Re: [Qemu-devel] [PATCH V19 1/7] Support for TPM command line options

[Stefan Berger]

On 11/08/2012 10:52 AM, Corey Bryant wrote:
> On 10/24/2012 03:06 PM, Stefan Berger wrote:
> > On 09/27/2012 10:12 AM, Corey Bryant wrote:
> > > On 06/04/2012 03:37 PM, Stefan Berger wrote:
> >
> > > > +    if (!QLIST_EMPTY(&tpm_backends)) {
> > > > +        error_report("Only one TPM is allowed.\n");
> > > > +        return 1;
> > > > +    }
> > >
> > > A list of tpm_backends is maintained and walked in a few places, but
> > > only one is allowed to be added to the list.  Will it ever make sense
> > > to enable multiple backends at one time?
> >
> > A list is also returned through the monitor. This list can at the moment
> > only have maximum of one entry. I would keep that list there unless
> > someone else opposes. It may be possible to create different types of
> > hardware emulation interfaces or simply replicate the TPM TIS at
> > different addresses. So I cannot say whether it will 'ever make sense'
> > to do that but I'd rather keep the opportunity there than close it and
> > with that also let the monitor return a list of items rather than a
> > single item.
> >
> > I removed the processing of the lists in this part of the code at least.
>
> Ok and it doesn't hurt to keep the list processing.  In that case you 
> might as well keep the list processing code everywhere that you 
> already have it.

I was only going to keep it in the monitor part now...
+ */
> > > > +int tpm_config_parse(QemuOptsList *opts_list, const char *optarg)
> > > > +{
> > > > +    QemuOpts *opts;
> > > > +
> > > > +    if (strcmp("none", optarg) != 0) {
> > >
> > > What's the point of supporting "-tpmdev none"?
> >
> > Removed.
>
> There must have been a reason you added it in the first place that I'm 
> just not aware of.  Did someone else suggest adding it?

Not that I can remember.The option would have been useful if every VM by 
default had a TPM, similar to the physical world today, but it's 
unlikely that this will happen.


Regards,
    Stefan