[PATCH RFC 08/10] KVM: Add guarded_by to members in struct kvm

[Marco Elver]

Add __guarded_by annotations to a subset of members in struct kvm where
the protecting locks reside in the same struct scope. Members protected
by locks across nested or parent struct boundaries are omitted due to C
lexical scoping limitations.

No functional change intended.

Signed-off-by: Marco Elver <elver@xxxxxxxxxx>
---
 include/linux/kvm_host.h | 12 ++++++------
 virt/kvm/eventfd.c       |  4 ++--
 virt/kvm/kvm_main.c      |  3 +++
 3 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 12f241304228..36edf0a59107 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -771,7 +771,7 @@ struct kvm {
 	/* The two memslot sets - active and inactive (per address space) */
 	struct kvm_memslots __memslots[KVM_MAX_NR_ADDRESS_SPACES][2];
 	/* The current active memslot set for each address space */
-	struct kvm_memslots __rcu *memslots[KVM_MAX_NR_ADDRESS_SPACES];
+	struct kvm_memslots __rcu *memslots[KVM_MAX_NR_ADDRESS_SPACES] __guarded_by(&srcu, &slots_lock, &slots_arch_lock);
 	struct xarray vcpu_array;
 	DECLARE_BITMAP(vcpu_ids, KVM_MAX_VCPU_IDS);
 	/*
@@ -787,7 +787,7 @@ struct kvm {
 
 	/* For management / invalidation of gfn_to_pfn_caches */
 	spinlock_t gpc_lock;
-	struct list_head gpc_list;
+	struct list_head gpc_list __guarded_by(&gpc_lock);
 
 	/*
 	 * created_vcpus is protected by kvm->lock, and is incremented
@@ -801,11 +801,11 @@ struct kvm {
 	int last_boosted_vcpu;
 	struct list_head vm_list;
 	struct mutex lock;
-	struct kvm_io_bus __rcu *buses[KVM_NR_BUSES];
+	struct kvm_io_bus __rcu *buses[KVM_NR_BUSES] __guarded_by(&srcu, &slots_lock);
 #ifdef CONFIG_HAVE_KVM_IRQCHIP
 	struct {
 		spinlock_t        lock;
-		struct list_head  items;
+		struct list_head  items __guarded_by(&lock);
 		/* resampler_list update side is protected by resampler_lock. */
 		struct list_head  resampler_list;
 		struct mutex      resampler_lock;
@@ -826,9 +826,9 @@ struct kvm {
 	/*
 	 * Update side is protected by irq_lock.
 	 */
-	struct kvm_irq_routing_table __rcu *irq_routing;
+	struct kvm_irq_routing_table __rcu *irq_routing __guarded_by(&irq_srcu, &irq_lock);
 
-	struct hlist_head irq_ack_notifier_list;
+	struct hlist_head irq_ack_notifier_list __guarded_by(&irq_srcu, &irq_lock);
 #endif
 
 	struct mmu_notifier mmu_notifier;
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 6701390336f6..6051fec5ec90 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -1046,8 +1046,8 @@ void
 kvm_eventfd_init(struct kvm *kvm)
 {
 #ifdef CONFIG_HAVE_KVM_IRQCHIP
-	spin_lock_init(&kvm->irqfds.lock);
-	INIT_LIST_HEAD(&kvm->irqfds.items);
+	scoped_guard(spinlock_init, &kvm->irqfds.lock)
+		INIT_LIST_HEAD(&kvm->irqfds.items);
 	INIT_LIST_HEAD(&kvm->irqfds.resampler_list);
 	mutex_init(&kvm->irqfds.resampler_lock);
 #endif
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 2f22d5439d39..871acc3aebbd 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1111,6 +1111,7 @@ void __weak kvm_arch_create_vm_debugfs(struct kvm *kvm)
 /* Called only on cleanup and destruction paths when there are no users. */
 static inline struct kvm_io_bus *kvm_get_bus_for_destruction(struct kvm *kvm,
 							     enum kvm_bus idx)
+	__context_unsafe(/* destruction */)
 {
 	return rcu_dereference_protected(kvm->buses[idx],
 					 !refcount_read(&kvm->users_count));
@@ -1120,6 +1121,7 @@ static int kvm_enable_virtualization(void);
 static void kvm_disable_virtualization(void);
 
 static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
+	__context_unsafe(/* constructor */)
 {
 	struct kvm *kvm = kvm_arch_alloc_vm();
 	struct kvm_memslots *slots;
@@ -1276,6 +1278,7 @@ static void kvm_destroy_devices(struct kvm *kvm)
 }
 
 static void kvm_destroy_vm(struct kvm *kvm)
+	__context_unsafe(/* destructor */)
 {
 	int i;
 	struct mm_struct *mm = kvm->mm;
-- 
2.55.0.1003.g10538fe699-goog