From patchwork Thu Sep 16 18:15:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Upton X-Patchwork-Id: 12500019 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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 DA312C433EF for ; Thu, 16 Sep 2021 18:56:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C0EDA6058D for ; Thu, 16 Sep 2021 18:56:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344089AbhIPS5u (ORCPT ); Thu, 16 Sep 2021 14:57:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51640 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245508AbhIPS53 (ORCPT ); Thu, 16 Sep 2021 14:57:29 -0400 Received: from mail-qk1-x749.google.com (mail-qk1-x749.google.com [IPv6:2607:f8b0:4864:20::749]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9501DC04A155 for ; Thu, 16 Sep 2021 11:15:43 -0700 (PDT) Received: by mail-qk1-x749.google.com with SMTP id e22-20020a05620a209600b003d5ff97bff7so44934123qka.1 for ; Thu, 16 Sep 2021 11:15:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=EqfJ4nsZ26w2OY+w0/ZRQGVHhFarrWqQ77C9H9qe4wk=; b=jCgTfuzY3Xi/FfyO0lx2uvq5fA0lVuB+u2I9budg5JdSmdUW6fkucj/6Iswn5+9u81 S5Hii45+Igo8DnjUigtICHwVREClRsu6Tt94jvAfHqx/W4EdvzOWJfxyBJRSO/PtALZt 511OJi7qp+hjaP2T2gNjcMes9QckyDHsJh+2BGWhGKw0M1JamoY1Gp59mcwwonYWw3jo YzlI/iWllIFsVn66gc/48kc2LhIAYzj4gD09j2aRz8ifMS/+7cKghKSzkamlf41sDmLH xwJx2x4VOpX8THrVq3tJaaLDKzBQd47kw3OExONFC73ii1Dcr8WZjUXHO6zWaFv0mYYj 2w9g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=EqfJ4nsZ26w2OY+w0/ZRQGVHhFarrWqQ77C9H9qe4wk=; b=N01Is4iHvMqi5KY3fjT1c4Af0I2SqQYlFuXt/gK3rEaKgayQX5OeEToB6saX138ro8 QH0fBlOPPoVIBcW1cxjLwDRnZ9qEI5DINgpK9l8BFY5aFlpWwg8+xuUrsssNkpzJjTMr 5uCRjcT7nYTIvQ6nLY8BAYdibnEIjJnLP6LP0WoYN7gpeAMh54v5j/Svg805GuVPXdvj AjlF+SBK/HHXj272ZXQkmoDC/G0iOuW9CYhicvyjYFxfjgq86N9CABgAMgCr4Yn29Yed pn/mab6UWxWoaX6YJPyTaKapn7TwlNARHHgLGfX9OEhKVBtKA4kPnvjs+BOznc8X+xdt vRfQ== X-Gm-Message-State: AOAM533z1XFMRLuU5PBUdXNMtpPeJbt2OZsSa+in93N7THad7effb1eV XHEEJqCtCk/SVpypyWHKXDbFDrWGKaYcN/XvWlTGKEeQJPIu1oGPr5/9eH3Vtb8mBsG8W7vnkpS FXg61HDjYbc3ZApZoD2OwJh75Bbgx/C52KX1fgdZBfifnEl++mBIfdEkQDw== X-Google-Smtp-Source: ABdhPJzJVShjUP9eV6I0zKA9rrR+wmqb3KVny8yYAxYLYNtJU8sisB/xFAD1ErUlrDRx7ismNi4ONuO4ygA= X-Received: from oupton.c.googlers.com ([fda3:e722:ac3:cc00:2b:ff92:c0a8:404]) (user=oupton job=sendgmr) by 2002:a05:6214:431:: with SMTP id a17mr6549014qvy.48.1631816142691; Thu, 16 Sep 2021 11:15:42 -0700 (PDT) Date: Thu, 16 Sep 2021 18:15:32 +0000 In-Reply-To: <20210916181538.968978-1-oupton@google.com> Message-Id: <20210916181538.968978-2-oupton@google.com> Mime-Version: 1.0 References: <20210916181538.968978-1-oupton@google.com> X-Mailer: git-send-email 2.33.0.464.g1972c5931b-goog Subject: [PATCH v8 1/7] kvm: x86: abstract locking around pvclock_update_vm_gtod_copy From: Oliver Upton To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu Cc: Paolo Bonzini , Sean Christopherson , Marc Zyngier , Peter Shier , Jim Mattson , David Matlack , Ricardo Koller , Jing Zhang , Raghavendra Rao Anata , James Morse , Alexandru Elisei , Suzuki K Poulose , linux-arm-kernel@lists.infradead.org, Andrew Jones , Will Deacon , Catalin Marinas , Oliver Upton Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Paolo Bonzini Updates to the kvmclock parameters needs to do a complicated dance of KVM_REQ_MCLOCK_INPROGRESS and KVM_REQ_CLOCK_UPDATE in addition to taking pvclock_gtod_sync_lock. Place that in two functions that can be called on all of master clock update, KVM_SET_CLOCK, and Hyper-V reenlightenment. Signed-off-by: Paolo Bonzini Signed-off-by: Oliver Upton --- arch/x86/include/asm/kvm_host.h | 1 - arch/x86/kvm/x86.c | 62 +++++++++++++++------------------ 2 files changed, 29 insertions(+), 34 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index f8f48a7ec577..be6805fc0260 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1866,7 +1866,6 @@ u64 kvm_calc_nested_tsc_multiplier(u64 l1_multiplier, u64 l2_multiplier); unsigned long kvm_get_linear_rip(struct kvm_vcpu *vcpu); bool kvm_is_linear_rip(struct kvm_vcpu *vcpu, unsigned long linear_rip); -void kvm_make_mclock_inprogress_request(struct kvm *kvm); void kvm_make_scan_ioapic_request(struct kvm *kvm); void kvm_make_scan_ioapic_request_mask(struct kvm *kvm, unsigned long *vcpu_bitmap); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 28ef14155726..1082b48418c3 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2755,35 +2755,42 @@ static void pvclock_update_vm_gtod_copy(struct kvm *kvm) #endif } -void kvm_make_mclock_inprogress_request(struct kvm *kvm) +static void kvm_make_mclock_inprogress_request(struct kvm *kvm) { kvm_make_all_cpus_request(kvm, KVM_REQ_MCLOCK_INPROGRESS); } -static void kvm_gen_update_masterclock(struct kvm *kvm) +static void kvm_start_pvclock_update(struct kvm *kvm) { -#ifdef CONFIG_X86_64 - int i; - struct kvm_vcpu *vcpu; struct kvm_arch *ka = &kvm->arch; - unsigned long flags; - - kvm_hv_invalidate_tsc_page(kvm); kvm_make_mclock_inprogress_request(kvm); /* no guest entries from this point */ - spin_lock_irqsave(&ka->pvclock_gtod_sync_lock, flags); - pvclock_update_vm_gtod_copy(kvm); - spin_unlock_irqrestore(&ka->pvclock_gtod_sync_lock, flags); + spin_lock_irq(&ka->pvclock_gtod_sync_lock); +} +static void kvm_end_pvclock_update(struct kvm *kvm) +{ + struct kvm_arch *ka = &kvm->arch; + struct kvm_vcpu *vcpu; + int i; + + spin_unlock_irq(&ka->pvclock_gtod_sync_lock); kvm_for_each_vcpu(i, vcpu, kvm) kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu); /* guest entries allowed */ kvm_for_each_vcpu(i, vcpu, kvm) kvm_clear_request(KVM_REQ_MCLOCK_INPROGRESS, vcpu); -#endif +} + +static void kvm_update_masterclock(struct kvm *kvm) +{ + kvm_hv_invalidate_tsc_page(kvm); + kvm_start_pvclock_update(kvm); + pvclock_update_vm_gtod_copy(kvm); + kvm_end_pvclock_update(kvm); } u64 get_kvmclock_ns(struct kvm *kvm) @@ -6079,12 +6086,10 @@ long kvm_arch_vm_ioctl(struct file *filp, goto out; r = 0; - /* - * TODO: userspace has to take care of races with VCPU_RUN, so - * kvm_gen_update_masterclock() can be cut down to locked - * pvclock_update_vm_gtod_copy(). - */ - kvm_gen_update_masterclock(kvm); + + kvm_hv_invalidate_tsc_page(kvm); + kvm_start_pvclock_update(kvm); + pvclock_update_vm_gtod_copy(kvm); /* * This pairs with kvm_guest_time_update(): when masterclock is @@ -6093,15 +6098,12 @@ long kvm_arch_vm_ioctl(struct file *filp, * is slightly ahead) here we risk going negative on unsigned * 'system_time' when 'user_ns.clock' is very small. */ - spin_lock_irq(&ka->pvclock_gtod_sync_lock); if (kvm->arch.use_master_clock) now_ns = ka->master_kernel_ns; else now_ns = get_kvmclock_base_ns(); ka->kvmclock_offset = user_ns.clock - now_ns; - spin_unlock_irq(&ka->pvclock_gtod_sync_lock); - - kvm_make_all_cpus_request(kvm, KVM_REQ_CLOCK_UPDATE); + kvm_end_pvclock_update(kvm); break; } case KVM_GET_CLOCK: { @@ -8107,14 +8109,13 @@ static void tsc_khz_changed(void *data) static void kvm_hyperv_tsc_notifier(void) { struct kvm *kvm; - struct kvm_vcpu *vcpu; int cpu; - unsigned long flags; mutex_lock(&kvm_lock); list_for_each_entry(kvm, &vm_list, vm_list) kvm_make_mclock_inprogress_request(kvm); + /* no guest entries from this point */ hyperv_stop_tsc_emulation(); /* TSC frequency always matches when on Hyper-V */ @@ -8125,16 +8126,11 @@ static void kvm_hyperv_tsc_notifier(void) list_for_each_entry(kvm, &vm_list, vm_list) { struct kvm_arch *ka = &kvm->arch; - spin_lock_irqsave(&ka->pvclock_gtod_sync_lock, flags); + spin_lock_irq(&ka->pvclock_gtod_sync_lock); pvclock_update_vm_gtod_copy(kvm); - spin_unlock_irqrestore(&ka->pvclock_gtod_sync_lock, flags); - - kvm_for_each_vcpu(cpu, vcpu, kvm) - kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu); - - kvm_for_each_vcpu(cpu, vcpu, kvm) - kvm_clear_request(KVM_REQ_MCLOCK_INPROGRESS, vcpu); + kvm_end_pvclock_update(kvm); } + mutex_unlock(&kvm_lock); } #endif @@ -9418,7 +9414,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) if (kvm_check_request(KVM_REQ_MIGRATE_TIMER, vcpu)) __kvm_migrate_timers(vcpu); if (kvm_check_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu)) - kvm_gen_update_masterclock(vcpu->kvm); + kvm_update_masterclock(vcpu->kvm); if (kvm_check_request(KVM_REQ_GLOBAL_CLOCK_UPDATE, vcpu)) kvm_gen_kvmclock_update(vcpu); if (kvm_check_request(KVM_REQ_CLOCK_UPDATE, vcpu)) {