Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM updates from Paolo Bonzini:
 "First batch of KVM changes for 4.4.

  s390:
     A bunch of fixes and optimizations for interrupt and time handling.

  PPC:
     Mostly bug fixes.

  ARM:
     No big features, but many small fixes and prerequisites including:

      - a number of fixes for the arch-timer

      - introducing proper level-triggered semantics for the arch-timers

      - a series of patches to synchronously halt a guest (prerequisite
        for IRQ forwarding)

      - some tracepoint improvements

      - a tweak for the EL2 panic handlers

      - some more VGIC cleanups getting rid of redundant state

  x86:
     Quite a few changes:

      - support for VT-d posted interrupts (i.e. PCI devices can inject
        interrupts directly into vCPUs).  This introduces a new
        component (in virt/lib/) that connects VFIO and KVM together.
        The same infrastructure will be used for ARM interrupt
        forwarding as well.

      - more Hyper-V features, though the main one Hyper-V synthetic
        interrupt controller will have to wait for 4.5.  These will let
        KVM expose Hyper-V devices.

      - nested virtualization now supports VPID (same as PCID but for
        vCPUs) which makes it quite a bit faster

      - for future hardware that supports NVDIMM, there is support for
        clflushopt, clwb, pcommit

      - support for "split irqchip", i.e.  LAPIC in kernel +
        IOAPIC/PIC/PIT in userspace, which reduces the attack surface of
        the hypervisor

      - obligatory smattering of SMM fixes

      - on the guest side, stable scheduler clock support was rewritten
        to not require help from the hypervisor"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (123 commits)
  KVM: VMX: Fix commit which broke PML
  KVM: x86: obey KVM_X86_QUIRK_CD_NW_CLEARED in kvm_set_cr0()
  KVM: x86: allow RSM from 64-bit mode
  KVM: VMX: fix SMEP and SMAP without EPT
  KVM: x86: move kvm_set_irq_inatomic to legacy device assignment
  KVM: device assignment: remove pointless #ifdefs
  KVM: x86: merge kvm_arch_set_irq with kvm_set_msi_inatomic
  KVM: x86: zero apic_arb_prio on reset
  drivers/hv: share Hyper-V SynIC constants with userspace
  KVM: x86: handle SMBASE as physical address in RSM
  KVM: x86: add read_phys to x86_emulate_ops
  KVM: x86: removing unused variable
  KVM: don't pointlessly leave KVM_COMPAT=y in non-KVM configs
  KVM: arm/arm64: Merge vgic_set_lr() and vgic_sync_lr_elrsr()
  KVM: arm/arm64: Clean up vgic_retire_lr() and surroundings
  KVM: arm/arm64: Optimize away redundant LR tracking
  KVM: s390: use simple switch statement as multiplexer
  KVM: s390: drop useless newline in debugging data
  KVM: s390: SCA must not cross page boundaries
  KVM: arm: Do not indent the arguments of DECLARE_BITMAP
  ...

6 files changed, 127 insertions, 145 deletions

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 7f654308817c..efaac2c3bb77 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -644,5 +644,7 @@ static inline void kvm_arch_memslots_updated(struct kvm *kvm, struct kvm_memslot
 static inline void kvm_arch_flush_shadow_all(struct kvm *kvm) {}
 static inline void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
 		struct kvm_memory_slot *slot) {}
+static inline void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) {}
+static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {}
 
 #endif
diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
index 7365e8a46032..b4a5aa110cec 100644
--- a/arch/s390/kvm/intercept.c
+++ b/arch/s390/kvm/intercept.c
@@ -336,28 +336,28 @@ static int handle_partial_execution(struct kvm_vcpu *vcpu)
 	return -EOPNOTSUPP;
 }
 
-static const intercept_handler_t intercept_funcs[] = {
-	[0x00 >> 2] = handle_noop,
-	[0x04 >> 2] = handle_instruction,
-	[0x08 >> 2] = handle_prog,
-	[0x10 >> 2] = handle_noop,
-	[0x14 >> 2] = handle_external_interrupt,
-	[0x18 >> 2] = handle_noop,
-	[0x1C >> 2] = kvm_s390_handle_wait,
-	[0x20 >> 2] = handle_validity,
-	[0x28 >> 2] = handle_stop,
-	[0x38 >> 2] = handle_partial_execution,
-};
-
 int kvm_handle_sie_intercept(struct kvm_vcpu *vcpu)
 {
-	intercept_handler_t func;
-	u8 code = vcpu->arch.sie_block->icptcode;
-
-	if (code & 3 || (code >> 2) >= ARRAY_SIZE(intercept_funcs))
+	switch (vcpu->arch.sie_block->icptcode) {
+	case 0x00:
+	case 0x10:
+	case 0x18:
+		return handle_noop(vcpu);
+	case 0x04:
+		return handle_instruction(vcpu);
+	case 0x08:
+		return handle_prog(vcpu);
+	case 0x14:
+		return handle_external_interrupt(vcpu);
+	case 0x1c:
+		return kvm_s390_handle_wait(vcpu);
+	case 0x20:
+		return handle_validity(vcpu);
+	case 0x28:
+		return handle_stop(vcpu);
+	case 0x38:
+		return handle_partial_execution(vcpu);
+	default:
 		return -EOPNOTSUPP;
-	func = intercept_funcs[code >> 2];
-	if (func)
-		return func(vcpu);
-	return -EOPNOTSUPP;
+	}
 }
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 5c2c169395c3..373e32346d68 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -51,11 +51,9 @@ static int psw_mchk_disabled(struct kvm_vcpu *vcpu)
 
 static int psw_interrupts_disabled(struct kvm_vcpu *vcpu)
 {
-	if ((vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PER) ||
-	    (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_IO) ||
-	    (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_EXT))
-		return 0;
-	return 1;
+	return psw_extint_disabled(vcpu) &&
+	       psw_ioint_disabled(vcpu) &&
+	       psw_mchk_disabled(vcpu);
 }
 
 static int ckc_interrupts_enabled(struct kvm_vcpu *vcpu)
@@ -71,13 +69,8 @@ static int ckc_interrupts_enabled(struct kvm_vcpu *vcpu)
 
 static int ckc_irq_pending(struct kvm_vcpu *vcpu)
 {
-	preempt_disable();
-	if (!(vcpu->arch.sie_block->ckc <
-	      get_tod_clock_fast() + vcpu->arch.sie_block->epoch)) {
-		preempt_enable();
+	if (vcpu->arch.sie_block->ckc >= kvm_s390_get_tod_clock_fast(vcpu->kvm))
 		return 0;
-	}
-	preempt_enable();
 	return ckc_interrupts_enabled(vcpu);
 }
 
@@ -109,14 +102,10 @@ static inline u8 int_word_to_isc(u32 int_word)
 	return (int_word & 0x38000000) >> 27;
 }
 
-static inline unsigned long pending_floating_irqs(struct kvm_vcpu *vcpu)
+static inline unsigned long pending_irqs(struct kvm_vcpu *vcpu)
 {
-	return vcpu->kvm->arch.float_int.pending_irqs;
-}
-
-static inline unsigned long pending_local_irqs(struct kvm_vcpu *vcpu)
-{
-	return vcpu->arch.local_int.pending_irqs;
+	return vcpu->kvm->arch.float_int.pending_irqs |
+	       vcpu->arch.local_int.pending_irqs;
 }
 
 static unsigned long disable_iscs(struct kvm_vcpu *vcpu,
@@ -135,8 +124,7 @@ static unsigned long deliverable_irqs(struct kvm_vcpu *vcpu)
 {
 	unsigned long active_mask;
 
-	active_mask = pending_local_irqs(vcpu);
-	active_mask |= pending_floating_irqs(vcpu);
+	active_mask = pending_irqs(vcpu);
 	if (!active_mask)
 		return 0;
 
@@ -204,7 +192,7 @@ static void __set_cpuflag(struct kvm_vcpu *vcpu, u32 flag)
 
 static void set_intercept_indicators_io(struct kvm_vcpu *vcpu)
 {
-	if (!(pending_floating_irqs(vcpu) & IRQ_PEND_IO_MASK))
+	if (!(pending_irqs(vcpu) & IRQ_PEND_IO_MASK))
 		return;
 	else if (psw_ioint_disabled(vcpu))
 		__set_cpuflag(vcpu, CPUSTAT_IO_INT);
@@ -214,7 +202,7 @@ static void set_intercept_indicators_io(struct kvm_vcpu *vcpu)
 
 static void set_intercept_indicators_ext(struct kvm_vcpu *vcpu)
 {
-	if (!(pending_local_irqs(vcpu) & IRQ_PEND_EXT_MASK))
+	if (!(pending_irqs(vcpu) & IRQ_PEND_EXT_MASK))
 		return;
 	if (psw_extint_disabled(vcpu))
 		__set_cpuflag(vcpu, CPUSTAT_EXT_INT);
@@ -224,7 +212,7 @@ static void set_intercept_indicators_ext(struct kvm_vcpu *vcpu)
 
 static void set_intercept_indicators_mchk(struct kvm_vcpu *vcpu)
 {
-	if (!(pending_local_irqs(vcpu) & IRQ_PEND_MCHK_MASK))
+	if (!(pending_irqs(vcpu) & IRQ_PEND_MCHK_MASK))
 		return;
 	if (psw_mchk_disabled(vcpu))
 		vcpu->arch.sie_block->ictl |= ICTL_LPSW;
@@ -815,23 +803,21 @@ int kvm_s390_ext_call_pending(struct kvm_vcpu *vcpu)
 
 int kvm_s390_vcpu_has_irq(struct kvm_vcpu *vcpu, int exclude_stop)
 {
-	int rc;
+	if (deliverable_irqs(vcpu))
+		return 1;
 
-	rc = !!deliverable_irqs(vcpu);
-
-	if (!rc && kvm_cpu_has_pending_timer(vcpu))
-		rc = 1;
+	if (kvm_cpu_has_pending_timer(vcpu))
+		return 1;
 
 	/* external call pending and deliverable */
-	if (!rc && kvm_s390_ext_call_pending(vcpu) &&
+	if (kvm_s390_ext_call_pending(vcpu) &&
 	    !psw_extint_disabled(vcpu) &&
 	    (vcpu->arch.sie_block->gcr[0] & 0x2000ul))
-		rc = 1;
-
-	if (!rc && !exclude_stop && kvm_s390_is_stop_irq_pending(vcpu))
-		rc = 1;
+		return 1;
 
-	return rc;
+	if (!exclude_stop && kvm_s390_is_stop_irq_pending(vcpu))
+		return 1;
+	return 0;
 }
 
 int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
@@ -846,7 +832,7 @@ int kvm_s390_handle_wait(struct kvm_vcpu *vcpu)
 	vcpu->stat.exit_wait_state++;
 
 	/* fast path */
-	if (kvm_cpu_has_pending_timer(vcpu) || kvm_arch_vcpu_runnable(vcpu))
+	if (kvm_arch_vcpu_runnable(vcpu))
 		return 0;
 
 	if (psw_interrupts_disabled(vcpu)) {
@@ -860,9 +846,7 @@ int kvm_s390_handle_wait(struct kvm_vcpu *vcpu)
 		goto no_timer;
 	}
 
-	preempt_disable();
-	now = get_tod_clock_fast() + vcpu->arch.sie_block->epoch;
-	preempt_enable();
+	now = kvm_s390_get_tod_clock_fast(vcpu->kvm);
 	sltime = tod_to_ns(vcpu->arch.sie_block->ckc - now);
 
 	/* underflow */
@@ -901,9 +885,7 @@ enum hrtimer_restart kvm_s390_idle_wakeup(struct hrtimer *timer)
 	u64 now, sltime;
 
 	vcpu = container_of(timer, struct kvm_vcpu, arch.ckc_timer);
-	preempt_disable();
-	now = get_tod_clock_fast() + vcpu->arch.sie_block->epoch;
-	preempt_enable();
+	now = kvm_s390_get_tod_clock_fast(vcpu->kvm);
 	sltime = tod_to_ns(vcpu->arch.sie_block->ckc - now);
 
 	/*
@@ -981,39 +963,30 @@ static int __inject_prog(struct kvm_vcpu *vcpu, struct kvm_s390_irq *irq)
 	trace_kvm_s390_inject_vcpu(vcpu->vcpu_id, KVM_S390_PROGRAM_INT,
 				   irq->u.pgm.code, 0);
 
-	li->irq.pgm = irq->u.pgm;
+	if (irq->u.pgm.code == PGM_PER) {
+		li->irq.pgm.code |= PGM_PER;
+		/* only modify PER related information */
+		li->irq.pgm.per_address = irq->u.pgm.per_address;
+		li->irq.pgm.per_code = irq->u.pgm.per_code;
+		li->irq.pgm.per_atmid = irq->u.pgm.per_atmid;
+		li->irq.pgm.per_access_id = irq->u.pgm.per_access_id;
+	} else if (!(irq->u.pgm.code & PGM_PER)) {
+		li->irq.pgm.code = (li->irq.pgm.code & PGM_PER) |
+				   irq->u.pgm.code;
+		/* only modify non-PER information */
+		li->irq.pgm.trans_exc_code = irq->u.pgm.trans_exc_code;
+		li->irq.pgm.mon_code = irq->u.pgm.mon_code;
+		li->irq.pgm.data_exc_code = irq->u.pgm.data_exc_code;
+		li->irq.pgm.mon_class_nr = irq->u.pgm.mon_class_nr;
+		li->irq.pgm.exc_access_id = irq->u.pgm.exc_access_id;
+		li->irq.pgm.op_access_id = irq->u.pgm.op_access_id;
+	} else {
+		li->irq.pgm = irq->u.pgm;
+	}
 	set_bit(IRQ_PEND_PROG, &li->pending_irqs);
 	return 0;
 }
 
-int kvm_s390_inject_program_int(struct kvm_vcpu *vcpu, u16 code)
-{
-	struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int;
-	struct kvm_s390_irq irq;
-
-	spin_lock(&li->lock);
-	irq.u.pgm.code = code;
-	__inject_prog(vcpu, &irq);
-	BUG_ON(waitqueue_active(li->wq));
-	spin_unlock(&li->lock);
-	return 0;
-}
-
-int kvm_s390_inject_prog_irq(struct kvm_vcpu *vcpu,
-			     struct kvm_s390_pgm_info *pgm_info)
-{
-	struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int;
-	struct kvm_s390_irq irq;
-	int rc;
-
-	spin_lock(&li->lock);
-	irq.u.pgm = *pgm_info;
-	rc = __inject_prog(vcpu, &irq);
-	BUG_ON(waitqueue_active(li->wq));
-	spin_unlock(&li->lock);
-	return rc;
-}
-
 static int __inject_pfault_init(struct kvm_vcpu *vcpu, struct kvm_s390_irq *irq)
 {
 	struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int;
@@ -1390,12 +1363,9 @@ static void __floating_irq_kick(struct kvm *kvm, u64 type)
 
 static int __inject_vm(struct kvm *kvm, struct kvm_s390_interrupt_info *inti)
 {
-	struct kvm_s390_float_interrupt *fi;
 	u64 type = READ_ONCE(inti->type);
 	int rc;
 
-	fi = &kvm->arch.float_int;
-
 	switch (type) {
 	case KVM_S390_MCHK:
 		rc = __inject_float_mchk(kvm, inti);
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index c6b4063fce29..8fe2f1c722dc 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -514,35 +514,20 @@ static int kvm_s390_set_tod_high(struct kvm *kvm, struct kvm_device_attr *attr)
 
 	if (gtod_high != 0)
 		return -EINVAL;
-	VM_EVENT(kvm, 3, "SET: TOD extension: 0x%x\n", gtod_high);
+	VM_EVENT(kvm, 3, "SET: TOD extension: 0x%x", gtod_high);
 
 	return 0;
 }
 
 static int kvm_s390_set_tod_low(struct kvm *kvm, struct kvm_device_attr *attr)
 {
-	struct kvm_vcpu *cur_vcpu;
-	unsigned int vcpu_idx;
-	u64 host_tod, gtod;
-	int r;
+	u64 gtod;
 
 	if (copy_from_user(&gtod, (void __user *)attr->addr, sizeof(gtod)))
 		return -EFAULT;
 
-	r = store_tod_clock(&host_tod);
-	if (r)
-		return r;
-
-	mutex_lock(&kvm->lock);
-	preempt_disable();
-	kvm->arch.epoch = gtod - host_tod;
-	kvm_s390_vcpu_block_all(kvm);
-	kvm_for_each_vcpu(vcpu_idx, cur_vcpu, kvm)
-		cur_vcpu->arch.sie_block->epoch = kvm->arch.epoch;
-	kvm_s390_vcpu_unblock_all(kvm);
-	preempt_enable();
-	mutex_unlock(&kvm->lock);
-	VM_EVENT(kvm, 3, "SET: TOD base: 0x%llx\n", gtod);
+	kvm_s390_set_tod_clock(kvm, gtod);
+	VM_EVENT(kvm, 3, "SET: TOD base: 0x%llx", gtod);
 	return 0;
 }
 
@@ -574,26 +559,19 @@ static int kvm_s390_get_tod_high(struct kvm *kvm, struct kvm_device_attr *attr)
 	if (copy_to_user((void __user *)attr->addr, &gtod_high,
 					 sizeof(gtod_high)))
 		return -EFAULT;
-	VM_EVENT(kvm, 3, "QUERY: TOD extension: 0x%x\n", gtod_high);
+	VM_EVENT(kvm, 3, "QUERY: TOD extension: 0x%x", gtod_high);
 
 	return 0;
 }
 
 static int kvm_s390_get_tod_low(struct kvm *kvm, struct kvm_device_attr *attr)
 {
-	u64 host_tod, gtod;
-	int r;
+	u64 gtod;
 
-	r = store_tod_clock(&host_tod);
-	if (r)
-		return r;
-
-	preempt_disable();
-	gtod = host_tod + kvm->arch.epoch;
-	preempt_enable();
+	gtod = kvm_s390_get_tod_clock_fast(kvm);
 	if (copy_to_user((void __user *)attr->addr, &gtod, sizeof(gtod)))
 		return -EFAULT;
-	VM_EVENT(kvm, 3, "QUERY: TOD base: 0x%llx\n", gtod);
+	VM_EVENT(kvm, 3, "QUERY: TOD base: 0x%llx", gtod);
 
 	return 0;
 }
@@ -1120,7 +1098,9 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 	if (!kvm->arch.sca)
 		goto out_err;
 	spin_lock(&kvm_lock);
-	sca_offset = (sca_offset + 16) & 0x7f0;
+	sca_offset += 16;
+	if (sca_offset + sizeof(struct sca_block) > PAGE_SIZE)
+		sca_offset = 0;
 	kvm->arch.sca = (struct sca_block *) ((char *) kvm->arch.sca + sca_offset);
 	spin_unlock(&kvm_lock);
 
@@ -1911,6 +1891,22 @@ retry:
 	return 0;
 }
 
+void kvm_s390_set_tod_clock(struct kvm *kvm, u64 tod)
+{
+	struct kvm_vcpu *vcpu;
+	int i;
+
+	mutex_lock(&kvm->lock);
+	preempt_disable();
+	kvm->arch.epoch = tod - get_tod_clock();
+	kvm_s390_vcpu_block_all(kvm);
+	kvm_for_each_vcpu(i, vcpu, kvm)
+		vcpu->arch.sie_block->epoch = kvm->arch.epoch;
+	kvm_s390_vcpu_unblock_all(kvm);
+	preempt_enable();
+	mutex_unlock(&kvm->lock);
+}
+
 /**
  * kvm_arch_fault_in_page - fault-in guest page if necessary
  * @vcpu: The corresponding virtual cpu
diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index c446aabf60d3..1e70e00d3c5e 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -175,6 +175,7 @@ static inline int kvm_s390_user_cpu_state_ctrl(struct kvm *kvm)
 	return kvm->arch.user_cpu_state_ctrl != 0;
 }
 
+/* implemented in interrupt.c */
 int kvm_s390_handle_wait(struct kvm_vcpu *vcpu);
 void kvm_s390_vcpu_wakeup(struct kvm_vcpu *vcpu);
 enum hrtimer_restart kvm_s390_idle_wakeup(struct hrtimer *timer);
@@ -185,7 +186,25 @@ int __must_check kvm_s390_inject_vm(struct kvm *kvm,
 				    struct kvm_s390_interrupt *s390int);
 int __must_check kvm_s390_inject_vcpu(struct kvm_vcpu *vcpu,
 				      struct kvm_s390_irq *irq);
-int __must_check kvm_s390_inject_program_int(struct kvm_vcpu *vcpu, u16 code);
+static inline int kvm_s390_inject_prog_irq(struct kvm_vcpu *vcpu,
+					   struct kvm_s390_pgm_info *pgm_info)
+{
+	struct kvm_s390_irq irq = {
+		.type = KVM_S390_PROGRAM_INT,
+		.u.pgm = *pgm_info,
+	};
+
+	return kvm_s390_inject_vcpu(vcpu, &irq);
+}
+static inline int kvm_s390_inject_program_int(struct kvm_vcpu *vcpu, u16 code)
+{
+	struct kvm_s390_irq irq = {
+		.type = KVM_S390_PROGRAM_INT,
+		.u.pgm.code = code,
+	};
+
+	return kvm_s390_inject_vcpu(vcpu, &irq);
+}
 struct kvm_s390_interrupt_info *kvm_s390_get_io_int(struct kvm *kvm,
 						    u64 isc_mask, u32 schid);
 int kvm_s390_reinject_io_int(struct kvm *kvm,
@@ -212,6 +231,7 @@ int kvm_s390_handle_sigp(struct kvm_vcpu *vcpu);
 int kvm_s390_handle_sigp_pei(struct kvm_vcpu *vcpu);
 
 /* implemented in kvm-s390.c */
+void kvm_s390_set_tod_clock(struct kvm *kvm, u64 tod);
 long kvm_arch_fault_in_page(struct kvm_vcpu *vcpu, gpa_t gpa, int writable);
 int kvm_s390_store_status_unloaded(struct kvm_vcpu *vcpu, unsigned long addr);
 int kvm_s390_store_adtl_status_unloaded(struct kvm_vcpu *vcpu,
@@ -231,9 +251,6 @@ extern unsigned long kvm_s390_fac_list_mask[];
 
 /* implemented in diag.c */
 int kvm_s390_handle_diag(struct kvm_vcpu *vcpu);
-/* implemented in interrupt.c */
-int kvm_s390_inject_prog_irq(struct kvm_vcpu *vcpu,
-			     struct kvm_s390_pgm_info *pgm_info);
 
 static inline void kvm_s390_vcpu_block_all(struct kvm *kvm)
 {
@@ -254,6 +271,16 @@ static inline void kvm_s390_vcpu_unblock_all(struct kvm *kvm)
 		kvm_s390_vcpu_unblock(vcpu);
 }
 
+static inline u64 kvm_s390_get_tod_clock_fast(struct kvm *kvm)
+{
+	u64 rc;
+
+	preempt_disable();
+	rc = get_tod_clock_fast() + kvm->arch.epoch;
+	preempt_enable();
+	return rc;
+}
+
 /**
  * kvm_s390_inject_prog_cond - conditionally inject a program check
  * @vcpu: virtual cpu
diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index 4d21dc4d1a84..77191b85ea7a 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -33,11 +33,9 @@
 /* Handle SCK (SET CLOCK) interception */
 static int handle_set_clock(struct kvm_vcpu *vcpu)
 {
-	struct kvm_vcpu *cpup;
-	s64 hostclk, val;
-	int i, rc;
+	int rc;
 	ar_t ar;
-	u64 op2;
+	u64 op2, val;
 
 	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
 		return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
@@ -49,19 +47,8 @@ static int handle_set_clock(struct kvm_vcpu *vcpu)
 	if (rc)
 		return kvm_s390_inject_prog_cond(vcpu, rc);
 
-	if (store_tod_clock(&hostclk)) {
-		kvm_s390_set_psw_cc(vcpu, 3);
-		return 0;
-	}
 	VCPU_EVENT(vcpu, 3, "SCK: setting guest TOD to 0x%llx", val);
-	val = (val - hostclk) & ~0x3fUL;
-
-	mutex_lock(&vcpu->kvm->lock);
-	preempt_disable();
-	kvm_for_each_vcpu(i, cpup, vcpu->kvm)
-		cpup->arch.sie_block->epoch = val;
-	preempt_enable();
-	mutex_unlock(&vcpu->kvm->lock);
+	kvm_s390_set_tod_clock(vcpu->kvm, val);
 
 	kvm_s390_set_psw_cc(vcpu, 0);
 	return 0;