linux-kernel - Re: [PATCH v5 04/12] x86/tdx: Add protected guest support for TDX guest

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Message-ID: <ca4aa25c-7d88-9812-4852-ced3274493a8@linux.intel.com>
Date:   Wed, 4 Aug 2021 16:00:18 -0700
From:   "Kuppuswamy, Sathyanarayanan" 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>
To:     Sean Christopherson <seanjc@...gle.com>
Cc:     Dave Hansen <dave.hansen@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Andy Lutomirski <luto@...nel.org>,
        Peter H Anvin <hpa@...or.com>,
        Tony Luck <tony.luck@...el.com>,
        Dan Williams <dan.j.williams@...el.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Kirill Shutemov <kirill.shutemov@...ux.intel.com>,
        Kuppuswamy Sathyanarayanan <knsathya@...nel.org>,
        x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 04/12] x86/tdx: Add protected guest support for TDX
 guest



On 8/4/21 3:42 PM, Sean Christopherson wrote:
> What other possible use case is there for invoking tdx_prot_guest_has() beyond
> running as a TDX guest?  If it were e.g. intel_prot_guest_has() then I would at
> least understand the code, if not agree with the sub-optimal approach, but as is
> it makes no sense.

Yes. I think his original intention is to implement intel_prot_guest_has() in
arch/x86/kernel/cpu/intel.c and then call tdx_prot_guest_has() from it. But since
we have no other use cases, we have called tdx_prot_*() directly here.

Boris, how do you want to proceed? Do you want me to implement intel_prot_guest_has()
or change comparison log to TDX specific?


> 
> Given amd_prot_guest_has(), my guess is Boris intended intel_prot_guest_has()...

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer