spapr/irq: initialize the IRQ device only once

Add a check to make sure that the routine initializing the emulated
IRQ device is called once. We don't have much to test on the XICS
side, so we introduce a 'init' boolean under ICSState.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20190513084245.25755-13-clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

hw/intc/spapr_xive.c

@@ -338,6 +338,15 @@ void spapr_xive_init(SpaprXive *xive, Error **errp)
     XiveSource *xsrc = &xive->source;
     XiveENDSource *end_xsrc = &xive->end_source;
 
+    /*
+     * The emulated XIVE device can only be initialized once. If the
+     * ESB memory region has been already mapped, it means we have been
+     * through there.
+     */
+    if (memory_region_is_mapped(&xsrc->esb_mmio)) {
+        return;
+    }
+
     /* TIMA initialization */
     memory_region_init_io(&xive->tm_mmio, OBJECT(xive), &xive_tm_ops, xive,
                           "xive.tima", 4ull << TM_SHIFT);

hw/intc/xics_spapr.c

@@ -239,6 +239,13 @@ static void rtas_int_on(PowerPCCPU *cpu, SpaprMachineState *spapr,
 
 void xics_spapr_init(SpaprMachineState *spapr)
 {
+    /* Emulated mode can only be initialized once. */
+    if (spapr->ics->init) {
+        return;
+    }
+
+    spapr->ics->init = true;
+
     /* Registration of global state belongs into realize */
     spapr_rtas_register(RTAS_IBM_SET_XIVE, "ibm,set-xive", rtas_set_xive);
     spapr_rtas_register(RTAS_IBM_GET_XIVE, "ibm,get-xive", rtas_get_xive);

include/hw/ppc/xics.h

@@ -119,6 +119,7 @@ struct ICSState {
     uint32_t offset;
     ICSIRQState *irqs;
     XICSFabric *xics;
+    bool init; /* sPAPR ICS device initialized */
 };
 
 #define ICS_PROP_XICS "xics"