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KVM: x86: do not execute halted vcpus

Browse source 
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 <mtosatti <at> redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
This commit is contained in:
Marcelo Tosatti 2008-09-08 15:23:48 -03:00 committed by Avi Kivity
parent a6a3034cb9
commit d76901750a
5 changed files with 69 additions and 67 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

5
arch/x86/kvm/i8254.c
View file

@ -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);

16
arch/x86/kvm/lapic.c
View file

@ -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(

104
arch/x86/kvm/x86.c
View file

@ -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 @@ static int __vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
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 @@ static int __vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
kvm_lapic_sync_from_vapic(vcpu);
r = kvm_x86_ops->handle_exit(kvm_run, vcpu);
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;
}
out:
up_read(&vcpu->kvm->slots_lock);
if (r > 0) {
kvm_resched(vcpu);
down_read(&vcpu->kvm->slots_lock);
goto again;
return r;
}
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;
}
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;
}

1
include/linux/kvm_host.h
View file

@ -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;

10
virt/kvm/kvm_main.c
View file

@ -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;