mainline inclusion
from mainline-v5.4-rc1
commit 3109741a
category: feature
feature: >256U kvm guest

-------------------------------------------------

At the moment we use 2 IO devices per GICv3 redistributor: one
one for the RD_base frame and one for the SGI_base frame.

Instead we can use a single IO device per redistributor (the 2
frames are contiguous). This saves slots on the KVM_MMIO_BUS
which is currently limited to NR_IOBUS_DEVS (1000).

This change allows to instantiate up to 512 redistributors and may
speed the guest boot with a large number of VCPUs.
Signed-off-by: NEric Auger <eric.auger@redhat.com>
Signed-off-by: NMarc Zyngier <maz@kernel.org>
Signed-off-by: NZenghui Yu <yuzenghui@huawei.com>
Reviewed-by: NHailiang Zhang <zhang.zhanghailiang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>