KVM: SEV: Set sev_info.active after initial checks in sev_guest_init()

Set sev_info.active during SEV/SEV-ES activation before calling any code
that can potentially consume sev_info.es_active, e.g. set "active" and
"es_active" as a pair immediately after the initial sanity checks.  KVM
generally expects that es_active can be true if and only if active is
true, e.g. sev_asid_new() deliberately avoids sev_es_guest() so that it
doesn't get a false negative.  This will allow WARNing in sev_es_guest()
if the VM is tagged as SEV-ES but not SEV.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211109215101.2211373-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/svm/sev.c

@@ -229,7 +229,6 @@ static void sev_unbind_asid(struct kvm *kvm, unsigned int handle)
 static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
 {
 	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-	bool es_active = argp->id == KVM_SEV_ES_INIT;
 	int asid, ret;
 
 	if (kvm->created_vcpus)
@@ -239,7 +238,8 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
 	if (unlikely(sev->active))
 		return ret;
 
-	sev->es_active = es_active;
+	sev->active = true;
+	sev->es_active = argp->id == KVM_SEV_ES_INIT;
 	asid = sev_asid_new(sev);
 	if (asid < 0)
 		goto e_no_asid;
@@ -249,7 +249,6 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
 	if (ret)
 		goto e_free;
 
-	sev->active = true;
 	sev->asid = asid;
 	INIT_LIST_HEAD(&sev->regions_list);
 
@@ -260,6 +259,7 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
 	sev->asid = 0;
 e_no_asid:
 	sev->es_active = false;
+	sev->active = false;
 	return ret;
 }