Re: [PATCH v2 1/3] Add vmware_hw to xl.cfg

[Ian Campbell <Ian.Campbell@citrix.com>]

On Tue, 2014-09-09 at 13:02 -0400, Don Slutz wrote:
> On 09/09/14 05:39, Ian Campbell wrote:
> > Just updating the description to give users some clue as to what number
> > they should use would be enough.
> 
> How does the following look:
> 
>    vmware_hw numbers come from VMware config files.
> 
>    In a .vmx it is virtualHW.version
> 
>    In a .ovf it is part of the value of vssd:VirtualSystemType
> 
>    for vssd:VirtualSystemType == vmx-07, vmware_hw = 7
> 
> Should I refer them to the vmware web site?

Probably. Will the above make sense to a normal vmware user? Since it is
essentially Greek to me. The includes how to dig into a .vmx or .ovf to
find these values. e..g are they plain text files? Are specific tools
needed?

> >>> Other than parroting this value back to the guest in a cpuid leaf does
> >>> this value control anything else? If so then we may want to consider
> >>> something like an enum to allow us to advertise more precisely which
> >>> versions of vmware we are prepared to ape, but at the least we need to
> >>> range check this input somewhere along the way.
> >> See above, mostly just QEMU.
> > What does qemu do with a number which it doesn't understand, perhaps
> > corresponding to a newer vmware version which it hasn't learnt about
> > yet?
> 
> My version currently checks for various ranges.  Like != 0, >= 4,
>  >= 4 && < 7, >= 7.  I do not expect that I can upstream it with this,
> but it should be similar.
> 
> 
> > This sort of issue is why I was proposing an enum, or at least some sort
> > of range checking.
> 
> Since most of the use is in QEMU, I see no need for an enum in xen.
> All xen uses I know of are == 0 or != 0.  I can add some range checking
> but think a warning might be better so that a newer QEMU with support
> for a given value could be used with an older xen without change to
> xen.

Will qemu error out in an obvious way if an unsupported number is used?