KVM: PPC: Book3S HV: Stop returning internal values to userspace

Our kvm_arch_vcpu_ioctl_run currently returns the RESUME_HOST values
to userspace, against the API of the KVM_RUN ioctl which returns 0 on
success.
Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220125215655.1026224-2-farosas@linux.ibm.com

arch/powerpc/kvm/powerpc.c

@@ -1841,6 +1841,14 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 #ifdef CONFIG_ALTIVEC
 out:
 #endif
+
+	/*
+	 * We're already returning to userspace, don't pass the
+	 * RESUME_HOST flags along.
+	 */
+	if (r > 0)
+		r = 0;
+
 	vcpu_put(vcpu);
 	return r;
 }