Re: [PATCH v8 02/18] hw/usb/hcd-xhci: Add an auto-hub property and leave it off

[Junjie Cao <junjie.cao@xxxxxxxxx>]

Hi Jamin,

On Mon, Nov 02, 2026 at 09:22:05AM +0000, Jamin Lin wrote:
> Add auto-hub and leave it off. hw_compat_11_1 turns it on, so an older
> machine type keeps the hub it has today and a guest saved by an older
> QEMU still loads.

Reran the migration check from v7: with pc-q35-11.1, a guest saved
without the series loads on v8 with the hub in place, for qemu-xhci
with four HID devices and for q35 -usb with six.

But this missed the 11.2 soft freeze, so in 12.0 pc-q35-11.2 is an old
machine type too, and hw_compat_11_1 (my suggestion on v7) doesn't
cover it. Saved with pc-q35-11.2 on master, both cases fail on v8:

  Unknown section or instance '0000:00:01.0/4/usb-hub' 0
  Unknown section or instance '0000:00:1d.7/6/usb-hub' 0

The entries from 02-05 want hw_compat_11_2 once the 12.0 machine types
are in.

Junjie