Merge branches 'cleanup-udc' and 'cleanup-dma' into cleanup

[~andy/linux] / drivers / tty / hvc / hvc_xen.c

diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
index d3d91dae065cfdceb3c6b4918c27ad6c252caf33..944eaeb8e0cff62b89ea735b0d98e167ddd806d0 100644 (file)
--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -214,24 +214,24 @@ static int xen_hvm_console_init(void)
        /* already configured */
        if (info->intf != NULL)
                return 0;
-
+       /*
+        * If the toolstack (or the hypervisor) hasn't set these values, the
+        * default value is 0. Even though mfn = 0 and evtchn = 0 are
+        * theoretically correct values, in practice they never are and they
+        * mean that a legacy toolstack hasn't initialized the pv console correctly.
+        */
        r = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
-       if (r < 0) {
-               kfree(info);
-               return -ENODEV;
-       }
+       if (r < 0 || v == 0)
+               goto err;
        info->evtchn = v;
-       hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
-       if (r < 0) {
-               kfree(info);
-               return -ENODEV;
-       }
+       v = 0;
+       r = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
+       if (r < 0 || v == 0)
+               goto err;
        mfn = v;
        info->intf = ioremap(mfn << PAGE_SHIFT, PAGE_SIZE);
-       if (info->intf == NULL) {
-               kfree(info);
-               return -ENODEV;
-       }
+       if (info->intf == NULL)
+               goto err;
        info->vtermno = HVC_COOKIE;
 
        spin_lock(&xencons_lock);
@@ -239,6 +239,9 @@ static int xen_hvm_console_init(void)
        spin_unlock(&xencons_lock);
 
        return 0;
+err:
+       kfree(info);
+       return -ENODEV;
 }
 
 static int xen_pv_console_init(void)