9 files changed, 76 insertions, 74 deletions

diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index d1f7bcda2c7f..5c766bd82b05 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -337,13 +337,12 @@ static struct kvm_vcpu *lid_to_vcpu(struct kvm *kvm, unsigned long id,
 {
         union ia64_lid lid;
         int i;
+        struct kvm_vcpu *vcpu;
 
-        for (i = 0; i < atomic_read(&kvm->online_vcpus); i++) {
-                if (kvm->vcpus[i]) {
-                        lid.val = VCPU_LID(kvm->vcpus[i]);
-                        if (lid.id == id && lid.eid == eid)
-                                return kvm->vcpus[i];
-                }
+        kvm_for_each_vcpu(i, vcpu, kvm) {
+                lid.val = VCPU_LID(vcpu);
+                if (lid.id == id && lid.eid == eid)
+                        return vcpu;
         }
 
         return NULL;
@@ -409,21 +408,21 @@ static int handle_global_purge(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
         struct kvm *kvm = vcpu->kvm;
         struct call_data call_data;
         int i;
+        struct kvm_vcpu *vcpui;
 
         call_data.ptc_g_data = p->u.ptc_g_data;
 
-        for (i = 0; i < atomic_read(&kvm->online_vcpus); i++) {
-                if (!kvm->vcpus[i] || kvm->vcpus[i]->arch.mp_state ==
-                                                KVM_MP_STATE_UNINITIALIZED ||
-                                        vcpu == kvm->vcpus[i])
+        kvm_for_each_vcpu(i, vcpui, kvm) {
+                if (vcpui->arch.mp_state == KVM_MP_STATE_UNINITIALIZED ||
+                                vcpu == vcpui)
                         continue;
 
-                if (waitqueue_active(&kvm->vcpus[i]->wq))
-                        wake_up_interruptible(&kvm->vcpus[i]->wq);
+                if (waitqueue_active(&vcpui->wq))
+                        wake_up_interruptible(&vcpui->wq);
 
-                if (kvm->vcpus[i]->cpu != -1) {
-                        call_data.vcpu = kvm->vcpus[i];
-                        smp_call_function_single(kvm->vcpus[i]->cpu,
+                if (vcpui->cpu != -1) {
+                        call_data.vcpu = vcpui;
+                        smp_call_function_single(vcpui->cpu,
                                         vcpu_global_purge, &call_data, 1);
                 } else
                         printk(KERN_WARNING"kvm: Uninit vcpu received ipi!\n");
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 2cf915e51e7e..7ad30e0a1b9a 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -122,13 +122,17 @@ struct kvm *kvm_arch_create_vm(void)
 static void kvmppc_free_vcpus(struct kvm *kvm)
 {
         unsigned int i;
+        struct kvm_vcpu *vcpu;
 
-        for (i = 0; i < KVM_MAX_VCPUS; ++i) {
-                if (kvm->vcpus[i]) {
-                        kvm_arch_vcpu_free(kvm->vcpus[i]);
-                        kvm->vcpus[i] = NULL;
-                }
-        }
+        kvm_for_each_vcpu(i, vcpu, kvm)
+                kvm_arch_vcpu_free(vcpu);
+
+        mutex_lock(&kvm->lock);
+        for (i = 0; i < atomic_read(&kvm->online_vcpus); i++)
+                kvm->vcpus[i] = NULL;
+
+        atomic_set(&kvm->online_vcpus, 0);
+        mutex_unlock(&kvm->lock);
 }
 
 void kvm_arch_sync_events(struct kvm *kvm)
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 098bfa6fbdf6..07ced89740d7 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -211,13 +211,17 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
 static void kvm_free_vcpus(struct kvm *kvm)
 {
         unsigned int i;
+        struct kvm_vcpu *vcpu;
 
-        for (i = 0; i < KVM_MAX_VCPUS; ++i) {
-                if (kvm->vcpus[i]) {
-                        kvm_arch_vcpu_destroy(kvm->vcpus[i]);
-                        kvm->vcpus[i] = NULL;
-                }
-        }
+        kvm_for_each_vcpu(i, vcpu, kvm)
+                kvm_arch_vcpu_destroy(vcpu);
+
+        mutex_lock(&kvm->lock);
+        for (i = 0; i < atomic_read(&kvm->online_vcpus); i++)
+                kvm->vcpus[i] = NULL;
+
+        atomic_set(&kvm->online_vcpus, 0);
+        mutex_unlock(&kvm->lock);
 }
 
 void kvm_arch_sync_events(struct kvm *kvm)
@@ -314,8 +318,6 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
         BUG_ON(!kvm->arch.sca);
         if (!kvm->arch.sca->cpu[id].sda)
                 kvm->arch.sca->cpu[id].sda = (__u64) vcpu->arch.sie_block;
-        else
-                BUG_ON(!kvm->vcpus[id]); /* vcpu does already exist */
         vcpu->arch.sie_block->scaoh = (__u32)(((__u64)kvm->arch.sca) >> 32);
         vcpu->arch.sie_block->scaol = (__u32)(__u64)kvm->arch.sca;
 
@@ -683,6 +685,7 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
                                 int user_alloc)
 {
         int i;
+        struct kvm_vcpu *vcpu;
 
         /* A few sanity checks. We can have exactly one memory slot which has
            to start at guest virtual zero and which has to be located at a
@@ -707,14 +710,10 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
                 return -EINVAL;
 
         /* request update of sie control block for all available vcpus */
-        for (i = 0; i < KVM_MAX_VCPUS; ++i) {
-                if (kvm->vcpus[i]) {
-                        if (test_and_set_bit(KVM_REQ_MMU_RELOAD,
-                                                &kvm->vcpus[i]->requests))
-                                continue;
-                        kvm_s390_inject_sigp_stop(kvm->vcpus[i],
-                                                  ACTION_RELOADVCPU_ON_STOP);
-                }
+        kvm_for_each_vcpu(i, vcpu, kvm) {
+                if (test_and_set_bit(KVM_REQ_MMU_RELOAD, &vcpu->requests))
+                        continue;
+                kvm_s390_inject_sigp_stop(vcpu, ACTION_RELOADVCPU_ON_STOP);
         }
 
         return 0;
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 06d8f84ae8a2..15fc95b2fc05 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -669,11 +669,8 @@ static void __inject_pit_timer_intr(struct kvm *kvm)
          * VCPU0, and only if its LVT0 is in EXTINT mode.
          */
         if (kvm->arch.vapics_in_nmi_mode > 0)
-                for (i = 0; i < KVM_MAX_VCPUS; ++i) {
-                        vcpu = kvm->vcpus[i];
-                        if (vcpu)
-                                kvm_apic_nmi_wd_deliver(vcpu);
-                }
+                kvm_for_each_vcpu(i, vcpu, kvm)
+                        kvm_apic_nmi_wd_deliver(vcpu);
 }
 
 void kvm_inject_pit_timer_irqs(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index d443a421ca3e..5f97dbd24291 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1347,10 +1347,10 @@ static void kvm_mmu_put_page(struct kvm_mmu_page *sp, u64 *parent_pte)
 static void kvm_mmu_reset_last_pte_updated(struct kvm *kvm)
 {
         int i;
+        struct kvm_vcpu *vcpu;
 
-        for (i = 0; i < KVM_MAX_VCPUS; ++i)
-                if (kvm->vcpus[i])
-                        kvm->vcpus[i]->arch.last_pte_updated = NULL;
+        kvm_for_each_vcpu(i, vcpu, kvm)
+                vcpu->arch.last_pte_updated = NULL;
 }
 
 static void kvm_mmu_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d8adc1da76dd..89862a80e32c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2946,10 +2946,7 @@ static int kvmclock_cpufreq_notifier(struct notifier_block *nb, unsigned long va
 
         spin_lock(&kvm_lock);
         list_for_each_entry(kvm, &vm_list, vm_list) {
-                for (i = 0; i < KVM_MAX_VCPUS; ++i) {
-                        vcpu = kvm->vcpus[i];
-                        if (!vcpu)
-                                continue;
+                kvm_for_each_vcpu(i, vcpu, kvm) {
                         if (vcpu->cpu != freq->cpu)
                                 continue;
                         if (!kvm_request_guest_time_update(vcpu))
@@ -4678,20 +4675,22 @@ static void kvm_unload_vcpu_mmu(struct kvm_vcpu *vcpu)
 static void kvm_free_vcpus(struct kvm *kvm)
 {
         unsigned int i;
+        struct kvm_vcpu *vcpu;
 
         /*
          * Unpin any mmu pages first.
          */
-        for (i = 0; i < KVM_MAX_VCPUS; ++i)
-                if (kvm->vcpus[i])
-                        kvm_unload_vcpu_mmu(kvm->vcpus[i]);
-        for (i = 0; i < KVM_MAX_VCPUS; ++i) {
-                if (kvm->vcpus[i]) {
-                        kvm_arch_vcpu_free(kvm->vcpus[i]);
-                        kvm->vcpus[i] = NULL;
-                }
-        }
+        kvm_for_each_vcpu(i, vcpu, kvm)
+                kvm_unload_vcpu_mmu(vcpu);
+        kvm_for_each_vcpu(i, vcpu, kvm)
+                kvm_arch_vcpu_free(vcpu);
+
+        mutex_lock(&kvm->lock);
+        for (i = 0; i < atomic_read(&kvm->online_vcpus); i++)
+                kvm->vcpus[i] = NULL;
 
+        atomic_set(&kvm->online_vcpus, 0);
+        mutex_unlock(&kvm->lock);
 }
 
 void kvm_arch_sync_events(struct kvm *kvm)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index d3fdf1a738c9..c6e4d02067fe 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -179,6 +179,17 @@ struct kvm {
 #define kvm_printf(kvm, fmt ...) printk(KERN_DEBUG fmt)
 #define vcpu_printf(vcpu, fmt...) kvm_printf(vcpu->kvm, fmt)
 
+static inline struct kvm_vcpu *kvm_get_vcpu(struct kvm *kvm, int i)
+{
+        smp_rmb();
+        return kvm->vcpus[i];
+}
+
+#define kvm_for_each_vcpu(idx, vcpup, kvm) \
+        for (idx = 0, vcpup = kvm_get_vcpu(kvm, idx); \
+             idx < atomic_read(&kvm->online_vcpus) && vcpup; \
+             vcpup = kvm_get_vcpu(kvm, ++idx))
+
 int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id);
 void kvm_vcpu_uninit(struct kvm_vcpu *vcpu);
 
diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index 08a9a49481b2..bb8a1b5e41c1 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -68,10 +68,8 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
                         kvm_is_dm_lowest_prio(irq))
                 printk(KERN_INFO "kvm: apic: phys broadcast and lowest prio\n");
 
-        for (i = 0; i < KVM_MAX_VCPUS; i++) {
-                vcpu = kvm->vcpus[i];
-
-                if (!vcpu || !kvm_apic_present(vcpu))
+        kvm_for_each_vcpu(i, vcpu, kvm) {
+                if (!kvm_apic_present(vcpu))
                         continue;
 
                 if (!kvm_apic_match_dest(vcpu, src, irq->shorthand,
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 25e1f9c97b1a..777fe533cfe7 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -738,10 +738,7 @@ static bool make_all_cpus_request(struct kvm *kvm, unsigned int req)
 
         me = get_cpu();
         spin_lock(&kvm->requests_lock);
-        for (i = 0; i < KVM_MAX_VCPUS; ++i) {
-                vcpu = kvm->vcpus[i];
-                if (!vcpu)
-                        continue;
+        kvm_for_each_vcpu(i, vcpu, kvm) {
                 if (test_and_set_bit(req, &vcpu->requests))
                         continue;
                 cpu = vcpu->cpu;
@@ -1718,7 +1715,7 @@ static int create_vcpu_fd(struct kvm_vcpu *vcpu)
 static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
 {
         int r;
-        struct kvm_vcpu *vcpu;
+        struct kvm_vcpu *vcpu, *v;
 
         vcpu = kvm_arch_vcpu_create(kvm, id);
         if (IS_ERR(vcpu))
@@ -1736,8 +1733,8 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
                 goto vcpu_destroy;
         }
 
-        for (r = 0; r < atomic_read(&kvm->online_vcpus); r++)
-                if (kvm->vcpus[r]->vcpu_id == id) {
+        kvm_for_each_vcpu(r, v, kvm)
+                if (v->vcpu_id == id) {
                         r = -EEXIST;
                         goto vcpu_destroy;
                 }
@@ -2526,11 +2523,9 @@ static int vcpu_stat_get(void *_offset, u64 *val)
         *val = 0;
         spin_lock(&kvm_lock);
         list_for_each_entry(kvm, &vm_list, vm_list)
-                for (i = 0; i < KVM_MAX_VCPUS; ++i) {
-                        vcpu = kvm->vcpus[i];
-                        if (vcpu)
-                                *val += *(u32 *)((void *)vcpu + offset);
-                }
+                kvm_for_each_vcpu(i, vcpu, kvm)
+                        *val += *(u32 *)((void *)vcpu + offset);
+
         spin_unlock(&kvm_lock);
         return 0;
 }