Re: [Xen-devel] [PATCH 2/2] xen: add update indicator to vcpu_runstate_info

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 20.05.16 at 17:54, <JGross@xxxxxxxx> wrote:
> On 20/05/16 17:36, Jan Beulich wrote:
>>>>> On 20.05.16 at 17:04, <JGross@xxxxxxxx> wrote:
>>> On 20/05/16 16:49, Jan Beulich wrote:
>>>>>>> On 20.05.16 at 15:22, <JGross@xxxxxxxx> wrote:
>>>>>      if ( guest_handle_is_null(runstate_guest(v)) )
>>>>>          return 1;
>>>>>  
>>>>> +    update_flag = VM_ASSIST(v->domain, runstate_update_flag);
>>>>> +
>>>>>      smap_policy = smap_policy_change(v, SMAP_CHECK_ENABLED);
>>>>>  
>>>>> +    if ( update_flag )
>>>>> +    {
>>>>> +        off = offsetof(struct vcpu_runstate_info, state_entry_time) + 7;
>>>>
>>>> How come this is outside the following if()? Also sizeof(...) - 1 please
>>>> instead of the literal 7.
>>>
>>> I'm using off for the source address in __raw_copy_to_guest(), too.
>> 
>> But the offset should, afaict, be different for 32-bit (x86) and
>> 64-bit (or ARM).
> 
> Why? The offset is applied to v->runstate which clearly is the same
> for 32 and 64 bit domains, as it is the hypervisor private structure.
> Different offsets have to be applied at the destination side only, and
> this is done properly (at least I think so).

But as you say you use the offset for two purposes: The use on
the guest handle is which is problematic; the use on the hypervisor
internal structure is of course fine.

Jan


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