Re: About the instance_finalize callback in VFIO PCI

From: "Cédric Le Goater" <clg@kaod.org>
To: Yang Zhong <yang.zhong@linux.intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>, <qemu-devel@nongnu.org>
Subject: Re: About the instance_finalize callback in VFIO PCI
Date: Wed, 22 Mar 2023 13:56:13 +0100	[thread overview]
Message-ID: <62b9e8b3-a619-573d-c641-d80a12c3ab59@kaod.org> (raw)
In-Reply-To: <ZBr0dr7xPjZrn3e5@yangzhon>

On 3/22/23 13:28, Yang Zhong wrote:
> On Tue, Mar 21, 2023 at 06:30:14PM +0100, Cédric Le Goater wrote:
>> On 3/20/23 10:31, Yang Zhong wrote:
>>> Hello Alex and Paolo,
>>>
>>> There is one instance_finalize callback definition in hw/vfio/pci.c, but
>>> i find this callback(vfio_instance_finalize()) never be called during the
>>> VM shutdown with close VM or "init 0" command in guest.
>>>
>>> The Qemu related command:
>>>      ......
>>>      -device vfio-pci,host=d9:00.0
>>>      ......
>>
>> well, the finalize op is correctly called for hot unplugged devices, using
>> device_add.
>>
>     Thanks Cédric, i can use device_del command in the monitor to
>     trigger this instance_finalize callback function in the VFIO PCI.
>     thanks!

yes. I think that in the shutdown case, QEMU simply relies on exit() to
do the cleanup. On the kernel side, unmaps, fds being closed trigger any
allocated resources.

Out of curiosity, what were you trying to achieve in the finalize op ?

Thanks,

C.