The VCPU ids are currently computed and assigned to each individual
CPU threads in spapr_cpu_core_realize(). But the numbering logic
of VCPU ids is actually a machine-level concept, and many places
in hw/ppc/spapr.c also have to compute VCPU ids out of CPU indexes.
The current formula used in spapr_cpu_core_realize() is:
vcpu_id = (cc->core_id * spapr->vsmt / smp_threads) + i
where:
cc->core_id is a multiple of smp_threads
cpu_index = cc->core_id + i
0 <= i < smp_threads
So we have:
cpu_index % smp_threads == i
cc->core_id / smp_threads == cpu_index / smp_threads
hence:
vcpu_id =
(cpu_index / smp_threads) * spapr->vsmt + cpu_index % smp_threads;
This formula was used before VSMT at the time VCPU ids where computed
at the target emulation level. It has the advantage of being useable
to derive a VPCU id out of a CPU index only. It is fitted for all the
places where the machine code has to compute a VCPU id.
This patch introduces an accessor to set the VCPU id in a PowerPCCPU object
using the above formula. It is a first step to consolidate all the VCPU id
logic in a single place.
Signed-off-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
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