[2/6] xive, xics: Fix reference counting on CPU objects
diff mbox series

Message ID 157184232497.3053790.5571330781863409160.stgit@bahia.lan
State New
Headers show
Series
  • ppc: Reparent the interrupt presenter
Related show

Commit Message

Greg Kurz Oct. 23, 2019, 2:52 p.m. UTC
When a VCPU gets connected to the XIVE interrupt controller, we add a
const link targetting the CPU object to the TCTX object. Similar links
are added to the ICP object when using the XICS interrupt controller.

As explained in <qom/object.h>:

 * The caller must ensure that @target stays alive as long as
 * this property exists.  In the case @target is a child of @obj,
 * this will be the case.  Otherwise, the caller is responsible for
 * taking a reference.

We're in the latter case for both XICS and XIVE. Add the missing
calls to object_ref() and object_unref().

This doesn't fix any known issue because the life cycle of the TCTX or
ICP happens to be shorter than the one of the CPU or XICS fabric, but
better safe than sorry.

Signed-off-by: Greg Kurz <groug@kaod.org>
---
 hw/intc/xics.c |    8 +++++++-
 hw/intc/xive.c |    6 +++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

Comments

David Gibson Oct. 24, 2019, 2:50 a.m. UTC | #1
On Wed, Oct 23, 2019 at 04:52:05PM +0200, Greg Kurz wrote:
> When a VCPU gets connected to the XIVE interrupt controller, we add a
> const link targetting the CPU object to the TCTX object. Similar links
> are added to the ICP object when using the XICS interrupt controller.
> 
> As explained in <qom/object.h>:
> 
>  * The caller must ensure that @target stays alive as long as
>  * this property exists.  In the case @target is a child of @obj,
>  * this will be the case.  Otherwise, the caller is responsible for
>  * taking a reference.
> 
> We're in the latter case for both XICS and XIVE. Add the missing
> calls to object_ref() and object_unref().
> 
> This doesn't fix any known issue because the life cycle of the TCTX or
> ICP happens to be shorter than the one of the CPU or XICS fabric, but
> better safe than sorry.
> 
> Signed-off-by: Greg Kurz <groug@kaod.org>

LGTM
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

> ---
>  hw/intc/xics.c |    8 +++++++-
>  hw/intc/xive.c |    6 +++++-
>  2 files changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/intc/xics.c b/hw/intc/xics.c
> index 935f325749cb..5f746079be46 100644
> --- a/hw/intc/xics.c
> +++ b/hw/intc/xics.c
> @@ -388,8 +388,10 @@ Object *icp_create(Object *cpu, const char *type, XICSFabric *xi, Error **errp)
>      obj = object_new(type);
>      object_property_add_child(cpu, type, obj, &error_abort);
>      object_unref(obj);
> +    object_ref(OBJECT(xi));
>      object_property_add_const_link(obj, ICP_PROP_XICS, OBJECT(xi),
>                                     &error_abort);
> +    object_ref(cpu);
>      object_property_add_const_link(obj, ICP_PROP_CPU, cpu, &error_abort);
>      object_property_set_bool(obj, true, "realized", &local_err);
>      if (local_err) {
> @@ -403,7 +405,11 @@ Object *icp_create(Object *cpu, const char *type, XICSFabric *xi, Error **errp)
>  
>  void icp_destroy(ICPState *icp)
>  {
> -    object_unparent(OBJECT(icp));
> +    Object *obj = OBJECT(icp);
> +
> +    object_unref(object_property_get_link(obj, ICP_PROP_CPU, &error_abort));
> +    object_unref(object_property_get_link(obj, ICP_PROP_XICS, &error_abort));
> +    object_unparent(obj);
>  }
>  
>  /*
> diff --git a/hw/intc/xive.c b/hw/intc/xive.c
> index 38257aa02083..952a461d5329 100644
> --- a/hw/intc/xive.c
> +++ b/hw/intc/xive.c
> @@ -682,6 +682,7 @@ Object *xive_tctx_create(Object *cpu, XiveRouter *xrtr, Error **errp)
>      obj = object_new(TYPE_XIVE_TCTX);
>      object_property_add_child(cpu, TYPE_XIVE_TCTX, obj, &error_abort);
>      object_unref(obj);
> +    object_ref(cpu);
>      object_property_add_const_link(obj, "cpu", cpu, &error_abort);
>      object_property_set_bool(obj, true, "realized", &local_err);
>      if (local_err) {
> @@ -698,7 +699,10 @@ error:
>  
>  void xive_tctx_destroy(XiveTCTX *tctx)
>  {
> -    object_unparent(OBJECT(tctx));
> +    Object *obj = OBJECT(tctx);
> +
> +    object_unref(object_property_get_link(obj, "cpu", &error_abort));
> +    object_unparent(obj);
>  }
>  
>  /*
>

Patch
diff mbox series

diff --git a/hw/intc/xics.c b/hw/intc/xics.c
index 935f325749cb..5f746079be46 100644
--- a/hw/intc/xics.c
+++ b/hw/intc/xics.c
@@ -388,8 +388,10 @@  Object *icp_create(Object *cpu, const char *type, XICSFabric *xi, Error **errp)
     obj = object_new(type);
     object_property_add_child(cpu, type, obj, &error_abort);
     object_unref(obj);
+    object_ref(OBJECT(xi));
     object_property_add_const_link(obj, ICP_PROP_XICS, OBJECT(xi),
                                    &error_abort);
+    object_ref(cpu);
     object_property_add_const_link(obj, ICP_PROP_CPU, cpu, &error_abort);
     object_property_set_bool(obj, true, "realized", &local_err);
     if (local_err) {
@@ -403,7 +405,11 @@  Object *icp_create(Object *cpu, const char *type, XICSFabric *xi, Error **errp)
 
 void icp_destroy(ICPState *icp)
 {
-    object_unparent(OBJECT(icp));
+    Object *obj = OBJECT(icp);
+
+    object_unref(object_property_get_link(obj, ICP_PROP_CPU, &error_abort));
+    object_unref(object_property_get_link(obj, ICP_PROP_XICS, &error_abort));
+    object_unparent(obj);
 }
 
 /*
diff --git a/hw/intc/xive.c b/hw/intc/xive.c
index 38257aa02083..952a461d5329 100644
--- a/hw/intc/xive.c
+++ b/hw/intc/xive.c
@@ -682,6 +682,7 @@  Object *xive_tctx_create(Object *cpu, XiveRouter *xrtr, Error **errp)
     obj = object_new(TYPE_XIVE_TCTX);
     object_property_add_child(cpu, TYPE_XIVE_TCTX, obj, &error_abort);
     object_unref(obj);
+    object_ref(cpu);
     object_property_add_const_link(obj, "cpu", cpu, &error_abort);
     object_property_set_bool(obj, true, "realized", &local_err);
     if (local_err) {
@@ -698,7 +699,10 @@  error:
 
 void xive_tctx_destroy(XiveTCTX *tctx)
 {
-    object_unparent(OBJECT(tctx));
+    Object *obj = OBJECT(tctx);
+
+    object_unref(object_property_get_link(obj, "cpu", &error_abort));
+    object_unparent(obj);
 }
 
 /*