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Date:   Mon, 9 Aug 2021 18:06:27 +0200
From:   Borislav Petkov <bp@alien8.de>
To:     Yu-cheng Yu <yu-cheng.yu@intel.com>
Cc:     x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, linux-kernel@vger.kernel.org,
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        linux-arch@vger.kernel.org, linux-api@vger.kernel.org,
        Arnd Bergmann <arnd@arndb.de>,
        Andy Lutomirski <luto@kernel.org>,
        Balbir Singh <bsingharora@gmail.com>,
        Cyrill Gorcunov <gorcunov@gmail.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Eugene Syromiatnikov <esyr@redhat.com>,
        Florian Weimer <fweimer@redhat.com>,
        "H.J. Lu" <hjl.tools@gmail.com>, Jann Horn <jannh@google.com>,
        Jonathan Corbet <corbet@lwn.net>,
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        Mike Kravetz <mike.kravetz@oracle.com>,
        Nadav Amit <nadav.amit@gmail.com>,
        Oleg Nesterov <oleg@redhat.com>, Pavel Machek <pavel@ucw.cz>,
        Peter Zijlstra <peterz@infradead.org>,
        Randy Dunlap <rdunlap@infradead.org>,
        "Ravi V. Shankar" <ravi.v.shankar@intel.com>,
        Vedvyas Shanbhogue <vedvyas.shanbhogue@intel.com>,
        Dave Martin <Dave.Martin@arm.com>,
        Weijiang Yang <weijiang.yang@intel.com>,
        Pengfei Xu <pengfei.xu@intel.com>,
        Haitao Huang <haitao.huang@intel.com>,
        Rick P Edgecombe <rick.p.edgecombe@intel.com>
Subject: Re: [PATCH v28 04/32] x86/cpufeatures: Introduce CPU setup and
 option parsing for CET
Message-ID: <YRFSg45dDMfeiGbt@zn.tnic>
References: <20210722205219.7934-1-yu-cheng.yu@intel.com>
 <20210722205219.7934-5-yu-cheng.yu@intel.com>
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On Thu, Jul 22, 2021 at 01:51:51PM -0700, Yu-cheng Yu wrote:
>  /*
>   * Some CPU features depend on higher CPUID levels, which may not always
>   * be available due to CPUID level capping or broken virtualization
> @@ -1249,6 +1257,11 @@ static void __init cpu_parse_early_param(void)
>  	if (cmdline_find_option_bool(boot_command_line, "noxsaves"))
>  		setup_clear_cpu_cap(X86_FEATURE_XSAVES);
>  
> +	if (cmdline_find_option_bool(boot_command_line, "no_user_shstk"))
> +		setup_clear_cpu_cap(X86_FEATURE_SHSTK);
> +	if (cmdline_find_option_bool(boot_command_line, "no_user_ibt"))
> +		setup_clear_cpu_cap(X86_FEATURE_IBT);

Patch 1 says:

"Disabling shadow stack also disables IBT."

I don't see that here.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette