[PATCH 3.12 55/63] arm/arm64: KVM: Correct KVM_ARM_VCPU_INIT power off option

From: Jiri Slaby
Date: Thu Apr 30 2015 - 08:18:56 EST

From: Christoffer Dall <christoffer.dall@xxxxxxxxxx>

3.12-stable review patch. If anyone has any objections, please let me know.


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@xxxxxxx>
Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
Documentation/virtual/kvm/api.txt | 3 ++-
arch/arm/kvm/arm.c | 2 ++
2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 858aecf21db2..0d578c0f5749 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2299,7 +2299,8 @@ 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).

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 7dc8e010c200..137cee9f3fd2 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -678,6 +678,8 @@ 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;

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