[PATCH 0/5] gicv3: Use right number of prio bits for the CPU

[Peter Maydell]

This patchset fills in an odd inconsistency in our GICv3 emulation
that I noticed while I was doing the GICv4 work. At the moment we
allow the CPU to specify the number of bits of virtual priority
(via the ARMCPU::gic_vpribits field), but we always use 8 bits of
physical priority, even though to my knowledge no real Arm CPU
hardware has that many.

This series makes the GICv3 emulation use a runtime-configurable
number of physical priority bits, and sets it to match the number
used by the various CPUs we implement (which is 5 for all the
Cortex-Axx CPUs we emulate). Because changing the number of
priority bits is a migration compatibility break, we use a compat
property to keep the number of priority bits at 8 for older
versions of the virt board.

There is one TODO left in this series, which is that I don't know
the right value to use for the A64FX, so I've guessed that it
is 5, like all the Arm implementations.

Patch 1 is an independent bugfix; patch 5 is cleanup.

thanks
-- PMM

Peter Maydell (5):
  hw/intc/arm_gicv3: report correct PRIbits field in ICV_CTLR_EL1
  hw/intc/arm_gicv3_kvm.c: Stop using GIC_MIN_BPR constant
  hw/intc/arm_gicv3: Support configurable number of physical priority
    bits
  hw/intc/arm_gicv3: Use correct number of priority bits for the CPU
  hw/intc/arm_gicv3: Provide ich_num_aprs()

 include/hw/intc/arm_gicv3_common.h |   8 +-
 target/arm/cpu.h                   |   1 +
 hw/core/machine.c                  |   4 +-
 hw/intc/arm_gicv3_common.c         |   5 +
 hw/intc/arm_gicv3_cpuif.c          | 208 ++++++++++++++++++++---------
 hw/intc/arm_gicv3_kvm.c            |  16 ++-
 target/arm/cpu64.c                 |   9 ++
 7 files changed, 179 insertions(+), 72 deletions(-)

-- 
2.25.1