Commit a0d7215e33 ("vhost-vdpa: do not cleanup the vdpa/vhost-net
structures if peer nic is present") effectively delayed the backend
cleanup, allowing the frontend or the guest to access it resources as
long as the frontend NIC is still visible to the guest.

However it does not clean up the resources until the qemu process is
over.  This causes an effective leak if the device is deleted with
device_del, as there is no way to close the vdpa device.  This makes
impossible to re-add that device to this or other QEMU instances until
the first instance of QEMU is finished.

Move the cleanup from qemu_cleanup to the NIC deletion.

v3:
Remove shadowed declaration of NetClientState nc variable in 2/2.

v2:
Remove NIC peer also at net_cleanup. vhost-user trust all the
backends are clean before qemu removes char devices.

This is not a requisite introduced by this commit as
system/runstate.c:qemu_cleanup shows.

Eugenio Pérez (2):
  net: parameterize the removing client from nc list
  net: move backend cleanup to NIC cleanup

 net/net.c        | 44 ++++++++++++++++++++++++++++++++++----------
 net/vhost-vdpa.c |  8 --------
 2 files changed, 34 insertions(+), 18 deletions(-)

-- 
2.43.5

On Mon, Jan 6, 2025 at 11:58 PM Jonah Palmer <jonah.palmer@oracle.com> wrote:
>
> Commit a0d7215e33 ("vhost-vdpa: do not cleanup the vdpa/vhost-net
> structures if peer nic is present") effectively delayed the backend
> cleanup, allowing the frontend or the guest to access it resources as
> long as the frontend NIC is still visible to the guest.
>
> However it does not clean up the resources until the qemu process is
> over.  This causes an effective leak if the device is deleted with
> device_del, as there is no way to close the vdpa device.  This makes
> impossible to re-add that device to this or other QEMU instances until
> the first instance of QEMU is finished.
>
> Move the cleanup from qemu_cleanup to the NIC deletion.
>
> v3:
> Remove shadowed declaration of NetClientState nc variable in 2/2.
>
> v2:
> Remove NIC peer also at net_cleanup. vhost-user trust all the
> backends are clean before qemu removes char devices.
>
> This is not a requisite introduced by this commit as
> system/runstate.c:qemu_cleanup shows.
>
> Eugenio Pérez (2):
>   net: parameterize the removing client from nc list
>   net: move backend cleanup to NIC cleanup
>
>  net/net.c        | 44 ++++++++++++++++++++++++++++++++++----------
>  net/vhost-vdpa.c |  8 --------
>  2 files changed, 34 insertions(+), 18 deletions(-)
>
> --
> 2.43.5
>

Queued.

Thanks

I tested this series of patches with virtio-net regression
tests,everything works fine.

Tested-by: Lei Yang <leiyang@redhat.com>

On Mon, Jan 6, 2025 at 11:57 PM Jonah Palmer <jonah.palmer@oracle.com> wrote:
>
> Commit a0d7215e33 ("vhost-vdpa: do not cleanup the vdpa/vhost-net
> structures if peer nic is present") effectively delayed the backend
> cleanup, allowing the frontend or the guest to access it resources as
> long as the frontend NIC is still visible to the guest.
>
> However it does not clean up the resources until the qemu process is
> over.  This causes an effective leak if the device is deleted with
> device_del, as there is no way to close the vdpa device.  This makes
> impossible to re-add that device to this or other QEMU instances until
> the first instance of QEMU is finished.
>
> Move the cleanup from qemu_cleanup to the NIC deletion.
>
> v3:
> Remove shadowed declaration of NetClientState nc variable in 2/2.
>
> v2:
> Remove NIC peer also at net_cleanup. vhost-user trust all the
> backends are clean before qemu removes char devices.
>
> This is not a requisite introduced by this commit as
> system/runstate.c:qemu_cleanup shows.
>
> Eugenio Pérez (2):
>   net: parameterize the removing client from nc list
>   net: move backend cleanup to NIC cleanup
>
>  net/net.c        | 44 ++++++++++++++++++++++++++++++++++----------
>  net/vhost-vdpa.c |  8 --------
>  2 files changed, 34 insertions(+), 18 deletions(-)
>
> --
> 2.43.5
>