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Subject: Re: [RFC v2-fix-v2 1/1] x86: Introduce generic protected guest
 abstraction
To:     Tom Lendacky <thomas.lendacky@amd.com>,
        Sean Christopherson <seanjc@google.com>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Andy Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@intel.com>,
        Tony Luck <tony.luck@intel.com>,
        Borislav Petkov <bp@alien8.de>,
        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
References: <20210527042356.3983284-2-sathyanarayanan.kuppuswamy@linux.intel.com>
 <20210601211417.2177598-1-sathyanarayanan.kuppuswamy@linux.intel.com>
 <YLe92NXx1jZPtPqB@google.com> <3036a655-9d09-0f04-62a2-7a72ba9af5c7@amd.com>
From:   "Kuppuswamy, Sathyanarayanan" 
        <sathyanarayanan.kuppuswamy@linux.intel.com>
Message-ID: <ebd50589-2cc3-6b6e-37ec-5bc968c40fe3@linux.intel.com>
Date:   Wed, 2 Jun 2021 11:25:43 -0700
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On 6/2/21 11:15 AM, Tom Lendacky wrote:
> The original suggestion from Boris, IIRC, was for protected_guest_has()
> function (below) to be:
> 
> 	if (intel)
> 		return intel_protected_guest_has();

Yes. But for Intel, I think currently we can only check for is_tdx_guest() here.

if (is_tdx_guest())
	return intel_protected_guest_has();

So if we use is_tdx_guest(), it is better to call tdx_protected_guest_has() here.

Once we start using protected_guest_has for other Intel technologies, may be
we can generalize it. Let me know your comments.

> 	else if (amd)
> 		return amd_protected_guest_has();
> 	else
> 		return false;
> 
> And then you could check for TDX or SME/SEV in the respective functions.

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer