s390x/pci: make hot-unplug handler smoother

The current implementation of hot-unplug handler is abrupt. Any pci
operation will be just rejected if pci device is unconfigured. Thus a
pci device can not be reset or destroyed in a right, smooth and safe
way.

Improve this as follows:
- Notify the guest via a HP_EVENT_DECONFIGURE_REQUEST(0x303) event in
  the unplug handler, giving it a chance to deconfigure the device via
  sclp and allowing us to continue hot-unplug afterwards.
- Set up a timer that will generate the HP_EVENT_CONFIGURE_TO_STBRES
  (0x304) event as before if the guest did not react after an adequate
  time.

Signed-off-by: Yi Min Zhao <zyimin@linux.vnet.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/hw/s390x/s390-pci-bus.h b/hw/s390x/s390-pci-bus.h
index 71cdd7a..f1fbd3c 100644
--- a/hw/s390x/s390-pci-bus.h
+++ b/hw/s390x/s390-pci-bus.h
@@ -34,6 +34,7 @@
 #define ZPCI_MAX_UID 0xffff
 #define UID_UNDEFINED 0
 #define UID_CHECKING_ENABLED 0x01
+#define HOT_UNPLUG_TIMEOUT (NANOSECONDS_PER_SECOND * 60 * 5)
 
 #define S390_PCI_HOST_BRIDGE(obj) \
     OBJECT_CHECK(S390pciState, (obj), TYPE_S390_PCI_HOST_BRIDGE)
@@ -44,6 +45,7 @@
 
 #define HP_EVENT_TO_CONFIGURED        0x0301
 #define HP_EVENT_RESERVED_TO_STANDBY  0x0302
+#define HP_EVENT_DECONFIGURE_REQUEST  0x0303
 #define HP_EVENT_CONFIGURED_TO_STBRES 0x0304
 #define HP_EVENT_STANDBY_TO_RESERVED  0x0308
 
@@ -283,6 +285,7 @@ typedef struct S390PCIBusDevice {
     MemoryRegion iommu_mr;
     IndAddr *summary_ind;
     IndAddr *indicator;
+    QEMUTimer *release_timer;
 } S390PCIBusDevice;
 
 typedef struct S390PCIBus {