KVM: PPC: Book3S HV: Relax check on H_SVM_INIT_ABORT

The commit 8c47b6ff ("KVM: PPC: Book3S HV: Check caller of H_SVM_*
Hcalls") added checks of secure bit of SRR1 to filter out the Hcall
reserved to the Ultravisor.

However, the Hcall H_SVM_INIT_ABORT is made by the Ultravisor passing the
context of the VM calling UV_ESM. This allows the Hypervisor to return to
the guest without going through the Ultravisor. Thus the Secure bit of SRR1
is not set in that particular case.

In the case a regular VM is calling H_SVM_INIT_ABORT, this hcall will be
filtered out in kvmppc_h_svm_init_abort() because kvm->arch.secure_guest is
not set in that case.

Fixes: 8c47b6ff ("KVM: PPC: Book3S HV: Check caller of H_SVM_* Hcalls")
Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

arch/powerpc/kvm/book3s_hv.c

@@ -1097,8 +1097,13 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu)
 			ret = kvmppc_h_svm_init_done(vcpu->kvm);
 		break;
 	case H_SVM_INIT_ABORT:
-		ret = H_UNSUPPORTED;
-		if (kvmppc_get_srr1(vcpu) & MSR_S)
+		/*
+		 * Even if that call is made by the Ultravisor, the SSR1 value
+		 * is the guest context one, with the secure bit clear as it has
+		 * not yet been secured. So we can't check it here.
+		 * Instead the kvm->arch.secure_guest flag is checked inside
+		 * kvmppc_h_svm_init_abort().
+		 */
 		ret = kvmppc_h_svm_init_abort(vcpu->kvm);
 		break;