KVM: Keep an upper bound of initialized vcpus

That way, we don't need to loop for KVM_MAX_VCPUS for a single vcpu
vm.

Signed-off-by: Avi Kivity <avi@qumranet.com>

diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index d49b16c..528a56b 100644 (file)
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -379,6 +379,7 @@ struct kvm {
        struct list_head active_mmu_pages;
        int n_free_mmu_pages;
        struct hlist_head mmu_page_hash[KVM_NUM_MMU_PAGES];
+       int nvcpus;
        struct kvm_vcpu vcpus[KVM_MAX_VCPUS];
        int memory_config_version;
        int busy;

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 5564169..4e1a017 100644 (file)
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -2391,6 +2391,11 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, int n)
        if (r < 0)
                goto out_free_vcpus;
 
+       spin_lock(&kvm_lock);
+       if (n >= kvm->nvcpus)
+               kvm->nvcpus = n + 1;
+       spin_unlock(&kvm_lock);
+
        return r;
 
 out_free_vcpus: