IPI's in Xen are implemented through hypervisor event channels.
The MP code creates a pair of IRQs for each base IPI per CPU
(one for IPI function dispatch calls, one for IPI bitmap dispatch calls.)
Using PCPU_GET() was returning the IRQ of the IPI handler for the
current CPU; thus calls to ipi_cpu() were sending itself a message.
Instead, looking up the IPI in the target CPU ipi-to-irq map is needed.
Note: This doesn't fix Xen SMP (far from it!) but it at least
sends IPI's to the right places. Next - sending IPIs..
PR: 135069
I'm not sure what series of events is leading up to this watch event
being received with no callback info and it should be investigated.
I'm triggering it somehow by registering an RTC device (which will
show up in a subsequent commit.)
Log:
- merge in latest xenbus from dfr's xenhvm
- fix race condition in xs_read_reply by converting tsleep to mtx_sleep
Log:
unmask evtchn in bind_{virq, ipi}_to_irq
Log:
- remove code for handling case of not being able to sleep
- eliminate tsleep - make sleeps atomic
