1 files changed, 41 insertions, 14 deletions

diff --git a/drivers/s390/kvm/kvm_virtio.c b/drivers/s390/kvm/kvm_virtio.c
index 8491111aec1..a1349653c6d 100644
--- a/drivers/s390/kvm/kvm_virtio.c
+++ b/drivers/s390/kvm/kvm_virtio.c
@@ -166,11 +166,15 @@ static void kvm_reset(struct virtio_device *vdev)
  * make a hypercall.  We hand the address  of the virtqueue so the Host
  * knows which virtqueue we're talking about.
  */
-static void kvm_notify(struct virtqueue *vq)
+static bool kvm_notify(struct virtqueue *vq)
 {
+	long rc;
 	struct kvm_vqconfig *config = vq->priv;
 
-	kvm_hypercall1(KVM_S390_VIRTIO_NOTIFY, config->address);
+	rc = kvm_hypercall1(KVM_S390_VIRTIO_NOTIFY, config->address);
+	if (rc < 0)
+		return false;
+	return true;
 }
 
 /*
@@ -275,7 +279,7 @@ static const char *kvm_bus_name(struct virtio_device *vdev)
 /*
  * The config ops structure as defined by virtio config
  */
-static struct virtio_config_ops kvm_vq_configspace_ops = {
+static const struct virtio_config_ops kvm_vq_configspace_ops = {
 	.get_features = kvm_get_features,
 	.finalize_features = kvm_finalize_features,
 	.get = kvm_get,
@@ -422,35 +426,58 @@ static void kvm_extint_handler(struct ext_code ext_code,
 }
 
 /*
+ * For s390-virtio, we expect a page above main storage containing
+ * the virtio configuration. Try to actually load from this area
+ * in order to figure out if the host provides this page.
+ */
+static int __init test_devices_support(unsigned long addr)
+{
+	int ret = -EIO;
+
+	asm volatile(
+		"0:	lura	0,%1\n"
+		"1:	xgr	%0,%0\n"
+		"2:\n"
+		EX_TABLE(0b,2b)
+		EX_TABLE(1b,2b)
+		: "+d" (ret)
+		: "a" (addr)
+		: "0", "cc");
+	return ret;
+}
+/*
  * Init function for virtio
- * devices are in a single page above top of "normal" mem
+ * devices are in a single page above top of "normal" + standby mem
  */
 static int __init kvm_devices_init(void)
 {
 	int rc;
+	unsigned long total_memory_size = sclp_get_rzm() * sclp_get_rnmax();
 
 	if (!MACHINE_IS_KVM)
 		return -ENODEV;
 
+	if (test_devices_support(total_memory_size) < 0)
+		return -ENODEV;
+
+	rc = vmem_add_mapping(total_memory_size, PAGE_SIZE);
+	if (rc)
+		return rc;
+
+	kvm_devices = (void *) total_memory_size;
+
 	kvm_root = root_device_register("kvm_s390");
 	if (IS_ERR(kvm_root)) {
 		rc = PTR_ERR(kvm_root);
 		printk(KERN_ERR "Could not register kvm_s390 root device");
+		vmem_remove_mapping(total_memory_size, PAGE_SIZE);
 		return rc;
 	}
 
-	rc = vmem_add_mapping(real_memory_size, PAGE_SIZE);
-	if (rc) {
-		root_device_unregister(kvm_root);
-		return rc;
-	}
-
-	kvm_devices = (void *) real_memory_size;
-
 	INIT_WORK(&hotplug_work, hotplug_devices);
 
-	service_subclass_irq_register();
-	register_external_interrupt(0x2603, kvm_extint_handler);
+	irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
+	register_external_irq(EXT_IRQ_CP_SERVICE, kvm_extint_handler);
 
 	scan_devices();
 	return 0;