arm/arm64: KVM: Correct KVM_ARM_VCPU_INIT power off option

The implementation of KVM_ARM_VCPU_INIT is currently not doing what userspace expects, namely making sure that a vcpu which may have been turned off using PSCI is returned to its initial state, which would be powered on if userspace does not set the KVM_ARM_VCPU_POWER_OFF flag. Implement the expected functionality and clarify the ABI. Acked-by: Marc Zyngier <[email protected]> Signed-off-by: Christoffer Dall <[email protected]>
torvalds · Dec 13, 2014 · 3ad8b3d · 3ad8b3d
1 parent 03f1d4c
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diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
@@ -2455,7 +2455,8 @@ should be created before this ioctl is invoked.
 
 Possible features:
 	- KVM_ARM_VCPU_POWER_OFF: Starts the CPU in a power-off state.
-	  Depends on KVM_CAP_ARM_PSCI.
+	  Depends on KVM_CAP_ARM_PSCI.  If not set, the CPU will be powered on
+	  and execute guest code when KVM_RUN is called.
 	- KVM_ARM_VCPU_EL1_32BIT: Starts the CPU in a 32bit mode.
 	  Depends on KVM_CAP_ARM_EL1_32BIT (arm64 only).
 	- KVM_ARM_VCPU_PSCI_0_2: Emulate PSCI v0.2 for the CPU.

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
@@ -663,6 +663,8 @@ static int kvm_arch_vcpu_ioctl_vcpu_init(struct kvm_vcpu *vcpu,
 	 */
 	if (test_bit(KVM_ARM_VCPU_POWER_OFF, vcpu->arch.features))
 		vcpu->arch.pause = true;
+	else
+		vcpu->arch.pause = false;
 
 	return 0;
 }