Re: [PATCH 0/9] in-kernel APIC v9 (kernel side)

[Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

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Avi Kivity wrote:
> Gregory Haskins wrote:
>> Incorporates v8 plus the following changes:
>>
>> 1) Fix for hang on AMD
>> 2) Fixes issue where irq-windows are inaccurately reported to userspace
>> 3) Fixed issue where irq-window-exiting requests can be ignored in 
>> some cases
>>
>>   
>
> FC6 x86_64 hangs on this (AMD) after 'Detected 62.502 MHz APIC 
> Timer.'.  At least it doesn't kill the machine -- just the guest.  
> I'll try to see what's wrong.
>
> Note that this is with just the kernel patches applied.
>
> The patchset is available as the lapic branch in kvm.git (with some 
> whitespace damage fixed).
>

Things are a little better with the attached patch.

On AMD, to detect the interrupt window opening, we queue an interrupt 
and then ask for an intercept immediately before interrupt disaptching.  
Effectively that means an intercept after sti, as on vmx.

The problem occurs when we want to inject an interrupt _and_ request an 
interrupt window.  Using the current code, we loop immediately because 
we queue the requested interrupt, then ask for an intercept when it is 
dispatched.  A complex way to spin.

The fix is to inject the interrupt instead of queueing it.  Injected 
events are not intercepted, so we can ask for an interrupt window 
concurrently with injecting an interrupt.

However, there are still problems (like Windows spontaneously 
rebooting).  Will investigate further.

-- 
error compiling committee.c: too many arguments to function


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diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index bdc5d98..651c860 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -1425,13 +1425,18 @@ static void do_intr_requests(struct kvm_vcpu *vcpu,
 
 		if (ack.flags & KVM_IRQACKDATA_VECTOR_VALID) {
 			control = &vcpu->svm->vmcb->control;
+#if 0
 			control->int_vector = ack.vector;
 			control->int_ctl &= ~V_INTR_PRIO_MASK;
 			control->int_ctl |= V_IRQ_MASK |
 				((/*control->int_vector >> 4*/ 0xf) <<
 				 V_INTR_PRIO_SHIFT);
+#endif
+			control->event_inj = ack.vector
+				| SVM_EVTINJ_VALID
+				| SVM_EVTINJ_TYPE_INTR;
 
 			++vcpu->stat.irq_accepted;
 		}
 	}
 

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