From: Junaid Shahid Date: Thu, 3 Jan 2019 17:14:28 -0800 Subject: kvm: Convert kvm_lock to a mutex Git-commit: 0d9ce162cf46c99628cc5da9510b959c7976735b Patch-mainline: v5.3-rc1 References: bsc#1117665 It doesn't seem as if there is any particular need for kvm_lock to be a spinlock, so convert the lock to a mutex so that sleepable functions (in particular cond_resched()) can be called while holding it. Signed-off-by: Junaid Shahid Signed-off-by: Paolo Bonzini Acked-by: Joerg Roedel --- Documentation/virtual/kvm/locking.txt | 4 +--- arch/s390/kvm/kvm-s390.c | 4 ++-- arch/x86/kvm/mmu.c | 4 ++-- arch/x86/kvm/x86.c | 14 +++++++------- include/linux/kvm_host.h | 2 +- virt/kvm/kvm_main.c | 30 +++++++++++++++--------------- 6 files changed, 28 insertions(+), 30 deletions(-) --- a/Documentation/virtual/kvm/locking.txt +++ b/Documentation/virtual/kvm/locking.txt @@ -15,8 +15,6 @@ The acquisition orders for mutexes are a On x86, vcpu->mutex is taken outside kvm->arch.hyperv.hv_lock. -For spinlocks, kvm_lock is taken outside kvm->mmu_lock. - Everything else is a leaf: no other lock is taken inside the critical sections. @@ -169,7 +167,7 @@ which time it will be set using the Dirt ------------ Name: kvm_lock -Type: spinlock_t +Type: mutex Arch: any Protects: - vm_list --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -1961,13 +1961,13 @@ int kvm_arch_init_vm(struct kvm *kvm, un kvm->arch.sca = (struct bsca_block *) get_zeroed_page(alloc_flags); if (!kvm->arch.sca) goto out_err; - spin_lock(&kvm_lock); + mutex_lock(&kvm_lock); sca_offset += 16; if (sca_offset + sizeof(struct bsca_block) > PAGE_SIZE) sca_offset = 0; kvm->arch.sca = (struct bsca_block *) ((char *) kvm->arch.sca + sca_offset); - spin_unlock(&kvm_lock); + mutex_unlock(&kvm_lock); sprintf(debug_name, "kvm-%u", current->pid); --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -5485,7 +5485,7 @@ mmu_shrink_scan(struct shrinker *shrink, int nr_to_scan = sc->nr_to_scan; unsigned long freed = 0; - spin_lock(&kvm_lock); + mutex_lock(&kvm_lock); list_for_each_entry(kvm, &vm_list, vm_list) { int idx; @@ -5535,7 +5535,7 @@ unlock: break; } - spin_unlock(&kvm_lock); + mutex_unlock(&kvm_lock); return freed; } --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6147,7 +6147,7 @@ static int kvmclock_cpufreq_notifier(str smp_call_function_single(freq->cpu, tsc_khz_changed, freq, 1); - spin_lock(&kvm_lock); + mutex_lock(&kvm_lock); list_for_each_entry(kvm, &vm_list, vm_list) { kvm_for_each_vcpu(i, vcpu, kvm) { if (vcpu->cpu != freq->cpu) @@ -6157,7 +6157,7 @@ static int kvmclock_cpufreq_notifier(str send_ipi = 1; } } - spin_unlock(&kvm_lock); + mutex_unlock(&kvm_lock); if (freq->old < freq->new && send_ipi) { /* @@ -6294,12 +6294,12 @@ static void pvclock_gtod_update_fn(struc struct kvm_vcpu *vcpu; int i; - spin_lock(&kvm_lock); + mutex_lock(&kvm_lock); list_for_each_entry(kvm, &vm_list, vm_list) kvm_for_each_vcpu(i, vcpu, kvm) kvm_make_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu); atomic_set(&kvm_guest_has_master_clock, 0); - spin_unlock(&kvm_lock); + mutex_unlock(&kvm_lock); } static DECLARE_WORK(pvclock_gtod_work, pvclock_gtod_update_fn); --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -140,7 +140,7 @@ static inline bool is_error_page(struct extern struct kmem_cache *kvm_vcpu_cache; -extern spinlock_t kvm_lock; +extern struct mutex kvm_lock; extern struct list_head vm_list; struct kvm_io_range { --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -92,7 +92,7 @@ EXPORT_SYMBOL_GPL(halt_poll_ns_shrink); * kvm->lock --> kvm->slots_lock --> kvm->irq_lock */ -DEFINE_SPINLOCK(kvm_lock); +DEFINE_MUTEX(kvm_lock); static DEFINE_RAW_SPINLOCK(kvm_count_lock); LIST_HEAD(vm_list); @@ -713,9 +713,9 @@ static struct kvm *kvm_create_vm(unsigne if (r) goto out_err; - spin_lock(&kvm_lock); + mutex_lock(&kvm_lock); list_add(&kvm->vm_list, &vm_list); - spin_unlock(&kvm_lock); + mutex_unlock(&kvm_lock); preempt_notifier_inc(); @@ -761,9 +761,9 @@ static void kvm_destroy_vm(struct kvm *k kvm_uevent_notify_change(KVM_EVENT_DESTROY_VM, kvm); kvm_destroy_vm_debugfs(kvm); kvm_arch_sync_events(kvm); - spin_lock(&kvm_lock); + mutex_lock(&kvm_lock); list_del(&kvm->vm_list); - spin_unlock(&kvm_lock); + mutex_unlock(&kvm_lock); kvm_free_irq_routing(kvm); for (i = 0; i < KVM_NR_BUSES; i++) { struct kvm_io_bus *bus = kvm_get_bus(kvm, i); @@ -3842,13 +3842,13 @@ static int vm_stat_get(void *_offset, u6 u64 tmp_val; *val = 0; - spin_lock(&kvm_lock); + mutex_lock(&kvm_lock); list_for_each_entry(kvm, &vm_list, vm_list) { stat_tmp.kvm = kvm; vm_stat_get_per_vm((void *)&stat_tmp, &tmp_val); *val += tmp_val; } - spin_unlock(&kvm_lock); + mutex_unlock(&kvm_lock); return 0; } @@ -3861,12 +3861,12 @@ static int vm_stat_clear(void *_offset, if (val) return -EINVAL; - spin_lock(&kvm_lock); + mutex_lock(&kvm_lock); list_for_each_entry(kvm, &vm_list, vm_list) { stat_tmp.kvm = kvm; vm_stat_clear_per_vm((void *)&stat_tmp, 0); } - spin_unlock(&kvm_lock); + mutex_unlock(&kvm_lock); return 0; } @@ -3881,13 +3881,13 @@ static int vcpu_stat_get(void *_offset, u64 tmp_val; *val = 0; - spin_lock(&kvm_lock); + mutex_lock(&kvm_lock); list_for_each_entry(kvm, &vm_list, vm_list) { stat_tmp.kvm = kvm; vcpu_stat_get_per_vm((void *)&stat_tmp, &tmp_val); *val += tmp_val; } - spin_unlock(&kvm_lock); + mutex_unlock(&kvm_lock); return 0; } @@ -3900,12 +3900,12 @@ static int vcpu_stat_clear(void *_offset if (val) return -EINVAL; - spin_lock(&kvm_lock); + mutex_lock(&kvm_lock); list_for_each_entry(kvm, &vm_list, vm_list) { stat_tmp.kvm = kvm; vcpu_stat_clear_per_vm((void *)&stat_tmp, 0); } - spin_unlock(&kvm_lock); + mutex_unlock(&kvm_lock); return 0; } @@ -3926,7 +3926,7 @@ static void kvm_uevent_notify_change(uns if (!kvm_dev.this_device || !kvm) return; - spin_lock(&kvm_lock); + mutex_lock(&kvm_lock); if (type == KVM_EVENT_CREATE_VM) { kvm_createvm_count++; kvm_active_vms++; @@ -3935,7 +3935,7 @@ static void kvm_uevent_notify_change(uns } created = kvm_createvm_count; active = kvm_active_vms; - spin_unlock(&kvm_lock); + mutex_unlock(&kvm_lock); env = kzalloc(sizeof(*env), GFP_KERNEL); if (!env)