From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752624AbbIPJGQ (ORCPT ); Wed, 16 Sep 2015 05:06:16 -0400 Received: from mga14.intel.com ([192.55.52.115]:38797 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752198AbbIPJEa (ORCPT ); Wed, 16 Sep 2015 05:04:30 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.17,538,1437462000"; d="scan'208";a="790482408" From: Feng Wu To: pbonzini@redhat.com, alex.williamson@redhat.com, joro@8bytes.org, mtosatti@redhat.com Cc: eric.auger@linaro.org, kvm@vger.kernel.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Feng Wu Subject: [PATCH v8 11/13] KVM: Update Posted-Interrupts Descriptor when vCPU is blocked Date: Wed, 16 Sep 2015 16:50:07 +0800 Message-Id: <1442393409-2623-12-git-send-email-feng.wu@intel.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1442393409-2623-1-git-send-email-feng.wu@intel.com> References: <1442393409-2623-1-git-send-email-feng.wu@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch updates the Posted-Interrupts Descriptor when vCPU is blocked. pre-block: - Add the vCPU to the blocked per-CPU list - Set 'NV' to POSTED_INTR_WAKEUP_VECTOR post-block: - Remove the vCPU from the per-CPU list Signed-off-by: Feng Wu --- v8: - Rename 'pi_pre_block' to 'pre_block' - Rename 'pi_post_block' to 'post_block' - Change some comments - Only add the vCPU to the blocking list when the VM has assigned devices. arch/x86/include/asm/kvm_host.h | 13 ++++ arch/x86/kvm/vmx.c | 157 +++++++++++++++++++++++++++++++++++++++- arch/x86/kvm/x86.c | 53 +++++++++++--- include/linux/kvm_host.h | 3 + virt/kvm/kvm_main.c | 3 + 5 files changed, 217 insertions(+), 12 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 0ddd353..304fbb5 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -552,6 +552,8 @@ struct kvm_vcpu_arch { */ bool write_fault_to_shadow_pgtable; + bool halted; + /* set at EPT violation at this point */ unsigned long exit_qualification; @@ -864,6 +866,17 @@ struct kvm_x86_ops { /* pmu operations of sub-arch */ const struct kvm_pmu_ops *pmu_ops; + /* + * Architecture specific hooks for vCPU blocking due to + * HLT instruction. + * Returns for .pre_block(): + * - 0 means continue to block the vCPU. + * - 1 means we cannot block the vCPU since some event + * happens during this period, such as, 'ON' bit in + * posted-interrupts descriptor is set. + */ + int (*pre_block)(struct kvm_vcpu *vcpu); + void (*post_block)(struct kvm_vcpu *vcpu); int (*update_pi_irte)(struct kvm *kvm, unsigned int host_irq, uint32_t guest_irq, bool set); }; diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 5ceb280..9888c43 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -879,6 +879,13 @@ static DEFINE_PER_CPU(struct vmcs *, current_vmcs); static DEFINE_PER_CPU(struct list_head, loaded_vmcss_on_cpu); static DEFINE_PER_CPU(struct desc_ptr, host_gdt); +/* + * We maintian a per-CPU linked-list of vCPU, so in wakeup_handler() we + * can find which vCPU should be waken up. + */ +static DEFINE_PER_CPU(struct list_head, blocked_vcpu_on_cpu); +static DEFINE_PER_CPU(spinlock_t, blocked_vcpu_on_cpu_lock); + static unsigned long *vmx_io_bitmap_a; static unsigned long *vmx_io_bitmap_b; static unsigned long *vmx_msr_bitmap_legacy; @@ -1959,10 +1966,10 @@ static void vmx_vcpu_pi_load(struct kvm_vcpu *vcpu, int cpu) /* * If 'nv' field is POSTED_INTR_WAKEUP_VECTOR, there * are two possible cases: - * 1. After running 'pi_pre_block', context switch + * 1. After running 'pre_block', context switch * happened. For this case, 'sn' was set in * vmx_vcpu_put(), so we need to clear it here. - * 2. After running 'pi_pre_block', we were blocked, + * 2. After running 'pre_block', we were blocked, * and woken up by some other guy. For this case, * we don't need to do anything, 'pi_post_block' * will do everything for us. However, we cannot @@ -2985,6 +2992,8 @@ static int hardware_enable(void) return -EBUSY; INIT_LIST_HEAD(&per_cpu(loaded_vmcss_on_cpu, cpu)); + INIT_LIST_HEAD(&per_cpu(blocked_vcpu_on_cpu, cpu)); + spin_lock_init(&per_cpu(blocked_vcpu_on_cpu_lock, cpu)); /* * Now we can enable the vmclear operation in kdump @@ -6105,6 +6114,25 @@ static void update_ple_window_actual_max(void) ple_window_grow, INT_MIN); } +/* + * Handler for POSTED_INTERRUPT_WAKEUP_VECTOR. + */ +static void wakeup_handler(void) +{ + struct kvm_vcpu *vcpu; + int cpu = smp_processor_id(); + + spin_lock(&per_cpu(blocked_vcpu_on_cpu_lock, cpu)); + list_for_each_entry(vcpu, &per_cpu(blocked_vcpu_on_cpu, cpu), + blocked_vcpu_list) { + struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu); + + if (pi_test_on(pi_desc) == 1) + kvm_vcpu_kick(vcpu); + } + spin_unlock(&per_cpu(blocked_vcpu_on_cpu_lock, cpu)); +} + static __init int hardware_setup(void) { int r = -ENOMEM, i, msr; @@ -6289,6 +6317,8 @@ static __init int hardware_setup(void) kvm_x86_ops->enable_log_dirty_pt_masked = NULL; } + kvm_set_posted_intr_wakeup_handler(wakeup_handler); + return alloc_kvm_area(); out8: @@ -10414,6 +10444,126 @@ static void vmx_enable_log_dirty_pt_masked(struct kvm *kvm, } /* + * This routine does the following things for vCPU which is going + * to be blocked if VT-d PI is enabled. + * - Store the vCPU to the wakeup list, so when interrupts happen + * we can find the right vCPU to wake up. + * - Change the Posted-interrupt descriptor as below: + * 'NDST' <-- vcpu->pre_pcpu + * 'NV' <-- POSTED_INTR_WAKEUP_VECTOR + * - If 'ON' is set during this process, which means at least one + * interrupt is posted for this vCPU, we cannot block it, in + * this case, return 1, otherwise, return 0. + * + */ +static int vmx_pre_block(struct kvm_vcpu *vcpu) +{ + unsigned long flags; + unsigned int dest; + struct pi_desc old, new; + struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu); + + if (!irq_remapping_cap(IRQ_POSTING_CAP) || + (!kvm_arch_has_assigned_device(vcpu->kvm))) + return 0; + + vcpu->pre_pcpu = vcpu->cpu; + spin_lock_irqsave(&per_cpu(blocked_vcpu_on_cpu_lock, + vcpu->pre_pcpu), flags); + list_add_tail(&vcpu->blocked_vcpu_list, + &per_cpu(blocked_vcpu_on_cpu, + vcpu->pre_pcpu)); + spin_unlock_irqrestore(&per_cpu(blocked_vcpu_on_cpu_lock, + vcpu->pre_pcpu), flags); + + do { + old.control = new.control = pi_desc->control; + + /* + * We should not block the vCPU if + * an interrupt is posted for it. + */ + if (pi_test_on(pi_desc) == 1) { + spin_lock_irqsave(&per_cpu(blocked_vcpu_on_cpu_lock, + vcpu->pre_pcpu), flags); + list_del(&vcpu->blocked_vcpu_list); + spin_unlock_irqrestore( + &per_cpu(blocked_vcpu_on_cpu_lock, + vcpu->pre_pcpu), flags); + vcpu->pre_pcpu = -1; + + return 1; + } + + WARN((pi_desc->sn == 1), + "Warning: SN field of posted-interrupts " + "is set before blocking\n"); + + /* + * Since vCPU can be preempted during this process, + * vcpu->cpu could be different with pre_pcpu, we + * need to set pre_pcpu as the destination of wakeup + * notification event, then we can find the right vCPU + * to wakeup in wakeup handler if interrupts happen + * when the vCPU is in blocked state. + */ + dest = cpu_physical_id(vcpu->pre_pcpu); + + if (x2apic_enabled()) + new.ndst = dest; + else + new.ndst = (dest << 8) & 0xFF00; + + /* set 'NV' to 'wakeup vector' */ + new.nv = POSTED_INTR_WAKEUP_VECTOR; + } while (cmpxchg(&pi_desc->control, old.control, + new.control) != old.control); + + return 0; +} + +static void vmx_post_block(struct kvm_vcpu *vcpu) +{ + struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu); + struct pi_desc old, new; + unsigned int dest; + unsigned long flags; + + if (!irq_remapping_cap(IRQ_POSTING_CAP) || + (!kvm_arch_has_assigned_device(vcpu->kvm))) + return; + + do { + old.control = new.control = pi_desc->control; + + dest = cpu_physical_id(vcpu->cpu); + + if (x2apic_enabled()) + new.ndst = dest; + else + new.ndst = (dest << 8) & 0xFF00; + + /* Allow posting non-urgent interrupts */ + new.sn = 0; + + /* set 'NV' to 'notification vector' */ + new.nv = POSTED_INTR_VECTOR; + } while (cmpxchg(&pi_desc->control, old.control, + new.control) != old.control); + + if(vcpu->pre_pcpu != -1) { + spin_lock_irqsave( + &per_cpu(blocked_vcpu_on_cpu_lock, + vcpu->pre_pcpu), flags); + list_del(&vcpu->blocked_vcpu_list); + spin_unlock_irqrestore( + &per_cpu(blocked_vcpu_on_cpu_lock, + vcpu->pre_pcpu), flags); + vcpu->pre_pcpu = -1; + } +} + +/* * vmx_update_pi_irte - set IRTE for Posted-Interrupts * * @kvm: kvm @@ -10604,6 +10754,9 @@ static struct kvm_x86_ops vmx_x86_ops = { .flush_log_dirty = vmx_flush_log_dirty, .enable_log_dirty_pt_masked = vmx_enable_log_dirty_pt_masked, + .pre_block = vmx_pre_block, + .post_block = vmx_post_block, + .pmu_ops = &intel_pmu_ops, .update_pi_irte = vmx_update_pi_irte, diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index e189a94..106a0c0 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5869,7 +5869,12 @@ int kvm_vcpu_halt(struct kvm_vcpu *vcpu) { ++vcpu->stat.halt_exits; if (irqchip_in_kernel(vcpu->kvm)) { - vcpu->arch.mp_state = KVM_MP_STATE_HALTED; + /* Handle posted-interrupt when vCPU is to be halted */ + if (!kvm_x86_ops->pre_block || + kvm_x86_ops->pre_block(vcpu) == 0) { + vcpu->arch.halted = true; + vcpu->arch.mp_state = KVM_MP_STATE_HALTED; + } return 1; } else { vcpu->run->exit_reason = KVM_EXIT_HLT; @@ -6518,6 +6523,20 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) kvm_vcpu_reload_apic_access_page(vcpu); } + /* + * KVM_REQ_EVENT is not set when posted interrupts are set by + * VT-d hardware, so we have to update RVI unconditionally. + */ + if (kvm_lapic_enabled(vcpu)) { + /* + * Update architecture specific hints for APIC + * virtual interrupt delivery. + */ + if (kvm_x86_ops->hwapic_irr_update) + kvm_x86_ops->hwapic_irr_update(vcpu, + kvm_lapic_find_highest_irr(vcpu)); + } + if (kvm_check_request(KVM_REQ_EVENT, vcpu) || req_int_win) { kvm_apic_accept_events(vcpu); if (vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED) { @@ -6534,13 +6553,6 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) kvm_x86_ops->enable_irq_window(vcpu); if (kvm_lapic_enabled(vcpu)) { - /* - * Update architecture specific hints for APIC - * virtual interrupt delivery. - */ - if (kvm_x86_ops->hwapic_irr_update) - kvm_x86_ops->hwapic_irr_update(vcpu, - kvm_lapic_find_highest_irr(vcpu)); update_cr8_intercept(vcpu); kvm_lapic_sync_to_vapic(vcpu); } @@ -6711,10 +6723,31 @@ static int vcpu_run(struct kvm_vcpu *vcpu) for (;;) { if (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE && - !vcpu->arch.apf.halted) + !vcpu->arch.apf.halted) { + /* + * For some cases, we can get here with + * vcpu->arch.halted being true. + */ + if (kvm_x86_ops->post_block && vcpu->arch.halted) { + kvm_x86_ops->post_block(vcpu); + vcpu->arch.halted = false; + } + r = vcpu_enter_guest(vcpu); - else + } else { r = vcpu_block(kvm, vcpu); + + /* + * post_block() must be called after + * pre_block() which is called in + * kvm_vcpu_halt(). + */ + if (kvm_x86_ops->post_block && vcpu->arch.halted) { + kvm_x86_ops->post_block(vcpu); + vcpu->arch.halted = false; + } + } + if (r <= 0) break; diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index feba1fb..bf462e7 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -231,6 +231,9 @@ struct kvm_vcpu { unsigned long requests; unsigned long guest_debug; + int pre_pcpu; + struct list_head blocked_vcpu_list; + struct mutex mutex; struct kvm_run *run; diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 8b8a444..191c7eb 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -220,6 +220,9 @@ int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id) init_waitqueue_head(&vcpu->wq); kvm_async_pf_vcpu_init(vcpu); + vcpu->pre_pcpu = -1; + INIT_LIST_HEAD(&vcpu->blocked_vcpu_list); + page = alloc_page(GFP_KERNEL | __GFP_ZERO); if (!page) { r = -ENOMEM; -- 2.1.0