Re: [Xen-devel] [PATCH v10] x86/hvm: Allow guest_request vm_events coming from userspace

[Tamas K Lengyel <tamas@xxxxxxxxxxxxx>]

On Tue, Aug 29, 2017 at 3:36 AM, Jan Beulich <JBeulich@xxxxxxxx> wrote:
>>>> On 29.08.17 at 11:23, <aisaila@xxxxxxxxxxxxxxx> wrote:
>> In some introspection usecases, an in-guest agent needs to communicate
>> with the external introspection agent.  An existing mechanism is
>> HVMOP_guest_request_vm_event, but this is restricted to kernel usecases
>> like all other hypercalls.
>>
>> Introduce a mechanism whereby the introspection agent can whitelist the
>> use of HVMOP_guest_request_vm_event directly from userspace.
>>
>> Signed-off-by: Alexandru Isaila <aisaila@xxxxxxxxxxxxxxx>
>> Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>
>
> For the pieces it applies to
> Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
>
> However, as I keep looking at pieces which shouldn't really require
> my attention, I've noticed one more cosmetic issue:
>
>> --- a/xen/include/asm-arm/monitor.h
>> +++ b/xen/include/asm-arm/monitor.h
>> @@ -26,6 +26,12 @@
>>  #include <public/domctl.h>
>>
>>  static inline
>> +void arch_monitor_allow_userspace(struct domain *d, bool allow_userspace)
>> +{
>> +    return;
>> +}
>
> I don't see the point of the return statement here. But I'll leave
> it to the ARM maintainers, and it would be easy to drop while
> committing if no other issues are going to arise.
>

I would bet that a sane compiler wouldn't generate anything for that
with or without return in there but sure, if we can drop it then why
not.

Tamas

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel