[Qemu-devel] [PATCH 1/2] spapr/xive: fix multiple resets when using the 'dual' interrupt mode

["Cédric Le Goater" <clg@kaod.org>]

Today, when a reset occurs on a pseries machine using the 'dual'
interrupt mode, the KVM devices are released and recreated depending
on the interrupt mode selected by CAS. If XIVE is selected, the SysBus
memory regions of the SpaprXive model are initialized by the KVM
backend initialization routine each time a reset occurs. This leads to
a crash after a couple of resets because the machine reaches the
QDEV_MAX_MMIO limit of SysBusDevice :

qemu-system-ppc64: hw/core/sysbus.c:193: sysbus_init_mmio: Assertion `dev->num_mmio < QDEV_MAX_MMIO' failed.

To fix, initialize the SysBus memory regions in spapr_xive_realize()
called only once and remove the same inits from the QEMU and KVM
backend initialization routines which are called at each reset.

Reported-by: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
---
 hw/intc/spapr_xive.c     | 11 +++++------
 hw/intc/spapr_xive_kvm.c |  4 ----
 2 files changed, 5 insertions(+), 10 deletions(-)

diff --git a/hw/intc/spapr_xive.c b/hw/intc/spapr_xive.c
index f6f6c29d6ae4..62e0ef8fa5b4 100644
--- a/hw/intc/spapr_xive.c
+++ b/hw/intc/spapr_xive.c
@@ -331,12 +331,16 @@ static void spapr_xive_realize(DeviceState *dev, Error **errp)
                            xive->tm_base + XIVE_TM_USER_PAGE * (1 << TM_SHIFT));
 
     qemu_register_reset(spapr_xive_reset, dev);
+
+    /* Define all XIVE MMIO regions on SysBus */
+    sysbus_init_mmio(SYS_BUS_DEVICE(xive), &xsrc->esb_mmio);
+    sysbus_init_mmio(SYS_BUS_DEVICE(xive), &end_xsrc->esb_mmio);
+    sysbus_init_mmio(SYS_BUS_DEVICE(xive), &xive->tm_mmio);
 }
 
 void spapr_xive_init(SpaprXive *xive, Error **errp)
 {
     XiveSource *xsrc = &xive->source;
-    XiveENDSource *end_xsrc = &xive->end_source;
 
     /*
      * The emulated XIVE device can only be initialized once. If the
@@ -351,11 +355,6 @@ void spapr_xive_init(SpaprXive *xive, Error **errp)
     memory_region_init_io(&xive->tm_mmio, OBJECT(xive), &xive_tm_ops, xive,
                           "xive.tima", 4ull << TM_SHIFT);
 
-    /* Define all XIVE MMIO regions on SysBus */
-    sysbus_init_mmio(SYS_BUS_DEVICE(xive), &xsrc->esb_mmio);
-    sysbus_init_mmio(SYS_BUS_DEVICE(xive), &end_xsrc->esb_mmio);
-    sysbus_init_mmio(SYS_BUS_DEVICE(xive), &xive->tm_mmio);
-
     /* Map all regions */
     spapr_xive_map_mmio(xive);
 }
diff --git a/hw/intc/spapr_xive_kvm.c b/hw/intc/spapr_xive_kvm.c
index ec170b304555..b48f135838f2 100644
--- a/hw/intc/spapr_xive_kvm.c
+++ b/hw/intc/spapr_xive_kvm.c
@@ -693,7 +693,6 @@ static void *kvmppc_xive_mmap(SpaprXive *xive, int pgoff, size_t len,
 void kvmppc_xive_connect(SpaprXive *xive, Error **errp)
 {
     XiveSource *xsrc = &xive->source;
-    XiveENDSource *end_xsrc = &xive->end_source;
     Error *local_err = NULL;
     size_t esb_len = (1ull << xsrc->esb_shift) * xsrc->nr_irqs;
     size_t tima_len = 4ull << TM_SHIFT;
@@ -731,12 +730,10 @@ void kvmppc_xive_connect(SpaprXive *xive, Error **errp)
 
     memory_region_init_ram_device_ptr(&xsrc->esb_mmio, OBJECT(xsrc),
                                       "xive.esb", esb_len, xsrc->esb_mmap);
-    sysbus_init_mmio(SYS_BUS_DEVICE(xive), &xsrc->esb_mmio);
 
     /*
      * 2. END ESB pages (No KVM support yet)
      */
-    sysbus_init_mmio(SYS_BUS_DEVICE(xive), &end_xsrc->esb_mmio);
 
     /*
      * 3. TIMA pages - KVM mapping
@@ -749,7 +746,6 @@ void kvmppc_xive_connect(SpaprXive *xive, Error **errp)
     }
     memory_region_init_ram_device_ptr(&xive->tm_mmio, OBJECT(xive),
                                       "xive.tima", tima_len, xive->tm_mmap);
-    sysbus_init_mmio(SYS_BUS_DEVICE(xive), &xive->tm_mmio);
 
     xive->change = qemu_add_vm_change_state_handler(
         kvmppc_xive_change_state_handler, xive);
-- 
2.20.1