spapr: introduce a new sPAPR IRQ backend supporting XIVE and XICS

The 'dual' sPAPR IRQ backend supports both interrupt mode, XIVE
exploitation mode and the legacy compatibility mode (XICS). both modes
are not supported at the same time.

The machine starts with the legacy mode and a new interrupt mode can
then be negotiated by the CAS process. In this case, the new mode is
activated after a reset to take into account the required changes in
the machine. These impact the device tree layout, the interrupt
presenter object and the exposed MMIO regions in the case of XIVE.

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

1 files changed, 7 insertions, 3 deletions

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 59faeccf4b..83081defde 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -2686,11 +2686,11 @@ static void spapr_machine_init(MachineState *machine)
     spapr_ovec_set(spapr->ov5, OV5_DRMEM_V2);
 
     /* advertise XIVE on POWER9 machines */
-    if (spapr->irq->ov5 & SPAPR_OV5_XIVE_EXPLOIT) {
+    if (spapr->irq->ov5 & (SPAPR_OV5_XIVE_EXPLOIT | SPAPR_OV5_XIVE_BOTH)) {
         if (ppc_type_check_compat(machine->cpu_type, CPU_POWERPC_LOGICAL_3_00,
                                   0, spapr->max_compat_pvr)) {
             spapr_ovec_set(spapr->ov5, OV5_XIVE_EXPLOIT);
-        } else {
+        } else if (spapr->irq->ov5 & SPAPR_OV5_XIVE_EXPLOIT) {
             error_report("XIVE-only machines require a POWER9 CPU");
             exit(1);
         }
@@ -3116,6 +3116,8 @@ static char *spapr_get_ic_mode(Object *obj, Error **errp)
         return g_strdup("xics");
     } else if (spapr->irq == &spapr_irq_xive) {
         return g_strdup("xive");
+    } else if (spapr->irq == &spapr_irq_dual) {
+        return g_strdup("dual");
     }
     g_assert_not_reached();
 }
@@ -3129,6 +3131,8 @@ static void spapr_set_ic_mode(Object *obj, const char *value, Error **errp)
         spapr->irq = &spapr_irq_xics;
     } else if (strcmp(value, "xive") == 0) {
         spapr->irq = &spapr_irq_xive;
+    } else if (strcmp(value, "dual") == 0) {
+        spapr->irq = &spapr_irq_dual;
     } else {
         error_setg(errp, "Bad value for \"ic-mode\" property");
     }
@@ -3177,7 +3181,7 @@ static void spapr_instance_init(Object *obj)
     object_property_add_str(obj, "ic-mode", spapr_get_ic_mode,
                             spapr_set_ic_mode, NULL);
     object_property_set_description(obj, "ic-mode",
-                 "Specifies the interrupt controller mode (xics, xive)",
+                 "Specifies the interrupt controller mode (xics, xive, dual)",
                  NULL);
 }