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

[Don Slutz <dslutz@xxxxxxxxxxx>]

On 09/23/14 08:20, Ian Campbell wrote:
> On Mon, 2014-09-22 at 12:42 -0400, Don Slutz wrote:
> > > The latter would allow moving to buildinfo.u.hvm, which would be nicer
> > > from the libxl PoV, I think.
> > I could not find "buildinfo.u.hvm":
> >
> >
> > dcs-xen-54:~/xen>git grep buildinfo.u.hvm
> > dcs-xen-54:~/xen>
> >
> >
> > So unable to comment.
> It's in the idl, next to createinfo.
I take that to mean:


libxl_domain_config = Struct("domain_config", [
    ("c_info", libxl_domain_create_info),
    ("b_info", libxl_domain_build_info),
...

I.E.

b_info->u.hvm


> > > If yes then I still think you would want to set the default based on
> > > vmware-hw, wouldn't you?
> > I guess so since this is a BOOLEAN.
> defbool I hope.
Yes.

> >    Currently I do not know of a way to
> > say "set vmware_hw to 7
> > if vmware_port is true and vmware_hw is not specified".
> That's an error case, isn't it? Or at least a vmware_port is ignored
> case.
Nope.  But I will agree that I have not done a lot with 3 (at least)
state booleans.  The 3 states being true, false, and not specified.

And vmware_port is not ignored.

> What I suggested was "if vmware_hw is non-zero then set vmware_port".
I am reading that as "set vmware_port if not specified".  To avoid
complexity, I am treating vmware_hw as a boolean.  Using this
I get the following table:

_hw   _port
 0     0        Just like today
 1     0        Only cpuid leaves change -- very unlikey
 1     1        Full VMware mode
 0     1        VMware hyper call mode.

Adding U for unspecified:

_hw   _port
 U     U        ==> _hw=0 _port=0
 0     U        ==> _hw=0 _port=0
 1     U        The case in question.
 U     0        ==> _hw=0 _port=0
 U     1        What I was talking about.
 0     0        Just like today
 1     0        Only cpuid leaves change -- very unlikey
 1     1        Full VMware mode
 0     1        VMware hyper call mode.

The problem here is that vmware_hw is not a boolean and there is
currently not a value that lets you know it has not been specified.

So I think it is just more confusing to have vmware_hw change
the default of vmware_port but the inverse is not true.

   -Don Slutz

> >    Which would be
> > the inverse.  I lean to
> > not having the default of vmware_port based on vmware_hw.


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