[Qemu-ppc] [PATCH v3 7/9] xics: Implement xics_ics_free()

[Alexey Kardashevskiy]

This implements interrupt release function so IRQs can be returned back
to the pool for reuse in cases such as PCI hot plug.

Signed-off-by: Alexey Kardashevskiy <address@hidden>
---
Changes:
v3:
* xics_free() now accepts "irq" instead of server:srcno and does sanity
checks
---
 hw/intc/xics.c        | 27 +++++++++++++++++++++++++++
 include/hw/ppc/xics.h |  1 +
 trace-events          |  2 ++
 3 files changed, 30 insertions(+)

diff --git a/hw/intc/xics.c b/hw/intc/xics.c
index 0dfd173..01dbc3e 100644
--- a/hw/intc/xics.c
+++ b/hw/intc/xics.c
@@ -767,6 +767,33 @@ int xics_alloc_block(XICSState *icp, int src, int num, 
bool lsi, bool align)
     return first;
 }
 
+static void ics_free(ICSState *ics, int srcno, int num)
+{
+    int i;
+
+    for (i = srcno; i < srcno + num; ++i) {
+        if (ICS_IRQ_FREE(ics, i)) {
+            trace_xics_ics_free_warn(ics - ics->icp->ics, i + ics->offset);
+        }
+        memset(&ics->irqs[i], 0, sizeof(ICSIRQState));
+    }
+}
+
+void xics_free(XICSState *icp, int irq, int num)
+{
+    int src = xics_find_source(icp, irq);
+
+    if (src >= 0) {
+        ICSState *ics = &icp->ics[src];
+
+        /* FIXME: implement multiple sources */
+        assert(src == 0);
+
+        trace_xics_ics_free(ics - icp->ics, irq, num);
+        ics_free(ics, irq - ics->offset, num);
+    }
+}
+
 /*
  * Guest interfaces
  */
diff --git a/include/hw/ppc/xics.h b/include/hw/ppc/xics.h
index 0d8af1b..d4931f9 100644
--- a/include/hw/ppc/xics.h
+++ b/include/hw/ppc/xics.h
@@ -159,6 +159,7 @@ struct ICSIRQState {
 qemu_irq xics_get_qirq(XICSState *icp, int irq);
 int xics_alloc(XICSState *icp, int src, int irq_hint, bool lsi);
 int xics_alloc_block(XICSState *icp, int src, int num, bool lsi, bool align);
+void xics_free(XICSState *icp, int irq, int num);
 
 void xics_cpu_setup(XICSState *icp, PowerPCCPU *cpu);
 
diff --git a/trace-events b/trace-events
index f1b6571..0f9f54d 100644
--- a/trace-events
+++ b/trace-events
@@ -1186,6 +1186,8 @@ xics_alloc(int src, int irq) "source#%d, irq %d"
 xics_alloc_failed_hint(int src, int irq) "source#%d, irq %d is already in use"
 xics_alloc_failed_no_left(int src) "source#%d, no irq left"
 xics_alloc_block(int src, int first, int num, bool lsi, int align) "source#%d, 
first irq %d, %d irqs, lsi=%d, alignnum %d"
+xics_ics_free(int src, int irq, int num) "Source#%d, first irq %d, %d irqs"
+xics_ics_free_warn(int src, int irq) "Source#%d, irq %d is already free"
 
 # hw/ppc/spapr.c
 spapr_cas_failed(unsigned long n) "DT diff buffer is too small: %ld bytes"
-- 
2.0.0