quoted
+
+ /*
+ * Allocate a power of 2 size so alignment to that size is
+ * guaranteed, since the hypercall input and output areas
+ * must not cross a page boundary.
+ */
+ input = kzalloc(roundup_pow_of_two(sizeof(input->header) +
+ sizeof(input->element[0])), GFP_ATOMIC);
+ output = kmalloc(roundup_pow_of_two(sizeof(*output)), GFP_ATOMIC);
+
Check for null from these malloc routines? Here and in other places.
Between, is there a plan to setup a percpu input/output page for hypercall
input/output on ARM (like we do for x64)? I didn't check the specific size requirement
for this particular call, but, that generally will remove the need for these
allocations.