Re: [PATCH v10 02/10] xen: Add support for VMware cpuid leaves

[Julien Grall <julien.grall@citrix.com>]

Hi,

On 19/05/2015 21:02, Andrew Cooper wrote:
>> diff --git a/xen/include/public/arch-x86/xen.h b/xen/include/public/arch-x86/xen.h
>> index cea3fe7..5a5bad6 100644
>> --- a/xen/include/public/arch-x86/xen.h
>> +++ b/xen/include/public/arch-x86/xen.h
>> @@ -263,7 +263,7 @@ struct arch_shared_info {
>>   typedef struct arch_shared_info arch_shared_info_t;
>>
>>   struct xen_arch_domainconfig {
>> -    char dummy;
>> +    uint64_t vmware_hwver;
>
> Julien: (as the author of the introducing patch) Given that this
> structure is used as part of a domain_create hypercall only, I think a
> comment is warrented stating that its API/ABI is covered by the
> DOMCTL_INTERFACE_VERSION.

It's part of DOMCTL_INTERFACE_VERSION. Feel free to send a patch to add 
a comment.

> Strictly speaking, this is currently part of the public ABI which must
> always maintain backwards compatibility.

I don't think it's necessary to maintain backwards compatibility.  This 
has been added during this is release cycle.

> Don:  Feel free to retain my Reviewed-by, subject to the adjustments listed.

It's rather strange to have a separate patch for adding vmware_hwver 
version in the tools. You are relying on the fact that the toolstack 
memset zero xen_arch_domainconfig to zero which is hidden in the maze of 
the code (the memset is done on an upper container).

It would be worth to add an explicit vmware_hwver = 0 in the 
libxl__arch_domain_prepare_config.

Regards,

-- 
Julien Grall