Re: [PATCH v7 3/7] usb/hcd-xhci: Split pci wrapper for xhci base model

[Gerd Hoffmann]

  Hi,

> +static const VMStateDescription vmstate_xhci_pci = {
> +    .name = "xhci-pci",
> +    .version_id = 1,
> +    .fields = (VMStateField[]) {
> +        VMSTATE_PCI_DEVICE(parent_obj, XHCIPciState),
> +        VMSTATE_MSIX(parent_obj, XHCIPciState),
> +        VMSTATE_UINT8_ARRAY(msix_used, XHCIPciState, MAXINTRS),
> +        VMSTATE_END_OF_LIST()
> +    }
> +};

> @@ -3634,7 +3527,6 @@ static const VMStateDescription vmstate_xhci_intr = {
>          VMSTATE_UINT32(erdp_high,     XHCIInterrupter),
>  
>          /* state */
> -        VMSTATE_BOOL(msix_used,       XHCIInterrupter),
>          VMSTATE_BOOL(er_pcs,          XHCIInterrupter),
>          VMSTATE_UINT64(er_start,      XHCIInterrupter),
>          VMSTATE_UINT32(er_size,       XHCIInterrupter),
> @@ -3657,9 +3549,6 @@ static const VMStateDescription vmstate_xhci = {
>      .version_id = 1,
>      .post_load = usb_xhci_post_load,
>      .fields = (VMStateField[]) {
> -        VMSTATE_PCI_DEVICE(parent_obj, XHCIState),
> -        VMSTATE_MSIX(parent_obj, XHCIState),
> -
>          VMSTATE_STRUCT_VARRAY_UINT32(ports, XHCIState, numports, 1,
>                                       vmstate_xhci_port, XHCIPort),
>          VMSTATE_STRUCT_VARRAY_UINT32(slots, XHCIState, numslots, 1,

Uh oh, that'll break cross-version live migration (i.e. save state with
5.1, load with 5.2).  Sorry for not noticing this earlier.

You can't remove the msix_used field.  I guess easiest is to just leave
that in XHCIInterrupter even if only xhci-pci actually uses it.

The vmstate_xhci + vmstate_xhci_pci reorganization should work with a
few changes:
 * First it must be one vmstate which keeps the fields in order.
   I think you can do that by not registering vmstate_xhci directly, but
   using an VMSTATE_STRUCT() entry in vmstate_xhci_pci.
 * Second the name must not change, so vmstate_xhci_pci must continue to
   use the "xhci" name.
 * I think for vmstates referenced by VMSTATE_STRUCT the name doesn't
   matter, so you could rename vmstate_xhci to -- for example --
   "xhci-core" so vmstate_xhci and vmstate_xhci_pci have different
   names.

take care,
  Gerd