From d76901750ab9f71091d33ef3d2b5909d8a9a4ad4 Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Mon, 8 Sep 2008 15:23:48 -0300 Subject: [PATCH] KVM: x86: do not execute halted vcpus Offline or uninitialized vcpu's can be executed if requested to perform userspace work. Follow Avi's suggestion to handle halted vcpu's in the main loop, simplifying kvm_emulate_halt(). Introduce a new vcpu->requests bit to indicate events that promote state from halted to running. Also standardize vcpu wake sites. Signed-off-by: Marcelo Tosatti redhat.com> Signed-off-by: Avi Kivity --- arch/x86/kvm/i8254.c | 5 +-- arch/x86/kvm/lapic.c | 16 ++------ arch/x86/kvm/x86.c | 100 ++++++++++++++++++++++++++--------------------- include/linux/kvm_host.h | 1 + virt/kvm/kvm_main.c | 10 ++--- 5 files changed, 67 insertions(+), 65 deletions(-) diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c index 4cb4430..634132a 100644 --- a/arch/x86/kvm/i8254.c +++ b/arch/x86/kvm/i8254.c @@ -200,10 +200,9 @@ static int __pit_timer_fn(struct kvm_kpit_state *ps) if (!atomic_inc_and_test(&pt->pending)) set_bit(KVM_REQ_PENDING_TIMER, &vcpu0->requests); - if (vcpu0 && waitqueue_active(&vcpu0->wq)) { - vcpu0->arch.mp_state = KVM_MP_STATE_RUNNABLE; + + if (vcpu0 && waitqueue_active(&vcpu0->wq)) wake_up_interruptible(&vcpu0->wq); - } pt->timer.expires = ktime_add_ns(pt->timer.expires, pt->period); pt->scheduled = ktime_to_ns(pt->timer.expires); diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index be94f93..fd00f69 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -339,13 +339,7 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode, } else apic_clear_vector(vector, apic->regs + APIC_TMR); - if (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE) - kvm_vcpu_kick(vcpu); - else if (vcpu->arch.mp_state == KVM_MP_STATE_HALTED) { - vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE; - if (waitqueue_active(&vcpu->wq)) - wake_up_interruptible(&vcpu->wq); - } + kvm_vcpu_kick(vcpu); result = (orig_irr == 0); break; @@ -384,8 +378,7 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode, if (vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED) { vcpu->arch.sipi_vector = vector; vcpu->arch.mp_state = KVM_MP_STATE_SIPI_RECEIVED; - if (waitqueue_active(&vcpu->wq)) - wake_up_interruptible(&vcpu->wq); + kvm_vcpu_kick(vcpu); } break; @@ -950,10 +943,9 @@ static int __apic_timer_fn(struct kvm_lapic *apic) if(!atomic_inc_and_test(&apic->timer.pending)) set_bit(KVM_REQ_PENDING_TIMER, &apic->vcpu->requests); - if (waitqueue_active(q)) { - apic->vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE; + if (waitqueue_active(q)) wake_up_interruptible(q); - } + if (apic_lvtt_period(apic)) { result = 1; apic->timer.dev.expires = ktime_add_ns( diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 3f3cb71..bf98d40 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2798,11 +2798,6 @@ int kvm_emulate_halt(struct kvm_vcpu *vcpu) KVMTRACE_0D(HLT, vcpu, handler); if (irqchip_in_kernel(vcpu->kvm)) { vcpu->arch.mp_state = KVM_MP_STATE_HALTED; - up_read(&vcpu->kvm->slots_lock); - kvm_vcpu_block(vcpu); - down_read(&vcpu->kvm->slots_lock); - if (vcpu->arch.mp_state != KVM_MP_STATE_RUNNABLE) - return -EINTR; return 1; } else { vcpu->run->exit_reason = KVM_EXIT_HLT; @@ -3097,24 +3092,10 @@ static void vapic_exit(struct kvm_vcpu *vcpu) up_read(&vcpu->kvm->slots_lock); } -static int __vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) +static int vcpu_enter_guest(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) { int r; - if (unlikely(vcpu->arch.mp_state == KVM_MP_STATE_SIPI_RECEIVED)) { - pr_debug("vcpu %d received sipi with vector # %x\n", - vcpu->vcpu_id, vcpu->arch.sipi_vector); - kvm_lapic_reset(vcpu); - r = kvm_x86_ops->vcpu_reset(vcpu); - if (r) - return r; - vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE; - } - - down_read(&vcpu->kvm->slots_lock); - vapic_enter(vcpu); - -again: if (vcpu->requests) if (test_and_clear_bit(KVM_REQ_MMU_RELOAD, &vcpu->requests)) kvm_mmu_unload(vcpu); @@ -3151,22 +3132,13 @@ again: local_irq_disable(); - if (vcpu->requests || need_resched()) { + if (vcpu->requests || need_resched() || signal_pending(current)) { local_irq_enable(); preempt_enable(); r = 1; goto out; } - if (signal_pending(current)) { - local_irq_enable(); - preempt_enable(); - r = -EINTR; - kvm_run->exit_reason = KVM_EXIT_INTR; - ++vcpu->stat.signal_exits; - goto out; - } - if (vcpu->guest_debug.enabled) kvm_x86_ops->guest_debug_pre(vcpu); @@ -3227,26 +3199,63 @@ again: kvm_lapic_sync_from_vapic(vcpu); r = kvm_x86_ops->handle_exit(kvm_run, vcpu); +out: + return r; +} - if (r > 0) { - if (dm_request_for_irq_injection(vcpu, kvm_run)) { - r = -EINTR; - kvm_run->exit_reason = KVM_EXIT_INTR; - ++vcpu->stat.request_irq_exits; - goto out; - } - if (!need_resched()) - goto again; +static int __vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) +{ + int r; + + if (unlikely(vcpu->arch.mp_state == KVM_MP_STATE_SIPI_RECEIVED)) { + printk("vcpu %d received sipi with vector # %x\n", + vcpu->vcpu_id, vcpu->arch.sipi_vector); + kvm_lapic_reset(vcpu); + r = kvm_x86_ops->vcpu_reset(vcpu); + if (r) + return r; + vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE; } -out: - up_read(&vcpu->kvm->slots_lock); - if (r > 0) { - kvm_resched(vcpu); - down_read(&vcpu->kvm->slots_lock); - goto again; + down_read(&vcpu->kvm->slots_lock); + vapic_enter(vcpu); + + r = 1; + while (r > 0) { + if (kvm_arch_vcpu_runnable(vcpu)) + r = vcpu_enter_guest(vcpu, kvm_run); + else { + up_read(&vcpu->kvm->slots_lock); + kvm_vcpu_block(vcpu); + down_read(&vcpu->kvm->slots_lock); + if (test_and_clear_bit(KVM_REQ_UNHALT, &vcpu->requests)) + if (vcpu->arch.mp_state == KVM_MP_STATE_HALTED) + vcpu->arch.mp_state = + KVM_MP_STATE_RUNNABLE; + if (vcpu->arch.mp_state != KVM_MP_STATE_RUNNABLE) + r = -EINTR; + } + + if (r > 0) { + if (dm_request_for_irq_injection(vcpu, kvm_run)) { + r = -EINTR; + kvm_run->exit_reason = KVM_EXIT_INTR; + ++vcpu->stat.request_irq_exits; + } + if (signal_pending(current)) { + r = -EINTR; + kvm_run->exit_reason = KVM_EXIT_INTR; + ++vcpu->stat.signal_exits; + } + if (need_resched()) { + up_read(&vcpu->kvm->slots_lock); + kvm_resched(vcpu); + down_read(&vcpu->kvm->slots_lock); + } + } } + up_read(&vcpu->kvm->slots_lock); post_kvm_run_save(vcpu, kvm_run); vapic_exit(vcpu); @@ -3266,6 +3275,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) if (unlikely(vcpu->arch.mp_state == KVM_MP_STATE_UNINITIALIZED)) { kvm_vcpu_block(vcpu); + clear_bit(KVM_REQ_UNHALT, &vcpu->requests); r = -EAGAIN; goto out; } diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index a18aaad..4b03643 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -34,6 +34,7 @@ #define KVM_REQ_MMU_RELOAD 3 #define KVM_REQ_TRIPLE_FAULT 4 #define KVM_REQ_PENDING_TIMER 5 +#define KVM_REQ_UNHALT 6 struct kvm_vcpu; extern struct kmem_cache *kvm_vcpu_cache; diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index de3b029..63e661b 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -980,12 +980,12 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu) for (;;) { prepare_to_wait(&vcpu->wq, &wait, TASK_INTERRUPTIBLE); - if (kvm_cpu_has_interrupt(vcpu)) - break; - if (kvm_cpu_has_pending_timer(vcpu)) - break; - if (kvm_arch_vcpu_runnable(vcpu)) + if (kvm_cpu_has_interrupt(vcpu) || + kvm_cpu_has_pending_timer(vcpu) || + kvm_arch_vcpu_runnable(vcpu)) { + set_bit(KVM_REQ_UNHALT, &vcpu->requests); break; + } if (signal_pending(current)) break; -- 1.8.2.3