Re: [PATCH v14 04/17] Introduce pv guest type and has_hvm_container macros

[George Dunlap <george.dunlap@eu.citrix.com>]

On 04/11/13 16:20, Jan Beulich wrote:
>>>> On 04.11.13 at 13:14, George Dunlap <george.dunlap@eu.citrix.com> wrote:
>> The goal of this patch is to classify conditionals more clearly, as to
>> whether they relate to pv guests, hvm-only guests, or guests with an
>> "hvm container" (which will eventually include PVH).
>>
>> This patch introduces an enum for guest type, as well as two new macros
>> for switching behavior on and off: is_pv_* and has_hvm_container_*.  At the
>> moment is_pv_* <=> !has_hvm_container_*.  The purpose of having two is that
>> it seems to me different to take a path because something does *not* have PV
>> structures as to take a path because it *does* have HVM structures, even if
>> the
>> two happen to coincide 100% at the moment.  The exact usage is occasionally
>> a bit
>> fuzzy though, and a judgement call just needs to be made on which is
>> clearer.
>>
>> In general, a switch should use is_pv_* (or !is_pv_*) if the code in
>> question
>> relates directly to a PV guest.  Examples include use of pv_vcpu structs or
>> other behavior directly related to PV domains.
>>
>> hvm_container is more of a fuzzy concept, but in general:
> So sadly this is still being retained, despite its redundancy.

I understood our discussion at XenSummit to be that I should send the 
series as-is, once I had fixed the outstanding bugs.  I'm inclined to 
consider Tim's suggestion (as I understand it), that we get rid of the 
separate PVH mode, but instead have a number of features which can be 
enabled and disabled (apic, qemu, &c). But that shouldn't affect the 
interface to Linux.

  -George