xen/hvc: Fix error cases around HVM_PARAM_CONSOLE_PFN
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.
CC: stable@kernel.org
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
index afc7fc2..3277f0e 100644
--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -219,7 +219,8 @@
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;