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AHgh+RqUs/EmPI0iNe9tXcMpflo7P1ia6R64qezuJ8gphlAbf7FmWoXaUJjIlg70k1iDZ6/0nT0mLcJ7hA==@kvack.org X-Gm-Message-State: AOJu0YyFUBl9rPqIMq8ZMTTvuPQ95wdMWwQn5Tt8CvUi6ILu5Y65USrK o0yKdevcLlzgnbr3l5JydHnF3ekHbhNNLNjBKLnYLrqM/+0vHuqDJol5Ksbifl9kZY8+V3ECZGm WqzGJpQ== X-Received: from pjse9.prod.google.com ([2002:a17:90a:77c9:b0:384:934b:9128]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:590e:b0:38e:6a44:671b with SMTP id 98e67ed59e1d1-3909d301d9cmr33802476a91.0.1786402700758; Mon, 10 Aug 2026 15:58:20 -0700 (PDT) Date: Mon, 10 Aug 2026 15:58:20 -0700 In-Reply-To: <20260728121138.1103610-2-tarunsahu@google.com> Mime-Version: 1.0 References: <20260728121138.1103610-1-tarunsahu@google.com> <20260728121138.1103610-2-tarunsahu@google.com> Message-ID: Subject: Re: [PATCH v4 01/11] liveupdate: Add LIVEUPDATE_GUEST_MEMFD config option From: Sean Christopherson To: Tarun Sahu Cc: ackerleytng@google.com, fuad.tabba@linux.dev, Andrew Morton , dmatlack@google.com, Shuah Khan , Jonathan Corbet , david@redhat.com, Pasha Tatashin , Pratyush Yadav , sagis@google.com, Paolo Bonzini , Mike Rapoport , Alexander Graf , linux-kselftest@vger.kernel.org, andre.przywara@arm.com, michael.roth@amd.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, will@kernel.org, vannapurve@google.com, maz@kernel.org, fvdl@google.com, kvm@vger.kernel.org, oliver.upton@linux.dev, kvmarm@lists.linux.dev, alexandru.elisei@arm.com, skhawaja@google.com, aneesh.kumar@kernel.org, linux-doc@vger.kernel.org, David Hildenbrand , yan.y.zhao@intel.com, kexec@lists.infradead.org, suzuki.poulose@arm.com Content-Type: text/plain; charset="us-ascii" X-Rspamd-Queue-Id: 51297C0003 X-Stat-Signature: 7ttm43ppmcufdofdgpq879gd4mamces7 X-Rspam-User: X-Rspamd-Server: rspam04 X-HE-Tag: 1786402702-174676 X-HE-Meta: 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 +kA0RLZQ 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Jul 28, 2026, Tarun Sahu wrote: > Introduce the LIVEUPDATE_GUEST_MEMFD Kconfig option. This option > enables live update support for KVM guest_memfd files, enabling > guest_memfd-backed memory preservation across kernel upgrades. > > Currently this support only guest_memfd files that are full-shared > (INIT_SHARED and no support for private_mem). Why? Specifically, why do we need/want a separate Kconfig for guest_memfd liveupdate versus KVM liveupdate? I can _maybe_ see a KVM-wide Kconfig, but even that seems like a stretch given that (AFAIK) hypervisors are the one and only use-case for liveupdate.