[PATCH v2] spapr/xive: Use the xics flag to check for XIVE-only IRQ backends

["Cédric Le Goater" <clg@kaod.org>]

The sPAPR machine has four different IRQ backends, each implementing
the XICS or XIVE interrupt mode or both in the case of the 'dual'
backend.

If a machine is started in P8 compat mode, QEMU should necessarily
support the XICS interrupt mode and in that case, the XIVE-only IRQ
backend is invalid. Currently, spapr_irq_check() tests the pointer
value to the IRQ backend to check for this condition, instead use the
'xics' flag. It's equivalent and it will ease the introduction of new
XIVE-only IRQ backends if needed.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
---
 hw/ppc/spapr_irq.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/ppc/spapr_irq.c b/hw/ppc/spapr_irq.c
index 80cf1c3d6bb2..d036c8fef519 100644
--- a/hw/ppc/spapr_irq.c
+++ b/hw/ppc/spapr_irq.c
@@ -172,7 +172,7 @@ static int spapr_irq_check(SpaprMachineState *spapr, Error **errp)
          * To cover both and not confuse the OS, add an early failure in
          * QEMU.
          */
-        if (spapr->irq == &spapr_irq_xive) {
+        if (!spapr->irq->xics) {
             error_setg(errp, "XIVE-only machines require a POWER9 CPU");
             return -1;
         }
-- 
2.25.4