linux-kernel - Re: [RFC PATCH] platform/x86: Add sysfs interface for Intel TXT status

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Message-ID: <YiiF9wfx3V+K1J33@kroah.com>
Date:   Wed, 9 Mar 2022 11:48:23 +0100
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Jonathan McDowell <noodles@...com>
Cc:     Dmitrii Okunev <xaionaro@...com>,
        Hans de Goede <hdegoede@...hat.com>,
        Mark Gross <markgross@...nel.org>,
        Qiaowei Ren <qiaowei.ren@...el.com>,
        Matthew Garrett <mjg59@...f.ucam.org>,
        Xiaoyan Zhang <xiaoyan.zhang@...el.com>,
        Pavel Machek <pavel@...x.de>,
        "x86@...nel.org" <x86@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "platform-driver-x86@...r.kernel.org" 
        <platform-driver-x86@...r.kernel.org>
Subject: Re: [RFC PATCH] platform/x86: Add sysfs interface for Intel TXT
 status

On Wed, Mar 09, 2022 at 10:40:03AM +0000, Jonathan McDowell wrote:
> (This is an RFC to see if the approach is generally acceptable; unlike
> the previous driver this exposes the information purely as read-only
> status information, so userspace can make an informed decision about the
> system state without having to poke about in /dev/mem. There are still a
> few extra registers I'm trying to dig up information for before a proper
> submission.)
> 
> This module provides read-only access to the Intel TXT (Trusted
> Execution Technology) status registers, allowing userspace to determine
> the status of measured boot and whether the dynamic root of trust for
> measurement (DRTM) has been fully enabled.
> 
> Tools such as txt-stat from tboot
> <https://sourceforge.net/projects/tboot/> can make use of this driver to
> display state rather than relying on access to /dev/mem.
> 
> See Documentation/x86/intel_txt.rst for more information about Intel
> TXT.
> 
> Signed-off-by: Jonathan McDowell <noodles@...com>
> ---
>  arch/x86/include/asm/txt.h             |  34 +++++
>  drivers/platform/x86/intel/Kconfig     |  14 ++
>  drivers/platform/x86/intel/Makefile    |   2 +
>  drivers/platform/x86/intel/txt_sysfs.c | 185 +++++++++++++++++++++++++

No Documentation/ABI/ entry for your new sysfs entry?  How can we
evaluate if this is a good api then?

Wait, I don't see any sysfs code in here, are you sure you sent a viable
patch?

confused,

greg k-h