linux-kernel - Re: [PATCH v3 10/26] coco/tdx-host: Implement FW

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Message-ID: <065fcf039eacf79c1566a15fb1dc935b3ac1dc5a.camel@intel.com>
Date: Wed, 28 Jan 2026 03:30:33 +0000
From: "Huang, Kai" <kai.huang@...el.com>
To: "kvm@...r.kernel.org" <kvm@...r.kernel.org>, "linux-coco@...ts.linux.dev"
	<linux-coco@...ts.linux.dev>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, "Gao, Chao" <chao.gao@...el.com>,
	"x86@...nel.org" <x86@...nel.org>
CC: "dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>,
	"kas@...nel.org" <kas@...nel.org>, "seanjc@...gle.com" <seanjc@...gle.com>,
	"Chatre, Reinette" <reinette.chatre@...el.com>, "Weiny, Ira"
	<ira.weiny@...el.com>, "tglx@...utronix.de" <tglx@...utronix.de>, "Verma,
 Vishal L" <vishal.l.verma@...el.com>, "nik.borisov@...e.com"
	<nik.borisov@...e.com>, "mingo@...hat.com" <mingo@...hat.com>,
	"hpa@...or.com" <hpa@...or.com>, "sagis@...gle.com" <sagis@...gle.com>,
	"Chen, Farrah" <farrah.chen@...el.com>, "Duan, Zhenzhong"
	<zhenzhong.duan@...el.com>, "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>,
	"paulmck@...nel.org" <paulmck@...nel.org>, "Annapurve, Vishal"
	<vannapurve@...gle.com>, "yilun.xu@...ux.intel.com"
	<yilun.xu@...ux.intel.com>, "Williams, Dan J" <dan.j.williams@...el.com>,
	"bp@...en8.de" <bp@...en8.de>
Subject: Re: [PATCH v3 10/26] coco/tdx-host: Implement FW_UPLOAD sysfs ABI for
 TDX Module updates


> 2. TDX Module Updates complete synchronously within .write(), meaning
>    .poll_complete() is only called after successful updates and therefore
>    always returns success

Nit:

Why "updates" instead of "update"?  Is there multiple updates possible
within .write()?

[...]

> 
>  
> +struct tdx_fw_upload_status {
> +	bool cancel_request;
> +};
> +
> +struct fw_upload *tdx_fwl;

Can 'tdx_fwl' be static?

[...]

> 
> +static void seamldr_init(struct device *dev)
> +{
> +	const struct tdx_sys_info *tdx_sysinfo = tdx_get_sysinfo();
> +	int ret;
> +
> +	if (WARN_ON_ONCE(!tdx_sysinfo))
> +		return;
> +
> +	if (!IS_ENABLED(CONFIG_INTEL_TDX_MODULE_UPDATE))
> +		return;
> +
> +	if (!tdx_supports_runtime_update(tdx_sysinfo))
> +		pr_info("Current TDX Module cannot be updated. Consider BIOS updates\n");

What's the point of continuing if runtime update is not supported?

> +
> +	tdx_fwl = firmware_upload_register(THIS_MODULE, dev, "seamldr_upload",
> +					   &tdx_fw_ops, &tdx_fw_upload_status);
> +	ret = PTR_ERR_OR_ZERO(tdx_fwl);
> +	if (ret)
> +		pr_err("failed to register module uploader %d\n", ret);
> +}
> +
> +static void seamldr_deinit(void)
> +{
> +	if (tdx_fwl)
> +		firmware_upload_unregister(tdx_fwl);
> +}
> +
> +static int tdx_host_probe(struct faux_device *fdev)
> +{
> +	seamldr_init(&fdev->dev);

IMHO you need a comment to explain why seamldr_init() doesn't return error
and tdx_host_probe() already returns success?

> +	return 0;
> +}
> +
> +static void tdx_host_remove(struct faux_device *fdev)
> +{
> +	seamldr_deinit();
> +}
> +
> +static struct faux_device_ops tdx_host_ops = {
> +	.probe		= tdx_host_probe,
> +	.remove		= tdx_host_remove,
> +};
> +
>  static struct faux_device *fdev;
>  
>  static int __init tdx_host_init(void)
> @@ -107,7 +229,7 @@ static int __init tdx_host_init(void)
>  	if (!x86_match_cpu(tdx_host_ids) || !tdx_get_sysinfo())
>  		return -ENODEV;
>  
> -	fdev = faux_device_create_with_groups(KBUILD_MODNAME, NULL, NULL, tdx_host_groups);
> +	fdev = faux_device_create_with_groups(KBUILD_MODNAME, NULL, &tdx_host_ops, tdx_host_groups);
>  	if (!fdev)
>  		return -ENODEV;
>