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Date:   Mon, 11 Apr 2022 09:27:27 -0700
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To:     Borislav Petkov <bp@alien8.de>
Cc:     "Kirill A. Shutemov" <kirill@shutemov.name>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Andy Lutomirski <luto@kernel.org>,
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        Kuppuswamy Sathyanarayanan 
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        Mike Rapoport <rppt@linux.ibm.com>
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From:   Dave Hansen <dave.hansen@intel.com>
Subject: Re: [PATCHv4 1/8] mm: Add support for unaccepted memory
In-Reply-To: <YlRPdQP5c1DQqZeN@zn.tnic>
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On 4/11/22 08:55, Borislav Petkov wrote:
> On Sun, Apr 10, 2022 at 11:41:57PM -0700, Dave Hansen wrote:
>> Let's just call out the possible (probable?) need for new ABI here.
>> Maybe it will cue folks who care to speak up.
> Err, why would you teach the user to go poke at some arbitrary sysfs
> nodes when the accepting code can simply issue a printk from time to
> time
> 
>   "Guest unnaccepted memory progress: XX%. This slows down operations at the moment."

I guess that's not a horrible place to start.  It's also not *horribly*
different from how guests work today.  If hosts lazily allocate RAM,
they'll see largely the same kind of behavior.

What ends up determining how much memory is pre-accepted versus being
done from the guest?  Is that just a normal part of setting up a TDX
guest, like from the qemu cmdline?  Or, is there some convention with
the virtual firmware?