Commit b6958ce4 authored by Eddie Dong's avatar Eddie Dong Committed by Avi Kivity

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: default avatarGregory Haskins <ghaskins@novell.com>
Signed-off-by: default avatarYaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent 1fd4f2a5
......@@ -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)
......
......@@ -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);
}
......
......@@ -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;
......
......@@ -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:
......
......@@ -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);
......
......@@ -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,
......
......@@ -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
......
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