linux-kernel - Re: [PATCH v4] x86/speculation/l1tf: Add KConfig for setting the L1D cache flush mode

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Date:   Wed, 8 Jul 2020 12:34:01 -0700
From:   Randy Dunlap <rdunlap@...radead.org>
To:     Abhishek Bhardwaj <abhishekbh@...gle.com>,
        LKML <linux-kernel@...r.kernel.org>
Cc:     Anthony Steinhauser <asteinhauser@...gle.com>,
        Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Mark Gross <mgross@...ux.intel.com>,
        Mike Rapoport <rppt@...ux.ibm.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Tony Luck <tony.luck@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Waiman Long <longman@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>, kvm@...r.kernel.org,
        x86@...nel.org
Subject: Re: [PATCH v4] x86/speculation/l1tf: Add KConfig for setting the L1D
 cache flush mode

Hi again,

On 7/8/20 12:25 PM, Abhishek Bhardwaj wrote:
> diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
> index b277a2db62676..1f85374a0b812 100644
> --- a/arch/x86/kvm/Kconfig
> +++ b/arch/x86/kvm/Kconfig
> @@ -107,4 +107,17 @@ config KVM_MMU_AUDIT
>  	 This option adds a R/W kVM module parameter 'mmu_audit', which allows
>  	 auditing of KVM MMU events at runtime.
>  
> +config KVM_VMENTRY_L1D_FLUSH
> +	int "L1D cache flush settings (1-3)"
> +	range 1 3
> +	default "2"
> +	depends on KVM && X86_64
> +	help
> +	 This setting determines the L1D cache flush behavior before a VMENTER.
> +	 This is similar to setting the option / parameter to
> +	 kvm-intel.vmentry_l1d_flush.
> +	 1 - Never flush.
> +	 2 - Conditionally flush.
> +	 3 - Always flush.
> +
>  endif # VIRTUALIZATION

If you do a v5, the help text lines (under "help") should be indented
with one tab + 2 spaces according to Documentation/process/coding-style.rst.

-- 
~Randy