Re: [Xen-devel] [PATCH 6/7] xen: Allow hardare domain != dom0

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 11.04.14 at 20:22, <dgdegra@xxxxxxxxxxxxx> wrote:
> On 04/11/2014 11:20 AM, Jan Beulich wrote:
>>>>> On 11.04.14 at 17:07, <dgdegra@xxxxxxxxxxxxx> wrote:
>>> On 04/11/2014 05:13 AM, Jan Beulich wrote:
>>> Otherwise, I think the is_hardware_domain definition should be:
>>>
>>> #ifdef CONFIG_LATE_HWDOM
>>> #define is_hardware_domain(_d) ((_d)->domain_id == hardware_domid)
>>> #else
>>> #define is_hardware_domain(_d) ((_d)->domain_id == 0)
>>> #endif
>>>
>>> This also allows hardware_domid to be declared inside the #ifdef.
>>
>> But that still wouldn't necessarily do the correct thing for any use of
>> the macro before that new special case code in domain_create() got
>> run. Maybe my thinking of this is wrong, but as I tried to state above,
>> I would expect Dom0 to be the hardware domain up to the point
>> where the intended hardware domain gets created, at which point all
>> state Dom0 obtained because of having been the de-facto hardware
>> domain get transferred to hardware_domain.
> 
> I agree with this in most cases, and I think the few places where that
> is not true should be changed to make them more explicit.  This must
> include all checks in domain_create and those in functions called from
> domain_create, because (d == hardware_domain) is always false inside
> domain_create.  An initial version of this patch is below, but unless
> there are objections I plan to integrate it into patch 1 to avoid doing
> (d->domain_id == 0) => is_hardware_domain => is_hardware_domain_by_id
> for the ARM code.

Integration into any earlier patch would work only if we reverted
what was already applied.

> ------------------------------>8------------------------
> 
> Subject: [PATCH RFC 6/8] xen: introduce is_hardware_domain_by_id

Certainly not very nice a name, and also not very nice to then have
two ways to check, which likely people will not always distinguish
properly. I think this needs some better idea, albeit I can't immediately
offer one.

Jan


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