Re: [PATCH] x86: Reserve FIRST_DEVICE_VECTOR in used_vectors bitmap.

[Stefan Bader <stefan.bader@canonical.com>]

Ingo Molnar wrote:
>> Someone from the community found out, that after repeatedly unloading 
>> and loading a device driver that uses MSI IRQs, the system eventually 
>> assigned the vector initially reserved for IRQ0 to the device driver.
> 
>> The reason for this is, that although IRQ0 is tied to the 
>> FIRST_DEVICE_VECTOR when declaring the irq_vector table, the 
>> corresponding bit in the used_vectors map is not set. So, if vectors 
>> are released and assigned often enough, the vector will get assigned 
>> to another interrupt. This happens more often with MSI interrupts as 
>> those are exclusively using a vector.
>>
>> Fix this by setting the bit for the FIRST_DEVICE_VECTOR in the bitmap.
> 
> hi, the IO-APIC code got unified in the x86 tree for v2.6.28.
> 
> So could you please send the fix against tip/master:
> 
>   http://people.redhat.com/mingo/tip.git/README
> 
> Thanks,
> 
> 	Ingo

I can't see this as required for tip. FIRST_DEVICE_VECTOR is there defined
distinct to the ISA IRQs (IRQ15_VECTOR+2) while it is defined to be equal to
IRQ0_VECTOR on 2.6.27 and before (at least down to 2.6.24).

Regards,
Stefan
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