From f257d6dcda0187693407e0c2e5dab69bdab3223f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 19 Apr 2019 22:18:17 -0700 Subject: KVM: Directly return result from kvm_arch_check_processor_compat() Add a wrapper to invoke kvm_arch_check_processor_compat() so that the boilerplate ugliness of checking virtualization support on all CPUs is hidden from the arch specific code. x86's implementation in particular is quite heinous, as it unnecessarily propagates the out-param pattern into kvm_x86_ops. While the x86 specific issue could be resolved solely by changing kvm_x86_ops, make the change for all architectures as returning a value directly is prettier and technically more robust, e.g. s390 doesn't set the out param, which could lead to subtle breakage in the (highly unlikely) scenario where the out-param was not pre-initialized by the caller. Opportunistically annotate svm_check_processor_compat() with __init. Signed-off-by: Sean Christopherson Reviewed-by: Cornelia Huck Signed-off-by: Paolo Bonzini --- arch/s390/include/asm/kvm_host.h | 1 - arch/s390/kvm/kvm-s390.c | 5 +++++ 2 files changed, 5 insertions(+), 1 deletion(-) (limited to 'arch/s390') diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index 2b00a3ebee08..da5825a3c16b 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -905,7 +905,6 @@ extern int kvm_s390_gisc_register(struct kvm *kvm, u32 gisc); extern int kvm_s390_gisc_unregister(struct kvm *kvm, u32 gisc); static inline void kvm_arch_hardware_disable(void) {} -static inline void kvm_arch_check_processor_compat(void *rtn) {} static inline void kvm_arch_sync_events(struct kvm *kvm) {} static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 28ebd647784c..7936af0a971f 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -227,6 +227,11 @@ int kvm_arch_hardware_enable(void) return 0; } +int kvm_arch_check_processor_compat(void) +{ + return 0; +} + static void kvm_gmap_notifier(struct gmap *gmap, unsigned long start, unsigned long end); -- cgit 1.4.1 From 0d9ce162cf46c99628cc5da9510b959c7976735b Mon Sep 17 00:00:00 2001 From: Junaid Shahid Date: Thu, 3 Jan 2019 17:14:28 -0800 Subject: kvm: Convert kvm_lock to a mutex 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 --- 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(-) (limited to 'arch/s390') diff --git a/Documentation/virtual/kvm/locking.txt b/Documentation/virtual/kvm/locking.txt index 1bb8bcaf8497..635cd6eaf714 100644 --- a/Documentation/virtual/kvm/locking.txt +++ b/Documentation/virtual/kvm/locking.txt @@ -15,8 +15,6 @@ The acquisition orders for mutexes are as follows: 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 Dirty tracking mechanism described above. ------------ Name: kvm_lock -Type: spinlock_t +Type: mutex Arch: any Protects: - vm_list diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 7936af0a971f..0fef9192f6ac 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -2423,13 +2423,13 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) 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); diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 95ac393e2959..3384c539d150 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -5956,7 +5956,7 @@ mmu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) 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; @@ -5998,7 +5998,7 @@ mmu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) break; } - spin_unlock(&kvm_lock); + mutex_unlock(&kvm_lock); return freed; } diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 10feed6a01eb..6200d5a51f13 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6719,7 +6719,7 @@ static void kvm_hyperv_tsc_notifier(void) struct kvm_vcpu *vcpu; int cpu; - spin_lock(&kvm_lock); + mutex_lock(&kvm_lock); list_for_each_entry(kvm, &vm_list, vm_list) kvm_make_mclock_inprogress_request(kvm); @@ -6745,7 +6745,7 @@ static void kvm_hyperv_tsc_notifier(void) spin_unlock(&ka->pvclock_gtod_sync_lock); } - spin_unlock(&kvm_lock); + mutex_unlock(&kvm_lock); } #endif @@ -6796,17 +6796,17 @@ static void __kvmclock_cpufreq_notifier(struct cpufreq_freqs *freq, int cpu) smp_call_function_single(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 != cpu) continue; kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu); - if (vcpu->cpu != smp_processor_id()) + if (vcpu->cpu != raw_smp_processor_id()) send_ipi = 1; } } - spin_unlock(&kvm_lock); + mutex_unlock(&kvm_lock); if (freq->old < freq->new && send_ipi) { /* @@ -6929,12 +6929,12 @@ static void pvclock_gtod_update_fn(struct work_struct *work) 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); diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 5e9fd7ad8018..abafddb9fe2c 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -162,7 +162,7 @@ static inline bool is_error_page(struct page *page) 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 { diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index b2579841263f..9613987ef4c8 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -98,7 +98,7 @@ 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); @@ -683,9 +683,9 @@ static struct kvm *kvm_create_vm(unsigned long type) 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(); @@ -731,9 +731,9 @@ static void kvm_destroy_vm(struct kvm *kvm) 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); @@ -4034,13 +4034,13 @@ static int vm_stat_get(void *_offset, u64 *val) 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; } @@ -4053,12 +4053,12 @@ static int vm_stat_clear(void *_offset, u64 val) 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; } @@ -4073,13 +4073,13 @@ static int vcpu_stat_get(void *_offset, u64 *val) 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; } @@ -4092,12 +4092,12 @@ static int vcpu_stat_clear(void *_offset, u64 val) 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; } @@ -4118,7 +4118,7 @@ static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm) 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++; @@ -4127,7 +4127,7 @@ static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm) } created = kvm_createvm_count; active = kvm_active_vms; - spin_unlock(&kvm_lock); + mutex_unlock(&kvm_lock); env = kzalloc(sizeof(*env), GFP_KERNEL_ACCOUNT); if (!env) -- cgit 1.4.1