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authorJunaid Shahid <junaids@google.com>2019-01-03 17:14:28 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-11-12 19:19:05 +0100
commit05fe997e30d439e3ff0c7e7e46499e9d41d98ba7 (patch)
tree196c4cd7e0733c97f2e3be15eb7b33d9f4e47897
parent82e77746f07db70367f66ef272256037d6415353 (diff)
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kvm: Convert kvm_lock to a mutex
commit 0d9ce162cf46c99628cc5da9510b959c7976735b upstream. 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 <junaids@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--Documentation/virtual/kvm/locking.txt4
-rw-r--r--arch/s390/kvm/kvm-s390.c4
-rw-r--r--arch/x86/kvm/mmu.c4
-rw-r--r--arch/x86/kvm/x86.c10
-rw-r--r--include/linux/kvm_host.h2
-rw-r--r--virt/kvm/kvm_main.c30
6 files changed, 26 insertions, 28 deletions
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 cab41bc2572f..ff62a4fe2159 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -1926,13 +1926,13 @@ 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 87a0601b1c20..3ad5a853b948 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -5454,7 +5454,7 @@ 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;
@@ -5504,7 +5504,7 @@ unlock:
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 a6f7b75da27a..06d7df4331b1 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6156,17 +6156,17 @@ static int kvmclock_cpufreq_notifier(struct notifier_block *nb, unsigned long va
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)
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) {
/*
@@ -6303,12 +6303,12 @@ 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 eeabf9823164..31d566de33e9 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -140,7 +140,7 @@ 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 1ba7c312d26a..345f6cf36043 100644
--- 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);
@@ -668,9 +668,9 @@ 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();
@@ -716,9 +716,9 @@ 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);
@@ -3830,13 +3830,13 @@ 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;
}
@@ -3849,12 +3849,12 @@ 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;
}
@@ -3869,13 +3869,13 @@ 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;
}
@@ -3888,12 +3888,12 @@ 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;
}
@@ -3914,7 +3914,7 @@ 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++;
@@ -3923,7 +3923,7 @@ 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);
if (!env)