Re: [PATCH for-4.5 v6 05/16] tools: Add vmware_port support

[Don Slutz <dslutz@verizon.com>]

On 09/22/14 12:34, Andrew Cooper wrote:
> On 22/09/14 14:41, Ian Campbell wrote:
>> On Sat, 2014-09-20 at 14:07 -0400, Don Slutz wrote:
>>> This new libxl_domain_create_info field is used to set
>>> XEN_DOMCTL_CDF_vmware_port for the xc_domain_create() routine.
>> Does this really need to be a CDF, rather than a domctl/hvm param?
> I have made the argument that many things which are currently HVM Params
> should be CDF, as they absolutely should be set and immutable for the
> entire lifetime of the domain.
>
>  From recollection, we have had several XSAs in the past which are
> directly attributable to the toolstack or guest being able to play with
> an (insufficiently locked down) HVM param after boot.
>
> Using a CDF avoids potential issues along these lines.

It also allow setting up v->arch.hvm_vmx.exception_bitmap at
the right time.  domctl/hvm params are setup much latter in
the life of a domain.

>> The latter would allow moving to buildinfo.u.hvm, which would be nicer
>> from the libxl PoV, I think.
>>
> Whatever the decision regarding CDF/hvmparam/other is, getting it right
> in the hypervisor is a much higher priority than being nice in libxl.
>
> It is unfortunate that libxl exposes the internal implementation details
> of createinfo vs buildinfo in its API.  With hindsight, it was a poor
> design decision.

     -Don Slutz

> ~Andrew
>