linux-kernel - Re: [RFC] KVM: mm: fd-based approach for supporting KVM guest private memory

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <3b63a5d9-30e4-2ae8-2f01-a92b758e81de@redhat.com>
Date:   Wed, 1 Sep 2021 19:53:50 +0200
From:   David Hildenbrand <david@...hat.com>
To:     Sean Christopherson <seanjc@...gle.com>
Cc:     jejb@...ux.ibm.com, Andy Lutomirski <luto@...nel.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm list <kvm@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Borislav Petkov <bp@...en8.de>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Joerg Roedel <jroedel@...e.de>,
        Andi Kleen <ak@...ux.intel.com>,
        David Rientjes <rientjes@...gle.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Tom Lendacky <thomas.lendacky@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Varad Gautam <varad.gautam@...e.com>,
        Dario Faggioli <dfaggioli@...e.com>,
        the arch/x86 maintainers <x86@...nel.org>,
        linux-mm@...ck.org, linux-coco@...ts.linux.dev,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        "Kirill A . Shutemov" <kirill@...temov.name>,
        Sathyanarayanan Kuppuswamy 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>,
        Dave Hansen <dave.hansen@...el.com>,
        Yu Zhang <yu.c.zhang@...ux.intel.com>
Subject: Re: [RFC] KVM: mm: fd-based approach for supporting KVM guest private
 memory

On 01.09.21 19:50, Sean Christopherson wrote:
> On Wed, Sep 01, 2021, David Hildenbrand wrote:
>>>>> Well not necessarily, but it depends how clever we want to get.  If
>>>>> you look over on the OVMF/edk2 list, there's a proposal to do guest
>>>>> migration via a mirror VM that invokes a co-routine embedded in the
>>>>> OVMF binary:
>>>>
>>>> Yes, I heard of that. "Interesting" design.
>>>
>>> Heh, well what other suggestion do you have?  The problem is there
>>> needs to be code somewhere to perform some operations that's trusted by
>>> both the guest and the host.  The only element for a confidential VM
>>> that has this shared trust is the OVMF firmware, so it seems logical to
>>> use it.
>>
>> <offtopic>
>>
>> Let me put it this way: I worked with another architecture that doesn't
>> fault on access of a secure page, but instead automatically exports/encrypts
> 
> I thought s390 does fault on insecure accesses to secure pages, and it's the
> kernel's fault handler that "automatically" converts the page?  E.g. trap 0x3d
> -> do_secure_storage_access() -> arch_make_page_accessible().

"automatic" as in "the kernel can do it easily automatically under the 
hood when accessing such memory", yes that's what I meant :)

-- 
Thanks,

David / dhildenb