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From:   Andy Lutomirski <luto@amacapital.net>
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Subject: Re: [PATCH v3 1/1] x86/tdx: Handle MWAIT, MONITOR and WBINVD
Date:   Mon, 29 Mar 2021 19:58:13 -0700
Message-Id: <2FE32855-EA5D-44E4-AACC-25E9B1476547@amacapital.net>
References: <20210330020403.GA1285835@tassilo.jf.intel.com>
Cc:     Andy Lutomirski <luto@kernel.org>,
        Sean Christopherson <seanjc@google.com>,
        "Kuppuswamy, Sathyanarayanan" 
        <sathyanarayanan.kuppuswamy@linux.intel.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Dave Hansen <dave.hansen@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>,
        LKML <linux-kernel@vger.kernel.org>
In-Reply-To: <20210330020403.GA1285835@tassilo.jf.intel.com>
To:     Andi Kleen <ak@linux.intel.com>
Precedence: bulk


> On Mar 29, 2021, at 7:04 PM, Andi Kleen <ak@linux.intel.com> wrote:
>=20
> =EF=BB=BF
>>=20
>>> No, if these instructions take a #VE then they were executed at CPL=3D0.=
  MONITOR
>>> and MWAIT will #UD without VM-Exit->#VE.  Same for WBINVD, s/#UD/#GP.
>>=20
>> Dare I ask about XSETBV?
>=20
> XGETBV does not cause a #VE, it just works normally. The guest has full
> AVX capabilities.
>=20

X *SET* BV=