arm/arm64: KVM: Correct KVM_ARM_VCPU_INIT power off option

commit 3ad8b3de526a76fbe9466b366059e4958957b88f upstream.

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 <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 612e6e99d1e572239e12dc01587635bb8ca39b77..769c2cb7f9b302ac303f8b9ed17d469941039941 100644 (file)
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2382,7 +2382,8 @@ 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
index b38acec6c91827f9915e238f48389c4b78f82226..01c0511709e3c801030a41311924e4368d8f6007 100644 (file)
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -681,6 +681,8 @@ 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;
 }