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spapr_drc: Prevent detach racing against attach for CPU DR

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If a CPU is hot removed while hotplug of the same is still in progress,
the guest crashes. Prevent this by ensuring that detach is done only
after attach has completed.

The existing code already prevents such race for PCI hotplug. However
given that CPU is a logical DR unlike PCI and starts with ISOLATED
state, we need a logic that works for CPU too.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
               [Don't set awaiting_attach for PCI devices]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This commit is contained in:
Bharata B Rao 2016-05-12 09:18:21 +05:30 • committed by David Gibson
parent 4a4b344c7c
commit aab99135b6
2 changed files with 13 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

12
hw/ppc/spapr_drc.c
View file

@ -140,6 +140,8 @@ static uint32_t set_allocation_state(sPAPRDRConnector *drc,
DPRINTFN("finalizing device removal"); DPRINTFN("finalizing device removal");
drck->detach(drc, DEVICE(drc->dev), drc->detach_cb, drck->detach(drc, DEVICE(drc->dev), drc->detach_cb,
drc->detach_cb_opaque, NULL); drc->detach_cb_opaque, NULL);
} else if (drc->allocation_state == SPAPR_DR_ALLOCATION_STATE_USABLE) {
drc->awaiting_allocation = false;
} }
} }
return RTAS_OUT_SUCCESS; return RTAS_OUT_SUCCESS;
@ -373,6 +375,10 @@ static void attach(sPAPRDRConnector *drc, DeviceState *d, void *fdt,
drc->signalled = (drc->type != SPAPR_DR_CONNECTOR_TYPE_PCI) drc->signalled = (drc->type != SPAPR_DR_CONNECTOR_TYPE_PCI)
? true : coldplug; ? true : coldplug;
if (drc->type != SPAPR_DR_CONNECTOR_TYPE_PCI) {
drc->awaiting_allocation = true;
}
object_property_add_link(OBJECT(drc), "device", object_property_add_link(OBJECT(drc), "device",
object_get_typename(OBJECT(drc->dev)), object_get_typename(OBJECT(drc->dev)),
(Object **)(&drc->dev), (Object **)(&drc->dev),
@ -421,6 +427,12 @@ static void detach(sPAPRDRConnector *drc, DeviceState *d,
return; return;
} }
if (drc->awaiting_allocation) {
drc->awaiting_release = true;
DPRINTFN("awaiting allocation to complete before removal");
return;
}
drc->indicator_state = SPAPR_DR_INDICATOR_STATE_INACTIVE; drc->indicator_state = SPAPR_DR_INDICATOR_STATE_INACTIVE;
if (drc->detach_cb) { if (drc->detach_cb) {

1
include/hw/ppc/spapr_drc.h
View file

@ -152,6 +152,7 @@ typedef struct sPAPRDRConnector {
bool awaiting_release; bool awaiting_release;
bool signalled; bool signalled;
bool awaiting_allocation;
/* device pointer, via link property */ /* device pointer, via link property */
DeviceState *dev; DeviceState *dev;