[PATCH v1 2/2] KVM: arm64: Have kvm_psci_vcpu_on() use WRITE_ONCE() to update mp_state

[Reiji Watanabe]

All accessors of kvm_vcpu_arch::mp_state should be {READ,WRITE}_ONCE(),
since readers of the mp_state don't acquire the mp_state_lock.
Nonetheless, kvm_psci_vcpu_on() updates the mp_state without using
WRITE_ONCE(). So, fix the code to update the mp_state using WRITE_ONCE.

Signed-off-by: Reiji Watanabe <reijiw at google.com>
---
 arch/arm64/kvm/psci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/psci.c b/arch/arm64/kvm/psci.c
index 5767e6baa61a..d046e82e3723 100644
--- a/arch/arm64/kvm/psci.c
+++ b/arch/arm64/kvm/psci.c
@@ -110,7 +110,7 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
 	 */
 	smp_wmb();
 
-	vcpu->arch.mp_state.mp_state = KVM_MP_STATE_RUNNABLE;
+	WRITE_ONCE(vcpu->arch.mp_state.mp_state, KVM_MP_STATE_RUNNABLE);
 	kvm_vcpu_wake_up(vcpu);
 
 out_unlock:
-- 
2.40.0.396.gfff15efe05-goog