KVM: arm64: Workaround firmware wrongly advertising GICv2-on-v3 compatibility

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It looks like we have broken firmware out there that wrongly advertises
a GICv2 compatibility interface, despite the CPUs not being able to deal
with it.

To work around this, check that the CPU initialising KVM is actually able
to switch to MMIO instead of system registers, and use that as a
precondition to enable GICv2 compatibility in KVM.

Note that the detection happens on a single CPU. If the firmware is
lying *and* that the CPUs are asymetric, all hope is lost anyway.

Reported-by: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Message-Id: <20210305185254.3730990-8-maz@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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This commit is contained in:

Marc Zyngier 2021-03-05 18:52:53 +00:00 • committed by Paolo Bonzini

parent b9d699e269

commit 9739f6ef05

2 changed files with 39 additions and 4 deletions

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35

arch/arm64/kvm/hyp/vgic-v3-sr.c

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8

arch/arm64/kvm/vgic/vgic-v3.c

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