On Sat, Mar 25, 2023 at 11:20:38PM -0700, Kuppuswamy Sathyanarayanan wrote:
> Since GetQuote support requires usage of DMA APIs, convert TDX guest
> driver to a platform driver.
Sorry, but that's not a valid reason to use a platform device for fake
things like this:
> +static struct platform_device *tdx_dev;
Especially a single static one.
> +static int tdx_guest_probe(struct platform_device *pdev)
> +{
> + if (tdx_register_event_irq_cb(attestation_callback_handler, pdev))
> + return -EIO;
> +
> + return misc_register(&tdx_misc_dev);
> +}
> +
> +static int tdx_guest_remove(struct platform_device *pdev)
> +{
> + tdx_unregister_event_irq_cb(attestation_callback_handler, pdev);
> + misc_deregister(&tdx_misc_dev);
> + return 0;
> +}
> +
> +static struct platform_driver tdx_guest_driver = {
> + .probe = tdx_guest_probe,
> + .remove = tdx_guest_remove,
> + .driver.name = KBUILD_MODNAME,
> +};
> +
> static const struct x86_cpu_id tdx_guest_ids[] = {
> X86_MATCH_FEATURE(X86_FEATURE_TDX_GUEST, NULL),
> {}
> @@ -84,16 +310,35 @@ MODULE_DEVICE_TABLE(x86cpu, tdx_guest_ids);
>
> static int __init tdx_guest_init(void)
> {
> + int ret;
> +
> if (!x86_match_cpu(tdx_guest_ids))
> return -ENODEV;
>
> - return misc_register(&tdx_misc_dev);
> + ret = platform_driver_register(&tdx_guest_driver);
> + if (ret) {
> + pr_err("failed to register driver, err=%d\n", ret);
> + return ret;
> + }
No, please do not create a fake platform driver.
> + tdx_dev = platform_device_register_simple(KBUILD_MODNAME,
> + PLATFORM_DEVID_NONE,
> + NULL, 0);
And please do not create a fake platform device.
As always, do not create fake platform devices for things that are NOT
platform devices.
If this device needs DMA (but why?) then make it a real device and tie
it to the bus it belongs to (that it is obviously doing DMA on.)
But as-is, this isn't ok, sorry.
thanks,
greg k-h
