On 18.03.2013, at 03:55, David Gibson wrote: > On Fri, Mar 15, 2013 at 01:33:18PM +0100, Alexander Graf wrote: >> >> On 14.03.2013, at 02:53, David Gibson wrote: >> >>> Currently, the pseries machine initializes the cpus, then the XICS >>> interrupt controller. However, to support the upcoming in-kernel XICS >>> implementation we will need to initialize the irq controller before the >>> vcpus. This patch makes the necesssary rearrangement. This means the >> >> We're changing that notion in the in-kernel XICS discussions. The flow will >> look like this: >> >> * create vcpus >> * create XICS >> * foreach (vcpu) >> * enable_cap(vcpu, CAP_XICS_SERVER, xics_handle) >> >> However, that means we still need to know the maximum number of >> supported vcpus during the create phase. That number can be bigger >> than smp_cpus though, since you probably want to support hotplug add >> of CPUs later on. >> >> Can't we just make the number of supported "interrupt servers" a >> constant? > > I suppose, but we need an allocation for each one, so its a bit ugly. > In any case although the comment is a bit out of date, this patch also > creates a logical place to put per-cpu XICS initialization which we > will still need for the new interface.
So how would you model CPU hotplug add? Alex
