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

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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: cc33c4e201 ("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>

...

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Marc Zyngier 2018-11-05 15:30:26 +00:00 • committed by Christoffer Dall

parent e08d8d2960

commit 2292552102

1 changed files with 27 additions and 15 deletions

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arch/arm64/kvm/sys_regs.c

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