Thanks! Reply: [PATCH]vdpa-dev: Fix the issue of device status not updating when configuration interruption is triggered

[Gavin Liu]

Thanks

----- Original Message -----
From: Jason Wang jasowang@redhat.com
Sent: April 7, 2024 11:46 AM
To: Gavin Liu gavin.liu@jaguarmicro.com
Cc: eperezma@redhat.com; sgarzare@redhat.com; mst@redhat.com; 
qemu-stable@nongnu.org; qemu-devel@nongnu.org; kwolf@redhat.com
Subject: Re: [PATCH] vdpa-dev: Fix the issue of device status not updating when 
configuration interruption is triggered
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On Sun, Apr 7, 2024 at 11:22 AM lyx634449800 <yuxue.liu@jaguarmicro.com> wrote:
>
> The set_config callback function vhost_vdpa_device_get_config in 
> vdpa-dev does not fetch the current device status from the hardware 
> device, causing the GUEST OS to not receive the latest device status

nit: no need for upper case here.

> information.
>
> The hardware updates the config status of the vdpa device and then 
> notifies the OS. The GUEST OS receives an interrupt notification, 
> triggering a get_config access in the kernel, which then enters qemu 
> internally. Ultimately, the vhost_vdpa_device_get_config function of 
> vdpa-dev is called
>
> One scenario encountered is when the device needs to bring down the 
> vdpa net device. After modifying the status field of virtio_net_config 
> in the hardware, it sends an interrupt notification. However, the 
> guest OS always receives the STATUS field as VIRTIO_NET_S_LINK_UP.
>
> Signed-off-by: Yuxue Liu <yuxue.liu@jaguarmicro.com>

This aligns with the vhost-net support for vDPA.

Acked-by: Jason Wang <jasowang@redhat.com>

Thanks

> ---
>  hw/virtio/vdpa-dev.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/hw/virtio/vdpa-dev.c b/hw/virtio/vdpa-dev.c index 
> 13e87f06f6..64b96b226c 100644
> --- a/hw/virtio/vdpa-dev.c
> +++ b/hw/virtio/vdpa-dev.c
> @@ -195,7 +195,14 @@ static void
>  vhost_vdpa_device_get_config(VirtIODevice *vdev, uint8_t *config)  {
>      VhostVdpaDevice *s = VHOST_VDPA_DEVICE(vdev);
> +    int ret;
>
> +    ret = vhost_dev_get_config(&s->dev, s->config, s->config_size,
> +                            NULL);
> +    if (ret < 0) {
> +        error_report("get device config space failed");
> +        return;
> +    }
>      memcpy(config, s->config, s->config_size);
>  }
>
> --
> 2.43.0
>