KVM: arm64: Emulate the OS Lock

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The OS lock blocks all debug exceptions at every EL. To date, KVM has
not implemented the OS lock for its guests, despite the fact that it is
mandatory per the architecture. Simple context switching between the
guest and host is not appropriate, as its effects are not constrained to
the guest context.

Emulate the OS Lock by clearing MDE and SS in MDSCR_EL1, thereby
blocking all but software breakpoint instructions.

Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220203174159.2887882-5-oupton@google.com

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Oliver Upton 2022-02-03 17:41:57 +00:00 • committed by Marc Zyngier

parent f24adc65c5

commit 7dabf02f43

3 changed files with 29 additions and 7 deletions

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4

arch/arm64/include/asm/kvm_host.h

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26

arch/arm64/kvm/debug.c

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6

arch/arm64/kvm/sys_regs.c

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