Function register_vfio_new_id

crates/openshell-vfio/src/bind.rs:32–59

Best-effort registration of a device's vendor:device ID with `vfio-pci`. Some kernel configurations require the ID to be pre-registered in `/sys/bus/pci/drivers/vfio-pci/new_id` before `drivers_probe` will bind the device, even when `driver_override` is set. Writing an already registered ID returns `EEXIST`, which we silently ignore.

(sysfs: &SysfsRoot, bdf: &str)

/// the device, even when `driver_override` is set. Writing an already
/// registered ID returns `EEXIST`, which we silently ignore.
pub(crate) fn register_vfio_new_id(sysfs: &SysfsRoot, bdf: &str) {
    let Some(id_str) = vfio_id_string(sysfs, bdf) else {
        return;
    };

    let registration = VFIO_ID_REGISTRY.lock().unwrap().register(&id_str);

    if registration != VfioIdRegistration::FirstUser {
        tracing::debug!(
            bdf, id = %id_str,
            "vfio-pci new_id already registered by another device, refcount incremented"
        );
        return;
    }

    let new_id_path = sysfs.vfio_pci_new_id();
    match write_sysfs(&new_id_path, &id_str) {
        Ok(()) => {
            tracing::debug!(bdf, id = %id_str, "registered vfio-pci new_id");
        }
        Err(_) => {
            tracing::debug!(
                bdf, id = %id_str,
                "vfio-pci new_id write skipped (already registered or driver not loaded)"
            );
        }
    }
}

/// Best-effort deregistration of a device's vendor:device ID from `vfio-pci`.
///