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[PULL 11/22] spapr: Fix reset of transient DR connectors
From: |
David Gibson |
Subject: |
[PULL 11/22] spapr: Fix reset of transient DR connectors |
Date: |
Wed, 6 Jan 2021 14:38:05 +1100 |
From: Greg Kurz <groug@kaod.org>
Documentation of object_property_iter_init() clearly stipulates that
"it is forbidden to modify the property list while iterating". But this
is exactly what we do when resetting transient DR connectors during CAS.
The call to spapr_drc_reset() can finalize the hot-unplug sequence of a
PHB or a PCI bridge, both of which will then in turn destroy their PCI
DRCs. This could potentially invalidate the iterator. It is pure luck
that this haven't caused any issues so far.
Change spapr_drc_reset() to return true if it caused a device to be
removed. Restart from scratch in this case. This can potentially
increase the overall DRC reset time, especially with a high maxmem
which generates a lot of LMB DRCs. But this kind of setup is rare,
and so is the use case of rebooting a guest while doing hot-unplug.
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <20201218103400.689660-3-groug@kaod.org>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Tested-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
hw/ppc/spapr_drc.c | 6 +++++-
hw/ppc/spapr_hcall.c | 8 +++++++-
include/hw/ppc/spapr_drc.h | 3 ++-
3 files changed, 14 insertions(+), 3 deletions(-)
diff --git a/hw/ppc/spapr_drc.c b/hw/ppc/spapr_drc.c
index 8d62f55066..5b5e2ac58a 100644
--- a/hw/ppc/spapr_drc.c
+++ b/hw/ppc/spapr_drc.c
@@ -417,9 +417,10 @@ void spapr_drc_detach(SpaprDrc *drc)
spapr_drc_release(drc);
}
-void spapr_drc_reset(SpaprDrc *drc)
+bool spapr_drc_reset(SpaprDrc *drc)
{
SpaprDrcClass *drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
+ bool unplug_completed = false;
trace_spapr_drc_reset(spapr_drc_index(drc));
@@ -428,6 +429,7 @@ void spapr_drc_reset(SpaprDrc *drc)
*/
if (drc->unplug_requested) {
spapr_drc_release(drc);
+ unplug_completed = true;
}
if (drc->dev) {
@@ -444,6 +446,8 @@ void spapr_drc_reset(SpaprDrc *drc)
drc->ccs_offset = -1;
drc->ccs_depth = -1;
}
+
+ return unplug_completed;
}
static bool spapr_drc_unplug_requested_needed(void *opaque)
diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
index 4e9d50c254..aa22830ac4 100644
--- a/hw/ppc/spapr_hcall.c
+++ b/hw/ppc/spapr_hcall.c
@@ -1639,6 +1639,7 @@ static void
spapr_handle_transient_dev_before_cas(SpaprMachineState *spapr)
ObjectPropertyIterator iter;
drc_container = container_get(object_get_root(), "/dr-connector");
+restart:
object_property_iter_init(&iter, drc_container);
while ((prop = object_property_iter_next(&iter))) {
SpaprDrc *drc;
@@ -1652,8 +1653,13 @@ static void
spapr_handle_transient_dev_before_cas(SpaprMachineState *spapr)
/*
* This will complete any pending plug/unplug requests.
+ * In case of a unplugged PHB or PCI bridge, this will
+ * cause some DRCs to be destroyed and thus potentially
+ * invalidate the iterator.
*/
- spapr_drc_reset(drc);
+ if (spapr_drc_reset(drc)) {
+ goto restart;
+ }
}
spapr_clear_pending_hotplug_events(spapr);
diff --git a/include/hw/ppc/spapr_drc.h b/include/hw/ppc/spapr_drc.h
index cff5e707d0..5d80019f82 100644
--- a/include/hw/ppc/spapr_drc.h
+++ b/include/hw/ppc/spapr_drc.h
@@ -224,7 +224,8 @@ static inline bool spapr_drc_hotplugged(DeviceState *dev)
return dev->hotplugged && !runstate_check(RUN_STATE_INMIGRATE);
}
-void spapr_drc_reset(SpaprDrc *drc);
+/* Returns true if an unplug request completed */
+bool spapr_drc_reset(SpaprDrc *drc);
uint32_t spapr_drc_index(SpaprDrc *drc);
SpaprDrcType spapr_drc_type(SpaprDrc *drc);
--
2.29.2
- [PULL 00/22] ppc-for-6.0 queue 20210106, David Gibson, 2021/01/05
- [PULL 04/22] hw/ppc/ppc440_bamboo: Drop use of ppcuic_init(), David Gibson, 2021/01/05
- [PULL 03/22] hw/ppc/virtex_ml507: Drop use of ppcuic_init(), David Gibson, 2021/01/05
- [PULL 02/22] ppc: Convert PPC UIC to a QOM device, David Gibson, 2021/01/05
- [PULL 01/22] hw/ppc/ppc4xx_devs: Make code style fixes to UIC code, David Gibson, 2021/01/05
- [PULL 06/22] spapr/xive: Make spapr_xive_pic_print_info() static, David Gibson, 2021/01/05
- [PULL 05/22] spapr: DRC lookup cannot fail, David Gibson, 2021/01/05
- [PULL 09/22] spapr: Fix buffer overflow in spapr_numa_associativity_init(), David Gibson, 2021/01/05
- [PULL 11/22] spapr: Fix reset of transient DR connectors,
David Gibson <=
- [PULL 12/22] spapr: Introduce spapr_drc_reset_all(), David Gibson, 2021/01/05
- [PULL 08/22] spapr: Allow memory unplug to always succeed, David Gibson, 2021/01/05
- [PULL 13/22] spapr: Use spapr_drc_reset_all() at machine reset, David Gibson, 2021/01/05
- [PULL 14/22] spapr: Add drc_ prefix to the DRC realize and unrealize functions, David Gibson, 2021/01/05
- [PULL 15/22] ppc: Fix build with --without-default-devices, David Gibson, 2021/01/05
- [PULL 16/22] ppc: Simplify reverse dependencies of POWERNV and PSERIES on XICS and XIVE, David Gibson, 2021/01/05
- [PULL 07/22] spapr: Fix DR properties of the root node, David Gibson, 2021/01/05
- [PULL 10/22] spapr: Call spapr_drc_reset() for all DRCs at CAS, David Gibson, 2021/01/05
- [PULL 20/22] ppc440_pcix: Improve comment for IRQ mapping, David Gibson, 2021/01/05
- [PULL 19/22] sam460ex: Remove FDT_PPC dependency from KConfig, David Gibson, 2021/01/05