[PATCH v14 18/44] arm64: RMI: Activate realm on first VCPU run

[Steven Price <steven.price@arm.com>]

Use kvm_arch_vcpu_run_pid_change() to check if this is the first time
the realm guest has run. If this is the first run then activate the
realm.

Before the realm can be activated it must first be created, this is a
stub in this patch and will be filled in by a later patch.

Signed-off-by: Steven Price <steven.price@arm.com>
---
Changes since v12:
 * Fix commit message
 * Change realm_state checks to be >= REALM_STATE_ACTIVE to avoid a dead
   guest being revived by kvm_activate_realm().
---
 arch/arm64/include/asm/kvm_rmi.h |  1 +
 arch/arm64/kvm/arm.c             |  6 +++++
 arch/arm64/kvm/rmi.c             | 39 ++++++++++++++++++++++++++++++++
 3 files changed, 46 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_rmi.h b/arch/arm64/include/asm/kvm_rmi.h
index 06ba0d4745c6..8bd743093ccf 100644
--- a/arch/arm64/include/asm/kvm_rmi.h
+++ b/arch/arm64/include/asm/kvm_rmi.h
@@ -63,6 +63,7 @@ void kvm_init_rmi(void);
 u32 kvm_realm_ipa_limit(void);
 
 int kvm_init_realm(struct kvm *kvm);
+int kvm_activate_realm(struct kvm *kvm);
 void kvm_destroy_realm(struct kvm *kvm);
 void kvm_realm_destroy_rtts(struct kvm *kvm);
 
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 41d35b2d1dee..eb2b61fe1f0a 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1018,6 +1018,12 @@ int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu)
 			return ret;
 	}
 
+	if (kvm_is_realm(vcpu->kvm)) {
+		ret = kvm_activate_realm(kvm);
+		if (ret)
+			return ret;
+	}
+
 	mutex_lock(&kvm->arch.config_lock);
 	set_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &kvm->arch.flags);
 	mutex_unlock(&kvm->arch.config_lock);
diff --git a/arch/arm64/kvm/rmi.c b/arch/arm64/kvm/rmi.c
index 5b00ccca4af3..849111817af7 100644
--- a/arch/arm64/kvm/rmi.c
+++ b/arch/arm64/kvm/rmi.c
@@ -167,6 +167,45 @@ void kvm_realm_destroy_rtts(struct kvm *kvm)
 	realm_tear_down_rtt_range(realm, 0, (1UL << ia_bits));
 }
 
+static int realm_ensure_created(struct kvm *kvm)
+{
+	/* Provided in later patch */
+	return -ENXIO;
+}
+
+int kvm_activate_realm(struct kvm *kvm)
+{
+	struct realm *realm = &kvm->arch.realm;
+	int ret;
+
+	if (kvm_realm_state(kvm) >= REALM_STATE_ACTIVE)
+		return 0;
+
+	if (!irqchip_in_kernel(kvm)) {
+		/* Userspace irqchip not yet supported with realms */
+		return -EOPNOTSUPP;
+	}
+
+	guard(mutex)(&kvm->arch.config_lock);
+	/* Check again with the lock held */
+	if (kvm_realm_state(kvm) >= REALM_STATE_ACTIVE)
+		return 0;
+
+	ret = realm_ensure_created(kvm);
+	if (ret)
+		return ret;
+
+	/* Mark state as dead in case we fail */
+	kvm_set_realm_state(kvm, REALM_STATE_DEAD);
+
+	ret = rmi_realm_activate(virt_to_phys(realm->rd));
+	if (ret)
+		return -ENXIO;
+
+	kvm_set_realm_state(kvm, REALM_STATE_ACTIVE);
+	return 0;
+}
+
 void kvm_destroy_realm(struct kvm *kvm)
 {
 	struct realm *realm = &kvm->arch.realm;
-- 
2.43.0