KVM: Add build-time error check on kvm_run size

It's already going to reach 2400 Bytes (which is over half of page
size on 4K page archs), so maybe it's good to have this build-time
check in case it overflows when adding new fields.

Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 929d7fc..4f3ac8b 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2710,6 +2710,7 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
                goto vcpu_decrement;
        }
 
+       BUILD_BUG_ON(sizeof(struct kvm_run) > PAGE_SIZE);
        page = alloc_page(GFP_KERNEL | __GFP_ZERO);
        if (!page) {
                r = -ENOMEM;