_realm(struct kvm *kvm,
 	return realm_init_ipa_state(realm, addr, end);
 }
 
+static int kvm_activate_realm(struct kvm *kvm)
+{
+	struct realm *realm = &kvm->arch.realm;
+
+	if (kvm_realm_state(kvm) != REALM_STATE_NEW)
+		return -EINVAL;
+
+	if (rmi_realm_activate(virt_to_phys(realm->rd)))
+		return -ENXIO;
+
+	WRITE_ONCE(realm->state, REALM_STATE_ACTIVE);
+	return 0;
+}
+
 /* Protects access to rme_vmid_bitmap */
 static DEFINE_SPINLOCK(rme_vmid_lock);
 static unsigned long *rme_vmid_bitmap;
@@ -1343,6 +1357,9 @@ int kvm_realm_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap)
 		r = kvm_populate_realm(kvm, &args);
 		break;
 	}
+	case KVM_CAP_ARM_RME_ACTIVATE_REALM:
+		r = kvm_activate_realm(kvm);
+		break;
 	default:
 		r = -EINVAL;
 		break;
@@ -1607,5 +1624,5 @@ void kvm_init_rme(void)
 	if (rme_vmid_init())
 		return;
 
-	/* Future patch will enable static branch kvm_rme_is_available */
+	static_branch_enable(&kvm_rme_is_available);
 }
-- 
2.34.1