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 F295D606A31E for ; Wed, 21 Oct 2026 07:27:19 +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=kpZL7XT2; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=bUEsZ5IW DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Yaahl2NjM7LYJ3/VUSQG13ODgqUJA5kkV/j2CsiAkwA=; b=kpZL7XT2ROijscvzN0RvfMB/jU Fr1Npsm+2hgmNwm8CbV/0hNyUY4rVdDE0A7paFEawSpZAC7K6xHm1CHpavmr2iptEXxFtSuaWN0Qs 2mD7O2O827Yyj+/dQrvYZosgbJnC8sr6gGI1B4CKHyj9fhtlG7r3nTh8ugDsQtkXvN++wv9iWTuZO QoiVOID3iRpQ1l6tzyRMY3jfpZpwTOWEYcjqWpbSAD6paPvloNyZZLHxcA2R2gp3Kz9KGJcv/cElJ pfFRuDe8r3Mu1vPfBqmO4FtsqXc2vsq+9p5YAWYlhB6rEr0FIMi6+F+ye4obRQohlSEzi9f9ynXeH FAzabBXw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xJQj9-0000000BFfK-19Ws; Wed, 21 Oct 2026 07:27:11 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1xJQj7-0000000BFep-30aO; Wed, 21 Oct 2026 07:27:09 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id DFC9640334; Wed, 21 Oct 2026 07:27:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F48F1F000CA; Wed, 21 Oct 2026 07:27:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792567628; bh=Yaahl2NjM7LYJ3/VUSQG13ODgqUJA5kkV/j2CsiAkwA=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=bUEsZ5IW9a3Szer7bK9RTRwykZPLZWByrbcqBn+bd0n7lP4ZRRuV5OQXQGjOwoy8E BIYtLTNMkx8NTeMmbPOBJnWZRjkwca+gcJ1h0haQ7prOXdpniffU9ztJAo/CPtxhcl iAVVU1n60X+gDOtLmaGmW3wQAAiu05os2br3vplaE3SNIZ922wcZXuJMf6DQ8CAFou 4JhAjGFaXE3LG+yhA2TCRhXT5gy9PB4rmZ4KRLa9JQTUL87C5Ox7r7ojsB9kcdE568 EYPrtBF/A2MmJ6LvO0xUa19vYnNWp1tseqSuVUhflIGb996+bdy1xHcA3NUPK49+zR CV67lqrjbae+Q== Date: Wed, 21 Oct 2026 00:27:07 -0700 From: Wei Liu To: Shradha Gupta Cc: mhklinux@outlook.com, wei.liu@kernel.org, catalin.marinas@arm.com, baoquan.he@linux.dev, will@kernel.org, kys@microsoft.com, haiyangz@microsoft.com, decui@microsoft.com, longli@microsoft.com, akpm@linux-foundation.org, rppt@kernel.org, pasha.tatashin@soleen.com, pratyush@kernel.org, tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, arnd@arndb.de, hpa@zytor.com, maz@kernel.org, mark.rutland@arm.com, linux-hyperv@vger.kernel.org, kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, broonie@kernel.org, kees@kernel.org, brads@mainlining.org, namjain@linux.microsoft.com Subject: Re: [PATCH v4 0/2] hyperv: Run VMBus kexec cleanup from syscore shutdown Message-ID: <20261021072707.GH851443@liuwe-devbox-debian-v2.local> References: <20261009102215.3360863-1-shradhagupta@linux.microsoft.com> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261009102215.3360863-1-shradhagupta@linux.microsoft.com> X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" 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_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 On Fri, Oct 09, 2026 at 03:22:11AM -0700, Shradha Gupta wrote: > Kexec reboot fails on ARM64 Hyper-V guests because the VMBus connection > and SynIC CPU hotplug state are not torn down before the secondary CPUs > are stopped. Move this cleanup into the VMBus syscore shutdown callback, > which runs after device shutdown and before architecture-specific machine > shutdown. > > Patch 1 adds an exported helper for checking whether a normal kexec reboot > is in progress. Patch 2 runs the VMBus cleanup from the common syscore > shutdown path on x86 and ARM64, removes the old x86 handler interface, and > documents the shutdown ordering. > > On x86, VMBus teardown now precedes hv_stimer_global_cleanup(). This relies > on commit be0cfab740e5 ("clocksource: hyper-v: Remove support for stimer > interrupts in message mode"). Older kernels that retain message-mode > stimer interrupts need an ARM64-specific backport to preserve the existing > x86 ordering. > > Changes in v4: > - Document the VMBus kexec cleanup path in the Hyper-V overview. > - Combine adjacent kexec_in_progress checks in the x86 shutdown path. > > Changes in v3: > - Use the existing common VMBus syscore operations on all > architectures, as suggested by Michael. > - Remove the x86 handler pointer and the weak setup/remove interface. > - Add an exported read-only helper for modular VMBus builds. > - Correct the Fixes tag to the commit that enabled Hyper-V on ARM64. > > Changes in v2: > - Use syscore shutdown instead of an ARM64 machine_shutdown() hook, as > suggested by Catalin. > > Shradha Gupta (2): > kexec: Add helper to report an active kexec reboot > Drivers: hv: Run VMBus kexec cleanup from syscore shutdown > > Documentation/virt/hyperv/overview.rst | 12 +++++++----- > arch/x86/kernel/cpu/mshyperv.c | 27 ++++++--------------------- > drivers/hv/hv_common.c | 10 ---------- > drivers/hv/vmbus_drv.c | 22 ++++++++++++++-------- > include/asm-generic/mshyperv.h | 2 -- > include/linux/kexec.h | 2 ++ > kernel/kexec_core.c | 7 +++++++ > 7 files changed, 36 insertions(+), 46 deletions(-) Applied. Thanks. Wei