Merge tag 'kvm-s390-master-4.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into kvm-master

KVM: s390: Fixes for 4.4

1. disallow changing the SIMD mode when CPUs have been created.
   it allowed userspace to corrupt kernel memory
2. Fix vCPU lookup. Until now the vCPU number equals the vCPU id. Some
   kernel code places relied on that. This might
   a: cause guest failures
   b: allow userspace to corrupt kernel memory
3. Fencing of the PFMF instruction should use the guest facilities
   and not the host facilities.

arch/s390/kvm/interrupt.c

@@ -1030,8 +1030,7 @@ static int __inject_extcall(struct kvm_vcpu *vcpu, struct kvm_s390_irq *irq)
 				   src_id, 0);
 
 	/* sending vcpu invalid */
-	if (src_id >= KVM_MAX_VCPUS ||
-	    kvm_get_vcpu(vcpu->kvm, src_id) == NULL)
+	if (kvm_get_vcpu_by_id(vcpu->kvm, src_id) == NULL)
 		return -EINVAL;
 
 	if (sclp.has_sigpif)
@@ -1110,6 +1109,10 @@ static int __inject_sigp_emergency(struct kvm_vcpu *vcpu,
 	trace_kvm_s390_inject_vcpu(vcpu->vcpu_id, KVM_S390_INT_EMERGENCY,
 				   irq->u.emerg.code, 0);
 
+	/* sending vcpu invalid */
+	if (kvm_get_vcpu_by_id(vcpu->kvm, irq->u.emerg.code) == NULL)
+		return -EINVAL;
+
 	set_bit(irq->u.emerg.code, li->sigp_emerg_pending);
 	set_bit(IRQ_PEND_EXT_EMERGENCY, &li->pending_irqs);
 	atomic_or(CPUSTAT_EXT_INT, li->cpuflags);

arch/s390/kvm/kvm-s390.c

@@ -342,12 +342,16 @@ static int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap)
 		r = 0;
 		break;
 	case KVM_CAP_S390_VECTOR_REGISTERS:
-		if (MACHINE_HAS_VX) {
+		mutex_lock(&kvm->lock);
+		if (atomic_read(&kvm->online_vcpus)) {
+			r = -EBUSY;
+		} else if (MACHINE_HAS_VX) {
 			set_kvm_facility(kvm->arch.model.fac->mask, 129);
 			set_kvm_facility(kvm->arch.model.fac->list, 129);
 			r = 0;
 		} else
 			r = -EINVAL;
+		mutex_unlock(&kvm->lock);
 		VM_EVENT(kvm, 3, "ENABLE: CAP_S390_VECTOR_REGISTERS %s",
 			 r ? "(not available)" : "(success)");
 		break;

arch/s390/kvm/priv.c

@@ -660,7 +660,7 @@ static int handle_pfmf(struct kvm_vcpu *vcpu)
 
 	kvm_s390_get_regs_rre(vcpu, &reg1, &reg2);
 
-	if (!MACHINE_HAS_PFMF)
+	if (!test_kvm_facility(vcpu->kvm, 8))
 		return kvm_s390_inject_program_int(vcpu, PGM_OPERATION);
 
 	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)

arch/s390/kvm/sigp.c

@@ -291,12 +291,8 @@ static int handle_sigp_dst(struct kvm_vcpu *vcpu, u8 order_code,
 			   u16 cpu_addr, u32 parameter, u64 *status_reg)
 {
 	int rc;
-	struct kvm_vcpu *dst_vcpu;
+	struct kvm_vcpu *dst_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, cpu_addr);
 
-	if (cpu_addr >= KVM_MAX_VCPUS)
-		return SIGP_CC_NOT_OPERATIONAL;
-
-	dst_vcpu = kvm_get_vcpu(vcpu->kvm, cpu_addr);
 	if (!dst_vcpu)
 		return SIGP_CC_NOT_OPERATIONAL;
 
@@ -478,7 +474,7 @@ int kvm_s390_handle_sigp_pei(struct kvm_vcpu *vcpu)
 	trace_kvm_s390_handle_sigp_pei(vcpu, order_code, cpu_addr);
 
 	if (order_code == SIGP_EXTERNAL_CALL) {
-		dest_vcpu = kvm_get_vcpu(vcpu->kvm, cpu_addr);
+		dest_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, cpu_addr);
 		BUG_ON(dest_vcpu == NULL);
 
 		kvm_s390_vcpu_wakeup(dest_vcpu);

include/linux/kvm_host.h

@@ -460,6 +460,17 @@ static inline struct kvm_vcpu *kvm_get_vcpu(struct kvm *kvm, int i)
 	     (vcpup = kvm_get_vcpu(kvm, idx)) != NULL; \
 	     idx++)
 
+static inline struct kvm_vcpu *kvm_get_vcpu_by_id(struct kvm *kvm, int id)
+{
+	struct kvm_vcpu *vcpu;
+	int i;
+
+	kvm_for_each_vcpu(i, vcpu, kvm)
+		if (vcpu->vcpu_id == id)
+			return vcpu;
+	return NULL;
+}
+
 #define kvm_for_each_memslot(memslot, slots)	\
 	for (memslot = &slots->memslots[0];	\
 	      memslot < slots->memslots + KVM_MEM_SLOTS_NUM && memslot->npages;\