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Subject: Re: [Qemu-devel] [RFC v9 15/18] vfio: do hot bus reset when do
 virtual secondary bus reset
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To: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
Cc: izumi.taku@jp.fujitsu.com, qemu-devel@nongnu.org

On Tue, 2015-06-09 at 11:37 +0800, Chen Fan wrote:
> when do virtual secondary bus reset, the vfio device under
> this bus need to do host bus reset to reset the device.
> so add this case.
> 
> Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
> ---
>  hw/vfio/pci.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index 6507f39..655ac59 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -4239,6 +4239,15 @@ static void vfio_pci_reset(DeviceState *dev)
>  
>      vfio_pci_pre_reset(vdev);
>  
> +    if (vdev->needs_bus_reset) {
> +        vdev->needs_bus_reset = false;
> +        /* Avoid duplicate bus reset */
> +        if (vdev->vbasedev.needs_reset) {
> +            vfio_pci_hot_reset(vdev, false);
> +        }
> +        return;
> +    }

So if we call hot reset, then we do pre-reset twice, once here, once in
the hot reset function.  If we don't call hot reset, we fail to call
post-reset for cleanup.

> +
>      if (vdev->resetfn && !vdev->resetfn(vdev)) {
>          goto post_reset;
>      }