linux-kernel - Re: [PATCH v3 22/26] x86/virt/tdx: Update tdx

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Message-ID: <aXdK3pZJp4cEZeSl@tlindgre-MOBL1>
Date: Mon, 26 Jan 2026 13:07:10 +0200
From: Tony Lindgren <tony.lindgren@...ux.intel.com>
To: Chao Gao <chao.gao@...el.com>
Cc: linux-coco@...ts.linux.dev, linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org, x86@...nel.org, reinette.chatre@...el.com,
	ira.weiny@...el.com, kai.huang@...el.com, dan.j.williams@...el.com,
	yilun.xu@...ux.intel.com, sagis@...gle.com, vannapurve@...gle.com,
	paulmck@...nel.org, nik.borisov@...e.com, zhenzhong.duan@...el.com,
	seanjc@...gle.com, rick.p.edgecombe@...el.com, kas@...nel.org,
	dave.hansen@...ux.intel.com, vishal.l.verma@...el.com,
	Farrah Chen <farrah.chen@...el.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
	"H. Peter Anvin" <hpa@...or.com>
Subject: Re: [PATCH v3 22/26] x86/virt/tdx: Update tdx_sysinfo and check
 features post-update

On Fri, Jan 23, 2026 at 06:55:30AM -0800, Chao Gao wrote:
> +int tdx_module_post_update(struct tdx_sys_info *info)
> +{
...
> +	/*
> +	 * Blindly refreshing the entire tdx_sysinfo could disrupt running
> +	 * software, as it may subtly rely on the previous state unless
> +	 * proven otherwise.
> +	 *
> +	 * Only refresh version information (including handoff version)
> +	 * that does not affect functionality, and ignore all other
> +	 * changes.
> +	 */
> +	tdx_sysinfo.version	= info->version;
> +	tdx_sysinfo.handoff	= info->handoff;
> +
> +	if (!memcmp(&tdx_sysinfo, info, sizeof(*info)))
> +		return 0;
> +
> +	pr_info("TDX module features have changed after updates, but might not take effect.\n");
> +	pr_info("Please consider updating your BIOS to install the TDX Module.\n");
> +	return 0;
> +}

To me it seems that a Linux a TDX module loader recommending a BIOS module
loader is not very user friendly :)

Anyways that more stuff for future so:

Reviewed-by: Tony Lindgren <tony.lindgren@...ux.intel.com>