KVM: x86: Move pv_unhalted check out of kvm_vcpu_has_events()

KVM: x86: Move pv_unhalted check out of kvm_vcpu_has_events()

Move pv_unhalted check out of kvm_vcpu_has_events(), check pv_unhalted
explicitly when handling PV unhalt and expose kvm_vcpu_has_events().

kvm_vcpu_has_events() returns true if pv_unhalted is set, and pv_unhalted
is only cleared on transitions to KVM_MP_STATE_RUNNABLE.  If the guest
initiates a spurious wakeup, pv_unhalted could be left set in perpetuity.
Currently, this is not problematic because kvm_vcpu_has_events() is only
called when handling PV unhalt.  However, if kvm_vcpu_has_events() is used
for other purposes in the future, it could return the unexpected results.

Export kvm_vcpu_has_events() for its usage in broader contexts.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
Message-ID: <20250222014225.897298-3-binbin.wu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>