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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B5F9AE7C4E9 for ; Wed, 4 Oct 2023 18:29:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233788AbjJDS3l (ORCPT ); Wed, 4 Oct 2023 14:29:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40758 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233874AbjJDS3k (ORCPT ); Wed, 4 Oct 2023 14:29:40 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 33A2E98 for ; Wed, 4 Oct 2023 11:29:37 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 775CAC433C8; Wed, 4 Oct 2023 18:29:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1696444176; bh=axQ5ipgjjcNmiLKTynLoRhWGb9T7WYNCyjGt9bdTP80=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UTGaj9WWqJ7hQZNlSAjxYlfeR3QTVnIF/aXgV+YASTkOJm1DPQn8TiVu8SAIo/len 1KVf30p7kTg8umTcp04agg7sV8tjCz4vExduWKuGJlYnrFNeLwKec2Fni6VzMwxd2Y eVkDjzw9orPFrcwePwi3wkJ7XMJK63VeEKTtLvpk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Andrew Cooper , Sean Christopherson , Sasha Levin Subject: [PATCH 6.5 158/321] x86/reboot: VMCLEAR active VMCSes before emergency reboot Date: Wed, 4 Oct 2023 19:55:03 +0200 Message-ID: <20231004175236.563003673@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231004175229.211487444@linuxfoundation.org> References: <20231004175229.211487444@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 6.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sean Christopherson [ Upstream commit b23c83ad2c638420ec0608a9de354507c41bec29 ] VMCLEAR active VMCSes before any emergency reboot, not just if the kernel may kexec into a new kernel after a crash. Per Intel's SDM, the VMX architecture doesn't require the CPU to flush the VMCS cache on INIT. If an emergency reboot doesn't RESET CPUs, cached VMCSes could theoretically be kept and only be written back to memory after the new kernel is booted, i.e. could effectively corrupt memory after reboot. Opportunistically remove the setting of the global pointer to NULL to make checkpatch happy. Cc: Andrew Cooper Link: https://lore.kernel.org/r/20230721201859.2307736-2-seanjc@google.com Signed-off-by: Sean Christopherson Signed-off-by: Sasha Levin --- arch/x86/include/asm/kexec.h | 2 -- arch/x86/include/asm/reboot.h | 2 ++ arch/x86/kernel/crash.c | 31 ------------------------------- arch/x86/kernel/reboot.c | 22 ++++++++++++++++++++++ arch/x86/kvm/vmx/vmx.c | 10 +++------- 5 files changed, 27 insertions(+), 40 deletions(-) diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h index 5b77bbc28f969..819046974b997 100644 --- a/arch/x86/include/asm/kexec.h +++ b/arch/x86/include/asm/kexec.h @@ -205,8 +205,6 @@ int arch_kimage_file_post_load_cleanup(struct kimage *image); #endif #endif -typedef void crash_vmclear_fn(void); -extern crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss; extern void kdump_nmi_shootdown_cpus(void); #endif /* __ASSEMBLY__ */ diff --git a/arch/x86/include/asm/reboot.h b/arch/x86/include/asm/reboot.h index 9177b4354c3f5..dc201724a6433 100644 --- a/arch/x86/include/asm/reboot.h +++ b/arch/x86/include/asm/reboot.h @@ -25,6 +25,8 @@ void __noreturn machine_real_restart(unsigned int type); #define MRR_BIOS 0 #define MRR_APM 1 +typedef void crash_vmclear_fn(void); +extern crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss; void cpu_emergency_disable_virtualization(void); typedef void (*nmi_shootdown_cb)(int, struct pt_regs*); diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c index cdd92ab43cda4..54cd959cb3160 100644 --- a/arch/x86/kernel/crash.c +++ b/arch/x86/kernel/crash.c @@ -48,38 +48,12 @@ struct crash_memmap_data { unsigned int type; }; -/* - * This is used to VMCLEAR all VMCSs loaded on the - * processor. And when loading kvm_intel module, the - * callback function pointer will be assigned. - * - * protected by rcu. - */ -crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss = NULL; -EXPORT_SYMBOL_GPL(crash_vmclear_loaded_vmcss); - -static inline void cpu_crash_vmclear_loaded_vmcss(void) -{ - crash_vmclear_fn *do_vmclear_operation = NULL; - - rcu_read_lock(); - do_vmclear_operation = rcu_dereference(crash_vmclear_loaded_vmcss); - if (do_vmclear_operation) - do_vmclear_operation(); - rcu_read_unlock(); -} - #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC) static void kdump_nmi_callback(int cpu, struct pt_regs *regs) { crash_save_cpu(regs, cpu); - /* - * VMCLEAR VMCSs loaded on all cpus if needed. - */ - cpu_crash_vmclear_loaded_vmcss(); - /* * Disable Intel PT to stop its logging */ @@ -133,11 +107,6 @@ void native_machine_crash_shutdown(struct pt_regs *regs) crash_smp_send_stop(); - /* - * VMCLEAR VMCSs loaded on this cpu if needed. - */ - cpu_crash_vmclear_loaded_vmcss(); - cpu_emergency_disable_virtualization(); /* diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c index 3adbe97015c13..3fa4c6717a1db 100644 --- a/arch/x86/kernel/reboot.c +++ b/arch/x86/kernel/reboot.c @@ -787,6 +787,26 @@ void machine_crash_shutdown(struct pt_regs *regs) } #endif +/* + * This is used to VMCLEAR all VMCSs loaded on the + * processor. And when loading kvm_intel module, the + * callback function pointer will be assigned. + * + * protected by rcu. + */ +crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss; +EXPORT_SYMBOL_GPL(crash_vmclear_loaded_vmcss); + +static inline void cpu_crash_vmclear_loaded_vmcss(void) +{ + crash_vmclear_fn *do_vmclear_operation = NULL; + + rcu_read_lock(); + do_vmclear_operation = rcu_dereference(crash_vmclear_loaded_vmcss); + if (do_vmclear_operation) + do_vmclear_operation(); + rcu_read_unlock(); +} /* This is the CPU performing the emergency shutdown work. */ int crashing_cpu = -1; @@ -798,6 +818,8 @@ int crashing_cpu = -1; */ void cpu_emergency_disable_virtualization(void) { + cpu_crash_vmclear_loaded_vmcss(); + cpu_emergency_vmxoff(); cpu_emergency_svm_disable(); } diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index f2fb67a9dc050..bc6f0fea48b43 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -41,7 +41,7 @@ #include #include #include -#include +#include #include #include #include @@ -754,7 +754,6 @@ static int vmx_set_guest_uret_msr(struct vcpu_vmx *vmx, return ret; } -#ifdef CONFIG_KEXEC_CORE static void crash_vmclear_local_loaded_vmcss(void) { int cpu = raw_smp_processor_id(); @@ -764,7 +763,6 @@ static void crash_vmclear_local_loaded_vmcss(void) loaded_vmcss_on_cpu_link) vmcs_clear(v->vmcs); } -#endif /* CONFIG_KEXEC_CORE */ static void __loaded_vmcs_clear(void *arg) { @@ -8623,10 +8621,9 @@ static void __vmx_exit(void) { allow_smaller_maxphyaddr = false; -#ifdef CONFIG_KEXEC_CORE RCU_INIT_POINTER(crash_vmclear_loaded_vmcss, NULL); synchronize_rcu(); -#endif + vmx_cleanup_l1d_flush(); } @@ -8675,10 +8672,9 @@ static int __init vmx_init(void) pi_init_cpu(cpu); } -#ifdef CONFIG_KEXEC_CORE rcu_assign_pointer(crash_vmclear_loaded_vmcss, crash_vmclear_local_loaded_vmcss); -#endif + vmx_check_vmcs12_offsets(); /* -- 2.40.1