Currently, -M q35 boots linux quite a bit slower than the default machine type. This seems to be because it takes a few hundred ms to determine that there's nothing attached to the AHCI controller.
In virtio setups, there will probably never be anything attached to the AHCI controller. Would it be possible to add something like -machine default_storage=off to turn off default storage devices? This could include the AHCI on q35 and the cdrom and such on pc. There's precedent: -machine usb=off turns off the default USB controllers, which is great for setups that use xhci. Thanks, Andy