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Date: Sun, 28 Sep 2008 18:44:42 +0300
From: Avi Kivity <avi@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: kvm@...r.kernel.org, Marcelo Tosatti <mtosatti@...hat.com>
Subject: [PATCH 06/25] KVM: x86: do not execute halted vcpus
From: Marcelo Tosatti <mtosatti@...hat.com>
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@...ranet.com>
---
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;
--
1.6.0.1
--
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