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Re: [Qemu-devel] Re: [RFT][PATCH 07/15] qemu_irq: Add IRQ handlers with


From: Blue Swirl
Subject: Re: [Qemu-devel] Re: [RFT][PATCH 07/15] qemu_irq: Add IRQ handlers with delivery feedback
Date: Sun, 30 May 2010 20:21:30 +0000

On Sun, May 30, 2010 at 8:07 PM, Gleb Natapov <address@hidden> wrote:
> On Sun, May 30, 2010 at 07:37:59PM +0000, Blue Swirl wrote:
>> On Sun, May 30, 2010 at 1:49 PM, Gleb Natapov <address@hidden> wrote:
>> > On Sun, May 30, 2010 at 12:56:26PM +0000, Blue Swirl wrote:
>> >> >> Well, I'd like to get the test program also trigger it. Now I'm 
>> >> >> getting:
>> >> >> apic: write: 00000350 = 00000000
>> >> >> apic: apic_reset_irq_delivered: old coalescing 0
>> >> >> apic: apic_local_deliver: vector 3 delivery mode 0
>> >> >> apic: apic_set_irq: coalescing 1
>> >> >> apic: apic_get_irq_delivered: returning coalescing 1
>> >> >> apic: apic_reset_irq_delivered: old coalescing 1
>> >> >> apic: apic_local_deliver: vector 3 delivery mode 0
>> >> >> apic: apic_set_irq: coalescing 0
>> >> >> apic: apic_get_irq_delivered: returning coalescing 0
>> >> >> apic: apic_reset_irq_delivered: old coalescing 0
>> >> >> apic: apic_local_deliver: vector 3 delivery mode 0
>> >> >> apic: apic_set_irq: coalescing 0
>> >> >>
>> > So interrupt is _alway_ coalesced. If apic_get_irq_delivered() returns
>> > 0 it means the interrupt was not delivered.
>>
>> That seems strange. I changed the program so that the handler gets
>> executed, also output a dot to serial from the handler. I changed the
>> frequency to 2Hz.
>>
>> Now, if I leave out -rtc-td-hack, I get the dots at 2Hz as expected.
>> With -rtc-td-hack, the dots come out much faster. I added
>> DEBUG_COALESCING also to RTC, with that enabled I get:
>> qemu -L . -bios coalescing.bin -d in_asm,int -no-hpet -rtc-td-hack -serial 
>> stdio
>> cmos: coalesced irqs scaled to 0
>> cmos: coalesced irqs increased to 1
>> cmos: injecting on ack
>> .cmos: injecting on ack
>> .cmos: injecting on ack
>> .cmos: injecting on ack
>> .cmos: injecting on ack
>> .cmos: injecting on ack
>> .cmos: injecting on ack
>> .cmos: injecting on ack
>> .cmos: injecting on ack
>> .cmos: injecting on ack
>> .cmos: injecting on ack
>> .cmos: injecting on ack
>> .cmos: injecting on ack
>> .cmos: injecting on ack
>> .cmos: injecting on ack
>> .cmos: injecting on ack
>> .cmos: injecting on ack
>> .cmos: injecting on ack
>> .cmos: injecting on ack
>> .cmos: injecting on ack
>> ..cmos: injecting from timer
>> .cmos: coalesced irqs increased to 2
>> cmos: injecting on ack
>>
>> So, there are bogus injections.
>
> Looks like irr in apic is never cleared. Probably bug in userspace apic
> emulation. I'll look into it. Try to route interrupt via APIC (not ExtInt),
> or use qemu-kvm with in kernel irq chip.

With APIC you mean Fixed? Then the IRQ is not delivered at all.



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