From b6958ce44a11a9e9425d2b67a653b1ca2a27796f Mon Sep 17 00:00:00 2001 From: Eddie Dong Date: Wed, 18 Jul 2007 12:15:21 +0300 Subject: [PATCH] KVM: Emulate hlt in the kernel By sleeping in the kernel when hlt is executed, we simplify the in-kernel guest interrupt path considerably. Signed-off-by: Gregory Haskins Signed-off-by: Yaozu (Eddie) Dong Signed-off-by: Avi Kivity --- drivers/kvm/i8259.c | 3 +++ drivers/kvm/irq.c | 4 ++++ drivers/kvm/kvm.h | 2 ++ drivers/kvm/kvm_main.c | 41 +++++++++++++++++++++++++++++++++++------ drivers/kvm/svm.c | 9 ++++++--- drivers/kvm/vmx.c | 8 ++++++-- include/linux/kvm.h | 1 + 7 files changed, 57 insertions(+), 11 deletions(-) diff --git a/drivers/kvm/i8259.c b/drivers/kvm/i8259.c index 40ad10462238..ee6030dc5c04 100644 --- a/drivers/kvm/i8259.c +++ b/drivers/kvm/i8259.c @@ -413,8 +413,11 @@ static void picdev_read(struct kvm_io_device *this, static void pic_irq_request(void *opaque, int level) { struct kvm *kvm = opaque; + struct kvm_vcpu *vcpu = kvm->vcpus[0]; pic_irqchip(kvm)->output = level; + if (vcpu) + kvm_vcpu_kick(vcpu); } struct kvm_pic *kvm_create_pic(struct kvm *kvm) diff --git a/drivers/kvm/irq.c b/drivers/kvm/irq.c index 5265f8267b3b..e09cd65925d6 100644 --- a/drivers/kvm/irq.c +++ b/drivers/kvm/irq.c @@ -70,6 +70,10 @@ void kvm_vcpu_kick(struct kvm_vcpu *vcpu) { int ipi_pcpu = vcpu->cpu; + if (waitqueue_active(&vcpu->wq)) { + wake_up_interruptible(&vcpu->wq); + ++vcpu->stat.halt_wakeup; + } if (vcpu->guest_mode) smp_call_function_single(ipi_pcpu, vcpu_kick_intr, vcpu, 0, 0); } diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h index 8d07a993af94..bb506b71797d 100644 --- a/drivers/kvm/kvm.h +++ b/drivers/kvm/kvm.h @@ -231,6 +231,7 @@ struct kvm_stat { u32 signal_exits; u32 irq_window_exits; u32 halt_exits; + u32 halt_wakeup; u32 request_irq_exits; u32 irq_exits; u32 light_exits; @@ -353,6 +354,7 @@ struct kvm_vcpu { gva_t mmio_fault_cr2; struct kvm_pio_request pio; void *pio_data; + wait_queue_head_t wq; int sigset_active; sigset_t sigset; diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c index ffbdadd87971..4384364fc0c8 100644 --- a/drivers/kvm/kvm_main.c +++ b/drivers/kvm/kvm_main.c @@ -76,6 +76,7 @@ static struct kvm_stats_debugfs_item { { "signal_exits", STAT_OFFSET(signal_exits) }, { "irq_window", STAT_OFFSET(irq_window_exits) }, { "halt_exits", STAT_OFFSET(halt_exits) }, + { "halt_wakeup", STAT_OFFSET(halt_wakeup) }, { "request_irq", STAT_OFFSET(request_irq_exits) }, { "irq_exits", STAT_OFFSET(irq_exits) }, { "light_exits", STAT_OFFSET(light_exits) }, @@ -248,6 +249,7 @@ int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id) vcpu->mmu.root_hpa = INVALID_PAGE; vcpu->kvm = kvm; vcpu->vcpu_id = id; + init_waitqueue_head(&vcpu->wq); page = alloc_page(GFP_KERNEL | __GFP_ZERO); if (!page) { @@ -1307,15 +1309,41 @@ int emulate_instruction(struct kvm_vcpu *vcpu, } EXPORT_SYMBOL_GPL(emulate_instruction); -int kvm_emulate_halt(struct kvm_vcpu *vcpu) +/* + * The vCPU has executed a HLT instruction with in-kernel mode enabled. + */ +static void kvm_vcpu_kernel_halt(struct kvm_vcpu *vcpu) { - if (vcpu->irq_summary || - (irqchip_in_kernel(vcpu->kvm) && kvm_cpu_has_interrupt(vcpu))) - return 1; + DECLARE_WAITQUEUE(wait, current); + + add_wait_queue(&vcpu->wq, &wait); + + /* + * We will block until either an interrupt or a signal wakes us up + */ + while(!(irqchip_in_kernel(vcpu->kvm) && kvm_cpu_has_interrupt(vcpu)) + && !vcpu->irq_summary + && !signal_pending(current)) { + set_current_state(TASK_INTERRUPTIBLE); + vcpu_put(vcpu); + schedule(); + vcpu_load(vcpu); + } - vcpu->run->exit_reason = KVM_EXIT_HLT; + remove_wait_queue(&vcpu->wq, &wait); + set_current_state(TASK_RUNNING); +} + +int kvm_emulate_halt(struct kvm_vcpu *vcpu) +{ ++vcpu->stat.halt_exits; - return 0; + if (irqchip_in_kernel(vcpu->kvm)) { + kvm_vcpu_kernel_halt(vcpu); + return 1; + } else { + vcpu->run->exit_reason = KVM_EXIT_HLT; + return 0; + } } EXPORT_SYMBOL_GPL(kvm_emulate_halt); @@ -2916,6 +2944,7 @@ static long kvm_dev_ioctl(struct file *filp, switch (ext) { case KVM_CAP_IRQCHIP: + case KVM_CAP_HLT: r = 1; break; default: diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c index d576451827e7..a347b61644cd 100644 --- a/drivers/kvm/svm.c +++ b/drivers/kvm/svm.c @@ -1398,9 +1398,12 @@ static void do_interrupt_requests(struct vcpu_svm *svm, static void post_kvm_run_save(struct vcpu_svm *svm, struct kvm_run *kvm_run) { - kvm_run->ready_for_interrupt_injection - = (svm->vcpu.interrupt_window_open && - svm->vcpu.irq_summary == 0); + if (irqchip_in_kernel(svm->vcpu.kvm)) + kvm_run->ready_for_interrupt_injection = 1; + else + kvm_run->ready_for_interrupt_injection = + (svm->vcpu.interrupt_window_open && + svm->vcpu.irq_summary == 0); kvm_run->if_flag = (svm->vmcb->save.rflags & X86_EFLAGS_IF) != 0; kvm_run->cr8 = get_cr8(&svm->vcpu); kvm_run->apic_base = kvm_get_apic_base(&svm->vcpu); diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c index c4cc17cc00f7..7ec8cf84e6ea 100644 --- a/drivers/kvm/vmx.c +++ b/drivers/kvm/vmx.c @@ -1961,8 +1961,12 @@ static void post_kvm_run_save(struct kvm_vcpu *vcpu, kvm_run->if_flag = (vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF) != 0; kvm_run->cr8 = get_cr8(vcpu); kvm_run->apic_base = kvm_get_apic_base(vcpu); - kvm_run->ready_for_interrupt_injection = (vcpu->interrupt_window_open && - vcpu->irq_summary == 0); + if (irqchip_in_kernel(vcpu->kvm)) + kvm_run->ready_for_interrupt_injection = 1; + else + kvm_run->ready_for_interrupt_injection = + (vcpu->interrupt_window_open && + vcpu->irq_summary == 0); } static int handle_interrupt_window(struct kvm_vcpu *vcpu, diff --git a/include/linux/kvm.h b/include/linux/kvm.h index 997bb3e46f1e..b0a13d1b34cc 100644 --- a/include/linux/kvm.h +++ b/include/linux/kvm.h @@ -283,6 +283,7 @@ struct kvm_signal_mask { * Extension capability list. */ #define KVM_CAP_IRQCHIP 0 +#define KVM_CAP_HLT 1 /* * ioctls for VM fds -- GitLab