ARM/ARM64: KVM: Emulate PSCI v0.2 CPU_SUSPEND
ARM/ARM64: KVM: Emulate PSCI v0.2 CPU_SUSPEND

This patch adds emulation of PSCI v0.2 CPU_SUSPEND function call for
KVM ARM/ARM64. This is a CPU-level function call which can suspend
current CPU or current CPU cluster. We don't have VCPU clusters in
KVM so we only suspend the current VCPU.

The CPU_SUSPEND emulation is not tested much because currently there
is no CPUIDLE driver in Linux kernel that uses PSCI CPU_SUSPEND. The
PSCI CPU_SUSPEND implementation in ARM64 kernel was tested using a
Simple CPUIDLE driver which is not published due to unstable DT-bindings
for PSCI.
(For more info, http://lwn.net/Articles/574950/)

For simplicity, we implement CPU_SUSPEND emulation similar to WFI
(Wait-for-interrupt) emulation and we also treat power-down request
to be same as stand-by request. This is consistent with section
5.4.1 and section 5.4.2 of PSCI v0.2 specification.

Signed-off-by: Anup Patel <fb61748fec7a117698efa5f25a4808e4181391f0@linaro.org>
Signed-off-by: Pranavkumar Sawargaonkar <1deb621c9397018ae081058b4c214e0069ab898c@linaro.org>
Acked-by: Christoffer Dall <39e5ecfe2ecc327c3e39af72d8d83d1bd0709aad@linaro.org>
Acked-by: Marc Zyngier <a16cc0c82647c52d401177f8e50567df5499e36c@arm.com>
Signed-off-by: Christoffer Dall <39e5ecfe2ecc327c3e39af72d8d83d1bd0709aad@linaro.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs