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Date: Sun, 13 May 2012 13:54:19 +0300
From: "Michael S. Tsirkin" <mst@redhat.com>
Message-ID: <20120513105419.GA23755@redhat.com>
References: <4FACB4E4.2070708@redhat.com> <20120511145725.16518.77110.stgit@t>
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Subject: Re: [Qemu-devel] [PATCH] pci: unplug all devs of same slot once
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To: Amos Kong <akong@redhat.com>
Cc: pbonzini@redhat.com, aliguori@us.ibm.com, qemu-devel@nongnu.org

On Fri, May 11, 2012 at 10:57:25PM +0800, Amos Kong wrote:
> 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()

This is the bug IMO. PCI device delete request
through monitor simply notifies guest. It should not unparent
the object or do anything else.

> 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>
> ---

This was done as part of 57c9fafe0f759c9f1efa5451662b3627f9bb95e0.
Should we just call object_unparent before qdev_free?
Anthony?

-- 
MST