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
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
