linux-kernel - Re: [PATCH 1/2] x86/virt/tdx: Retrieve TDX module version

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Message-ID: <3f28d2dedfb64e66a97f07411b10a5db93a73342.camel@intel.com>
Date: Thu, 8 Jan 2026 20:18:12 +0000
From: "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>
To: "kvm@...r.kernel.org" <kvm@...r.kernel.org>, "linux-coco@...ts.linux.dev"
	<linux-coco@...ts.linux.dev>, "Verma, Vishal L" <vishal.l.verma@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC: "Gao, Chao" <chao.gao@...el.com>, "bp@...en8.de" <bp@...en8.de>, "Huang,
 Kai" <kai.huang@...el.com>, "kas@...nel.org" <kas@...nel.org>,
	"dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>,
	"mingo@...hat.com" <mingo@...hat.com>, "Williams, Dan J"
	<dan.j.williams@...el.com>, "tglx@...utronix.de" <tglx@...utronix.de>,
	"hpa@...or.com" <hpa@...or.com>, "x86@...nel.org" <x86@...nel.org>
Subject: Re: [PATCH 1/2] x86/virt/tdx: Retrieve TDX module version

On Wed, 2026-01-07 at 17:31 -0700, Vishal Verma wrote:
> From: Chao Gao <chao.gao@...el.com>
> 
> Each TDX module has several bits of metadata about which specific TDX
> module it is. 
> 


> The primary bit of info is the version, which has an x.y.z
> format, where x represents the major version, y the minor version, and z
> the update version.
> 

A bit of a run-on sentence.

>  Knowing the running TDX Module version is valuable
> for bug reporting and debugging. Note that the module does expose other
> pieces of version-related metadata, such as build number and date. Those
> aren't retrieved for now, that can be added if needed in the future.
> 
> Retrieve the TDX Module version using the existing metadata reading
> interface. Later changes will expose this information. The metadata
> reading interfaces have existed for quite some time, so this will work
> with older versions of the TDX module as well - i.e. this isn't a new
> interface.
> 
> As a side note, the global metadata reading code was originally set up
> to be auto-generated from a JSON definition [1]. However, later [2] this
> was found to be unsustainable, and the autogeneration approach was
> dropped in favor of just manually adding fields as needed (e.g. as in
> this patch).
> 
> Signed-off-by: Chao Gao <chao.gao@...el.com>
> Signed-off-by: Vishal Verma <vishal.l.verma@...el.com>
> Cc: Rick Edgecombe <rick.p.edgecombe@...el.com>
> Cc: Kai Huang <kai.huang@...el.com>
> Cc: Dave Hansen <dave.hansen@...ux.intel.com>
> Cc: Dan Williams <dan.j.williams@...el.com>
> Link: https://lore.kernel.org/kvm/CABgObfYXUxqQV_FoxKjC8U3t5DnyM45nz5DpTxYZv2x_uFK_Kw@mail.gmail.com/ # [1]
> Link: https://lore.kernel.org/all/1e7bcbad-eb26-44b7-97ca-88ab53467212@intel.com/ # [2]
> ---
>  arch/x86/include/asm/tdx_global_metadata.h  |  7 +++++++
>  arch/x86/virt/vmx/tdx/tdx_global_metadata.c | 16 ++++++++++++++++
>  2 files changed, 23 insertions(+)
> 
> diff --git a/arch/x86/include/asm/tdx_global_metadata.h b/arch/x86/include/asm/tdx_global_metadata.h
> index 060a2ad744bff..40689c8dc67eb 100644
> --- a/arch/x86/include/asm/tdx_global_metadata.h
> +++ b/arch/x86/include/asm/tdx_global_metadata.h
> @@ -5,6 +5,12 @@
>  
>  #include <linux/types.h>
>  
> +struct tdx_sys_info_version {
> +	u16 minor_version;
> +	u16 major_version;
> +	u16 update_version;
> +};
> +
>  struct tdx_sys_info_features {
>  	u64 tdx_features0;
>  };
> @@ -35,6 +41,7 @@ struct tdx_sys_info_td_conf {
>  };
>  
>  struct tdx_sys_info {
> +	struct tdx_sys_info_version version;
>  	struct tdx_sys_info_features features;
>  	struct tdx_sys_info_tdmr tdmr;
>  	struct tdx_sys_info_td_ctrl td_ctrl;
> diff --git a/arch/x86/virt/vmx/tdx/tdx_global_metadata.c b/arch/x86/virt/vmx/tdx/tdx_global_metadata.c
> index 13ad2663488b1..0454124803f36 100644
> --- a/arch/x86/virt/vmx/tdx/tdx_global_metadata.c
> +++ b/arch/x86/virt/vmx/tdx/tdx_global_metadata.c
> @@ -7,6 +7,21 @@
>   * Include this file to other C file instead.
>   */
>  
> +static int get_tdx_sys_info_version(struct tdx_sys_info_version *sysinfo_version)
> +{
> +	int ret = 0;
> +	u64 val;
> +
> +	if (!ret && !(ret = read_sys_metadata_field(0x0800000100000003, &val)))
> +		sysinfo_version->minor_version = val;
> +	if (!ret && !(ret = read_sys_metadata_field(0x0800000100000004, &val)))
> +		sysinfo_version->major_version = val;
> +	if (!ret && !(ret = read_sys_metadata_field(0x0800000100000005, &val)))
> +		sysinfo_version->update_version = val;
> +
> +	return ret;
> +}
> +
>  static int get_tdx_sys_info_features(struct tdx_sys_info_features *sysinfo_features)
>  {
>  	int ret = 0;
> @@ -89,6 +104,7 @@ static int get_tdx_sys_info(struct tdx_sys_info *sysinfo)
>  {
>  	int ret = 0;
>  
> +	ret = ret ?: get_tdx_sys_info_version(&sysinfo->version);
>  	ret = ret ?: get_tdx_sys_info_features(&sysinfo->features);
>  	ret = ret ?: get_tdx_sys_info_tdmr(&sysinfo->tdmr);
>  	ret = ret ?: get_tdx_sys_info_td_ctrl(&sysinfo->td_ctrl);
> 

Code looks good to me.

Reviewed-by: Rick Edgecombe <rick.p.edgecombe@...el.com>