Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index fcb55b0..d1ccc16 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -7,10 +7,14 @@
  *    Author(s): Carsten Otte <cotte@de.ibm.com>
  */
 
+#define KMSG_COMPONENT "kvm-s390"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
 #include <linux/interrupt.h>
 #include <linux/kvm_host.h>
 #include <linux/hrtimer.h>
 #include <linux/mmu_context.h>
+#include <linux/nospec.h>
 #include <linux/signal.h>
 #include <linux/slab.h>
 #include <linux/bitmap.h>
@@ -23,6 +27,7 @@
 #include <asm/gmap.h>
 #include <asm/switch_to.h>
 #include <asm/nmi.h>
+#include <asm/airq.h>
 #include "kvm-s390.h"
 #include "gaccess.h"
 #include "trace-s390.h"
@@ -31,6 +36,8 @@
 #define PFAULT_DONE 0x0680
 #define VIRTIO_PARAM 0x0d00
 
+static struct kvm_s390_gib *gib;
+
 /* handle external calls via sigp interpretation facility */
 static int sca_ext_call_pending(struct kvm_vcpu *vcpu, int *src_id)
 {
@@ -217,22 +224,100 @@
  */
 #define IPM_BIT_OFFSET (offsetof(struct kvm_s390_gisa, ipm) * BITS_PER_BYTE)
 
-static inline void kvm_s390_gisa_set_ipm_gisc(struct kvm_s390_gisa *gisa, u32 gisc)
+/**
+ * gisa_set_iam - change the GISA interruption alert mask
+ *
+ * @gisa: gisa to operate on
+ * @iam: new IAM value to use
+ *
+ * Change the IAM atomically with the next alert address and the IPM
+ * of the GISA if the GISA is not part of the GIB alert list. All three
+ * fields are located in the first long word of the GISA.
+ *
+ * Returns: 0 on success
+ *          -EBUSY in case the gisa is part of the alert list
+ */
+static inline int gisa_set_iam(struct kvm_s390_gisa *gisa, u8 iam)
+{
+	u64 word, _word;
+
+	do {
+		word = READ_ONCE(gisa->u64.word[0]);
+		if ((u64)gisa != word >> 32)
+			return -EBUSY;
+		_word = (word & ~0xffUL) | iam;
+	} while (cmpxchg(&gisa->u64.word[0], word, _word) != word);
+
+	return 0;
+}
+
+/**
+ * gisa_clear_ipm - clear the GISA interruption pending mask
+ *
+ * @gisa: gisa to operate on
+ *
+ * Clear the IPM atomically with the next alert address and the IAM
+ * of the GISA unconditionally. All three fields are located in the
+ * first long word of the GISA.
+ */
+static inline void gisa_clear_ipm(struct kvm_s390_gisa *gisa)
+{
+	u64 word, _word;
+
+	do {
+		word = READ_ONCE(gisa->u64.word[0]);
+		_word = word & ~(0xffUL << 24);
+	} while (cmpxchg(&gisa->u64.word[0], word, _word) != word);
+}
+
+/**
+ * gisa_get_ipm_or_restore_iam - return IPM or restore GISA IAM
+ *
+ * @gi: gisa interrupt struct to work on
+ *
+ * Atomically restores the interruption alert mask if none of the
+ * relevant ISCs are pending and return the IPM.
+ *
+ * Returns: the relevant pending ISCs
+ */
+static inline u8 gisa_get_ipm_or_restore_iam(struct kvm_s390_gisa_interrupt *gi)
+{
+	u8 pending_mask, alert_mask;
+	u64 word, _word;
+
+	do {
+		word = READ_ONCE(gi->origin->u64.word[0]);
+		alert_mask = READ_ONCE(gi->alert.mask);
+		pending_mask = (u8)(word >> 24) & alert_mask;
+		if (pending_mask)
+			return pending_mask;
+		_word = (word & ~0xffUL) | alert_mask;
+	} while (cmpxchg(&gi->origin->u64.word[0], word, _word) != word);
+
+	return 0;
+}
+
+static inline int gisa_in_alert_list(struct kvm_s390_gisa *gisa)
+{
+	return READ_ONCE(gisa->next_alert) != (u32)(u64)gisa;
+}
+
+static inline void gisa_set_ipm_gisc(struct kvm_s390_gisa *gisa, u32 gisc)
 {
 	set_bit_inv(IPM_BIT_OFFSET + gisc, (unsigned long *) gisa);
 }
 
-static inline u8 kvm_s390_gisa_get_ipm(struct kvm_s390_gisa *gisa)
+static inline u8 gisa_get_ipm(struct kvm_s390_gisa *gisa)
 {
 	return READ_ONCE(gisa->ipm);
 }
 
-static inline void kvm_s390_gisa_clear_ipm_gisc(struct kvm_s390_gisa *gisa, u32 gisc)
+static inline void gisa_clear_ipm_gisc(struct kvm_s390_gisa *gisa, u32 gisc)
 {
 	clear_bit_inv(IPM_BIT_OFFSET + gisc, (unsigned long *) gisa);
 }
 
-static inline int kvm_s390_gisa_tac_ipm_gisc(struct kvm_s390_gisa *gisa, u32 gisc)
+static inline int gisa_tac_ipm_gisc(struct kvm_s390_gisa *gisa, u32 gisc)
 {
 	return test_and_clear_bit_inv(IPM_BIT_OFFSET + gisc, (unsigned long *) gisa);
 }
@@ -245,8 +330,13 @@
 
 static inline unsigned long pending_irqs(struct kvm_vcpu *vcpu)
 {
-	return pending_irqs_no_gisa(vcpu) |
-		kvm_s390_gisa_get_ipm(vcpu->kvm->arch.gisa) << IRQ_PEND_IO_ISC_7;
+	struct kvm_s390_gisa_interrupt *gi = &vcpu->kvm->arch.gisa_int;
+	unsigned long pending_mask;
+
+	pending_mask = pending_irqs_no_gisa(vcpu);
+	if (gi->origin)
+		pending_mask |= gisa_get_ipm(gi->origin) << IRQ_PEND_IO_ISC_7;
+	return pending_mask;
 }
 
 static inline int isc_to_irq_type(unsigned long isc)
@@ -318,13 +408,13 @@
 static void __set_cpu_idle(struct kvm_vcpu *vcpu)
 {
 	kvm_s390_set_cpuflags(vcpu, CPUSTAT_WAIT);
-	set_bit(vcpu->vcpu_id, vcpu->kvm->arch.float_int.idle_mask);
+	set_bit(vcpu->vcpu_id, vcpu->kvm->arch.idle_mask);
 }
 
 static void __unset_cpu_idle(struct kvm_vcpu *vcpu)
 {
 	kvm_s390_clear_cpuflags(vcpu, CPUSTAT_WAIT);
-	clear_bit(vcpu->vcpu_id, vcpu->kvm->arch.float_int.idle_mask);
+	clear_bit(vcpu->vcpu_id, vcpu->kvm->arch.idle_mask);
 }
 
 static void __reset_intercept_indicators(struct kvm_vcpu *vcpu)
@@ -345,7 +435,7 @@
 {
 	if (!(pending_irqs_no_gisa(vcpu) & IRQ_PEND_IO_MASK))
 		return;
-	else if (psw_ioint_disabled(vcpu))
+	if (psw_ioint_disabled(vcpu))
 		kvm_s390_set_cpuflags(vcpu, CPUSTAT_IO_INT);
 	else
 		vcpu->arch.sie_block->lctl |= LCTL_CR6;
@@ -353,7 +443,7 @@
 
 static void set_intercept_indicators_ext(struct kvm_vcpu *vcpu)
 {
-	if (!(pending_irqs(vcpu) & IRQ_PEND_EXT_MASK))
+	if (!(pending_irqs_no_gisa(vcpu) & IRQ_PEND_EXT_MASK))
 		return;
 	if (psw_extint_disabled(vcpu))
 		kvm_s390_set_cpuflags(vcpu, CPUSTAT_EXT_INT);
@@ -363,7 +453,7 @@
 
 static void set_intercept_indicators_mchk(struct kvm_vcpu *vcpu)
 {
-	if (!(pending_irqs(vcpu) & IRQ_PEND_MCHK_MASK))
+	if (!(pending_irqs_no_gisa(vcpu) & IRQ_PEND_MCHK_MASK))
 		return;
 	if (psw_mchk_disabled(vcpu))
 		vcpu->arch.sie_block->ictl |= ICTL_LPSW;
@@ -956,6 +1046,7 @@
 {
 	struct list_head *isc_list;
 	struct kvm_s390_float_interrupt *fi;
+	struct kvm_s390_gisa_interrupt *gi = &vcpu->kvm->arch.gisa_int;
 	struct kvm_s390_interrupt_info *inti = NULL;
 	struct kvm_s390_io_info io;
 	u32 isc;
@@ -998,8 +1089,7 @@
 		goto out;
 	}
 
-	if (vcpu->kvm->arch.gisa &&
-	    kvm_s390_gisa_tac_ipm_gisc(vcpu->kvm->arch.gisa, isc)) {
+	if (gi->origin && gisa_tac_ipm_gisc(gi->origin, isc)) {
 		/*
 		 * in case an adapter interrupt was not delivered
 		 * in SIE context KVM will handle the delivery
@@ -1089,6 +1179,7 @@
 
 int kvm_s390_handle_wait(struct kvm_vcpu *vcpu)
 {
+	struct kvm_s390_gisa_interrupt *gi = &vcpu->kvm->arch.gisa_int;
 	u64 sltime;
 
 	vcpu->stat.exit_wait_state++;
@@ -1102,6 +1193,11 @@
 		return -EOPNOTSUPP; /* disabled wait */
 	}
 
+	if (gi->origin &&
+	    (gisa_get_ipm_or_restore_iam(gi) &
+	     vcpu->arch.sie_block->gcr[6] >> 24))
+		return 0;
+
 	if (!ckc_interrupts_enabled(vcpu) &&
 	    !cpu_timer_interrupts_enabled(vcpu)) {
 		VCPU_EVENT(vcpu, 3, "%s", "enabled wait w/o timer");
@@ -1128,28 +1224,11 @@
 
 void kvm_s390_vcpu_wakeup(struct kvm_vcpu *vcpu)
 {
-	/*
-	 * We cannot move this into the if, as the CPU might be already
-	 * in kvm_vcpu_block without having the waitqueue set (polling)
-	 */
 	vcpu->valid_wakeup = true;
+	kvm_vcpu_wake_up(vcpu);
+
 	/*
-	 * This is mostly to document, that the read in swait_active could
-	 * be moved before other stores, leading to subtle races.
-	 * All current users do not store or use an atomic like update
-	 */
-	smp_mb__after_atomic();
-	if (swait_active(&vcpu->wq)) {
-		/*
-		 * The vcpu gave up the cpu voluntarily, mark it as a good
-		 * yield-candidate.
-		 */
-		vcpu->preempted = true;
-		swake_up_one(&vcpu->wq);
-		vcpu->stat.halt_wakeup++;
-	}
-	/*
-	 * The VCPU might not be sleeping but is executing the VSIE. Let's
+	 * The VCPU might not be sleeping but rather executing VSIE. Let's
 	 * kick it, so it leaves the SIE to process the request.
 	 */
 	kvm_s390_vsie_kick(vcpu);
@@ -1533,18 +1612,19 @@
 
 static int get_top_gisa_isc(struct kvm *kvm, u64 isc_mask, u32 schid)
 {
+	struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int;
 	unsigned long active_mask;
 	int isc;
 
 	if (schid)
 		goto out;
-	if (!kvm->arch.gisa)
+	if (!gi->origin)
 		goto out;
 
-	active_mask = (isc_mask & kvm_s390_gisa_get_ipm(kvm->arch.gisa) << 24) << 32;
+	active_mask = (isc_mask & gisa_get_ipm(gi->origin) << 24) << 32;
 	while (active_mask) {
 		isc = __fls(active_mask) ^ (BITS_PER_LONG - 1);
-		if (kvm_s390_gisa_tac_ipm_gisc(kvm->arch.gisa, isc))
+		if (gisa_tac_ipm_gisc(gi->origin, isc))
 			return isc;
 		clear_bit_inv(isc, &active_mask);
 	}
@@ -1567,6 +1647,7 @@
 struct kvm_s390_interrupt_info *kvm_s390_get_io_int(struct kvm *kvm,
 						    u64 isc_mask, u32 schid)
 {
+	struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int;
 	struct kvm_s390_interrupt_info *inti, *tmp_inti;
 	int isc;
 
@@ -1584,7 +1665,7 @@
 	/* both types of interrupts present */
 	if (int_word_to_isc(inti->io.io_int_word) <= isc) {
 		/* classical IO int with higher priority */
-		kvm_s390_gisa_set_ipm_gisc(kvm->arch.gisa, isc);
+		gisa_set_ipm_gisc(gi->origin, isc);
 		goto out;
 	}
 gisa_out:
@@ -1596,7 +1677,7 @@
 			kvm_s390_reinject_io_int(kvm, inti);
 		inti = tmp_inti;
 	} else
-		kvm_s390_gisa_set_ipm_gisc(kvm->arch.gisa, isc);
+		gisa_set_ipm_gisc(gi->origin, isc);
 out:
 	return inti;
 }
@@ -1685,6 +1766,7 @@
 
 static int __inject_io(struct kvm *kvm, struct kvm_s390_interrupt_info *inti)
 {
+	struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int;
 	struct kvm_s390_float_interrupt *fi;
 	struct list_head *list;
 	int isc;
@@ -1692,9 +1774,9 @@
 	kvm->stat.inject_io++;
 	isc = int_word_to_isc(inti->io.io_int_word);
 
-	if (kvm->arch.gisa && inti->type & KVM_S390_INT_IO_AI_MASK) {
+	if (gi->origin && inti->type & KVM_S390_INT_IO_AI_MASK) {
 		VM_EVENT(kvm, 4, "%s isc %1u", "inject: I/O (AI/gisa)", isc);
-		kvm_s390_gisa_set_ipm_gisc(kvm->arch.gisa, isc);
+		gisa_set_ipm_gisc(gi->origin, isc);
 		kfree(inti);
 		return 0;
 	}
@@ -1726,7 +1808,6 @@
  */
 static void __floating_irq_kick(struct kvm *kvm, u64 type)
 {
-	struct kvm_s390_float_interrupt *fi = &kvm->arch.float_int;
 	struct kvm_vcpu *dst_vcpu;
 	int sigcpu, online_vcpus, nr_tries = 0;
 
@@ -1735,11 +1816,11 @@
 		return;
 
 	/* find idle VCPUs first, then round robin */
-	sigcpu = find_first_bit(fi->idle_mask, online_vcpus);
+	sigcpu = find_first_bit(kvm->arch.idle_mask, online_vcpus);
 	if (sigcpu == online_vcpus) {
 		do {
-			sigcpu = fi->next_rr_cpu;
-			fi->next_rr_cpu = (fi->next_rr_cpu + 1) % online_vcpus;
+			sigcpu = kvm->arch.float_int.next_rr_cpu++;
+			kvm->arch.float_int.next_rr_cpu %= online_vcpus;
 			/* avoid endless loops if all vcpus are stopped */
 			if (nr_tries++ >= online_vcpus)
 				return;
@@ -1753,7 +1834,8 @@
 		kvm_s390_set_cpuflags(dst_vcpu, CPUSTAT_STOP_INT);
 		break;
 	case KVM_S390_INT_IO_MIN...KVM_S390_INT_IO_MAX:
-		if (!(type & KVM_S390_INT_IO_AI_MASK && kvm->arch.gisa))
+		if (!(type & KVM_S390_INT_IO_AI_MASK &&
+		      kvm->arch.gisa_int.origin))
 			kvm_s390_set_cpuflags(dst_vcpu, CPUSTAT_IO_INT);
 		break;
 	default:
@@ -1879,6 +1961,16 @@
 	case KVM_S390_MCHK:
 		irq->u.mchk.mcic = s390int->parm64;
 		break;
+	case KVM_S390_INT_PFAULT_INIT:
+		irq->u.ext.ext_params = s390int->parm;
+		irq->u.ext.ext_params2 = s390int->parm64;
+		break;
+	case KVM_S390_RESTART:
+	case KVM_S390_INT_CLOCK_COMP:
+	case KVM_S390_INT_CPU_TIMER:
+		break;
+	default:
+		return -EINVAL;
 	}
 	return 0;
 }
@@ -2003,6 +2095,7 @@
 
 static int get_all_floating_irqs(struct kvm *kvm, u8 __user *usrbuf, u64 len)
 {
+	struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int;
 	struct kvm_s390_interrupt_info *inti;
 	struct kvm_s390_float_interrupt *fi;
 	struct kvm_s390_irq *buf;
@@ -2026,15 +2119,14 @@
 
 	max_irqs = len / sizeof(struct kvm_s390_irq);
 
-	if (kvm->arch.gisa &&
-	    kvm_s390_gisa_get_ipm(kvm->arch.gisa)) {
+	if (gi->origin && gisa_get_ipm(gi->origin)) {
 		for (i = 0; i <= MAX_ISC; i++) {
 			if (n == max_irqs) {
 				/* signal userspace to try again */
 				ret = -ENOMEM;
 				goto out_nolock;
 			}
-			if (kvm_s390_gisa_tac_ipm_gisc(kvm->arch.gisa, i)) {
+			if (gisa_tac_ipm_gisc(gi->origin, i)) {
 				irq = (struct kvm_s390_irq *) &buf[n];
 				irq->type = KVM_S390_INT_IO(1, 0, 0, 0);
 				irq->u.io.io_int_word = isc_to_int_word(i);
@@ -2209,6 +2301,7 @@
 {
 	if (id >= MAX_S390_IO_ADAPTERS)
 		return NULL;
+	id = array_index_nospec(id, MAX_S390_IO_ADAPTERS);
 	return kvm->arch.adapters[id];
 }
 
@@ -2222,8 +2315,13 @@
 			   (void __user *)attr->addr, sizeof(adapter_info)))
 		return -EFAULT;
 
-	if ((adapter_info.id >= MAX_S390_IO_ADAPTERS) ||
-	    (dev->kvm->arch.adapters[adapter_info.id] != NULL))
+	if (adapter_info.id >= MAX_S390_IO_ADAPTERS)
+		return -EINVAL;
+
+	adapter_info.id = array_index_nospec(adapter_info.id,
+					     MAX_S390_IO_ADAPTERS);
+
+	if (dev->kvm->arch.adapters[adapter_info.id] != NULL)
 		return -EINVAL;
 
 	adapter = kzalloc(sizeof(*adapter), GFP_KERNEL);
@@ -2278,7 +2376,7 @@
 		ret = -EFAULT;
 		goto out;
 	}
-	ret = get_user_pages_fast(map->addr, 1, 1, &map->page);
+	ret = get_user_pages_fast(map->addr, 1, FOLL_WRITE, &map->page);
 	if (ret < 0)
 		goto out;
 	BUG_ON(ret != 1);
@@ -2831,7 +2929,7 @@
 int kvm_s390_get_irq_state(struct kvm_vcpu *vcpu, __u8 __user *buf, int len)
 {
 	int scn;
-	unsigned long sigp_emerg_pending[BITS_TO_LONGS(KVM_MAX_VCPUS)];
+	DECLARE_BITMAP(sigp_emerg_pending, KVM_MAX_VCPUS);
 	struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int;
 	unsigned long pending_irqs;
 	struct kvm_s390_irq irq;
@@ -2884,27 +2982,278 @@
 	return n;
 }
 
+static void __airqs_kick_single_vcpu(struct kvm *kvm, u8 deliverable_mask)
+{
+	int vcpu_id, online_vcpus = atomic_read(&kvm->online_vcpus);
+	struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int;
+	struct kvm_vcpu *vcpu;
+
+	for_each_set_bit(vcpu_id, kvm->arch.idle_mask, online_vcpus) {
+		vcpu = kvm_get_vcpu(kvm, vcpu_id);
+		if (psw_ioint_disabled(vcpu))
+			continue;
+		deliverable_mask &= (u8)(vcpu->arch.sie_block->gcr[6] >> 24);
+		if (deliverable_mask) {
+			/* lately kicked but not yet running */
+			if (test_and_set_bit(vcpu_id, gi->kicked_mask))
+				return;
+			kvm_s390_vcpu_wakeup(vcpu);
+			return;
+		}
+	}
+}
+
+static enum hrtimer_restart gisa_vcpu_kicker(struct hrtimer *timer)
+{
+	struct kvm_s390_gisa_interrupt *gi =
+		container_of(timer, struct kvm_s390_gisa_interrupt, timer);
+	struct kvm *kvm =
+		container_of(gi->origin, struct sie_page2, gisa)->kvm;
+	u8 pending_mask;
+
+	pending_mask = gisa_get_ipm_or_restore_iam(gi);
+	if (pending_mask) {
+		__airqs_kick_single_vcpu(kvm, pending_mask);
+		hrtimer_forward_now(timer, ns_to_ktime(gi->expires));
+		return HRTIMER_RESTART;
+	};
+
+	return HRTIMER_NORESTART;
+}
+
+#define NULL_GISA_ADDR 0x00000000UL
+#define NONE_GISA_ADDR 0x00000001UL
+#define GISA_ADDR_MASK 0xfffff000UL
+
+static void process_gib_alert_list(void)
+{
+	struct kvm_s390_gisa_interrupt *gi;
+	struct kvm_s390_gisa *gisa;
+	struct kvm *kvm;
+	u32 final, origin = 0UL;
+
+	do {
+		/*
+		 * If the NONE_GISA_ADDR is still stored in the alert list
+		 * origin, we will leave the outer loop. No further GISA has
+		 * been added to the alert list by millicode while processing
+		 * the current alert list.
+		 */
+		final = (origin & NONE_GISA_ADDR);
+		/*
+		 * Cut off the alert list and store the NONE_GISA_ADDR in the
+		 * alert list origin to avoid further GAL interruptions.
+		 * A new alert list can be build up by millicode in parallel
+		 * for guests not in the yet cut-off alert list. When in the
+		 * final loop, store the NULL_GISA_ADDR instead. This will re-
+		 * enable GAL interruptions on the host again.
+		 */
+		origin = xchg(&gib->alert_list_origin,
+			      (!final) ? NONE_GISA_ADDR : NULL_GISA_ADDR);
+		/*
+		 * Loop through the just cut-off alert list and start the
+		 * gisa timers to kick idle vcpus to consume the pending
+		 * interruptions asap.
+		 */
+		while (origin & GISA_ADDR_MASK) {
+			gisa = (struct kvm_s390_gisa *)(u64)origin;
+			origin = gisa->next_alert;
+			gisa->next_alert = (u32)(u64)gisa;
+			kvm = container_of(gisa, struct sie_page2, gisa)->kvm;
+			gi = &kvm->arch.gisa_int;
+			if (hrtimer_active(&gi->timer))
+				hrtimer_cancel(&gi->timer);
+			hrtimer_start(&gi->timer, 0, HRTIMER_MODE_REL);
+		}
+	} while (!final);
+
+}
+
 void kvm_s390_gisa_clear(struct kvm *kvm)
 {
-	if (kvm->arch.gisa) {
-		memset(kvm->arch.gisa, 0, sizeof(struct kvm_s390_gisa));
-		kvm->arch.gisa->next_alert = (u32)(u64)kvm->arch.gisa;
-		VM_EVENT(kvm, 3, "gisa 0x%pK cleared", kvm->arch.gisa);
-	}
+	struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int;
+
+	if (!gi->origin)
+		return;
+	gisa_clear_ipm(gi->origin);
+	VM_EVENT(kvm, 3, "gisa 0x%pK cleared", gi->origin);
 }
 
 void kvm_s390_gisa_init(struct kvm *kvm)
 {
-	if (css_general_characteristics.aiv) {
-		kvm->arch.gisa = &kvm->arch.sie_page2->gisa;
-		VM_EVENT(kvm, 3, "gisa 0x%pK initialized", kvm->arch.gisa);
-		kvm_s390_gisa_clear(kvm);
-	}
+	struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int;
+
+	if (!css_general_characteristics.aiv)
+		return;
+	gi->origin = &kvm->arch.sie_page2->gisa;
+	gi->alert.mask = 0;
+	spin_lock_init(&gi->alert.ref_lock);
+	gi->expires = 50 * 1000; /* 50 usec */
+	hrtimer_init(&gi->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	gi->timer.function = gisa_vcpu_kicker;
+	memset(gi->origin, 0, sizeof(struct kvm_s390_gisa));
+	gi->origin->next_alert = (u32)(u64)gi->origin;
+	VM_EVENT(kvm, 3, "gisa 0x%pK initialized", gi->origin);
 }
 
 void kvm_s390_gisa_destroy(struct kvm *kvm)
 {
-	if (!kvm->arch.gisa)
+	struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int;
+
+	if (!gi->origin)
 		return;
-	kvm->arch.gisa = NULL;
+	if (gi->alert.mask)
+		KVM_EVENT(3, "vm 0x%pK has unexpected iam 0x%02x",
+			  kvm, gi->alert.mask);
+	while (gisa_in_alert_list(gi->origin))
+		cpu_relax();
+	hrtimer_cancel(&gi->timer);
+	gi->origin = NULL;
+}
+
+/**
+ * kvm_s390_gisc_register - register a guest ISC
+ *
+ * @kvm:  the kernel vm to work with
+ * @gisc: the guest interruption sub class to register
+ *
+ * The function extends the vm specific alert mask to use.
+ * The effective IAM mask in the GISA is updated as well
+ * in case the GISA is not part of the GIB alert list.
+ * It will be updated latest when the IAM gets restored
+ * by gisa_get_ipm_or_restore_iam().
+ *
+ * Returns: the nonspecific ISC (NISC) the gib alert mechanism
+ *          has registered with the channel subsystem.
+ *          -ENODEV in case the vm uses no GISA
+ *          -ERANGE in case the guest ISC is invalid
+ */
+int kvm_s390_gisc_register(struct kvm *kvm, u32 gisc)
+{
+	struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int;
+
+	if (!gi->origin)
+		return -ENODEV;
+	if (gisc > MAX_ISC)
+		return -ERANGE;
+
+	spin_lock(&gi->alert.ref_lock);
+	gi->alert.ref_count[gisc]++;
+	if (gi->alert.ref_count[gisc] == 1) {
+		gi->alert.mask |= 0x80 >> gisc;
+		gisa_set_iam(gi->origin, gi->alert.mask);
+	}
+	spin_unlock(&gi->alert.ref_lock);
+
+	return gib->nisc;
+}
+EXPORT_SYMBOL_GPL(kvm_s390_gisc_register);
+
+/**
+ * kvm_s390_gisc_unregister - unregister a guest ISC
+ *
+ * @kvm:  the kernel vm to work with
+ * @gisc: the guest interruption sub class to register
+ *
+ * The function reduces the vm specific alert mask to use.
+ * The effective IAM mask in the GISA is updated as well
+ * in case the GISA is not part of the GIB alert list.
+ * It will be updated latest when the IAM gets restored
+ * by gisa_get_ipm_or_restore_iam().
+ *
+ * Returns: the nonspecific ISC (NISC) the gib alert mechanism
+ *          has registered with the channel subsystem.
+ *          -ENODEV in case the vm uses no GISA
+ *          -ERANGE in case the guest ISC is invalid
+ *          -EINVAL in case the guest ISC is not registered
+ */
+int kvm_s390_gisc_unregister(struct kvm *kvm, u32 gisc)
+{
+	struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int;
+	int rc = 0;
+
+	if (!gi->origin)
+		return -ENODEV;
+	if (gisc > MAX_ISC)
+		return -ERANGE;
+
+	spin_lock(&gi->alert.ref_lock);
+	if (gi->alert.ref_count[gisc] == 0) {
+		rc = -EINVAL;
+		goto out;
+	}
+	gi->alert.ref_count[gisc]--;
+	if (gi->alert.ref_count[gisc] == 0) {
+		gi->alert.mask &= ~(0x80 >> gisc);
+		gisa_set_iam(gi->origin, gi->alert.mask);
+	}
+out:
+	spin_unlock(&gi->alert.ref_lock);
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(kvm_s390_gisc_unregister);
+
+static void gib_alert_irq_handler(struct airq_struct *airq, bool floating)
+{
+	inc_irq_stat(IRQIO_GAL);
+	process_gib_alert_list();
+}
+
+static struct airq_struct gib_alert_irq = {
+	.handler = gib_alert_irq_handler,
+	.lsi_ptr = &gib_alert_irq.lsi_mask,
+};
+
+void kvm_s390_gib_destroy(void)
+{
+	if (!gib)
+		return;
+	chsc_sgib(0);
+	unregister_adapter_interrupt(&gib_alert_irq);
+	free_page((unsigned long)gib);
+	gib = NULL;
+}
+
+int kvm_s390_gib_init(u8 nisc)
+{
+	int rc = 0;
+
+	if (!css_general_characteristics.aiv) {
+		KVM_EVENT(3, "%s", "gib not initialized, no AIV facility");
+		goto out;
+	}
+
+	gib = (struct kvm_s390_gib *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
+	if (!gib) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	gib_alert_irq.isc = nisc;
+	if (register_adapter_interrupt(&gib_alert_irq)) {
+		pr_err("Registering the GIB alert interruption handler failed\n");
+		rc = -EIO;
+		goto out_free_gib;
+	}
+
+	gib->nisc = nisc;
+	if (chsc_sgib((u32)(u64)gib)) {
+		pr_err("Associating the GIB with the AIV facility failed\n");
+		free_page((unsigned long)gib);
+		gib = NULL;
+		rc = -EIO;
+		goto out_unreg_gal;
+	}
+
+	KVM_EVENT(3, "gib 0x%pK (nisc=%d) initialized", gib, gib->nisc);
+	goto out;
+
+out_unreg_gal:
+	unregister_adapter_interrupt(&gib_alert_irq);
+out_free_gib:
+	free_page((unsigned long)gib);
+	gib = NULL;
+out:
+	return rc;
 }