Commit 4b123826 authored by Anup Patel's avatar Anup Patel Committed by Christoffer Dall
Browse files

ARM/ARM64: KVM: Emulate PSCI v0.2 SYSTEM_OFF and SYSTEM_RESET 



The PSCI v0.2 SYSTEM_OFF and SYSTEM_RESET functions are system-level
functions hence cannot be fully emulated by in-kernel PSCI emulation code.

To tackle this, we forward PSCI v0.2 SYSTEM_OFF and SYSTEM_RESET function
calls from vcpu to user space (i.e. QEMU or KVMTOOL) via kvm_run structure
using KVM_EXIT_SYSTEM_EVENT exit reasons.

Signed-off-by: default avatarAnup Patel <anup.patel@linaro.org>
Signed-off-by: default avatarPranavkumar Sawargaonkar <pranavkumar@linaro.org>
Reviewed-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
Acked-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
parent 8ad6b634

arch/arm/kvm/psci.c

+43 −3
Original line number Diff line number Diff line
@@ -85,6 +85,23 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu) 
	return PSCI_RET_SUCCESS;

}



static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type)

{

	memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));

	vcpu->run->system_event.type = type;

	vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;

}



static void kvm_psci_system_off(struct kvm_vcpu *vcpu)

{

	kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN);

}



static void kvm_psci_system_reset(struct kvm_vcpu *vcpu)

{

	kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET);

}



int kvm_psci_version(struct kvm_vcpu *vcpu)

{

	if (test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features))
@@ -95,6 +112,7 @@ int kvm_psci_version(struct kvm_vcpu *vcpu) 


static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)

{

	int ret = 1;

	unsigned long psci_fn = *vcpu_reg(vcpu, 0) & ~((u32) 0);

	unsigned long val;
@@ -114,13 +132,35 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu) 
	case PSCI_0_2_FN64_CPU_ON:

		val = kvm_psci_vcpu_on(vcpu);

		break;

	case PSCI_0_2_FN_SYSTEM_OFF:

		kvm_psci_system_off(vcpu);

		/*

		 * We should'nt be going back to guest VCPU after

		 * receiving SYSTEM_OFF request.

		 *

		 * If user space accidently/deliberately resumes

		 * guest VCPU after SYSTEM_OFF request then guest

		 * VCPU should see internal failure from PSCI return

		 * value. To achieve this, we preload r0 (or x0) with

		 * PSCI return value INTERNAL_FAILURE.

		 */

		val = PSCI_RET_INTERNAL_FAILURE;

		ret = 0;

		break;

	case PSCI_0_2_FN_SYSTEM_RESET:

		kvm_psci_system_reset(vcpu);

		/*

		 * Same reason as SYSTEM_OFF for preloading r0 (or x0)

		 * with PSCI return value INTERNAL_FAILURE.

		 */

		val = PSCI_RET_INTERNAL_FAILURE;

		ret = 0;

		break;

	case PSCI_0_2_FN_CPU_SUSPEND:

	case PSCI_0_2_FN_AFFINITY_INFO:

	case PSCI_0_2_FN_MIGRATE:

	case PSCI_0_2_FN_MIGRATE_INFO_TYPE:

	case PSCI_0_2_FN_MIGRATE_INFO_UP_CPU:

	case PSCI_0_2_FN_SYSTEM_OFF:

	case PSCI_0_2_FN_SYSTEM_RESET:

	case PSCI_0_2_FN64_CPU_SUSPEND:

	case PSCI_0_2_FN64_AFFINITY_INFO:

	case PSCI_0_2_FN64_MIGRATE:
@@ -132,7 +172,7 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu) 
	}



	*vcpu_reg(vcpu, 0) = val;

	return 1;

	return ret;

}



static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu)

CRA Git | Maintained and supported by SUSTech CRA and CCSE