Re: [question] lots of interrupts injected to vm when pressing some key w/o releasing

["Zhang Haoyu" <zhanghy@sangfor.com>]

>Hi all,
>On Thu, Nov 27, 2014 at 03:20:43PM +0800, Zhang Haoyu wrote:
>>>>>>>> I tested win-server-2008 with "-cpu 
>>>>>>>> core2duo,hv_spinlocks=0xffff,hv_relaxed,hv_time",
>>>>>>>> this problem still happened, about 200,000 vmexits per-second, 
>>>>>>>> bringing very bad experience, just like being stuck.
>>>>>>> 
>>>>>>> Please upload a full trace somewhere, or at least the "perf report" output.
>>>>>>> 
>>>>>> 
>>>>>> And, if I remove the commit of 0bc830b0, the problem disappeared.
>>>>> 
>>>>> Please send the full trace file.  If you compress it, it should be small.
>>>>> 
>>>> See the attach 1, please.
>>>> 
>>>>> Paolo
>>>
>>>Can you try the follow draft patch to see whether it solve your problem? This patch is based on commit 0bc830b0.
>>>
>>After applying this patch, VM got stuck with black-screen at boot stage,
>># trace-cmd report:
>>version = 6
>>CPU 0 is empty
>>CPU 1 is empty
>>CPU 2 is empty
>>CPU 3 is empty
>>CPU 5 is empty
>>CPU 7 is empty
>>cpus=8
>>             kvm-1266  [004] 14399.834397: kvm_set_irq:          gsi 9 level 1 source 0
>>             kvm-1266  [004] 14399.834403: kvm_pic_set_irq:      chip 1 pin 1 (edge|masked)
>>             kvm-1266  [004] 14399.834411: kvm_apic_accept_irq:  apicid 0 vec 177 (LowPrio|level)
>>             kvm-1266  [004] 14399.834412: kvm_ioapic_set_irq:   pin 9 dst 3 vec=177 (LowPrio|logical|level)
>>             kvm-1266  [004] 14402.180013: kvm_set_irq:          gsi 9 level 1 source 0
>>             kvm-1266  [004] 14402.180019: kvm_pic_set_irq:      chip 1 pin 1 (edge|masked)
>>             kvm-1266  [004] 14402.180028: kvm_apic_accept_irq:  apicid 1 vec 177 (LowPrio|level)
>>             kvm-1266  [004] 14402.180029: kvm_ioapic_set_irq:   pin 9 dst 3 vec=177 (LowPrio|logical|level)
>>             kvm-1266  [004] 14404.525627: kvm_set_irq:          gsi 9 level 1 source 0
>>             kvm-1266  [004] 14404.525634: kvm_pic_set_irq:      chip 1 pin 1 (edge|masked)
>>             kvm-1266  [004] 14404.525641: kvm_apic_accept_irq:  apicid 0 vec 177 (LowPrio|level)
>>             kvm-1266  [004] 14404.525642: kvm_ioapic_set_irq:   pin 9 dst 3 vec=177 (LowPrio|logical|level)
>>             kvm-1266  [004] 14406.871238: kvm_set_irq:          gsi 9 level 1 source 0
>>             kvm-1266  [004] 14406.871245: kvm_pic_set_irq:      chip 1 pin 1 (edge|masked)
>>             kvm-1266  [004] 14406.871254: kvm_apic_accept_irq:  apicid 1 vec 177 (LowPrio|level)
>>             kvm-1266  [004] 14406.871256: kvm_ioapic_set_irq:   pin 9 dst 3 vec=177 (LowPrio|logical|level)
>>             kvm-1266  [006] 14409.216849: kvm_set_irq:          gsi 9 level 1 source 0
>>             kvm-1266  [006] 14409.216855: kvm_pic_set_irq:      chip 1 pin 1 (edge|masked)
>>             kvm-1266  [006] 14409.216862: kvm_apic_accept_irq:  apicid 0 vec 177 (LowPrio|level)
>>             kvm-1266  [006] 14409.216863: kvm_ioapic_set_irq:   pin 9 dst 3 vec=177 (LowPrio|logical|level)
>>             kvm-1266  [006] 14411.562475: kvm_set_irq:          gsi 9 level 1 source 0
>>             kvm-1266  [006] 14411.562481: kvm_pic_set_irq:      chip 1 pin 1 (edge|masked)
>>             kvm-1266  [006] 14411.562489: kvm_apic_accept_irq:  apicid 1 vec 177 (LowPrio|level)
>>             kvm-1266  [006] 14411.562491: kvm_ioapic_set_irq:   pin 9 dst 3 vec=177 (LowPrio|logical|level)
>>             kvm-1266  [004] 14413.908074: kvm_set_irq:          gsi 9 level 1 source 0
>>             kvm-1266  [004] 14413.908080: kvm_pic_set_irq:      chip 1 pin 1 (edge|masked)
>>             kvm-1266  [004] 14413.908088: kvm_apic_accept_irq:  apicid 0 vec 177 (LowPrio|level)
>>             kvm-1266  [004] 14413.908089: kvm_ioapic_set_irq:   pin 9 dst 3 vec=177 (LowPrio|logical|level)
>>
>>Thanks,
>>Zhang Haoyu
>>
>>>diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
>>>index 25e16a6..8f4e211 100644
>>>--- a/virt/kvm/ioapic.c
>>>+++ b/virt/kvm/ioapic.c
>>>@@ -305,6 +305,7 @@ static int ioapic_service(struct kvm_ioapic *ioapic, int irq, bool line_status)
>>>        return ret;
>>> }
>>> 
>>>+static int irq_status[256];
>>> int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int irq_source_id,
>>>                       int level, bool line_status)
>>> {
>>>@@ -312,10 +313,13 @@ int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int irq_source_id,
>>>        u32 mask = 1 << irq;
>>>        union kvm_ioapic_redirect_entry entry;
>>>        int ret, irq_level;
>>>+       int old_irq;
>>> 
>
>I'm not sure which version of kvm the patch is against, anyway, all the 
>modification should be moved to ioapic_set_irq() against the upstream 
>kvm, I test the patch w/ win2k8 guest and w/o the Haoyu's comand line 
>and it can fix the bug mentioned by Haoyu, in addition, press any key 
>can reproduce the bug on my side instead of the small set which Haoyu 
>mentioned.
>
Yang's patch indeed can fix the problem.
Our rtc optimization together with Yang' patch causes the stuck happened at boot stage.

Thanks,
Zhang Haoyu

>Regards,
>Wanpeng Li 
>
>>>        BUG_ON(irq < 0 || irq >= IOAPIC_NUM_PINS);
>>> 
>>>        spin_lock(&ioapic->lock);
>>>+       old_irq = irq_status[irq];
>>>+       irq_status[irq] = level;
>>>        old_irr = ioapic->irr;
>>>        irq_level = __kvm_irq_line_state(&ioapic->irq_states[irq],
>>>                                         irq_source_id, level);
>>>@@ -332,6 +336,10 @@ int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int irq_source_id,
>>>                        goto out;
>>>                }
>>>                ioapic->irr |= mask;
>>>+               if (edge && old_irq == irq_status[irq] && old_irq) {
>>>+                       ret = 0;
>>>+                       goto out;
>>>+               }
>>>                if ((edge && old_irr != ioapic->irr) ||
>>>                    (!edge && !entry.fields.remote_irr))
>>>                        ret = ioapic_service(ioapic, irq, line_status);
>>>
>>>Best regards,
>>>Yang