linux-kernel - Re: [PATCH v21 08/28] x86/cpu/intel: Detect SGX support and update caps appropriately

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Date:   Wed, 24 Jul 2019 12:35:42 -0700
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Cc:     linux-kernel@...r.kernel.org, x86@...nel.org,
        linux-sgx@...r.kernel.org, akpm@...ux-foundation.org,
        dave.hansen@...el.com, nhorman@...hat.com, npmccallum@...hat.com,
        serge.ayoun@...el.com, shay.katz-zamir@...el.com,
        haitao.huang@...el.com, andriy.shevchenko@...ux.intel.com,
        tglx@...utronix.de, kai.svahn@...el.com, bp@...en8.de,
        josh@...htriplett.org, luto@...nel.org, kai.huang@...el.com,
        rientjes@...gle.com, cedric.xing@...el.com
Subject: Re: [PATCH v21 08/28] x86/cpu/intel: Detect SGX support and update
 caps appropriately

On Sat, Jul 13, 2019 at 08:07:44PM +0300, Jarkko Sakkinen wrote:
>  arch/x86/kernel/cpu/intel.c | 71 +++++++++++++++++++++++++++++++++++++
>  1 file changed, 71 insertions(+)
> 
> diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
> index 8d6d92ebeb54..1503b251d10f 100644
> --- a/arch/x86/kernel/cpu/intel.c
> +++ b/arch/x86/kernel/cpu/intel.c
> @@ -623,6 +623,72 @@ static void detect_tme(struct cpuinfo_x86 *c)
>  	c->x86_phys_bits -= keyid_bits;
>  }
>  
> +static void __maybe_unused detect_sgx(struct cpuinfo_x86 *c)
> +{
> +	unsigned long long fc;
> +
> +	rdmsrl(MSR_IA32_FEATURE_CONTROL, fc);
> +	if (!(fc & FEATURE_CONTROL_LOCKED)) {
> +		pr_err_once("sgx: The feature control MSR is not locked\n");
> +		goto err_unsupported;
> +	}
> +
> +	if (!(fc & FEATURE_CONTROL_SGX_ENABLE)) {
> +		pr_err_once("sgx: SGX is not enabled in IA32_FEATURE_CONTROL MSR\n");
> +		goto err_unsupported;
> +	}
> +
> +	if (!cpu_has(c, X86_FEATURE_SGX1)) {
> +		pr_err_once("sgx: SGX1 instruction set is not supported\n");
> +		goto err_unsupported;
> +	}
> +
> +	if (!(fc & FEATURE_CONTROL_SGX_LE_WR)) {
> +		pr_info_once("sgx: The launch control MSRs are not writable\n");
> +		goto err_msrs_rdonly;
> +	}
> +
> +	return;
> +
> +err_unsupported:
> +	setup_clear_cpu_cap(X86_FEATURE_SGX);
> +	setup_clear_cpu_cap(X86_FEATURE_SGX1);
> +	setup_clear_cpu_cap(X86_FEATURE_SGX2);
> +
> +err_msrs_rdonly:
> +	setup_clear_cpu_cap(X86_FEATURE_SGX_LC);
> +}
> +
> +static void init_intel_energy_perf(struct cpuinfo_x86 *c)
> +{
> +	u64 epb;
> +
> +	/*
> +	 * Initialize MSR_IA32_ENERGY_PERF_BIAS if not already initialized.
> +	 * (x86_energy_perf_policy(8) is available to change it at run-time.)
> +	 */
> +	if (!cpu_has(c, X86_FEATURE_EPB))
> +		return;
> +
> +	rdmsrl(MSR_IA32_ENERGY_PERF_BIAS, epb);
> +	if ((epb & 0xF) != ENERGY_PERF_BIAS_PERFORMANCE)
> +		return;
> +
> +	pr_warn_once("ENERGY_PERF_BIAS: Set to 'normal', was 'performance'\n");
> +	pr_warn_once("ENERGY_PERF_BIAS: View and update with x86_energy_perf_policy(8)\n");
> +	epb = (epb & ~0xF) | ENERGY_PERF_BIAS_NORMAL;
> +	wrmsrl(MSR_IA32_ENERGY_PERF_BIAS, epb);
> +}
> +
> +static void intel_bsp_resume(struct cpuinfo_x86 *c)
> +{
> +	/*
> +	 * MSR_IA32_ENERGY_PERF_BIAS is lost across suspend/resume,
> +	 * so reinitialize it properly like during bootup:
> +	 */
> +	init_intel_energy_perf(c);
> +}
> +
>  static void init_cpuid_fault(struct cpuinfo_x86 *c)
>  {
>  	u64 msr;
> @@ -760,6 +826,11 @@ static void init_intel(struct cpuinfo_x86 *c)
>  	if (cpu_has(c, X86_FEATURE_TME))
>  		detect_tme(c);
>  
> +	if (IS_ENABLED(CONFIG_INTEL_SGX) && cpu_has(c, X86_FEATURE_SGX))
> +		detect_sgx(c);
> +
> +	init_intel_energy_perf(c);

All of the energy_perf additions are bogus, looks like a rebase gone wrong.

> +
>  	init_intel_misc_features(c);
>  }
>  
> -- 
> 2.20.1
>