From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794377796; b=R0KZ7fSZx4d11W1w5hx8OwsIQbBkuBH8wtNMJF1+dqh5btacGtIg3xXioxFsl+kwJk1j +n+EDEvFkWlOW3vC1/IP8Mzo0Wpm0D/15Z3lhxO1kVa+9YjQ/3mxGDfXnt0Tk9QmLD4Xz kC7wVktTDUTdtbC46Xkjeh7IXcqKxBINgO1xbpiVq0Grbv3XL08soVJKogucsoWzG6fdR rURktfNPi5cYm0PQ8L4CrzqAJ4hdZiCrbpVhMX1AaYkAPbJfjN/gCnxvIhbkGlK8z/rMz o0uB3qCDUpZwNXZjtt+SOrcZWYwAEud1Czh5Qrmt2ICw5MbDS2j2DkGRveUmtDdGHWg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794377796; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=XpUjgykRN0vFDha3zJ8L+z/s5zYun/eYAgoPua1NoMA=; b=gnz94qNt9Cp6xZ4ijB6+o/pupEghMsvoAkZLOCL4/mea3S9efqpX83KdtHmyUdxGKPFN bLKD9Kv1ptAqEWrj4NWwR6mWzTdNCU2D+K3JZkFKB+fxVeVGowNMOyAalsUouZPm22Uwf dnMlXgZYV2bUcf1OnaDLk1uByNwLUuap/fJMSePpFHpVSS67CSzcgnzCP5t+r6CIThQyd W7mBoJcQqBoNyQy2jvG3nepi1SBIg6vG1ags2+JmeV2dxq6LQQ5Mgkp53zuaReAywxZzf q4ZPIfm4HMneomuCkSWwZVgRKGnUKfwpb1CvSbqS1D1AZ/YfWmyT0zCjUUET1AamgFg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=lRWyLjuc; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6D6B1606A332 for ; Wed, 11 Nov 2026 06:16:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=lRWyLjuc Received: by smtp.kernel.org (Postfix) with ESMTPSA id D372B1F00A0B; Wed, 11 Nov 2026 06:16:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794377796; bh=XpUjgykRN0vFDha3zJ8L+z/s5zYun/eYAgoPua1NoMA=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=lRWyLjuc4FqV1ZiNtvfr7F6uvGFhyVzqgThcTe1+qsr8fb9XeRBjhQMREF09XUmd9 NO+GYZidhttYb6TPwGnmncqvDO+xfoInFX1T9wXihWIZ+yux5utnpLx/A1FAqjDlyB OGBO4uNIeNIW/tyifSYQzJMCT0CH2tQZ2vr8HObe/BcEELWg9hhmTA/ycvXwiyoTk7 q5eWxl3V4b7EEhUeYCy9ZJ4JOWIzi4T5/MHmr2Oivl7C/TAeecu3zX16Le3yoCubyh 7ga0WzRSvV+/Bl/TZ2f5jeT/23MKETwOH/qFG0U80sLuLpIa3mPULZ7pjtenMWbEPg Vm2dT4qMunoWQ== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v4 05/19] kho: Add feature header for fine-grained ABI compatibility Reply-To: sashiko-reviews@lists.linux.dev To: "Tarun Sahu" , "Pasha Tatashin" , "Mike Rapoport" , robin.murphy@arm.com, maz@kernel.org, will@kernel.org, "David Matlack" , "Alexander Graf" , seanjc@google.com, jgg@nvidia.com, loganodell@google.com, arnd@arndb.de, dwmw2@infradead.org, baolu.lu@linux.intel.com, "Bjorn Helgaas" , oupton@kernel.org, alex@shazbot.org, gle.com@google.com, pbonzini@redhat.com, "Andrew Morton" , kevin.tian@intel.com, joro@8bytes.org Cc: linux-pci@vger.kernel.org, "Pratyush Yadav" , kexec@lists.infradead.org, skhawaja@google.com, sagis@google.com In-Reply-To: <20261110050202.529473-6-tarunsahu@google.com> References: <20261110050202.529473-1-tarunsahu@google.com> <20261110050202.529473-6-tarunsahu@google.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Wed, 11 Nov 2026 06:16:34 +0000 X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > Serialized structures in KHO and Live Update Orchestrator currently rely > on whole-structure compatibility strings or monolithic version fields to > validate handed-over state across kexec. Any change to a serialized > structure, even an optional additive field, requires bumping the > compatibility string or version number and breaks live update between > adjacent kernels. >=20 > Introduce a generic feature header (struct kho_ser_hdr) for serialized > binary structures in include/linux/kho/abi/feature.h. Each subsystem > groups the fields of its serialized structure under feature indices, > starting with index 0 for base fields. When a subsystem adds a new > capability, it appends 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 feature are kept intact until retired and > [ ... ] > layout while deserialization helpers follow the incoming header. >=20 > Suggested-by: David Matlack > Suggested-by: Pasha Tatashin > Signed-off-by: Tarun Sahu Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261110050202.5294= 73-1-tarunsahu@google.com?part=3D5