ARM/ARM64: KVM: Emulate PSCI v0.2 CPU_SUSPEND (b376d02b) · Commits · 戴 / test

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 <anup.patel@linaro.org> Signed-off-by:

Pranavkumar Sawargaonkar <pranavkumar@linaro.org> Acked-by:

Christoffer Dall <christoffer.dall@linaro.org> Acked-by:

Marc Zyngier <marc.zyngier@arm.com> Signed-off-by:

Christoffer Dall <christoffer.dall@linaro.org>

arch/arm/kvm/psci.c

+24 −4

Original line number	Diff line number	Diff line
		@@ -37,6 +37,26 @@ static unsigned long psci_affinity_mask(unsigned long affinity_level)
		return 0;
		}

		static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu *vcpu)
		{
		/*
		* NOTE: For simplicity, we make VCPU suspend emulation to be
		* same-as WFI (Wait-for-interrupt) emulation.
		*
		* This means for KVM the wakeup events are interrupts and
		* this is consistent with intended use of StateID as described
		* in section 5.4.1 of PSCI v0.2 specification (ARM DEN 0022A).
		*
		* Further, we also treat power-down request to be same as
		* stand-by request as-per section 5.4.2 clause 3 of PSCI v0.2
		* specification (ARM DEN 0022A). This means all suspend states
		* for KVM will preserve the register state.
		*/
		kvm_vcpu_block(vcpu);

		return PSCI_RET_SUCCESS;
		}

		static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu)
		{
		vcpu->arch.pause = true;
		@@ -183,6 +203,10 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
		*/
		val = 2;
		break;
		case PSCI_0_2_FN_CPU_SUSPEND:
		case PSCI_0_2_FN64_CPU_SUSPEND:
		val = kvm_psci_vcpu_suspend(vcpu);
		break;
		case PSCI_0_2_FN_CPU_OFF:
		kvm_psci_vcpu_off(vcpu);
		val = PSCI_RET_SUCCESS;
		@@ -235,10 +259,6 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
		val = PSCI_RET_INTERNAL_FAILURE;
		ret = 0;
		break;
		case PSCI_0_2_FN_CPU_SUSPEND:
		case PSCI_0_2_FN64_CPU_SUSPEND:
		val = PSCI_RET_NOT_SUPPORTED;
		break;
		default:
		return -EINVAL;
		}

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