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authorMark Rutland <mark.rutland@arm.com>2017-02-20 12:30:11 +0000
committerMarc Zyngier <marc.zyngier@arm.com>2017-03-07 14:50:45 +0000
commitf050fe7a9164945dd1c28be05bf00e8cfb082ccf (patch)
treea5b6a432b0371828356fd8e56ef71e488e1467a2 /arch/arm64/kvm/handle_exit.c
parentKVM: arm/arm64: Let vcpu thread modify its own active state (diff)
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arm: KVM: Survive unknown traps from guests
Currently we BUG() if we see a HSR.EC value we don't recognise. As configurable disables/enables are added to the architecture (controlled by RES1/RES0 bits respectively), with associated synchronous exceptions, it may be possible for a guest to trigger exceptions with classes that we don't recognise. While we can't service these exceptions in a manner useful to the guest, we can avoid bringing down the host. Per ARM DDI 0406C.c, all currently unallocated HSR EC encodings are reserved, and per ARM DDI 0487A.k_iss10775, page G6-4395, EC values within the range 0x00 - 0x2c are reserved for future use with synchronous exceptions, and EC values within the range 0x2d - 0x3f may be used for either synchronous or asynchronous exceptions. The patch makes KVM handle any unknown EC by injecting an UNDEFINED exception into the guest, with a corresponding (ratelimited) warning in the host dmesg. We could later improve on this with with a new (opt-in) exit to the host userspace. Cc: Dave Martin <dave.martin@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
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