From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 71639606A31A for ; Mon, 26 Oct 2026 17:53:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=aGL0DbGd; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=UUtTAD6Y DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Reply-To:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Date: Content-Transfer-Encoding:Content-Type:References:In-Reply-To:Cc:To:Subject: From:Message-ID:MIME-Version:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Unsubscribe-Post:List-Owner; bh=IWCtaOnVvPzXp0wppDZYwWsDRynq4pP6trEYtOMYIPA=; b=aGL0DbGdgT9j7tCCrqItooREuZ KLfUqr2DDw8ZCN6HC0XpBpmuemuhYFAQusSoYBNJvvTF7Z3ew9MTNs1LSM/m3gxGjyAbvACe/NMvg pwDaiPGrzZaj6+nI74IeIPBkFabJqmhnmu+5l1x2+9JNeHo7RSKNnzeuFF0D89Z4CO1fzntu9RWRH Q675Eyb40Lie2dHlekT2P/jAmfWu4oxnH23XsNQjUgYBfDlThrUS4ZVJUOqB47IZfU/XeQGztTwXb J8Bh+5QSVzKsTQWmNHX4HIlAzDI7PFWOqLSJXoW4K5Q2hdwwqI246jEp93cc4FM+2bvi8AtkK/W+J QaZUU6WA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLOtQ-000000031au-0fK6; Mon, 26 Oct 2026 17:53:56 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLOtP-000000031aP-0aEE for kexec@lists.infradead.org; Mon, 26 Oct 2026 17:53:55 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 9246060A6B; Mon, 26 Oct 2026 17:53:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4291B1F01825; Mon, 26 Oct 2026 17:53:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793037234; bh=IWCtaOnVvPzXp0wppDZYwWsDRynq4pP6trEYtOMYIPA=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=UUtTAD6YWjcnQMMWgPOoQlJF6dYZognm7qepdMXOSlMupr3AzgY9Hx0ghghZRH7nW YaCa/bDer9orwLj6rxvDD7fuZryH9g0NyotK9OdyRJAwVJMatCbdk+XCcuHghS3Pji yjZmFJdwDGzc5uSg0Q3l0SLuYzN1yUMaqlSD+/zCYeWsiEmCcV2CZr/hozTGqqAeIW FOgpT1SV+Xb5XoJ9dsPh8PI8Kyo7oVZJWyMcOIwzqDY3qk2Tr2v0s8utbePT/uj1kK ewg7mCVNK+/4NXJ53qWxDpFAWGsgfmhKgb3PQLWPvh4hwSjB1b6Oca4Mw7TA7Hk321 aalJmhn5YtUPw== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [RFC PATCH v3 2/4] liveupdate: Add feature header for fine-grained ABI compatibility To: "Tarun Sahu" , loganodell@google.com, alex@shazbot.org, dwmw2@infradead.org, seanjc@google.com, "Mike Rapoport" , will@kernel.org, pbonzini@redhat.com, jgg@nvidia.com, "Pasha Tatashin" , arnd@arndb.de, "Andrew Morton" , oupton@kernel.org, baolu.lu@linux.intel.com, "David Matlack" , robin.murphy@arm.com, maz@kernel.org, "Alexander Graf" , joro@8bytes.org, "Bjorn Helgaas" , kevin.tian@intel.com, "Pratyush Yadav" Cc: kexec@lists.infradead.org In-Reply-To: <20261026174217.603114-3-tarunsahu@google.com> References: <20261026174217.603114-1-tarunsahu@google.com> <20261026174217.603114-3-tarunsahu@google.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Mon, 26 Oct 2026 17:53:52 +0000 X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: sashiko-reviews@lists.linux.dev Sender: "kexec" X-Spam-Status: No, score=-11.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 X-Archived-By: > LUO and its file handlers currently rely solely on coarse-grained > compatibility strings (such as luo-v5 and memfd-v2) to validate > handed-over state across kexec. Because compatibility is checked only > at the whole-structure level, any change to a serialized structure, > even an optional additive field, requires bumping the compatibility > string and breaks live update between adjacent kernels. >=20 > Introduce a feature header (struct luo_ser_hdr) ahead of serialized LUO > structures so subsystems can evolve their serialized state at > per-feature granularity. Each subsystem groups the fields of its > serialized structure under feature indices, starting with index 0 for the > base fields. When a subsystem adds a new capability, it appends any new > fields to the end of its payload structure under a new feature index. > Retired fields are kept in place so existing field offsets never shift; > if the type or format of a field needs to change, the existing field and > [ ... ] > Also, introduce the LUO_CORE_FEAT_CORE for LUO for the existing mechanism > which is also a required feature. >=20 > Signed-off-by: Logan Odell > Signed-off-by: Tarun Sahu Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261026174217.6031= 14-1-tarunsahu@google.com?part=3D2