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Date:   Thu, 26 Oct 2023 14:27:21 -0700
From:   Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
To:     Sean Christopherson <seanjc@google.com>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
        "H. Peter Anvin" <hpa@zytor.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Josh Poimboeuf <jpoimboe@kernel.org>,
        Andy Lutomirski <luto@kernel.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Paolo Bonzini <pbonzini@redhat.com>, tony.luck@intel.com,
        ak@linux.intel.com, tim.c.chen@linux.intel.com,
        linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
        kvm@vger.kernel.org,
        Alyssa Milburn <alyssa.milburn@linux.intel.com>,
        Daniel Sneddon <daniel.sneddon@linux.intel.com>,
        antonio.gomez.iglesias@linux.intel.com
Subject: Re: [PATCH  v3 6/6] KVM: VMX: Move VERW closer to VMentry for MDS
 mitigation
Message-ID: <20231026212721.pukgqvg4izmyfvzv@desk>
References: <20231025-delay-verw-v3-0-52663677ee35@linux.intel.com>
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 <ZTq-b0uVyf6KLNV0@google.com>
 <ZTrJa9NFaAORipVL@google.com>
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On Thu, Oct 26, 2023 at 01:17:47PM -0700, Sean Christopherson wrote:
> Alternatively, and maybe even preferably, this would make it more obvious that
> the two are mutually exclusive and would also be a (very, very) small perf win
> when the mitigation is enabled.

Agree.

> -       vmx_disable_fb_clear(vmx);
> +       if (!cpu_feature_enabled(X86_FEATURE_CLEAR_CPU_BUF))
> +               vmx_disable_fb_clear(vmx);