KVM: s390: flush CPU on load control

commit 2dca485f upstream.

some control register changes will flush some aspects of the CPU, e.g.
POP explicitely mentions that for CR9-CR11 "TLBs may be cleared".
Instead of trying to be clever and only flush on specific CRs, let
play safe and flush on all lctl(g) as future machines might define
new bits in CRs. Load control intercept should not happen that often.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
[bwh: Backported to 3.2: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

arch/s390/kvm/intercept.c

@@ -58,6 +58,7 @@ static int handle_lctlg(struct kvm_vcpu *vcpu)
 			break;
 		reg = (reg + 1) % 16;
 	} while (1);
+	kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
 	return 0;
 }
 
@@ -97,6 +98,7 @@ static int handle_lctl(struct kvm_vcpu *vcpu)
 			break;
 		reg = (reg + 1) % 16;
 	} while (1);
+	kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
 	return 0;
 }