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From:   Paolo Bonzini <pbonzini@redhat.com>
Date:   Tue, 31 Oct 2023 23:18:04 +0100
Message-ID: <CABgObfbLonVYk2WE4TC6-J_0ShanY7TbcLXStxji=XDU+9qQ7g@mail.gmail.com>
Subject: Re: [PATCH v13 16/35] KVM: Add KVM_CREATE_GUEST_MEMFD ioctl() for
 guest-specific backing memory
To:     Sean Christopherson <seanjc@google.com>
Cc:     Fuad Tabba <tabba@google.com>, Marc Zyngier <maz@kernel.org>,
        Oliver Upton <oliver.upton@linux.dev>,
        Huacai Chen <chenhuacai@kernel.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Anup Patel <anup@brainfault.org>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Christian Brauner <brauner@kernel.org>,
        "Matthew Wilcox (Oracle)" <willy@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>, kvm@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
        linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org,
        linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, Xiaoyao Li <xiaoyao.li@intel.com>,
        Xu Yilun <yilun.xu@intel.com>,
        Chao Peng <chao.p.peng@linux.intel.com>,
        Jarkko Sakkinen <jarkko@kernel.org>,
        Anish Moorthy <amoorthy@google.com>,
        David Matlack <dmatlack@google.com>,
        Yu Zhang <yu.c.zhang@linux.intel.com>,
        Isaku Yamahata <isaku.yamahata@intel.com>,
        =?UTF-8?B?TWlja2HDq2wgU2FsYcO8bg==?= <mic@digikod.net>,
        Vlastimil Babka <vbabka@suse.cz>,
        Vishal Annapurve <vannapurve@google.com>,
        Ackerley Tng <ackerleytng@google.com>,
        Maciej Szmigiero <mail@maciej.szmigiero.name>,
        David Hildenbrand <david@redhat.com>,
        Quentin Perret <qperret@google.com>,
        Michael Roth <michael.roth@amd.com>,
        Wang <wei.w.wang@intel.com>,
        Liam Merwick <liam.merwick@oracle.com>,
        Isaku Yamahata <isaku.yamahata@gmail.com>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
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On Tue, Oct 31, 2023 at 11:13=E2=80=AFPM Sean Christopherson <seanjc@google=
.com> wrote:
> On Tue, Oct 31, 2023, Fuad Tabba wrote:
> > On Fri, Oct 27, 2023 at 7:23=E2=80=AFPM Sean Christopherson <seanjc@goo=
gle.com> wrote:
> Since we now know that at least pKVM will use guest_memfd for shared memo=
ry, and
> odds are quite good that "regular" VMs will also do the same, i.e. will w=
ant
> guest_memfd with the concept of private memory, I agree that we should av=
oid
> PRIVATE.
>
> Though I vote for KVM_MEM_GUEST_MEMFD (or KVM_MEM_GUEST_MEMFD_VALID or
> KVM_MEM_USE_GUEST_MEMFD).  I.e. do our best to avoid ambiguity between re=
ferring
> to "guest memory" at-large and guest_memfd.

I was going to propose KVM_MEM_HAS_GUESTMEMFD.  Any option
is okay for me so, if no one complains, I'll go for KVM_MEM_GUESTMEMFD
(no underscore because I found the repeated "_MEM" distracting).

Paolo