IPI and I/O interrupts

[Sushanth Rai]

Hi,

I would like to understand little bit about the FreeBSD interrupt handling on x86.

When a cpu is processing an IPI, let's say cpu is running IPI_STOP handler, are I/O interrupts like the timer interrupt disabled ? Conversely if the cpu is holding a spinlock, which means it has disabled interrupts, can it process an IPI. My understanding is executing "cli" instruction disables the maskable interrupts. I was wondering if IPIs are part of that.

Thanks,
Sushanth