From patchwork Mon May 31 11:00:53 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Krzysztof Kozlowski X-Patchwork-Id: 451335 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, 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 BD588C47096 for ; Mon, 31 May 2021 11:01:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9D89861355 for ; Mon, 31 May 2021 11:01:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231288AbhEaLCl (ORCPT ); Mon, 31 May 2021 07:02:41 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:36935 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231124AbhEaLCl (ORCPT ); Mon, 31 May 2021 07:02:41 -0400 Received: from mail-wr1-f71.google.com ([209.85.221.71]) by youngberry.canonical.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.93) (envelope-from ) id 1lnffJ-0001LX-6E for stable@vger.kernel.org; Mon, 31 May 2021 11:01:01 +0000 Received: by mail-wr1-f71.google.com with SMTP id t5-20020adfb7c50000b029010dd0bb24cfso3838169wre.2 for ; Mon, 31 May 2021 04:01:01 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Ix+9S7l2HoS++pqHLCNeVtqEf/juK7qm0x6yekPwBs0=; b=Qu05e8udVX37b0g+dl0EVtPlyx46tZR59zJG5G+QDleZVApEUniFc0Vx9icIHhuvSe pJqx1t8a7U6WAuE+lO/zEREd4enW5E5z3HGuaucbjISGQo6PIW/x/UPmAsl/VyYdFi0b M7IzOmL/FfF54wVZFdN93YXCNda3fVCKL1S+t0LZIJKfD6M6VIxAs89xL8CUfVs7KzOj 1tCPrj8VX5H5+MS4/hbg1zGzliD3V9IRHE3ou/Ei2ApbTWm6j1OW5D/sKQF2MM8bihdD zJ6Bj1OIog0vtB7B726kKBLWbrxf2esB0ve1j+z0OSXsKO9ypdNANnA1Ah/UEZJQ1vnp Ugmg== X-Gm-Message-State: AOAM532HDIYgfYzn9hXVtifnkcwPVjSkbQ3xxKmeARmrwgvGsoW5s2qs i5wLQ2KpOi4Dj3YpUTLaJeC6/BrAPdk6YLvop40ctvHVNv06VEYDw3jPCCmi0y9jCAQPWP1fIKo V1AUfE7wJLLRVbcvjjjLgegRsbelZCRIDZA== X-Received: by 2002:a05:6000:118b:: with SMTP id g11mr811984wrx.367.1622458860617; Mon, 31 May 2021 04:01:00 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxhcgxsUDmfPw+GQeyi+skRL+D9MKuU53hyhG6qwgvW7EJT+GHPizbKLidr2aocP7DdJuaByw== X-Received: by 2002:a05:6000:118b:: with SMTP id g11mr811970wrx.367.1622458860466; Mon, 31 May 2021 04:01:00 -0700 (PDT) Received: from localhost.localdomain (xdsl-188-155-185-9.adslplus.ch. [188.155.185.9]) by smtp.gmail.com with ESMTPSA id n20sm14608799wmk.12.2021.05.31.04.00.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 31 May 2021 04:00:59 -0700 (PDT) From: Krzysztof Kozlowski To: stable@vger.kernel.org Cc: Andrea Righi , Paolo Bonzini , Vitaly Kuznetsov , Krzysztof Kozlowski Subject: [PATCH v2 | stable v5.4+ 3/3] x86/kvm: Disable all PV features on crash Date: Mon, 31 May 2021 13:00:53 +0200 Message-Id: <20210531110053.14640-4-krzysztof.kozlowski@canonical.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20210531110053.14640-1-krzysztof.kozlowski@canonical.com> References: <20210531110053.14640-1-krzysztof.kozlowski@canonical.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Vitaly Kuznetsov commit 3d6b84132d2a57b5a74100f6923a8feb679ac2ce upstream. Crash shutdown handler only disables kvmclock and steal time, other PV features remain active so we risk corrupting memory or getting some side-effects in kdump kernel. Move crash handler to kvm.c and unify with CPU offline. Signed-off-by: Vitaly Kuznetsov Message-Id: <20210414123544.1060604-5-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini Signed-off-by: Andrea Righi Signed-off-by: Krzysztof Kozlowski --- arch/x86/include/asm/kvm_para.h | 5 ---- arch/x86/kernel/kvm.c | 44 ++++++++++++++++++++++++--------- arch/x86/kernel/kvmclock.c | 21 ---------------- 3 files changed, 32 insertions(+), 38 deletions(-) diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h index a617fd360023..7ff8ad490a78 100644 --- a/arch/x86/include/asm/kvm_para.h +++ b/arch/x86/include/asm/kvm_para.h @@ -91,7 +91,6 @@ unsigned int kvm_arch_para_hints(void); void kvm_async_pf_task_wait(u32 token, int interrupt_kernel); void kvm_async_pf_task_wake(u32 token); u32 kvm_read_and_reset_pf_reason(void); -extern void kvm_disable_steal_time(void); void do_async_page_fault(struct pt_regs *regs, unsigned long error_code, unsigned long address); #ifdef CONFIG_PARAVIRT_SPINLOCKS @@ -126,10 +125,6 @@ static inline u32 kvm_read_and_reset_pf_reason(void) return 0; } -static inline void kvm_disable_steal_time(void) -{ - return; -} #endif #endif /* _ASM_X86_KVM_PARA_H */ diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index f535ba7714f8..bff25b8166b7 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -34,6 +34,7 @@ #include #include #include +#include static int kvmapf = 1; @@ -352,6 +353,14 @@ static void kvm_pv_disable_apf(void) smp_processor_id()); } +static void kvm_disable_steal_time(void) +{ + if (!has_steal_clock) + return; + + wrmsr(MSR_KVM_STEAL_TIME, 0, 0); +} + static void kvm_pv_guest_cpu_reboot(void *unused) { /* @@ -394,14 +403,6 @@ static u64 kvm_steal_clock(int cpu) return steal; } -void kvm_disable_steal_time(void) -{ - if (!has_steal_clock) - return; - - wrmsr(MSR_KVM_STEAL_TIME, 0, 0); -} - static inline void __set_percpu_decrypted(void *ptr, unsigned long size) { early_set_memory_decrypted((unsigned long) ptr, size); @@ -548,13 +549,14 @@ static void __init kvm_smp_prepare_boot_cpu(void) kvm_spinlock_init(); } -static void kvm_guest_cpu_offline(void) +static void kvm_guest_cpu_offline(bool shutdown) { kvm_disable_steal_time(); if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) wrmsrl(MSR_KVM_PV_EOI_EN, 0); kvm_pv_disable_apf(); - apf_task_wake_all(); + if (!shutdown) + apf_task_wake_all(); kvmclock_disable(); } @@ -573,7 +575,7 @@ static int kvm_cpu_down_prepare(unsigned int cpu) unsigned long flags; local_irq_save(flags); - kvm_guest_cpu_offline(); + kvm_guest_cpu_offline(false); local_irq_restore(flags); return 0; } @@ -614,7 +616,7 @@ static void kvm_flush_tlb_others(const struct cpumask *cpumask, static int kvm_suspend(void) { - kvm_guest_cpu_offline(); + kvm_guest_cpu_offline(false); return 0; } @@ -629,6 +631,20 @@ static struct syscore_ops kvm_syscore_ops = { .resume = kvm_resume, }; +/* + * After a PV feature is registered, the host will keep writing to the + * registered memory location. If the guest happens to shutdown, this memory + * won't be valid. In cases like kexec, in which you install a new kernel, this + * means a random memory location will be kept being written. + */ +#ifdef CONFIG_KEXEC_CORE +static void kvm_crash_shutdown(struct pt_regs *regs) +{ + kvm_guest_cpu_offline(true); + native_machine_crash_shutdown(regs); +} +#endif + static void __init kvm_guest_init(void) { int i; @@ -672,6 +688,10 @@ static void __init kvm_guest_init(void) kvm_guest_cpu_init(); #endif +#ifdef CONFIG_KEXEC_CORE + machine_ops.crash_shutdown = kvm_crash_shutdown; +#endif + register_syscore_ops(&kvm_syscore_ops); /* diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index bd3962953f78..4a0802af2e3e 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -20,7 +20,6 @@ #include #include #include -#include #include static int kvmclock __initdata = 1; @@ -197,23 +196,6 @@ static void kvm_setup_secondary_clock(void) } #endif -/* - * After the clock is registered, the host will keep writing to the - * registered memory location. If the guest happens to shutdown, this memory - * won't be valid. In cases like kexec, in which you install a new kernel, this - * means a random memory location will be kept being written. So before any - * kind of shutdown from our side, we unregister the clock by writing anything - * that does not have the 'enable' bit set in the msr - */ -#ifdef CONFIG_KEXEC_CORE -static void kvm_crash_shutdown(struct pt_regs *regs) -{ - native_write_msr(msr_kvm_system_time, 0, 0); - kvm_disable_steal_time(); - native_machine_crash_shutdown(regs); -} -#endif - void kvmclock_disable(void) { native_write_msr(msr_kvm_system_time, 0, 0); @@ -344,9 +326,6 @@ void __init kvmclock_init(void) #endif x86_platform.save_sched_clock_state = kvm_save_sched_clock_state; x86_platform.restore_sched_clock_state = kvm_restore_sched_clock_state; -#ifdef CONFIG_KEXEC_CORE - machine_ops.crash_shutdown = kvm_crash_shutdown; -#endif kvm_get_preset_lpj(); /*