Re: RFC/patch portability: split kvm_vm_ioctl v3

Carsten Otte
2007-10-30T13:09:28Z

Avi Kivity wrote:
> A bitmap would do it, but what size? Expandable ones are messy.
We could have a #define KVM_CPU_BITMAP_SIZE in the arch specific
header files that go to include/asm/. For s390, we have one of our
rocket science virtualization accelerating facilities that limits us
to 64 cpus per guest. This may well be extended later on, but for now
that would be sufficient. Thinking about Christoph Lameter with his 4k
CPU boxes, I believe ia64 would want faaaar more than that.

> No, it's a command (mmio) to the APIC, you tell it which vector you want
> and to which cpus you want it delivered. So you can have many IPI
> interrupt vectors.
I see. But the interrupt vector can be encoded in __u64?