linux-kernel - Re: [PATCHv6 07/30] x86/traps: Add #VE support for TDX guest

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Message-ID: <20220318130313.tv7vecdahoakbetf@black.fi.intel.com>
Date:   Fri, 18 Mar 2022 16:03:13 +0300
From:   "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     Dave Hansen <dave.hansen@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>, mingo@...hat.com,
        bp@...en8.de, luto@...nel.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,
        pbonzini@...hat.com, sdeep@...are.com, seanjc@...gle.com,
        tony.luck@...el.com, vkuznets@...hat.com, wanpengli@...cent.com,
        thomas.lendacky@....com, brijesh.singh@....com, x86@...nel.org,
        linux-kernel@...r.kernel.org,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>
Subject: Re: [PATCHv6 07/30] x86/traps: Add #VE support for TDX guest

On Fri, Mar 18, 2022 at 11:55:11AM +0100, Peter Zijlstra wrote:
> On Thu, Mar 17, 2022 at 01:32:07PM -0700, Dave Hansen wrote:
> 
> > The TDX rules are *much* nicer than SEV.  They're also a lot nicer on
> > TDX _now_ than they used to be.  There are a few stubborn people at
> > Intel who managed to add some drops of sanity to the architecture.
> 
> Right; that is saner than it used to be. I have definite memories that
> pages could be taken back by the TDX thing and would need
> re-authentication. A pool of 'fixed' pages was talked about. I'm glad to
> hear all that is gone.

Right, VMM can still pull memory form the guest at any point, but
reference of such memory from the guest would lead not to #VE as before,
but to TD termination.

-- 
 Kirill A. Shutemov