[RFC 0/2] hw/arm/virt: kvm: allow gicv3 by default if host does not support v2

[Eric Auger <eric.auger@redhat.com>]

At the moment if the end-user does not specify the gic-version along
with KVM acceleration, v2 is set by default. However most of the
systems now have GICv3 and sometimes they do not support GICv2
compatibility. In that case we end up with this error:

qemu-system-aarch64: PMU: KVM_SET_DEVICE_ATTR: Invalid argument
qemu-system-aarch64: failed to set irq for PMU
and qemu aborts.

This patch keeps the default v2 selection in all cases except
in the KVM accelerated mode when the host does not support v2.
This case did not work anyway so we do not break any compatibility.
Now we get v3 selected in such a case. Also if the end-user explicitly
sets v2 whereas this latter is not supported, we also are
informed that v2 is not selected by thos host instead of getting the
above PMU related message.

Best Regards

Eric

This series can be found at:
https://github.com/eauger/qemu/tree/gic_version_rfc_v1


Eric Auger (2):
  target/arm/kvm: Let kvm_arm_vgic_probe() return a bitmap
  hw/arm/virt: kvm: allow gicv3 by default if host does not support v2

 hw/arm/virt.c         | 41 +++++++++++++++++++++++++++++++++++++++--
 include/hw/arm/virt.h |  1 +
 target/arm/kvm.c      | 14 ++++++++------
 target/arm/kvm_arm.h  |  3 +++
 4 files changed, 51 insertions(+), 8 deletions(-)

-- 
2.20.1