Re: [PATCH] x86/HVM: rewrite the start info structure definition in binary form

["Roger Pau Monné" <roger.pau@citrix.com>]

El 5/2/16 a les 14:13, Jan Beulich ha escrit:
>>>> On 05.02.16 at 13:28, <roger.pau@citrix.com> wrote:
>> This will prevent alignments from getting in the way. It's not safe to
>> define this memory structures using C anyway, since the ABI depends on the
>> bitness, while our protocol does not.
>>
>> Also add a command line parameter to each module, and a reserved field in
>> order to have the layout aligned. Note that the current implementation in
>> libxc doesn't make use of the module command line at all.
> 
> Which would seem wrong then - what use is the field if it doesn't
> get filled? Or is that because it has nowhere to come from?

Right now it has nowhere to come from as you say.

Once we enable this ABI for Dom0 boot we are just going to copy what's
in the "string" field defined in the multiboot spec for each module
structure that's passed to Dom0. That's the primary use I can see for
this ATM.

It was requested by Samuel, and I think it's fine to add it to the spec,
even if we are not going to use it right now. Samuel requires something
like this in order to properly pass parameters to boot modules in gnumach.

> But
> even then - wouldn't what I've read on the other thread mean
> at least the filename should be put there (as kind of the first
> command line element)?

Really? I didn't get that impression at all, what's the filename useful
for anyway?

IMHO this would need plumbing through libxl/xl in order to be able to
specify command line arguments for modules, which is something that we
don't support at the moment.

Roger.