Re: [PATCH v4] failover: unregister ROM on unplug

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 7/21/21 6:09 PM, Laurent Vivier wrote:
> The intend of failover is to allow to migrate a VM with a VFIO
> networking card without disrupting the network operation by switching
> to a virtio-net device during the migration.
> 
> This simple change allows to test failover with a simulated device
> like e1000e rather than a vfio device, even if it's useless in real
> life it can help to debug failover.
> 
> This is interesting to developers that want to test failover on
> a system with no vfio device. Moreover it simplifies host networking
> configuration as we can use the same bridge for virtio-net and
> the other failover networking device.
> 
> Without this change the migration of a system configured with failover
> fails with:
> 
>   ...
>   -device virtio-net-pci,id=virtionet0,failover=on,...  \
>   -device e1000,failover_pair_id=virtionet0,... \
>   ...
> 
>   (qemu) migrate ...
> 
>   Unknown ramblock "0000:00:01.1:00.0/e1000e.rom", cannot accept migration
>   error while loading state for instance 0x0 of device 'ram'
>   load of migration failed: Invalid argument
> 
> This happens because QEMU correctly unregisters the interface vmstate but
> not the ROM one. This patch fixes that.
> 
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> ---
> 
> Notes:
>     v4:
>       export and use pci_del_option_rom()
>     
>     v3:
>       remove useless space before comma
>     
>     v2:
>       reset has_rom to false
>       update commit log message
> 
>  include/hw/pci/pci.h | 2 ++
>  hw/net/virtio-net.c  | 1 +
>  hw/pci/pci.c         | 3 +--
>  3 files changed, 4 insertions(+), 2 deletions(-)

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>