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 X-Spam-Level: X-Spam-Status: No, score=-19.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 87F27C433E9 for ; Wed, 20 Jan 2021 03:24:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 431C023121 for ; Wed, 20 Jan 2021 03:24:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387438AbhATCbv (ORCPT ); Tue, 19 Jan 2021 21:31:51 -0500 Received: from mail.kernel.org ([198.145.29.99]:46620 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729348AbhATB13 (ORCPT ); Tue, 19 Jan 2021 20:27:29 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 30C4A23119; Wed, 20 Jan 2021 01:26:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1611105973; bh=SCjTXcyJf79brv8xJHXu5j97eu+y+qHap1CjffLVVJM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oEspaWD9LSowsKOxHjpLUWQZdPKEl/3tMb2EPOk91IJamtYSS7c8XxSE+9ZQlu41w kcBExBy5sGp96cV/cOdTG5alI+vpklruAqL8u70jykiz57jr2XS6XsXQLHnCmSTjZe CSs8dFSt/qJA7ToF2W5MMPI8CWusizmiMHeDA02KwieleCuF1TYg6kugwNxEX8Ynns 3TdSPARPHbCDv5HxRakxxZtJxjE56+cW2mOz2TAncf8hdZtWjXMEYC5rVRV+1d67HF Ky0mKi+DlSnSnfOS+MMX3X4YbBihRFLTrjmevGCfYC5doqW1vnrGM49GKKdHwE58xm ej2IUrygEYmGw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Dexuan Cui , Michael Kelley , Wei Liu , Sasha Levin , linux-hyperv@vger.kernel.org Subject: [PATCH AUTOSEL 5.10 08/45] x86/hyperv: Fix kexec panic/hang issues Date: Tue, 19 Jan 2021 20:25:25 -0500 Message-Id: <20210120012602.769683-8-sashal@kernel.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20210120012602.769683-1-sashal@kernel.org> References: <20210120012602.769683-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dexuan Cui [ Upstream commit dfe94d4086e40e92b1926bddcefa629b791e9b28 ] Currently the kexec kernel can panic or hang due to 2 causes: 1) hv_cpu_die() is not called upon kexec, so the hypervisor corrupts the old VP Assist Pages when the kexec kernel runs. The same issue is fixed for hibernation in commit 421f090c819d ("x86/hyperv: Suspend/resume the VP assist page for hibernation"). Now fix it for kexec. 2) hyperv_cleanup() is called too early. In the kexec path, the other CPUs are stopped in hv_machine_shutdown() -> native_machine_shutdown(), so between hv_kexec_handler() and native_machine_shutdown(), the other CPUs can still try to access the hypercall page and cause panic. The workaround "hv_hypercall_pg = NULL;" in hyperv_cleanup() is unreliabe. Move hyperv_cleanup() to a better place. Signed-off-by: Dexuan Cui Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20201222065541.24312-1-decui@microsoft.com Signed-off-by: Wei Liu Signed-off-by: Sasha Levin --- arch/x86/hyperv/hv_init.c | 4 ++++ arch/x86/include/asm/mshyperv.h | 2 ++ arch/x86/kernel/cpu/mshyperv.c | 18 ++++++++++++++++++ drivers/hv/vmbus_drv.c | 2 -- 4 files changed, 24 insertions(+), 2 deletions(-) diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index e04d90af4c27c..4638a52d8eaea 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #include #include @@ -26,6 +27,8 @@ #include #include +int hyperv_init_cpuhp; + void *hv_hypercall_pg; EXPORT_SYMBOL_GPL(hv_hypercall_pg); @@ -401,6 +404,7 @@ void __init hyperv_init(void) register_syscore_ops(&hv_syscore_ops); + hyperv_init_cpuhp = cpuhp; return; remove_cpuhp_state: diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h index ffc289992d1b0..30f76b9668579 100644 --- a/arch/x86/include/asm/mshyperv.h +++ b/arch/x86/include/asm/mshyperv.h @@ -74,6 +74,8 @@ static inline void hv_disable_stimer0_percpu_irq(int irq) {} #if IS_ENABLED(CONFIG_HYPERV) +extern int hyperv_init_cpuhp; + extern void *hv_hypercall_pg; extern void __percpu **hyperv_pcpu_input_arg; diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 05ef1f4550cbd..6cc50ab07bded 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -135,14 +135,32 @@ static void hv_machine_shutdown(void) { if (kexec_in_progress && hv_kexec_handler) hv_kexec_handler(); + + /* + * Call hv_cpu_die() on all the CPUs, otherwise later the hypervisor + * corrupts the old VP Assist Pages and can crash the kexec kernel. + */ + if (kexec_in_progress && hyperv_init_cpuhp > 0) + cpuhp_remove_state(hyperv_init_cpuhp); + + /* The function calls stop_other_cpus(). */ native_machine_shutdown(); + + /* Disable the hypercall page when there is only 1 active CPU. */ + if (kexec_in_progress) + hyperv_cleanup(); } static void hv_machine_crash_shutdown(struct pt_regs *regs) { if (hv_crash_handler) hv_crash_handler(regs); + + /* The function calls crash_smp_send_stop(). */ native_machine_crash_shutdown(regs); + + /* Disable the hypercall page when there is only 1 active CPU. */ + hyperv_cleanup(); } #endif /* CONFIG_KEXEC_CORE */ #endif /* CONFIG_HYPERV */ diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 4fad3e6745e53..a5a402e776c77 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -2542,7 +2542,6 @@ static void hv_kexec_handler(void) /* Make sure conn_state is set as hv_synic_cleanup checks for it */ mb(); cpuhp_remove_state(hyperv_cpuhp_online); - hyperv_cleanup(); }; static void hv_crash_handler(struct pt_regs *regs) @@ -2558,7 +2557,6 @@ static void hv_crash_handler(struct pt_regs *regs) cpu = smp_processor_id(); hv_stimer_cleanup(cpu); hv_synic_disable_regs(cpu); - hyperv_cleanup(); }; static int hv_synic_suspend(void) -- 2.27.0