Re: [PATCH v8 2/4] xen/arm: setup MMIO range trap handlers for hardware domain

[Julien Grall]

Hi Oleksandr,

On 09/12/2021 07:29, Oleksandr Andrushchenko wrote:
+unsigned int domain_vpci_get_num_mmio_handlers(struct domain *d)
+{
+    if ( !has_vpci(d) )
+        return 0;
+
+    if ( is_hardware_domain(d) )
+    {
+        int ret = pci_host_iterate_bridges_and_count(d, 
vpci_get_num_handlers_cb);
+
+        return ret < 0 ? 0 : ret;

Sorry I only spotted this now. AFAICT, ret is not meant to return ret < 
0 in this case. But if it were then I think it would be wrong to 
continue as nothing happened because the code will likely fall 
over/crash when registering the I/O handlers.

I would document this oddity with

if ( ret < 0 )
{
   ASSERT_UNREACHABLE();
   return 0;
}

I can do the change on commit if the others are happy with it.

Cheers,

--
Julien Grall