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Date:   Tue, 19 Jul 2022 15:02:26 -0700
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Subject: Re: [PATCHv7 00/14] mm, x86/cc: Implement support for unaccepted
 memory
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To:     Borislav Petkov <bp@alien8.de>
Cc:     Ard Biesheuvel <ardb@kernel.org>,
        Dionna Amalie Glaze <dionnaglaze@google.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Peter Gonda <pgonda@google.com>,
        Andy Lutomirski <luto@kernel.org>,
        Sean Christopherson <seanjc@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Joerg Roedel <jroedel@suse.de>,
        Andi Kleen <ak@linux.intel.com>,
        Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@linux.intel.com>,
        David Rientjes <rientjes@google.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Ingo Molnar <mingo@redhat.com>,
        Varad Gautam <varad.gautam@suse.com>,
        Dario Faggioli <dfaggioli@suse.com>,
        Mike Rapoport <rppt@kernel.org>,
        David Hildenbrand <david@redhat.com>,
        Marcelo Cerri <marcelo.cerri@canonical.com>,
        tim.gardner@canonical.com,
        Khalid ElMously <khalid.elmously@canonical.com>,
        philip.cox@canonical.com,
        the arch/x86 maintainers <x86@kernel.org>,
        Linux Memory Management List <linux-mm@kvack.org>,
        linux-coco@lists.linux.dev, linux-efi <linux-efi@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        "Yao, Jiewen" <jiewen.yao@intel.com>
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 <YtcnQbiRgZPtR+rQ@zn.tnic>
From:   Dave Hansen <dave.hansen@intel.com>
In-Reply-To: <YtcnQbiRgZPtR+rQ@zn.tnic>
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On 7/19/22 14:50, Borislav Petkov wrote:
> On Tue, Jul 19, 2022 at 02:35:45PM -0700, Dave Hansen wrote:
>> They're trying to design something that can (forever) handle guests that
>> might not be able to accept memory. 
> Wait, what?
> 
> If you can't modify those guests to teach them to accept memory, how do
> you add TDX or SNP guest support to them?

Mainline today, for instance, doesn't have unaccepted memory support for
TDX or SEV-SNP guests.  But, they both still boot fine because folks
either configure it on the host side not to *have* any unaccepted
memory.  Or, they just live with the small (4GB??) amount of
pre-accepted memory, which is fine for testing things.