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From:   "Huang, Kai" <kai.huang@intel.com>
To:     "Christopherson, Sean J" <sean.j.christopherson@intel.com>
CC:     "jarkko.sakkinen@linux.intel.com" <jarkko.sakkinen@linux.intel.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-sgx@vger.kernel.org" <linux-sgx@vger.kernel.org>,
        "x86@kernel.org" <x86@kernel.org>,
        "Svahn, Kai" <kai.svahn@intel.com>,
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        "josh@joshtriplett.org" <josh@joshtriplett.org>,
        "tglx@linutronix.de" <tglx@linutronix.de>,
        "Ayoun, Serge" <serge.ayoun@intel.com>,
        "Huang, Haitao" <haitao.huang@intel.com>,
        "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
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        "luto@kernel.org" <luto@kernel.org>,
        "Katz-zamir, Shay" <shay.katz-zamir@intel.com>,
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        "andriy.shevchenko@linux.intel.com" 
        <andriy.shevchenko@linux.intel.com>
Subject: RE: [PATCH v19,RESEND 08/27] x86/cpu/intel: Detect SGX support and
 update caps appropriately
Thread-Topic: [PATCH v19,RESEND 08/27] x86/cpu/intel: Detect SGX support and
 update caps appropriately
Thread-Index: AQHU3zky6JmIjy9D9kKUr6BC7GDLPqYdVzoAgAAkQICAAPek0P//hiCAgACc10A=
Date:   Tue, 26 Mar 2019 23:19:59 +0000
Message-ID: <105F7BF4D0229846AF094488D65A0989356F3436@PGSMSX112.gar.corp.intel.com>
References: <20190320162119.4469-1-jarkko.sakkinen@linux.intel.com>
 <20190320162119.4469-9-jarkko.sakkinen@linux.intel.com>
 <1553602654.17255.15.camel@intel.com>
 <20190326142719.GC3757@linux.intel.com>
 <105F7BF4D0229846AF094488D65A0989356F307D@PGSMSX112.gar.corp.intel.com>
 <20190326215727.GG3757@linux.intel.com>
In-Reply-To: <20190326215727.GG3757@linux.intel.com>
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> On Tue, Mar 26, 2019 at 02:25:52PM -0700, Huang, Kai wrote:
> > >
> > > That being said, this in no way impacts KVM's ability to virtualize SGX, e.g.
> > > KVM can directly do CPUID and {RD,WR}MSR to probe the capabilities
> > > of the platform as needed.
> >
> > I am not following. KVM can do whatever it wants, but it cannot change
> > the fact that KVM guest cannot run intel enclave if platform's MSRs
> > are configured to 3rd party and locked.
> >
> > Or am I misunderstanding?
> 
> What does that have to do with this patch?  The only thing this patch does is
> clear a *software* bit that says "SGX LC is enabled" so that the kernel can
> make the reasonable assumption that the MSRs are writable when
> X86_FEATURE_SGX_LC=1.

Sorted out offline discussion with you. Will let you handle :)

Thanks,
-Kai