3.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Konrad Rzeszutek Wilk <redacted>

commit a32c88b9386ce3df87f28dd46bdc3776cd6edf75 upstream.

We weren't resetting the parameter to be passed in to a
known default. Nor were we checking the return value of
hvm_get_parameter.

Signed-off-by: Konrad Rzeszutek Wilk <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/tty/hvc/hvc_xen.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c

@@ -219,7 +219,8 @@ static int xen_hvm_console_init(void)
 	if (r < 0)
 		goto err;
 	info->evtchn = v;
-	hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
+	v = 0;
+	r = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
 	if (r < 0)
 		goto err;
 	mfn = v;