spapr, xics, xive: Better use of assert()s on irq claim/free paths

The irq claim and free paths for both XICS and XIVE check for some
validity conditions.  Some of these represent genuine runtime failures,
however others - particularly checking that the basic irq number is in a
sane range - could only fail in the case of bugs in the callin code.
Therefore use assert()s instead of runtime failures for those.

In addition the non backend-specific part of the claim/free paths should
only be used for PAPR external irqs, that is in the range SPAPR_XIRQ_BASE
to the maximum irq number.  Put assert()s for that into the top level
dispatchers as well.

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

1 files changed, 10 insertions, 8 deletions

diff --git a/hw/ppc/spapr_irq.c b/hw/ppc/spapr_irq.c
index d2ac35b..025c802 100644
--- a/hw/ppc/spapr_irq.c
+++ b/hw/ppc/spapr_irq.c
@@ -118,11 +118,7 @@ static int spapr_irq_claim_xics(SpaprMachineState *spapr, int irq, bool lsi,
     ICSState *ics = spapr->ics;
 
     assert(ics);
-
-    if (!ics_valid_irq(ics, irq)) {
-        error_setg(errp, "IRQ %d is invalid", irq);
-        return -1;
-    }
+    assert(ics_valid_irq(ics, irq));
 
     if (!ics_irq_free(ics, irq - ics->offset)) {
         error_setg(errp, "IRQ %d is not free", irq);
@@ -138,9 +134,9 @@ static void spapr_irq_free_xics(SpaprMachineState *spapr, int irq)
     ICSState *ics = spapr->ics;
     uint32_t srcno = irq - ics->offset;
 
-    if (ics_valid_irq(ics, irq)) {
-        memset(&ics->irqs[srcno], 0, sizeof(ICSIRQState));
-    }
+    assert(ics_valid_irq(ics, irq));
+
+    memset(&ics->irqs[srcno], 0, sizeof(ICSIRQState));
 }
 
 static void spapr_irq_print_info_xics(SpaprMachineState *spapr, Monitor *mon)
@@ -623,6 +619,9 @@ void spapr_irq_init(SpaprMachineState *spapr, Error **errp)
 
 int spapr_irq_claim(SpaprMachineState *spapr, int irq, bool lsi, Error **errp)
 {
+    assert(irq >= SPAPR_XIRQ_BASE);
+    assert(irq < (spapr->irq->nr_xirqs + SPAPR_XIRQ_BASE));
+
     return spapr->irq->claim(spapr, irq, lsi, errp);
 }
 
@@ -630,6 +629,9 @@ void spapr_irq_free(SpaprMachineState *spapr, int irq, int num)
 {
     int i;
 
+    assert(irq >= SPAPR_XIRQ_BASE);
+    assert((irq + num) <= (spapr->irq->nr_xirqs + SPAPR_XIRQ_BASE));
+
     for (i = irq; i < (irq + num); i++) {
         spapr->irq->free(spapr, i);
     }