From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E4764CA5FF0 for ; Tue, 6 Oct 2026 10:08:46 +0000 (UTC) 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:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Gt1lp+Gdyr+I3+ep/fgfelXAWkuyT6J0SUoT/mWxGK4=; b=OE2KjPYUWOKKGk6twPcVma/YsZ hhCfp2rAqW16N1EiuLILV0bJEyqMfffbfvqudw9gTEeGdoshFWboa20FjstKwz2FDmvHowpVFlstU sQPWljLP0vyIiBQoDELsyurLRETSku3MLpFyD/C28b53UfhtxyiDZIZWY4TzA0VOsrA7AVkTC8eI0 2bfUfpeoFDEk+lobbHCXeJbsE5SiScLAlCnCUInWrVuUGL4UA8ZCn1Mdl+/WXSagkvWAZUc6T1BuD HNn6HkIcxIYhill+FvOIYMasI2dEG0cIcS0tdXhi41T7GZETqXpfS2m3mXnc/w5S1jmjP717bdI94 7OfsxZ/g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xE26C-00000000SSd-07rj; Tue, 06 Oct 2026 10:08:40 +0000 Received: from linux.microsoft.com ([13.77.154.182]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xE269-00000000SSA-2cK7; Tue, 06 Oct 2026 10:08:38 +0000 Received: from [10.95.66.108] (unknown [52.172.102.222]) by linux.microsoft.com (Postfix) with ESMTPSA id 7A7A720B7166; Tue, 6 Oct 2026 03:07:31 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 7A7A720B7166 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1791281257; bh=Gt1lp+Gdyr+I3+ep/fgfelXAWkuyT6J0SUoT/mWxGK4=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=qvjOFXrCl2Fm7UpQpdxBBERC1/pwNW9LxDDp3yH1tH7KYtGcXxKtDlsJpfibq4Vxk Bfi9nnVAY5937ciu1VKyQMFEYjye25C0BExY/t+G8WcJcHJSN6M88oNg75ZsdQb1qQ r6E4hq1xVBJAJYQEspNRjH1QwGQ0La7JWOgo7buE= Message-ID: <6c1752b6-d09b-4d64-ac33-ab401df266fd@linux.microsoft.com> Date: Tue, 6 Oct 2026 15:38:23 +0530 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 0/2] hyperv: Run VMBus kexec cleanup from syscore shutdown To: Shradha Gupta , Michael Kelley , Wei Liu , Catalin Marinas , Baoquan He Cc: Will Deacon , "K . Y . Srinivasan" , Haiyang Zhang , Dexuan Cui , Long Li , Andrew Morton , Mike Rapoport , Pasha Tatashin , Pratyush Yadav , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Arnd Bergmann , 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 References: <20261001132128.1703511-1-shradhagupta@linux.microsoft.com> Content-Language: en-US From: Naman Jain In-Reply-To: <20261001132128.1703511-1-shradhagupta@linux.microsoft.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261006_030837_703216_B8F828B8 X-CRM114-Status: GOOD ( 19.15 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 10/1/2026 6:51 PM, 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. The kexec kernel consequently starts with > the previous kernel's VMBus state still active. > > The previous version added an ARM64-specific syscore shutdown > implementation. This version follows Michael Kelley's review and moves > the cleanup into the existing architecture-independent VMBus syscore > operations. This removes the separate x86 handler dispatch and gives > x86 and ARM64 the same ordering: > > device_shutdown() > syscore_shutdown() > VMBus UNLOAD and SynIC CPU hotplug teardown > machine_shutdown() > > On x86, VMBus teardown now runs before hv_stimer_global_cleanup(). > This ordering is safe after commit be0cfab740e5 ("clocksource: hyper-v: > Remove support for stimer interrupts in message mode") removed the > VMBus dependency from synthetic timer handling. > > Patch 1 adds a read-only helper that reports whether a kexec reboot is > in progress. The helper is exported because HYPERV_VMBUS is tristate > and the common syscore callback must also link when VMBus is a module. > Patch 2 moves the cleanup into the common callback and removes the > obsolete architecture-specific setup/remove interface. > > For stable kernels that still support message-mode stimers, an > ARM64-specific backport will be needed to preserve the existing x86 > ordering. > > 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 > > arch/x86/kernel/cpu/mshyperv.c | 17 +---------------- > 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 +++++++ > 6 files changed, 24 insertions(+), 36 deletions(-) > > > base-commit: be0cfab740e58b70047ef6e7e3d578f00ed5d258 Since the approach changed in this version and previously reviewed-by tags were not applicable, sharing them again for the series. Reviewed-by: Naman Jain Regards, Naman