Re: oops in ioapic_write_entry

[ebiederm@xmission.com (Eric W. Biederman)]

Yinghai Lu <yinghai@kernel.org> writes:

> On 08/03/2010 12:19 AM, Yinghai Lu wrote:
>> On 08/02/2010 08:13 PM, Eric W. Biederman wrote:
>>> Yinghai Lu <yinghai@kernel.org> writes:

>>>> Index: linux-2.6/arch/x86/kernel/apic/io_apic.c
>>>> ===================================================================
>>>> --- linux-2.6.orig/arch/x86/kernel/apic/io_apic.c
>>>> +++ linux-2.6/arch/x86/kernel/apic/io_apic.c
>>>> @@ -1029,10 +1029,7 @@ static int pin_2_irq(int idx, int apic,
>>>>  	} else {
>>>>  		u32 gsi = mp_gsi_routing[apic].gsi_base + pin;
>>>>  
>>>> -		if (gsi >= NR_IRQS_LEGACY)
>>>> -			irq = gsi;
>>>> -		else
>>>> -			irq = gsi_top + gsi;
>>>> +		irq = gsi_to_irq(gsi);
>>>>  	}
>>>>  
>>>>  #ifdef CONFIG_X86_32
>> 
>> what is the point for making irq = gsi_top + gsi when mptable is used instead of acpi?
>> 
>
> just tried those blind shifting gsi cause kernel with acpi crash in virtual box.

What configuration did you try and had problems with?

> [    5.536000] querying PCI -> IRQ mapping bus:0, slot:11, pin:0.
> [    5.540000] ehci_hcd 0000:00:0b.0: can't find IRQ for PCI INT A; probably buggy MP table
> [

I don't have a clue what the mpptable looks like in virtual box.  My guess is that it
is buggy and untested like so many mptables these days.

> and on kvm it got:
> [    4.352280] e1000: Intel(R) PRO/1000 Network Driver - version 7.3.21-k6-NAPI
> [    4.356012] e1000: Copyright (c) 1999-2006 Intel Corporation.
> [    4.360120] querying PCI -> IRQ mapping bus:0, slot:3, pin:0.
> [    4.364006] PCI BIOS passed nonexistent PCI bus 0!
> [    4.368007] e1000 0000:00:03.0: can't find IRQ for PCI INT A; probably buggy MP table
> [    4.372049] e1000 0000:00:03.0: setting latency timer to 64


This example failed because mpparse said bus 0 was ISA.  Which is a
pretty bizarre thing to do, especially when bus 0 is pretty clearly
PCI.  That does sound like a buggy MP table.

Eric