pcie: expire pending delete

Add an expire time for pending delete, once the time is over allow
pressing the attention button again.

This makes pcie hotplug behave more like acpi hotplug, where one can
try sending an 'device_del' monitor command again in case the guest
didn't respond to the first attempt.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-Id: <20211111130859.1171890-7-kraxel@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/pci/pcie.c

@@ -548,6 +548,8 @@ void pcie_cap_slot_unplug_request_cb(HotplugHandler *hotplug_dev,
     }
 
     dev->pending_deleted_event = true;
+    dev->pending_deleted_expires_ms =
+        qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 5000; /* 5 secs */
 
     /* In case user cancel the operation of multi-function hot-add,
      * remove the function that is unexposed to guest individually,

include/hw/qdev-core.h

@@ -181,6 +181,7 @@ struct DeviceState {
     char *canonical_path;
     bool realized;
     bool pending_deleted_event;
+    int64_t pending_deleted_expires_ms;
     QDict *opts;
     int hotplugged;
     bool allow_unplug_during_migration;

softmmu/qdev-monitor.c

@@ -943,7 +943,9 @@ void qmp_device_del(const char *id, Error **errp)
 {
     DeviceState *dev = find_device_state(id, errp);
     if (dev != NULL) {
-        if (dev->pending_deleted_event) {
+        if (dev->pending_deleted_event &&
+            (dev->pending_deleted_expires_ms == 0 ||
+             dev->pending_deleted_expires_ms > qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL))) {
             error_setg(errp, "Device %s is already in the "
                              "process of unplug", id);
             return;