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 A84F9ECAAD3 for ; Fri, 2 Sep 2022 02:19:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235272AbiIBCT2 (ORCPT ); Thu, 1 Sep 2022 22:19:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59602 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232855AbiIBCS2 (ORCPT ); Thu, 1 Sep 2022 22:18:28 -0400 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 11BBDAA4DC; Thu, 1 Sep 2022 19:18:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1662085098; x=1693621098; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=fLNGduFRRxtLQpIKtq56JStZ/hOPYItGCAYaxL/38s0=; b=N08agcX79wnDRmlxcZ8hOjBOrEHmyqL7u6Kei4McQWOo3y0c2yz6jPyB G2nfmMHd9qmmnduGRuc3FzB+/q/BFkSyi6xk6iudcahXMeY4O4/FKtNjm 99UzoEW/WKDMVls1XHikoWPN+Ksfk4YsdV861aqcNEoeqRqqMVNu4xbBN jfoaf4m2reKiBaKXfYPgYaYTzHA+kOnzBt0dJhdobrRwcI34JI6IORgbW Bbda3nDn3aPVyJmAoFXJAFJFN7L3BEuhMtt+5VLHq2AhrUGn3MiaAGScC iWf+T/gwauC5acLSZ4AGF16pNKYR/MlrYtusDk9VZEdxDSULVGP1bqZLI Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10457"; a="297157854" X-IronPort-AV: E=Sophos;i="5.93,281,1654585200"; d="scan'208";a="297157854" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Sep 2022 19:18:17 -0700 X-IronPort-AV: E=Sophos;i="5.93,281,1654585200"; d="scan'208";a="608835646" Received: from ls.sc.intel.com (HELO localhost) ([143.183.96.54]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Sep 2022 19:18:17 -0700 From: isaku.yamahata@intel.com To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Paolo Bonzini , Sean Christopherson , Thomas Gleixner , Marc Zyngier , Will Deacon Cc: isaku.yamahata@intel.com, isaku.yamahata@gmail.com, Kai Huang , Chao Gao , Atish Patra , Shaokun Zhang , Qi Liu , John Garry , Daniel Lezcano , Huang Ying , Huacai Chen , Dave Hansen , Borislav Petkov Subject: [PATCH v3 14/22] KVM: Move out KVM arch PM hooks and hardware enable/disable logic Date: Thu, 1 Sep 2022 19:17:49 -0700 Message-Id: <1c0165a7d2dd22810d9ae2cf8cf474a2e6dcb6d7.1662084396.git.isaku.yamahata@intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Isaku Yamahata To make clear that those files are default implementation that KVM/x86 (and other KVM arch in future) will override them, split out those into a single file. Once conversions for all kvm archs are done, the file will be deleted. kvm_arch_pre_hardware_unsetup() is introduced to avoid cross-arch code churn for now. Once it's settled down, kvm_arch_pre_hardware_unsetup() can be merged into kvm_arch_hardware_unsetup() in each arch code. Signed-off-by: Isaku Yamahata --- include/linux/kvm_host.h | 1 + virt/kvm/kvm_arch.c | 103 ++++++++++++++++++++++- virt/kvm/kvm_main.c | 172 +++++---------------------------------- 3 files changed, 124 insertions(+), 152 deletions(-) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index f78364e01ca9..60f4ae9d6f48 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -1437,6 +1437,7 @@ static inline void kvm_create_vcpu_debugfs(struct kvm_vcpu *vcpu) {} int kvm_arch_hardware_enable(void); void kvm_arch_hardware_disable(void); int kvm_arch_hardware_setup(void *opaque); +void kvm_arch_pre_hardware_unsetup(void); void kvm_arch_hardware_unsetup(void); int kvm_arch_check_processor_compat(void); int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu); diff --git a/virt/kvm/kvm_arch.c b/virt/kvm/kvm_arch.c index 0eac996f4981..0648d4463d9e 100644 --- a/virt/kvm/kvm_arch.c +++ b/virt/kvm/kvm_arch.c @@ -6,49 +6,148 @@ * Author: * Isaku Yamahata * + * + * TODO: Delete this file once the conversion of all KVM arch is done. */ #include +static cpumask_t cpus_hardware_enabled = CPU_MASK_NONE; +static atomic_t hardware_enable_failed; + __weak int kvm_arch_post_init_vm(struct kvm *kvm) { return 0; } +static void hardware_enable_nolock(void *caller_name) +{ + int cpu = raw_smp_processor_id(); + int r; + + WARN_ON_ONCE(preemptible()); + + if (cpumask_test_cpu(cpu, &cpus_hardware_enabled)) + return; + + cpumask_set_cpu(cpu, &cpus_hardware_enabled); + + r = kvm_arch_hardware_enable(); + + if (r) { + cpumask_clear_cpu(cpu, &cpus_hardware_enabled); + atomic_inc(&hardware_enable_failed); + pr_warn("kvm: enabling virtualization on CPU%d failed during %s()\n", + cpu, (const char *)caller_name); + } +} + +static void hardware_disable_nolock(void *junk) +{ + int cpu = raw_smp_processor_id(); + + WARN_ON_ONCE(preemptible()); + + if (!cpumask_test_cpu(cpu, &cpus_hardware_enabled)) + return; + cpumask_clear_cpu(cpu, &cpus_hardware_enabled); + kvm_arch_hardware_disable(); +} + +__weak void kvm_arch_pre_hardware_unsetup(void) +{ + on_each_cpu(hardware_disable_nolock, NULL, 1); +} + /* * Called after the VM is otherwise initialized, but just before adding it to * the vm_list. */ __weak int kvm_arch_add_vm(struct kvm *kvm, int usage_count) { - return kvm_arch_post_init_vm(kvm); + int r = 0; + + if (usage_count != 1) + return 0; + + atomic_set(&hardware_enable_failed, 0); + on_each_cpu(hardware_enable_nolock, (void *)__func__, 1); + + if (atomic_read(&hardware_enable_failed)) { + r = -EBUSY; + goto err; + } + + r = kvm_arch_post_init_vm(kvm); +err: + if (r) + on_each_cpu(hardware_disable_nolock, NULL, 1); + return r; } __weak int kvm_arch_del_vm(int usage_count) { + if (usage_count) + return 0; + + on_each_cpu(hardware_disable_nolock, NULL, 1); return 0; } __weak int kvm_arch_online_cpu(unsigned int cpu, int usage_count) { - return 0; + int ret = 0; + + ret = kvm_arch_check_processor_compat(); + if (ret) + return ret; + + /* + * Abort the CPU online process if hardware virtualization cannot + * be enabled. Otherwise running VMs would encounter unrecoverable + * errors when scheduled to this CPU. + */ + if (usage_count) { + WARN_ON_ONCE(atomic_read(&hardware_enable_failed)); + + hardware_enable_nolock((void *)__func__); + if (atomic_read(&hardware_enable_failed)) { + atomic_set(&hardware_enable_failed, 0); + ret = -EIO; + } + } + return ret; } __weak int kvm_arch_offline_cpu(unsigned int cpu, int usage_count) { + if (usage_count) + hardware_disable_nolock(NULL); return 0; } __weak int kvm_arch_reboot(int val) { + on_each_cpu(hardware_disable_nolock, NULL, 1); return NOTIFY_OK; } __weak int kvm_arch_suspend(int usage_count) { + if (usage_count) + hardware_disable_nolock(NULL); return 0; } __weak void kvm_arch_resume(int usage_count) { + if (kvm_arch_check_processor_compat()) + /* + * No warning here because kvm_arch_check_processor_compat() + * would have warned with more information. + */ + return; /* FIXME: disable KVM */ + + if (usage_count) + hardware_enable_nolock((void *)__func__); } diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 90e1dcfc9ace..5373127dcdb6 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -102,9 +102,7 @@ EXPORT_SYMBOL_GPL(halt_poll_ns_shrink); DEFINE_MUTEX(kvm_lock); LIST_HEAD(vm_list); -static cpumask_var_t cpus_hardware_enabled; static int kvm_usage_count; -static atomic_t hardware_enable_failed; static struct kmem_cache *kvm_vcpu_cache; @@ -142,9 +140,6 @@ static int kvm_no_compat_open(struct inode *inode, struct file *file) #define KVM_COMPAT(c) .compat_ioctl = kvm_no_compat_ioctl, \ .open = kvm_no_compat_open #endif -static int hardware_enable_all(void); -static void hardware_disable_all(void); -static void hardware_disable_nolock(void *junk); static void kvm_del_vm(void); static void kvm_io_bus_destroy(struct kvm_io_bus *bus); @@ -1196,10 +1191,6 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname) if (r) goto out_err_no_arch_destroy_vm; - r = hardware_enable_all(); - if (r) - goto out_err_no_disable; - #ifdef CONFIG_HAVE_KVM_IRQFD INIT_HLIST_HEAD(&kvm->irq_ack_notifier_list); #endif @@ -1216,14 +1207,28 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname) if (r) goto out_err_no_debugfs; + /* + * During onlining a CPU, cpu_online_mask is set before kvm_online_cpu() + * is called. on_each_cpu() between them includes the CPU. As a result, + * hardware_enable_nolock() may get invoked before kvm_online_cpu(). + * This would enable hardware virtualization on that cpu without + * compatibility checks, which can potentially crash system or break + * running VMs. + * + * Disable CPU hotplug to prevent this case from happening. + */ + cpus_read_lock(); mutex_lock(&kvm_lock); + kvm_usage_count++; r = kvm_arch_add_vm(kvm, kvm_usage_count); if (r) { + /* the following kvm_del_vm() decrements kvm_usage_count. */ mutex_unlock(&kvm_lock); goto out_err; } list_add(&kvm->vm_list, &vm_list); mutex_unlock(&kvm_lock); + cpus_read_unlock(); preempt_notifier_inc(); kvm_init_pm_notifier(kvm); @@ -1240,9 +1245,7 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname) mmu_notifier_unregister(&kvm->mmu_notifier, current->mm); #endif out_err_no_mmu_notifier: - hardware_disable_all(); kvm_del_vm(); -out_err_no_disable: kvm_arch_destroy_vm(kvm); out_err_no_arch_destroy_vm: WARN_ON_ONCE(!refcount_dec_and_test(&kvm->users_count)); @@ -1321,7 +1324,6 @@ static void kvm_destroy_vm(struct kvm *kvm) cleanup_srcu_struct(&kvm->srcu); kvm_arch_free_vm(kvm); preempt_notifier_dec(); - hardware_disable_all(); kvm_del_vm(); mmdrop(mm); module_put(kvm_chardev_ops.owner); @@ -4986,149 +4988,37 @@ static struct miscdevice kvm_dev = { &kvm_chardev_ops, }; -static void hardware_enable_nolock(void *caller_name) -{ - int cpu = raw_smp_processor_id(); - int r; - - WARN_ON_ONCE(preemptible()); - - if (cpumask_test_cpu(cpu, cpus_hardware_enabled)) - return; - - cpumask_set_cpu(cpu, cpus_hardware_enabled); - - r = kvm_arch_hardware_enable(); - - if (r) { - cpumask_clear_cpu(cpu, cpus_hardware_enabled); - atomic_inc(&hardware_enable_failed); - pr_warn("kvm: enabling virtualization on CPU%d failed during %s()\n", - cpu, (const char *)caller_name); - } -} - static int kvm_online_cpu(unsigned int cpu) { int ret; - ret = kvm_arch_check_processor_compat(); - if (ret) - return ret; - mutex_lock(&kvm_lock); - /* - * Abort the CPU online process if hardware virtualization cannot - * be enabled. Otherwise running VMs would encounter unrecoverable - * errors when scheduled to this CPU. - */ - if (kvm_usage_count) { - WARN_ON_ONCE(atomic_read(&hardware_enable_failed)); - - hardware_enable_nolock((void *)__func__); - if (atomic_read(&hardware_enable_failed)) { - atomic_set(&hardware_enable_failed, 0); - ret = -EIO; - } else { - ret = kvm_arch_online_cpu(cpu, kvm_usage_count); - if (ret) - hardware_disable_nolock(NULL); - } - } + ret = kvm_arch_online_cpu(cpu, kvm_usage_count); mutex_unlock(&kvm_lock); return ret; } -static void hardware_disable_nolock(void *junk) -{ - int cpu = raw_smp_processor_id(); - - WARN_ON_ONCE(preemptible()); - - if (!cpumask_test_cpu(cpu, cpus_hardware_enabled)) - return; - cpumask_clear_cpu(cpu, cpus_hardware_enabled); - kvm_arch_hardware_disable(); -} - static int kvm_offline_cpu(unsigned int cpu) { - int ret = 0; + int ret; mutex_lock(&kvm_lock); - if (kvm_usage_count) { - hardware_disable_nolock(NULL); - ret = kvm_arch_offline_cpu(cpu, kvm_usage_count); - if (ret) { - (void)hardware_enable_nolock(NULL); - atomic_set(&hardware_enable_failed, 0); - } - } + ret = kvm_arch_offline_cpu(cpu, kvm_usage_count); mutex_unlock(&kvm_lock); return ret; } -static void hardware_disable_all_nolock(void) -{ - BUG_ON(!kvm_usage_count); - - kvm_usage_count--; - if (!kvm_usage_count) - on_each_cpu(hardware_disable_nolock, NULL, 1); -} - -static void hardware_disable_all(void) -{ - cpus_read_lock(); - mutex_lock(&kvm_lock); - hardware_disable_all_nolock(); - mutex_unlock(&kvm_lock); - cpus_read_unlock(); -} - static void kvm_del_vm(void) { cpus_read_lock(); mutex_lock(&kvm_lock); + WARN_ON_ONCE(!kvm_usage_count); + kvm_usage_count--; kvm_arch_del_vm(kvm_usage_count); mutex_unlock(&kvm_lock); cpus_read_unlock(); } -static int hardware_enable_all(void) -{ - int r = 0; - - /* - * During onlining a CPU, cpu_online_mask is set before kvm_online_cpu() - * is called. on_each_cpu() between them includes the CPU. As a result, - * hardware_enable_nolock() may get invoked before kvm_online_cpu(). - * This would enable hardware virtualization on that cpu without - * compatibility checks, which can potentially crash system or break - * running VMs. - * - * Disable CPU hotplug to prevent this case from happening. - */ - cpus_read_lock(); - mutex_lock(&kvm_lock); - - kvm_usage_count++; - if (kvm_usage_count == 1) { - atomic_set(&hardware_enable_failed, 0); - on_each_cpu(hardware_enable_nolock, (void *)__func__, 1); - - if (atomic_read(&hardware_enable_failed)) { - hardware_disable_all_nolock(); - r = -EBUSY; - } - } - - mutex_unlock(&kvm_lock); - cpus_read_unlock(); - - return r; -} - static int kvm_reboot(struct notifier_block *notifier, unsigned long val, void *v) { @@ -5146,7 +5036,6 @@ static int kvm_reboot(struct notifier_block *notifier, unsigned long val, /* This hook is called without cpuhotplug disabled. */ cpus_read_lock(); mutex_lock(&kvm_lock); - on_each_cpu(hardware_disable_nolock, NULL, 1); r = kvm_arch_reboot(val); mutex_unlock(&kvm_lock); cpus_read_unlock(); @@ -5745,24 +5634,13 @@ static int kvm_suspend(void) * locking. */ lockdep_assert_not_held(&kvm_lock); - if (kvm_usage_count) - hardware_disable_nolock(NULL); return kvm_arch_suspend(kvm_usage_count); } static void kvm_resume(void) { - if (kvm_arch_check_processor_compat()) - /* - * No warning here because kvm_arch_check_processor_compat() - * would have warned with more information. - */ - return; /* FIXME: disable KVM */ - lockdep_assert_not_held(&kvm_lock); kvm_arch_resume(kvm_usage_count); - if (kvm_usage_count) - hardware_enable_nolock((void *)__func__); } static struct syscore_ops kvm_syscore_ops = { @@ -5900,11 +5778,6 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align, if (r) goto out_irqfd; - if (!zalloc_cpumask_var(&cpus_hardware_enabled, GFP_KERNEL)) { - r = -ENOMEM; - goto out_free_0; - } - r = kvm_arch_hardware_setup(opaque); if (r < 0) goto out_free_1; @@ -5981,8 +5854,6 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align, out_free_2: kvm_arch_hardware_unsetup(); out_free_1: - free_cpumask_var(cpus_hardware_enabled); -out_free_0: kvm_irqfd_exit(); out_irqfd: kvm_arch_exit(); @@ -6004,11 +5875,12 @@ void kvm_exit(void) unregister_syscore_ops(&kvm_syscore_ops); unregister_reboot_notifier(&kvm_reboot_notifier); cpuhp_remove_state_nocalls(CPUHP_AP_KVM_ONLINE); - on_each_cpu(hardware_disable_nolock, NULL, 1); + cpus_read_lock(); + kvm_arch_pre_hardware_unsetup(); kvm_arch_hardware_unsetup(); + cpus_read_unlock(); kvm_arch_exit(); kvm_irqfd_exit(); - free_cpumask_var(cpus_hardware_enabled); kvm_vfio_ops_exit(); } EXPORT_SYMBOL_GPL(kvm_exit); -- 2.25.1