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Date:   Wed, 15 Jul 2020 11:04:13 -0700
From:   Sean Christopherson <sean.j.christopherson@intel.com>
To:     Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Cc:     Dave Hansen <dave.hansen@intel.com>,
        Borislav Petkov <bp@alien8.de>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, x86@kernel.org,
        "H. Peter Anvin" <hpa@zytor.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>,
        Tony Luck <tony.luck@intel.com>,
        "Gomez Iglesias, Antonio" <antonio.gomez.iglesias@intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Fenghua Yu <fenghua.yu@intel.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Anthony Steinhauser <asteinhauser@google.com>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Mark Gross <mgross@linux.intel.com>,
        Waiman Long <longman@redhat.com>, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        Jonathan Corbet <corbet@lwn.net>
Subject: Re: [PATCH] x86/bugs/multihit: Fix mitigation reporting when KVM is
 not in use
Message-ID: <20200715180413.GB12349@linux.intel.com>
References: <267631f4db4fd7e9f7ca789c2efaeab44103f68e.1594689154.git.pawan.kumar.gupta@linux.intel.com>
 <20200714014540.GH29725@linux.intel.com>
 <099d6985-9e9f-1d9f-7098-58a9e26e4450@intel.com>
 <20200714191759.GA7116@guptapadev.amr>
 <ba442a51-294e-8624-9a69-5613ff050551@intel.com>
 <20200714210442.GA10488@guptapadev.amr>
 <e12cd3b8-7df1-94e8-e603-39e00648c026@intel.com>
 <20200715005130.GE14404@linux.intel.com>
 <20200715171820.GA12379@guptapadev.amr>
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On Wed, Jul 15, 2020 at 10:18:20AM -0700, Pawan Gupta wrote:
> On Tue, Jul 14, 2020 at 05:51:30PM -0700, Sean Christopherson wrote:
> > On Tue, Jul 14, 2020 at 02:20:59PM -0700, Dave Hansen wrote:
> > > On 7/14/20 2:04 PM, Pawan Gupta wrote:
> > > >> I see three inputs and four possible states (sorry for the ugly table,
> > > >> it was this or a spreadsheet :):
> > > >>
> > > >> X86_FEATURE_VMX	CONFIG_KVM_*	hpage split  Result	   Reason
> > > >> 	N			x	    x	     Not Affected  No VMX
> > > >> 	Y			N	    x	     Not affected  No KVM
> > 
> > This line item is pointless, the relevant itlb_multihit_show_state()
> > implementation depends on CONFIG_KVM_INTEL.  The !KVM_INTEL version simply
> > prints ""Processor vulnerable".
> 
> While we are on it, for CONFIG_KVM_INTEL=n would it make sense to report "Not
> affected(No KVM)"? "Processor vulnerable" is not telling much about the
> mitigation.

I know we don't care too much about out-of-tree hypervisors, but IMO stating
"Not affected" is unnecessarily hostile and "Processor vulnerable" is an
accurate statement.