Re: [Xen-devel] [PATCH 0/3] libxl: add framework for device types

[Ian Jackson <ian.jackson@xxxxxxxxxxxxx>]

Juergen Gross writes ("Re: [PATCH 0/3] libxl: add framework for device types"):
> On 06/07/16 14:47, Ian Jackson wrote:
> > Juergen Gross writes ("Re: [PATCH 0/3] libxl: add framework for device 
> > types"):
> >> On 06/07/16 13:04, Ian Jackson wrote:
> >>>> +    for (i = 0; i < d_config->num_pcidevs; i++) {
> >>>> +        rc = libxl__device_pci_add(gc, domid, &d_config->pcidevs[i], 1);
> >>>> +        if (rc < 0) {
> >>>> +            LOG(ERROR, "libxl_device_pci_add failed: %d", rc);
> >>>> +            goto out;
> >>>> +        }
> >>>> +    }
> >>>> +
> >>>
> >>> And there is similar code in 3/3 for dtdevs.  Could that be lifted
> >>> away somehow ?  (You'd have to take some care about the types, sadly;
> >>> ie, I think libxl__device_pci_add might have to start to take a
> >>> void*; maybe some macros could make things typesafe?)
> >>
> >> I thought about this idea already. I think we would end up with more
> >> code which would be rather unpleasant to read. Main reason is the
> >> need for a dtdev wrapper function and the pci backend creation.
> > 
> > I'm not sure what you mean by dtdev wrapper function.
> 
> The loop for dtdev calls a xc_ function with different parameters than
> the one for pci. We'd need a libxl__device_dtdev_add() wrapper function
> to do the xc_ call.

Oh, I see.

Sorry.  I was just suggesting that the iteration over the devices, and
the error handling, could be lifted out.  Not the contents of
libxl__device_FOO_add.

And yes, we'd need libxl__device_dtdev_add.

> 
> > But if you don't think this is feasible I won't insist on it.  The
> > approach you have is already a big improvement.
> 
> Thanks.
> 
> I'm planning to add more to it (e.g. I'd like to get rid of the
> MERGE() macro in libxl_retrieve_domain_configuration() in favor of a
> device type hook in order to be able to have _all_ stuff for one type
> in one source file.

Right.  That would be brilliant.

Ian.

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