KVM: Disable compat ioctl for s390

We never had a 31bit QEMU/kuli running. We would need to review several
ioctls to check if this creates holes, bugs or whatever to make it work.
Lets just disable compat support for KVM on s390.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>

virt/kvm/Kconfig

@@ -43,3 +43,7 @@ config HAVE_KVM_ARCH_TLB_FLUSH_ALL
 
 config KVM_GENERIC_DIRTYLOG_READ_PROTECT
        bool
+
+config KVM_COMPAT
+       def_bool y
+       depends on COMPAT && !S390

virt/kvm/kvm_main.c

@@ -92,7 +92,7 @@ struct dentry *kvm_debugfs_dir;
 
 static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
 			   unsigned long arg);
-#ifdef CONFIG_COMPAT
+#ifdef CONFIG_KVM_COMPAT
 static long kvm_vcpu_compat_ioctl(struct file *file, unsigned int ioctl,
 				  unsigned long arg);
 #endif
@@ -2052,7 +2052,7 @@ static int kvm_vcpu_release(struct inode *inode, struct file *filp)
 static struct file_operations kvm_vcpu_fops = {
 	.release        = kvm_vcpu_release,
 	.unlocked_ioctl = kvm_vcpu_ioctl,
-#ifdef CONFIG_COMPAT
+#ifdef CONFIG_KVM_COMPAT
 	.compat_ioctl   = kvm_vcpu_compat_ioctl,
 #endif
 	.mmap           = kvm_vcpu_mmap,
@@ -2342,7 +2342,7 @@ out:
 	return r;
 }
 
-#ifdef CONFIG_COMPAT
+#ifdef CONFIG_KVM_COMPAT
 static long kvm_vcpu_compat_ioctl(struct file *filp,
 				  unsigned int ioctl, unsigned long arg)
 {
@@ -2434,7 +2434,7 @@ static int kvm_device_release(struct inode *inode, struct file *filp)
 
 static const struct file_operations kvm_device_fops = {
 	.unlocked_ioctl = kvm_device_ioctl,
-#ifdef CONFIG_COMPAT
+#ifdef CONFIG_KVM_COMPAT
 	.compat_ioctl = kvm_device_ioctl,
 #endif
 	.release = kvm_device_release,
@@ -2721,7 +2721,7 @@ out:
 	return r;
 }
 
-#ifdef CONFIG_COMPAT
+#ifdef CONFIG_KVM_COMPAT
 struct compat_kvm_dirty_log {
 	__u32 slot;
 	__u32 padding1;
@@ -2768,7 +2768,7 @@ out:
 static struct file_operations kvm_vm_fops = {
 	.release        = kvm_vm_release,
 	.unlocked_ioctl = kvm_vm_ioctl,
-#ifdef CONFIG_COMPAT
+#ifdef CONFIG_KVM_COMPAT
 	.compat_ioctl   = kvm_vm_compat_ioctl,
 #endif
 	.llseek		= noop_llseek,