summaryrefslogtreecommitdiff
path: root/drivers/xen/xenbus/xenbus_probe.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/xen/xenbus/xenbus_probe.c')
-rw-r--r--drivers/xen/xenbus/xenbus_probe.c27
1 files changed, 26 insertions, 1 deletions
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index bd003ca8acbe..fe360c33ce71 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -909,7 +909,7 @@ static struct notifier_block xenbus_resume_nb = {
static int __init xenbus_init(void)
{
- int err = 0;
+ int err;
uint64_t v = 0;
xen_store_domain_type = XS_UNKNOWN;
@@ -949,6 +949,29 @@ static int __init xenbus_init(void)
err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
if (err)
goto out_error;
+ /*
+ * Uninitialized hvm_params are zero and return no error.
+ * Although it is theoretically possible to have
+ * HVM_PARAM_STORE_PFN set to zero on purpose, in reality it is
+ * not zero when valid. If zero, it means that Xenstore hasn't
+ * been properly initialized. Instead of attempting to map a
+ * wrong guest physical address return error.
+ *
+ * Also recognize all bits set as an invalid value.
+ */
+ if (!v || !~v) {
+ err = -ENOENT;
+ goto out_error;
+ }
+ /* Avoid truncation on 32-bit. */
+#if BITS_PER_LONG == 32
+ if (v > ULONG_MAX) {
+ pr_err("%s: cannot handle HVM_PARAM_STORE_PFN=%llx > ULONG_MAX\n",
+ __func__, v);
+ err = -EINVAL;
+ goto out_error;
+ }
+#endif
xen_store_gfn = (unsigned long)v;
xen_store_interface =
xen_remap(xen_store_gfn << XEN_PAGE_SHIFT,
@@ -983,8 +1006,10 @@ static int __init xenbus_init(void)
*/
proc_create_mount_point("xen");
#endif
+ return 0;
out_error:
+ xen_store_domain_type = XS_UNKNOWN;
return err;
}