[PATCH 09/10] kvm: struct kvm_memory_slot.id -> short

[Alex Williamson]

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.

Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
---
 include/linux/kvm_host.h |    4 ++--
 virt/kvm/kvm_main.c      |    2 ++
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 641f5fb..87089dd 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -255,7 +255,7 @@ struct kvm_memory_slot {
 	struct kvm_arch_memory_slot arch;
 	unsigned long userspace_addr;
 	u32 flags;
-	int id;
+	short id;
 	bool user_alloc;
 };
 
@@ -315,7 +315,7 @@ 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
index 6eeb101..6e4709f 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -469,6 +469,8 @@ 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)

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