[Qemu-ppc] [PATCH for-2.12 v3 06/11] spapr: store a reference IRQ bitmap

[Cédric Le Goater]

To save some state when the guest is migrated, we capture the IRQ
bitmap after all devices have been reseted and store it as a reference
for the machine.

Signed-off-by: Cédric Le Goater <address@hidden>
---

 We should probably merge this patch with the previous in the next
 versions of the patchset. For the moment, I thought it would be
 interesting to isolate the topic for discussion.

 hw/ppc/spapr.c         | 7 ++++++-
 include/hw/ppc/spapr.h | 1 +
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 4ef0b73559ca..bf0e5b4f815b 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1437,6 +1437,9 @@ static void ppc_spapr_reset(void)
     qemu_devices_reset();
     spapr_clear_pending_events(spapr);
 
+    spapr->irq_map_ref = bitmap_new(spapr->nr_irqs);
+    bitmap_copy(spapr->irq_map_ref, spapr->irq_map, spapr->nr_irqs);
+
     /*
      * We place the device tree and RTAS just below either the top of the RMA,
      * or just below 2GB, whichever is lowere, so that it can be
@@ -1683,7 +1686,9 @@ static const VMStateDescription vmstate_spapr_patb_entry 
= {
 
 static bool spapr_irq_map_needed(void *opaque)
 {
-    return true;
+    sPAPRMachineState *spapr = opaque;
+
+    return !bitmap_equal(spapr->irq_map, spapr->irq_map_ref, spapr->nr_irqs);
 }
 
 static const VMStateDescription vmstate_spapr_irq_map = {
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 5835c694caff..023436c32b2a 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -81,6 +81,7 @@ struct sPAPRMachineState {
     struct sPAPRNVRAM *nvram;
     int32_t nr_irqs;
     unsigned long *irq_map;
+    unsigned long *irq_map_ref;
     ICSState *ics;
     sPAPRRTCState rtc;
 
-- 
2.13.6