In a live migration scenario. If the number of VFs at the
destination is greater than the source, the recovery operation
will fail and qemu will not be able to complete the process and
exit after shutting down the device FD.

This will cause the driver to be unable to be unloaded normally due
to abnormal reference counting of the live migration driver caused
by the abnormal closing operation of fd.

Fixes: b0eed085903e ("hisi_acc_vfio_pci: Add support for VFIO live migration")
Signed-off-by: Longfang Liu <liulongfang@huawei.com>
Reviewed-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
---
 drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
index d96446f499ed..cadc82419dca 100644
--- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
+++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
@@ -1508,6 +1508,7 @@ static void hisi_acc_vfio_pci_close_device(struct vfio_device *core_vdev)
 	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(core_vdev);
 	struct hisi_qm *vf_qm = &hisi_acc_vdev->vf_qm;
 
+	hisi_acc_vf_disable_fds(hisi_acc_vdev);
 	mutex_lock(&hisi_acc_vdev->open_mutex);
 	hisi_acc_vdev->dev_opened = false;
 	iounmap(vf_qm->io_base);
-- 
2.24.0

On Tue, 18 Mar 2025 14:45:47 +0800
Longfang Liu <liulongfang@huawei.com> wrote:

> In a live migration scenario. If the number of VFs at the
> destination is greater than the source, the recovery operation
> will fail and qemu will not be able to complete the process and
> exit after shutting down the device FD.
> 
> This will cause the driver to be unable to be unloaded normally due
> to abnormal reference counting of the live migration driver caused
> by the abnormal closing operation of fd.

"Therefore, make sure the migration file descriptor references are
 always released when the device is closed."

The commit log identifies the problem, but it's generally also useful
to describe the resolution of the problem as well.  Thanks,

Alex

> Fixes: b0eed085903e ("hisi_acc_vfio_pci: Add support for VFIO live migration")
> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
> Reviewed-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> ---
>  drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> index d96446f499ed..cadc82419dca 100644
> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> @@ -1508,6 +1508,7 @@ static void hisi_acc_vfio_pci_close_device(struct vfio_device *core_vdev)
>  	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(core_vdev);
>  	struct hisi_qm *vf_qm = &hisi_acc_vdev->vf_qm;
>  
> +	hisi_acc_vf_disable_fds(hisi_acc_vdev);
>  	mutex_lock(&hisi_acc_vdev->open_mutex);
>  	hisi_acc_vdev->dev_opened = false;
>  	iounmap(vf_qm->io_base);

On 2025/3/21 23:51, Alex Williamson wrote:
> On Tue, 18 Mar 2025 14:45:47 +0800
> Longfang Liu <liulongfang@huawei.com> wrote:
> 
>> In a live migration scenario. If the number of VFs at the
>> destination is greater than the source, the recovery operation
>> will fail and qemu will not be able to complete the process and
>> exit after shutting down the device FD.
>>
>> This will cause the driver to be unable to be unloaded normally due
>> to abnormal reference counting of the live migration driver caused
>> by the abnormal closing operation of fd.
> 
> "Therefore, make sure the migration file descriptor references are
>  always released when the device is closed."
> 
> The commit log identifies the problem, but it's generally also useful
> to describe the resolution of the problem as well.  Thanks,
>

Okay, I will add these descriptions in the next release patchset.

Thanks.
Longfang.

> Alex
> 
>> Fixes: b0eed085903e ("hisi_acc_vfio_pci: Add support for VFIO live migration")
>> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
>> Reviewed-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
>> ---
>>  drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
>> index d96446f499ed..cadc82419dca 100644
>> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
>> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
>> @@ -1508,6 +1508,7 @@ static void hisi_acc_vfio_pci_close_device(struct vfio_device *core_vdev)
>>  	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(core_vdev);
>>  	struct hisi_qm *vf_qm = &hisi_acc_vdev->vf_qm;
>>  
>> +	hisi_acc_vf_disable_fds(hisi_acc_vdev);
>>  	mutex_lock(&hisi_acc_vdev->open_mutex);
>>  	hisi_acc_vdev->dev_opened = false;
>>  	iounmap(vf_qm->io_base);
> 
> 
> .
>