linux-kernel - Re: [PATCH v4 1/6] x86/feat_ctl: Add new VMX feature, Tertiary VM-Execution control

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Message-ID: <YTvNLd0PwX+PijH7@google.com>
Date:   Fri, 10 Sep 2021 21:25:01 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Zeng Guang <guang.zeng@...el.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Tony Luck <tony.luck@...el.com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Kim Phillips <kim.phillips@....com>,
        Jarkko Sakkinen <jarkko@...nel.org>,
        Jethro Beekman <jethro@...tanix.com>,
        Kai Huang <kai.huang@...el.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org, Robert Hu <robert.hu@...el.com>,
        Gao Chao <chao.gao@...el.com>,
        Robert Hoo <robert.hu@...ux.intel.com>
Subject: Re: [PATCH v4 1/6] x86/feat_ctl: Add new VMX feature, Tertiary
 VM-Execution control

x86/cpu: is probaby more appropriate, this touches more than just feat_ctl.

On Mon, Aug 09, 2021, Zeng Guang wrote:
> From: Robert Hoo <robert.hu@...ux.intel.com>
> 
> New VMX capability MSR IA32_VMX_PROCBASED_CTLS3 conresponse to this new
> VM-Execution control field. And it is 64bit allow-1 semantics, not like
> previous capability MSRs 32bit allow-0 and 32bit allow-1. So with Tertiary
> VM-Execution control field introduced, 2 vmx_feature leaves are introduced,
> TERTIARY_CTLS_LOW and TERTIARY_CTLS_HIGH.
> 
> Signed-off-by: Robert Hoo <robert.hu@...ux.intel.com>
> Signed-off-by: Zeng Guang <guang.zeng@...el.com>
> ---

Nits aside,

Reviewed-by: Sean Christopherson <seanjc@...gle.com>

> @@ -22,7 +24,7 @@ enum vmx_feature_leafs {
>  
>  static void init_vmx_capabilities(struct cpuinfo_x86 *c)
>  {
> -	u32 supported, funcs, ept, vpid, ign;
> +	u32 supported, funcs, ept, vpid, ign, low, high;
>  
>  	BUILD_BUG_ON(NVMXINTS != NR_VMX_FEATURE_WORDS);
>  
> @@ -42,6 +44,13 @@ static void init_vmx_capabilities(struct cpuinfo_x86 *c)
>  	rdmsr_safe(MSR_IA32_VMX_PROCBASED_CTLS2, &ign, &supported);
>  	c->vmx_capability[SECONDARY_CTLS] = supported;
>  
> +	/*
> +	 * For tertiary execution controls MSR, it's actually a 64bit allowed-1.
> +	 */

Maybe something like this to better fit on one line?

	/* All 64 bits of tertiary controls MSR are allowed-1 settings. */

> +	rdmsr_safe(MSR_IA32_VMX_PROCBASED_CTLS3, &low, &high);
> +	c->vmx_capability[TERTIARY_CTLS_LOW] = low;
> +	c->vmx_capability[TERTIARY_CTLS_HIGH] = high;
> +
>  	rdmsr(MSR_IA32_VMX_PINBASED_CTLS, ign, supported);
>  	rdmsr_safe(MSR_IA32_VMX_VMFUNC, &ign, &funcs);
>  
> -- 
> 2.25.1
>