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Date:   Mon, 29 Mar 2021 23:39:11 +0000
From:   Sean Christopherson <seanjc@google.com>
To:     Andy Lutomirski <luto@amacapital.net>
Cc:     Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@linux.intel.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Andy Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@intel.com>,
        Andi Kleen <ak@linux.intel.com>,
        Kirill Shutemov <kirill.shutemov@linux.intel.com>,
        Kuppuswamy Sathyanarayanan <knsathya@kernel.org>,
        Dan Williams <dan.j.williams@intel.com>,
        Raj Ashok <ashok.raj@intel.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 1/1] x86/tdx: Handle MWAIT, MONITOR and WBINVD
Message-ID: <YGJlH76t+BGrIDVc@google.com>
References: <837afe840f5826bf7fcba07a5e483d7e2283db34.1617059703.git.sathyanarayanan.kuppuswamy@linux.intel.com>
 <377A7B0B-9959-4AFC-A575-7AC20FEE6077@amacapital.net>
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On Mon, Mar 29, 2021, Andy Lutomirski wrote:
> 
> > On Mar 29, 2021, at 4:17 PM, Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> wrote:
> > 
> > ﻿In non-root TDX guest mode, MWAIT, MONITOR and WBINVD instructions
> > are not supported. So handle #VE due to these instructions
> > appropriately.
> 
> Is there something I missed elsewhere in the code that checks CPL?

#GP due to CPL!=0 has priority over VM-Exit, i.e. userspace will get a #GP
directly; there will be no VM-Exit to the TDX Module and thus no #VE.

SDM section "25.1.1 - Relative Priority of Faults and VM Exits".