From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=115.124.30.98 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793693390; b=srlT69xoeu2bJQ9LeNoTB+tf16tnOzagWQQ8yN35c8Mtc7Jngr+QruYR0B/D487GRRgt +dNtZYbYeTmLfUiPcN/ubW2tr69nyk133+Ca1BOOTHMdfys+u4r2jgScAe7qkhZ/9GfRC g5uRyhlv7zbzjvK3qSRnYWefW1E1/oLIRdri25GXisX6PAJz5rgRgQuhYoqNE23TW0L/R +9Y7crKTj07KyQCCBiaf1vLxF3SN38kTFuxECMjiE2FaY+DR9/TX5zPlMqQ3ImVb98fCL Yr/SQo4NkhkJf+/+24L56QosJEe0mv0upQgIFKnh51JAQgPG9DFrI3f9OTfjw/zKXBw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793693390; h=DMARC-Filter:DKIM-Signature:X-Alimail-AntiSpam:Received:From:To:Cc: Subject:Date:Message-ID:X-Mailer:MIME-Version: Content-Transfer-Encoding; bh=hZSS8pIphBraD9CLXDgq7aSqfm0V64ZlrBCsq6wroQE=; b=bwbbd3vYrGWlMU9LwZ3H3my47AOUcprAafahm7dn2Wy8CJ/FDdzZiAtc0Xe/fOZusEAj pQGwtLaLe1FLo/8yNXVrelWTiHdTNPDvf9ysfrVv9CVeCthbUslTTO+wEGCQJXYdHg7k6 v6XwJu1HzBoU3Dy1uWikevzSMEpG2ShPEDd5+kUDntZtS4QtnGFW0bnp52VUoWNJjhVIf 9u9qpfwc1XeoIWZSzpAktPNUnlf9aPQ7vT3wlrhJ8wayLYWK6MOFwZS4/vZ0j30ESme6N uJn11ByjwpI8/AqotAe4cKwy0wlPZg/CRpJCHBLmL/5KhnRtjtwQFBvOoIIe3bS0wGA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass header.d=linux.alibaba.com header.i=@linux.alibaba.com header.a=rsa-sha256 header.s=default header.b=k3+9NMTv; arc=none smtp.remote-ip=115.124.30.98 Received: from out30-98.freemail.mail.aliyun.com (out30-98.freemail.mail.aliyun.com [115.124.30.98]) (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 819DF606A32C; Tue, 3 Nov 2026 08:09:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 819DF606A32C Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.a=rsa-sha256 header.s=default header.b=k3+9NMTv DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1793693380; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=hZSS8pIphBraD9CLXDgq7aSqfm0V64ZlrBCsq6wroQE=; b=k3+9NMTvOTcsQlIoPgLSTXIBifkXBNDcs5kuWXjFq71JvItapbbbsn30eMnAMKbhOzqcJTZYj6mxd13R9hFZhwDkvuMteIVO+v8ywaGeD0+atsUasFUXfAz6HTX1VXENidMA8BxE7vQp+jlSQgDXMz9NZ4FB9WwYQ7hb5cJtpbU= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R151e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam011083073210;MF=cp0613@linux.alibaba.com;NM=1;PH=DS;RN=14;SR=0;TI=SMTPD_---0XE27KwW_1793693367; Received: from DESKTOP-S9E58SO.localdomain(mailfrom:cp0613@linux.alibaba.com fp:SMTPD_---0XE27KwW_1793693367 cluster:ay36) by smtp.aliyun-inc.com; Tue, 03 Nov 2026 16:09:39 +0800 From: Chen Pei To: pjw@kernel.org, palmer@dabbelt.com, alex@ghiti.fr, rppt@kernel.org, pasha.tatashin@soleen.com, pratyush@kernel.org, graf@amazon.com, shuah@kernel.org Cc: guoren@kernel.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, kexec@lists.infradead.org Subject: [PATCH v2 0/5] riscv: Enable kexec handover and live update Date: Tue, 3 Nov 2026 16:09:21 +0800 Message-ID: <20261103080926.2079-1-cp0613@linux.alibaba.com> X-Mailer: git-send-email 2.43.0 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Host kernel updates in the cloud should not require draining the machine: next to live migration to another host, replacing the kernel in place while preserving selected workload state ("live update") is what KHO/LUO were built for, and LUO's documentation names hypervisor hosts as its primary use case. This series closes the gap for riscv64 and validates it with both upstream test runners. KHO has been architecture independent since it was merged: the outgoing kernel publishes the handover FDT and the scratch descriptor array in the /chosen node of the DTB it builds for the incoming kernel, and the incoming kernel collects both while scanning that node -- which is why the arm64 integration (commit 274cdcb1c004) needed only three lines of arch code. Patch 1 is generic and comes first because enabling KHO on riscv64 needs it: is_kho_boot() runs the handover FDT address through phys_to_virt() only to return a boolean, and on riscv64 that is a BUG() before the linear map offset exists. Neither caller dereferences the value, so testing the physical address is enough. RISC-V otherwise already walks the generic paths (load_extra_segments() -> of_kexec_alloc_and_setup_fdt(), parse_dtb() -> early_init_dt_scan()). The remaining blocker is ordering: setup_arch() runs early_ioremap_setup() *after* parse_dtb(), so kho_populate()'s early_memremap() of the handover FDT returns "offset + 0" -- NULL for a page aligned address -- and the handover is dropped: KHO: setup: failed to memremap FDT (0x810bb000) KHO: disabling KHO revival Patch 2 fixes that ordering, matching arm64/x86 and standing on its own regardless of KHO. Patch 3 enables ARCH_SUPPORTS_KEXEC_HANDOVER as "def_bool 64BIT && MMU" rather than arm64's "def_bool y": ARCH_SUPPORTS_KEXEC_FILE is already 64BIT-only, and KEXEC_HANDOVER selects CMA, which depends on MMU. Patches 4 and 5 teach the two upstream vmtest runners about riscv64. LIVEUPDATE depends only on KEXEC_HANDOVER, so patch 3 makes it selectable on riscv as well. No DT schema changes are needed: linux,kho-fdt / linux,kho-scratch are the properties arm64 introduced (commit 274cdcb1c004), and their binding lives in the external dt-schema repository [1] rather than in Documentation. [1] https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/chosen.yaml Changes since v1: - New patch 1: kho: Do not translate the handover FDT address in is_kho_boot(), a generic fix the riscv enablement needs. - Rebased onto linux-next-20261102 (2637bdec0535). Test ---- Testing on linux-next-20261102 (2637bdec0535) with qemu-system-riscv64 (virt, -cpu max, TCG); method and logs under the --- of patches 1, 4 and 5: - patch 1, UEFI handover boot (edk2 on pflash over OpenSBI fw_dynamic, DEBUG_VIRTUAL=y): a BUG_ON in the incoming kernel on the first handover without the patch, 29 consecutive handovers with it - the same two kernels handing over from a device tree boot instead: both succeed, so what fails is the UEFI path and not the handover - kho vmtest: "ok 1 KHO succeeded" - liveupdate vmtest, all four suites passed one by one (simple, multi-session, 500 files, 2000 sessions) - riscv defconfig with and without CONFIG_KEXEC_HANDOVER both boot to userspace with no oops on the console; builds: riscv defconfig (+KHO), rv32_defconfig, arm64 defconfig (+KHO), x86_64 defconfig (+KHO) Additionally, a workload-continuity test was run outside the selftests: a counter process was snapshot with criu 4.3, the dump was carried across the kexec in an LUO-preserved memfd, and criu restored it in the new kernel. The process resumed with the same PID and open log file and kept counting from where it was dumped (500006 -> 500007, no lost or duplicated ticks). Chen Pei (5): kho: Do not translate the handover FDT address in is_kho_boot() riscv: Call early_ioremap_setup() before parsing the DTB riscv: Add support for kexec handover (KHO) selftests: kho: Add riscv support selftests: liveupdate: Add riscv support arch/riscv/Kconfig | 3 +++ arch/riscv/kernel/setup.c | 2 +- kernel/liveupdate/kexec_handover.c | 2 +- tools/testing/selftests/kho/riscv.conf | 9 +++++++++ tools/testing/selftests/kho/vmtest.sh | 3 ++- tools/testing/selftests/liveupdate/config.riscv64 | 3 +++ tools/testing/selftests/liveupdate/run-vmtests.sh | 2 +- tools/testing/selftests/liveupdate/vmtest.sh | 8 +++++++- 8 files changed, 27 insertions(+), 5 deletions(-) create mode 100644 tools/testing/selftests/kho/riscv.conf create mode 100644 tools/testing/selftests/liveupdate/config.riscv64 base-commit: 2637bdec0535a2044cd830eba9a79363651d9043 -- 2.50.1