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AHgh+Rr8fJirP2OpHcgn8vfh638RYeFwWHwnKqHUJA4hAfTuLukVbGrnbD3Oy+Q1pJQffMJrgGxuUrOakjA=@vger.kernel.org X-Gm-Message-State: AOJu0Yzt/3aU7WN55Vr63nFZRKym5mqElbq0y9/4cidBMl+2kFDe/rxO 6ZIhFQ5qMr9Z/ILUQxAQ9JCL1IOK+48XEfrsYiKVXjkVI9p5eyaG1xyD9qHubRw9p3l1Iye0+vr IFztA4luxIhT3ZhIG0Q== X-Received: from edfy21.prod.google.com ([2002:a05:6402:a3d5:b0:698:3510:43a]) (user=tarunsahu job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6402:2b93:b0:69f:d5a9:c957 with SMTP id 4fb4d7f45d1cf-6a034a765a3mr1074401a12.35.1785240701982; Tue, 28 Jul 2026 05:11:41 -0700 (PDT) Date: Tue, 28 Jul 2026 12:11:28 +0000 In-Reply-To: <20260728121138.1103610-1-tarunsahu@google.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260728121138.1103610-1-tarunsahu@google.com> X-Mailer: git-send-email 2.55.0.229.g6434b31f56-goog Message-ID: <20260728121138.1103610-2-tarunsahu@google.com> Subject: [PATCH v4 01/11] liveupdate: Add LIVEUPDATE_GUEST_MEMFD config option From: Tarun Sahu To: ackerleytng@google.com, fuad.tabba@linux.dev, Andrew Morton , seanjc@google.com, dmatlack@google.com, Shuah Khan , Jonathan Corbet , david@redhat.com, Tarun Sahu , Pasha Tatashin , Pratyush Yadav , sagis@google.com, Paolo Bonzini , Mike Rapoport , Alexander Graf Cc: 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="UTF-8" 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). Signed-off-by: Tarun Sahu --- kernel/liveupdate/Kconfig | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/kernel/liveupdate/Kconfig b/kernel/liveupdate/Kconfig index c13af38ba23a..2490f9a9b838 100644 --- a/kernel/liveupdate/Kconfig +++ b/kernel/liveupdate/Kconfig @@ -86,4 +86,19 @@ config LIVEUPDATE_MEMFD If unsure, say N. +config LIVEUPDATE_GUEST_MEMFD + bool "Live update support for guest_memfd" + depends on LIVEUPDATE + depends on KVM_GUEST_MEMFD + default LIVEUPDATE + help + Enable live update support for KVM guest_memfd files. This allows + preserving VM Memory backed by guest_memfd file across kernel live + updates. + + This can only be used for the guest_memfd that are fully-shared + and pre-faulted. + + If unsure, say N. + endmenu -- 2.55.0.229.g6434b31f56-goog