Re: [Xen-devel] [PATCH] Change spec of callback IRQ for PV-on-HVM onIA64

[Doi.Tsunehisa@xxxxxxxxxxxxxx]

Hi Kevin,

You (kevin.tian) said:
>>  * pvdrv.patch2
>>    - Modify to change the spec of callback IRQ in PV-driver side.
>>    - This patch brakes compatibility with previous version on IA64.
>>
>>  I tested with our simple test of PV-on-HVM on RHEL4 U2 for IA64
>>with hypervisor side modification.
>>
>>Thanks,
>>- Tsunehisa Doi
> 
> Maybe I'm missing something and you can help me understand. :-) 
> Whatever the value is mangled in pdev->irq, you should always 
> keep following two instances same:
>       if ((ret = request_irq(pdev->irq, evtchn_interrupt, SA_SHIRQ,...
> and
>       if ((ret = set_callback_irq(pdev->irq)))

  In x86-linux, two instances are same. But in IA64-linux, previous one
is a external interrupt vector for xen-platform interruption. Although
latter one is a hardware IRQ id. Both values are not same in IA64-linux.

> Before your patch, say pdev->irq is 0x27 (ISA irq 9), platform-pci 
> driver binds handler to 0x27 and xen will inject by callback_irq 0x27. 
> However in your patch, request_irq is still using pdev->irq (0x27) 
> while set_callback_irq instead wants (0x9). In this case, how can you 
> still make things working when two sides don't match...

  With the modification of hypervisor side, the callback_irq(it's hardware
IRQ) becomes to be converted to external interrupt vector with a emulator
of IOSAPIC.

Thanks,
- Tsunehisa Doi

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel