linux-kernel - Re: [PATCH 03/26] x86/tdx: Add __tdx_module_call() and __tdx

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Message-ID: <20211224103410.okuku7njt2cnk6mz@black.fi.intel.com>
Date:   Fri, 24 Dec 2021 13:34:10 +0300
From:   "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Borislav Petkov <bp@...en8.de>, tglx@...utronix.de,
        mingo@...hat.com, dave.hansen@...el.com, luto@...nel.org,
        peterz@...radead.org, sathyanarayanan.kuppuswamy@...ux.intel.com,
        aarcange@...hat.com, ak@...ux.intel.com, dan.j.williams@...el.com,
        david@...hat.com, hpa@...or.com, jgross@...e.com,
        jmattson@...gle.com, joro@...tes.org, jpoimboe@...hat.com,
        knsathya@...nel.org, sdeep@...are.com, seanjc@...gle.com,
        tony.luck@...el.com, vkuznets@...hat.com, wanpengli@...cent.com,
        x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 03/26] x86/tdx: Add __tdx_module_call() and
 __tdx_hypercall() helper functions

On Fri, Dec 24, 2021 at 10:16:16AM +0100, Paolo Bonzini wrote:
> On 12/23/21 17:55, Kirill A. Shutemov wrote:
> > 	In a TDX based VM, since the VMM is an untrusted entity, an intermediary
> > 	layer -- TDX module -- facilitates secure communication between the host
> > 	and the guest. TDX module is loaded like a firmware into a special CPU
> > 	mode called SEAM. TDX guests communicate with the TDX module using the
> > 	TDCALL instruction.
> > 
> > Does it look fine?
> 
> Looks good but I wouldn't say "like a firmware".  The TDX module is the
> "real" hypervisor, it's not firmware.

We are talking about the way it gets loaded, not about its functionality.
> 
> Paolo
> 

-- 
 Kirill A. Shutemov