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Message-ID: <0ffa85dbb54ddeecdbfdef3a22c077156268001b.camel@intel.com>
Subject: Re: [RFC 0/3] Expose Confidential Computing capabilities on sysfs
From:   Kai Huang <kai.huang@intel.com>
To:     Isaku Yamahata <isaku.yamahata@gmail.com>,
        Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
Cc:     Dave Hansen <dave.hansen@intel.com>, tglx@linutronix.de,
        mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
        luto@kernel.org, peterz@infradead.org, x86@kernel.org,
        linux-kernel@vger.kernel.org, thomas.lendacky@amd.com,
        brijesh.singh@amd.com, kirill.shutemov@linux.intel.com,
        hpa@zytor.com, pbonzini@redhat.com, seanjc@google.com,
        srutherford@google.com, ashish.kalra@amd.com,
        darren.kenny@oracle.com, venu.busireddy@oracle.com,
        boris.ostrovsky@oracle.com, kvm@vger.kernel.org
Date:   Tue, 15 Mar 2022 14:17:42 +1300
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> 
> More concretely
> - CPU feature (Secure Arbitration Mode: SEAM) as "seam" flag in /proc/cpuinfo

In my current patchset we don't have "seam" flag in /proc/cpuinfo.  

https://lore.kernel.org/kvm/cover.1647167475.git.kai.huang@intel.com/T/#m02542eb723394a81c35b9542b2763c783222d594

TDX architecture doesn't have a CPUID to report SEAM, so we will need a
synthetic flag if we want to add.  If userspace has requirement to use it, then
it makes sense to add it and expose to /proc/cpuinfo.  But so far I don't know
there's any.

Thanks
-Kai