Re: [Qemu-devel] [PATCH 1/4] vmxnet3: The vmxnet3 device is a PCIE endpoint

[Shmulik Ladkani <shmulik.ladkani@ravellosystems.com>]

Hi,

On Wed, 25 Nov 2015 16:24:39 +0800 Jason Wang <jasowang@redhat.com> wrote:
> >>> @@ -2568,6 +2572,7 @@ static void vmxnet3_class_init(ObjectClass *class, void *data)
> >>>      c->class_id = PCI_CLASS_NETWORK_ETHERNET;
> >>>      c->subsystem_vendor_id = PCI_VENDOR_ID_VMWARE;
> >>>      c->subsystem_id = PCI_DEVICE_ID_VMWARE_VMXNET3;
> >>> +    c->is_express = 1;
> >> Should we do this conditionally? And how about the migration
> >> compatibility? Looks like pcie device is using vmstate_pcie_device
> >> instead of vmstate_pci_device, maybe need a new property bit for this.
> > (Responding for the entire series)
> >
> > Agreed. Will limit these changes for new versions.
> >
> > What's your suggested plan?
> > Does it make sense to have a property for each change (as they are not
> > necessarily related), or is it too tedious and one property will suffice?
> 
> Since they are not necessarily related, we'd better use a property for
> each change.

Would it make sense if we expose a new vmxnet3 type to differenciate
pcie vs pci instances of vmxnet3?

Otherwise, migration gets more complicated, as we need to use either
vmstate_pci_device or vmstate_pcie_device; also, upon vm load, we need
to preserve the semantics saved (whether the instance was pci or pcie).

I have managed to do so, but is a bit tedious; Exposing a new type seems
cleaner.