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b=F42UrrbiccUhcCUSVJCgw2tcCnaIjw608SkwFChMt+FV99UTr9rMAqlQpMruTCF+u5 osuBs3v9BX17IR1L1wlLM1q6WgDg3LoXdojoJNdY895GpMUzSZ4RUq/1Wm08hPyQ/utV UJnrGFjlugHm6ubORrK6vOiFJuqcpOdxnYRbfokecdUz1RxAsoOkeAP2UKIbsHbEoa8F Ga7xo8BtQPap3FnMf1VCM+wbUNiutSam/429sJok5f4Hn3NmVXRan7wvMFjhnpwEx+FW K4D2QuG25n0PWwzfGWs8rFtam2+XoxOvzRSq8r/IGGl4slwjvL6RDg8rTsiId2ldybmw dYNg== X-Forwarded-Encrypted: i=1; AHgh+RojJpJnnN4ZHr+4dU5xxGyye7LdxzoIMrkyhVwEFCD1Hnt8ju+N6NU25A1R9mN0IgGSWnl4OzrPyg==@kvack.org X-Gm-Message-State: AOJu0Yyv7DfYHsK22WhyBq433fOw79iskThHUxDDJh7to7IRP0dw9yyz iyITQuDaj6UO17R/xR1E8lWwYzug7OQ0ZYS2Bb8N0JWFsFde/6dLzRmyIbmXjppDdf1A6pvlSDA svvJqTnrQs9EyuT8W4A== 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> 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" X-Rspam-User: X-Rspamd-Queue-Id: CE54E1C000C X-Rspamd-Server: rspam01 X-Stat-Signature: 5tsscan7b6dgneqfnmwie8bwrpwrhs87 X-HE-Tag: 1785240703-572457 X-HE-Meta: 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 9T56Jxbi 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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