KVM: struct kvm_memory_slot.id -> short

We're currently offering a whopping 32 memory slots to user space, an int is a bit excessive for storing this. We would like to increase our memslots, but SHRT_MAX should be more than enough. Reviewed-by: Gleb Natapov <[email protected]> Signed-off-by: Alex Williamson <[email protected]> Signed-off-by: Marcelo Tosatti <[email protected]>
progmanos · Dec 14, 2012 · 1e702d9 · 1e702d9
1 parent 6104f47
commit 1e702d9
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Showing 2 changed files with 4 additions and 2 deletions.
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
@@ -270,7 +270,7 @@ struct kvm_memory_slot {
 	struct kvm_arch_memory_slot arch;
 	unsigned long userspace_addr;
 	u32 flags;
-	int id;
+	short id;
 	bool user_alloc;
 };
 
@@ -330,7 +330,7 @@ struct kvm_memslots {
 	u64 generation;
 	struct kvm_memory_slot memslots[KVM_MEM_SLOTS_NUM];
 	/* The mapping table from slot id to the index in memslots[]. */
-	int id_to_index[KVM_MEM_SLOTS_NUM];
+	short id_to_index[KVM_MEM_SLOTS_NUM];
 };
 
 struct kvm {

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
@@ -474,6 +474,8 @@ static struct kvm *kvm_create_vm(unsigned long type)
 	INIT_HLIST_HEAD(&kvm->irq_ack_notifier_list);
 #endif
 
+	BUILD_BUG_ON(KVM_MEM_SLOTS_NUM > SHRT_MAX);
+
 	r = -ENOMEM;
 	kvm->memslots = kzalloc(sizeof(struct kvm_memslots), GFP_KERNEL);
 	if (!kvm->memslots)