tree a9c920b5116e2d626e43d367c16911ffe80ccb00
parent e08d8d296079e8fd7eefd53f73dcafebd3a5bf9f
author Marc Zyngier <marc.zyngier@arm.com> 1541431826 +0000
committer Christoffer Dall <christoffer.dall@arm.com> 1548409328 +0100

arm64: KVM: Don't generate UNDEF when LORegion feature is present

We currently hide the LORegion feature, and generate an UNDEF
if the guest dares using the corresponding registers. This is
a bit extreme, as ARMv8.1 guarantees the feature to be present.

The guest should check the feature register before doing anything,
but we could also give the guest some slack (read "allow the
guest to be a bit stupid").

So instead of unconditionnaly deliver an exception, let's
only do it when the host doesn't support LORegion at all (or
when the feature has been sanitized out), and treat the registers
as RAZ/WI otherwise (with the exception of LORID_EL1 being RO).

Fixes: cc33c4e20185 ("arm64/kvm: Prohibit guest LOR accesses")
Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>