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

[Gleb Natapov]

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.

> >> It looks like some other IRQs cause the coalescing, because also
> >> looking at RTC code, it seems it's not possible for RTC to raise the
> >> IRQ (except update IRQ, alarm etc.) without calling
> >> apic_reset_irq_delivered().
> >>
> >> I've attached my test program. Compile:
> >> gcc -m32 -o coalescing coalescing.S -ffreestanding -nostdlib -Wl,-T
> >> coalescing.ld -g && objcopy -Obinary coalescing coalescing.bin
> >>
> >> Run:
> >> qemu -L . -bios coalescing.bin -no-hpet -rtc-td-hack
> >>
> > The application does not work for me. Looks like it fails to enter
> > protected mode. $pc jumps from 0x00000000fffffff0 to 0x00000000000f003e
> > and back.
> 
> Strange. Here's a working binary.
> 
Your binary works here too. What compiler are you using?

--
                        Gleb.