Re: [regression] KVM: hangs and "irq timeout" booting HURD unless -no-kvm-irqchip passed

[Gleb Natapov <gleb@redhat.com>]

On Mon, Feb 07, 2011 at 07:40:55PM -0600, Jonathan Nieder wrote:
> Gleb Natapov wrote:
> 
> > Is this patch helps?
> > 
> > diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
> > index 3cece05..62b1dde 100644
> > --- a/arch/x86/kvm/i8259.c
> > +++ b/arch/x86/kvm/i8259.c
> > @@ -549,6 +549,9 @@ static void pic_irq_request(struct kvm *kvm, int level)
> >  	struct kvm_pic *s = pic_irqchip(kvm);
> >  	int irq = pic_get_irq(&s->pics[0]);
> >  
> > +	if (s->output && !level)
> > +		s->pics[0].isr_ack = 0xff;
> > +
> 
> Yes, it does (tested on top of kvm/master).  Thanks!
Thanks for testing. Can you test this one too please:

diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
index 3cece05..5528484 100644
--- a/arch/x86/kvm/i8259.c
+++ b/arch/x86/kvm/i8259.c
@@ -62,9 +62,6 @@ static void pic_unlock(struct kvm_pic *s)
 		}
 
 		if (!found)
-			found = s->kvm->bsp_vcpu;
-
-		if (!found)
 			return;
 
 		kvm_make_request(KVM_REQ_EVENT, found);
@@ -75,7 +72,6 @@ static void pic_unlock(struct kvm_pic *s)
 static void pic_clear_isr(struct kvm_kpic_state *s, int irq)
 {
 	s->isr &= ~(1 << irq);
-	s->isr_ack |= (1 << irq);
 	if (s != &s->pics_state->pics[0])
 		irq += 8;
 	/*
@@ -89,16 +85,6 @@ static void pic_clear_isr(struct kvm_kpic_state *s, int irq)
 	pic_lock(s->pics_state);
 }
 
-void kvm_pic_clear_isr_ack(struct kvm *kvm)
-{
-	struct kvm_pic *s = pic_irqchip(kvm);
-
-	pic_lock(s);
-	s->pics[0].isr_ack = 0xff;
-	s->pics[1].isr_ack = 0xff;
-	pic_unlock(s);
-}
-
 /*
  * set irq level. If an edge is detected, then the IRR is set to 1
  */
@@ -281,7 +267,6 @@ void kvm_pic_reset(struct kvm_kpic_state *s)
 	s->irr = 0;
 	s->imr = 0;
 	s->isr = 0;
-	s->isr_ack = 0xff;
 	s->priority_add = 0;
 	s->irq_base = 0;
 	s->read_reg_select = 0;
@@ -545,15 +530,11 @@ static int picdev_read(struct kvm_io_device *this,
  */
 static void pic_irq_request(struct kvm *kvm, int level)
 {
-	struct kvm_vcpu *vcpu = kvm->bsp_vcpu;
 	struct kvm_pic *s = pic_irqchip(kvm);
-	int irq = pic_get_irq(&s->pics[0]);
 
-	s->output = level;
-	if (vcpu && level && (s->pics[0].isr_ack & (1 << irq))) {
-		s->pics[0].isr_ack &= ~(1 << irq);
+	if (!s->output)
 		s->wakeup_needed = true;
-	}
+	s->output = level;	
 }
 
 static const struct kvm_io_device_ops picdev_ops = {
@@ -575,8 +556,6 @@ struct kvm_pic *kvm_create_pic(struct kvm *kvm)
 	s->pics[1].elcr_mask = 0xde;
 	s->pics[0].pics_state = s;
 	s->pics[1].pics_state = s;
-	s->pics[0].isr_ack = 0xff;
-	s->pics[1].isr_ack = 0xff;
 
 	/*
 	 * Initialize PIO device
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index bcc0efc..2dc5fc4 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2648,8 +2648,6 @@ static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu,
 	vcpu->arch.interrupt.pending = events->interrupt.injected;
 	vcpu->arch.interrupt.nr = events->interrupt.nr;
 	vcpu->arch.interrupt.soft = events->interrupt.soft;
-	if (vcpu->arch.interrupt.pending && irqchip_in_kernel(vcpu->kvm))
-		kvm_pic_clear_isr_ack(vcpu->kvm);
 	if (events->flags & KVM_VCPUEVENT_VALID_SHADOW)
 		kvm_x86_ops->set_interrupt_shadow(vcpu,
 						  events->interrupt.shadow);
@@ -5617,8 +5615,6 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
 	if (pending_vec < max_bits) {
 		kvm_queue_interrupt(vcpu, pending_vec, false);
 		pr_debug("Set back pending irq %d\n", pending_vec);
-		if (irqchip_in_kernel(vcpu->kvm))
-			kvm_pic_clear_isr_ack(vcpu->kvm);
 	}
 
 	kvm_set_segment(vcpu, &sregs->cs, VCPU_SREG_CS);
--
			Gleb.