After registering with this notifier, other drivers that are dependent on KVM can get notified whenever a VM is created or destroyed. This also provides a way for sharing the KVM instance pointer with other drivers.
Signed-off-by: Vivek Kasireddy vivek.kasireddy@intel.com --- include/linux/kvm_host.h | 5 +++++ virt/kvm/kvm_main.c | 20 ++++++++++++++++++-- 2 files changed, 23 insertions(+), 2 deletions(-)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index f3b1013fb22c..fc1a688301a0 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -88,6 +88,9 @@ #define KVM_PFN_ERR_HWPOISON (KVM_PFN_ERR_MASK + 1) #define KVM_PFN_ERR_RO_FAULT (KVM_PFN_ERR_MASK + 2)
+#define KVM_EVENT_CREATE_VM 0 +#define KVM_EVENT_DESTROY_VM 1 + /* * error pfns indicate that the gfn is in slot but faild to * translate it to pfn on host. @@ -1494,5 +1497,7 @@ static inline void kvm_handle_signal_exit(struct kvm_vcpu *vcpu)
/* Max number of entries allowed for each kvm dirty ring */ #define KVM_DIRTY_RING_MAX_ENTRIES 65536 +int kvm_vm_register_notifier(struct notifier_block *nb); +int kvm_vm_unregister_notifier(struct notifier_block *nb);
#endif diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 5f260488e999..8a0e8bb02a5f 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -101,6 +101,8 @@ DEFINE_MUTEX(kvm_lock); static DEFINE_RAW_SPINLOCK(kvm_count_lock); LIST_HEAD(vm_list);
+static struct blocking_notifier_head kvm_vm_notifier; + static cpumask_var_t cpus_hardware_enabled; static int kvm_usage_count; static atomic_t hardware_enable_failed; @@ -148,12 +150,20 @@ static void kvm_io_bus_destroy(struct kvm_io_bus *bus); __visible bool kvm_rebooting; EXPORT_SYMBOL_GPL(kvm_rebooting);
-#define KVM_EVENT_CREATE_VM 0 -#define KVM_EVENT_DESTROY_VM 1 static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm); static unsigned long long kvm_createvm_count; static unsigned long long kvm_active_vms;
+inline int kvm_vm_register_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_register(&kvm_vm_notifier, nb); +} + +inline int kvm_vm_unregister_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_unregister(&kvm_vm_notifier, nb); +} + __weak void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm, unsigned long start, unsigned long end) { @@ -808,6 +818,8 @@ static struct kvm *kvm_create_vm(unsigned long type)
preempt_notifier_inc();
+ blocking_notifier_call_chain(&kvm_vm_notifier, + KVM_EVENT_CREATE_VM, kvm); return kvm;
out_err: @@ -886,6 +898,8 @@ static void kvm_destroy_vm(struct kvm *kvm) preempt_notifier_dec(); hardware_disable_all(); mmdrop(mm); + blocking_notifier_call_chain(&kvm_vm_notifier, + KVM_EVENT_DESTROY_VM, kvm); }
void kvm_get_kvm(struct kvm *kvm) @@ -4968,6 +4982,8 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align, r = kvm_vfio_ops_init(); WARN_ON(r);
+ BLOCKING_INIT_NOTIFIER_HEAD(&kvm_vm_notifier); + return 0;
out_unreg: