[Qemu-devel] [PATCH] pci: unplug all devs of same slot once

[Amos Kong <akong@redhat.com>]

The whole PCI slot should be removed once. Currently only one func
is cleaned in pci_unplug_device(), if you try to remove a single
func by monitor cmd.

Start VM with 8 multiple-function block devs, hot-removing
those block devs by 'device_del ...' would cause qemu abort.

| (qemu) device_del virti0-0-0
| (qemu) **
|ERROR:qom/object.c:389:object_delete: assertion failed: (obj->ref == 0)

Execute 'device_del $blkid' in monitor
 \_handle_user_command()
    \_qmp_device_del()
       \_qdev_unplug()
          \_pci_unplug_device()
               | //only one obj(func) is unpluged
               v //need process funcs here
   object_unparent()
    \_object_finalize_child_property()

Guest sets pci dev by ioport write (eject from acpi)
 \_kvm_handle_io()
    \_pciej_write()
      \_acpi_piix_eject_slot()
           |
           v  //all qdevs(funcs) will be free
 QTAILQ_FOREACH_SAFE(qdev, &bus->children, sibling, next) {
     PCIDevice *dev = PCI_DEVICE(qdev);
     if (PCI_SLOT(dev->devfn) == slot) {
         qdev_free()

Signed-off-by: Amos Kong <akong@redhat.com>
---
 hw/pci.c |   34 ++++++++++++++++++++++++++--------
 1 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/hw/pci.c b/hw/pci.c
index b706e69..960cf53 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -1520,16 +1520,34 @@ static int pci_qdev_init(DeviceState *qdev)
 
 static int pci_unplug_device(DeviceState *qdev)
 {
-    PCIDevice *dev = PCI_DEVICE(qdev);
-    PCIDeviceClass *pc = PCI_DEVICE_GET_CLASS(dev);
+    DeviceState *dev, *next;
+    PCIDevice *cur;
+    int ret, slot = PCI_SLOT(PCI_DEVICE(qdev)->devfn);
+    BusState *bus = qdev->parent_bus;
+
+    ret = 0;
+    QTAILQ_FOREACH_SAFE(dev, &bus->children, sibling, next) {
+        cur = PCI_DEVICE(dev);
+
+        if (PCI_SLOT(cur->devfn) == slot) {
+            PCIDeviceClass *pc = PCI_DEVICE_GET_CLASS(cur);
+            if (pc->no_hotplug) {
+                qerror_report(QERR_DEVICE_NO_HOTPLUG,
+                              object_get_typename(OBJECT(dev)));
+                return -1;
+            }
 
-    if (pc->no_hotplug) {
-        qerror_report(QERR_DEVICE_NO_HOTPLUG, object_get_typename(OBJECT(dev)));
-        return -1;
+            object_unparent(OBJECT(cur));
+            ret = cur->bus->hotplug(cur->bus->hotplug_qdev, cur,
+                                    PCI_HOTPLUG_DISABLED);
+            if (ret < 0) {
+                qerror_report(QERR_UNDEFINED_ERROR,
+                              object_get_typename(OBJECT(dev)));
+                break;
+            }
+        }
     }
-    object_unparent(OBJECT(dev));
-    return dev->bus->hotplug(dev->bus->hotplug_qdev, dev,
-                             PCI_HOTPLUG_DISABLED);
+    return ret;
 }
 
 PCIDevice *pci_create_multifunction(PCIBus *bus, int devfn, bool multifunction,