VMCI: fix error handling path when registering guest driver

When host capabilities check failed or when we were unable to register doorbell
bitmap we were forgetting to set error code and were returning 0 which would
make upper layers believe that probe was successful.

Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Acked-by: Andy King <acking@vmware.com>
Signed-off-by: Dmitry Torokhov <dtor@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/vmw_vmci/vmci_guest.c

@@ -165,7 +165,7 @@ static void vmci_guest_cid_update(u32 sub_id,
  * true if required hypercalls (or fallback hypercalls) are
  * supported by the host, false otherwise.
  */
-static bool vmci_check_host_caps(struct pci_dev *pdev)
+static int vmci_check_host_caps(struct pci_dev *pdev)
 {
 	bool result;
 	struct vmci_resource_query_msg *msg;
@@ -176,7 +176,7 @@ static bool vmci_check_host_caps(struct pci_dev *pdev)
 	check_msg = kmalloc(msg_size, GFP_KERNEL);
 	if (!check_msg) {
 		dev_err(&pdev->dev, "%s: Insufficient memory\n", __func__);
-		return false;
+		return -ENOMEM;
 	}
 
 	check_msg->dst = vmci_make_handle(VMCI_HYPERVISOR_CONTEXT_ID,
@@ -196,7 +196,7 @@ static bool vmci_check_host_caps(struct pci_dev *pdev)
 		__func__, result ? "PASSED" : "FAILED");
 
 	/* We need the vector. There are no fallbacks. */
-	return result;
+	return result ? 0 : -ENXIO;
 }
 
 /*
@@ -564,12 +564,14 @@ static int vmci_guest_probe_device(struct pci_dev *pdev,
 			dev_warn(&pdev->dev,
 				 "VMCI device unable to register notification bitmap with PPN 0x%x\n",
 				 (u32) bitmap_ppn);
+			error = -ENXIO;
 			goto err_remove_vmci_dev_g;
 		}
 	}
 
 	/* Check host capabilities. */
-	if (!vmci_check_host_caps(pdev))
+	error = vmci_check_host_caps(pdev);
+	if (error)
 		goto err_remove_bitmap;
 
 	/* Enable device. */