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Re: [Xen-devel] Size of irq field



(CC Stefano and Ian)

On 02/04/2015 16:05, Iurii Konovalenko wrote:
Hi, Julien!

Hello Iurii,


During bringing up Xen on Renesas Lager board we faced with problem.
A lot of Xen sources relies on statement, that IRQ number is less then
256 and variables, parameters, fields etc. are of type uint8_t. But we
can have IRQs, that are greater then 255, for example on RCar H2 SoC.
Also, as I saw from one of your latest commits, GICv supports 1020
physical interrupts. As a result, overflow can occur. So it seems
logical to increase all irq staff to uint16_t or uint32_t. We have
local patches for increasing some structures, functions etc.
But before pushing these patches I want to know your opinion, what do
you think about this problem? What type should we use uint16_t or
uint32_t? How to find all places where uint8_t type is used for IRQ?

I'm a bit surprised. I looked through the hypervisor and libxl and I was able to found only one place (DOMCTL_irq_permission which is not really supported on ARM). We are usually using uint32_t/int for IRQ.

Can you give an example of files/structures using uint8_t for IRQ?

Ideally the IRQ should use uint32_t. This is allow us to support LPIs (IRQ number start a 8192 up to a very high number).

Best regards.

Regards,

--
Julien Grall

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