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[1/5] spapr: Remove 'awaiting_allocation' DRC flag

Message ID 20170621091848.28256-2-david@gibson.dropbear.id.au
State New, archived
Headers show

Commit Message

David Gibson June 21, 2017, 9:18 a.m. UTC
The awaiting_allocation flag in the DRC was introduced by aab9913
"spapr_drc: Prevent detach racing against attach for CPU DR", allegedly to
prevent a guest crash on racing attach and detach.  Except.. information
from the BZ actually suggests a qemu crash, not a guest crash.  And there
shouldn't be a problem here anyway: if the guest has already moved the DRC
away from UNUSABLE state, the detach would already be deferred, and if it
hadn't it should be safe to detach it (the guest should fail gracefully
when it attempts to change the allocation state).

I think this was probably just a bandaid for some other problem in the
state management.  So, remove awaiting_allocation and associated code.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 hw/ppc/spapr_drc.c         | 23 +++--------------------
 include/hw/ppc/spapr_drc.h |  1 -
 2 files changed, 3 insertions(+), 21 deletions(-)
diff mbox

Patch

diff --git a/hw/ppc/spapr_drc.c b/hw/ppc/spapr_drc.c
index f34355d..59e19f8 100644
--- a/hw/ppc/spapr_drc.c
+++ b/hw/ppc/spapr_drc.c
@@ -170,19 +170,13 @@  static uint32_t drc_set_usable(sPAPRDRConnector *drc)
     if (!drc->dev) {
         return RTAS_OUT_NO_SUCH_INDICATOR;
     }
-    if (drc->awaiting_release && drc->awaiting_allocation) {
-        /* kernel is acknowledging a previous hotplug event
-         * while we are already removing it.
-         * it's safe to ignore awaiting_allocation here since we know the
-         * situation is predicated on the guest either already having done
-         * so (boot-time hotplug), or never being able to acquire in the
-         * first place (hotplug followed by immediate unplug).
-         */
+    if (drc->awaiting_release) {
+        /* Don't allow the guest to move a device away from UNUSABLE
+         * state when we want to unplug it */
         return RTAS_OUT_NO_SUCH_INDICATOR;
     }
 
     drc->allocation_state = SPAPR_DR_ALLOCATION_STATE_USABLE;
-    drc->awaiting_allocation = false;
 
     return RTAS_OUT_SUCCESS;
 }
@@ -357,10 +351,6 @@  void spapr_drc_attach(sPAPRDRConnector *drc, DeviceState *d, void *fdt,
     drc->fdt = fdt;
     drc->fdt_start_offset = fdt_start_offset;
 
-    if (spapr_drc_type(drc) != SPAPR_DR_CONNECTOR_TYPE_PCI) {
-        drc->awaiting_allocation = true;
-    }
-
     object_property_add_link(OBJECT(drc), "device",
                              object_get_typename(OBJECT(drc->dev)),
                              (Object **)(&drc->dev),
@@ -398,12 +388,6 @@  void spapr_drc_detach(sPAPRDRConnector *drc, DeviceState *d, Error **errp)
         return;
     }
 
-    if (drc->awaiting_allocation) {
-        drc->awaiting_release = true;
-        trace_spapr_drc_awaiting_allocation(spapr_drc_index(drc));
-        return;
-    }
-
     spapr_drc_release(drc);
 }
 
@@ -490,7 +474,6 @@  static const VMStateDescription vmstate_spapr_drc = {
         VMSTATE_UINT32(dr_indicator, sPAPRDRConnector),
         VMSTATE_BOOL(configured, sPAPRDRConnector),
         VMSTATE_BOOL(awaiting_release, sPAPRDRConnector),
-        VMSTATE_BOOL(awaiting_allocation, sPAPRDRConnector),
         VMSTATE_END_OF_LIST()
     }
 };
diff --git a/include/hw/ppc/spapr_drc.h b/include/hw/ppc/spapr_drc.h
index d15e9eb..42c3722 100644
--- a/include/hw/ppc/spapr_drc.h
+++ b/include/hw/ppc/spapr_drc.h
@@ -199,7 +199,6 @@  typedef struct sPAPRDRConnector {
     sPAPRConfigureConnectorState *ccs;
 
     bool awaiting_release;
-    bool awaiting_allocation;
 
     /* device pointer, via link property */
     DeviceState *dev;