Re: [dpdk-dev] [PATCH] net/virtio: wait device ready in device reset

[Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>]

On 8/23/21 9:39 AM, Xueming Li wrote:
> According to virtio spec, the device MUST reset when 0 is written to
> device_status, and present a 0 in device_status once that is done.
> 
> This patch adds the missing part of waiting status 0 in reset function.
> 
> Signed-off-by: Xueming Li <xuemingl@nvidia.com>
> ---
>  drivers/net/virtio/virtio.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio.c b/drivers/net/virtio/virtio.c
> index 7e1e77797f..f003f612d6 100644
> --- a/drivers/net/virtio/virtio.c
> +++ b/drivers/net/virtio/virtio.c
> @@ -3,6 +3,8 @@
>   * Copyright(c) 2020 Red Hat, Inc.
>   */
>  
> +#include <unistd.h>
> +
>  #include "virtio.h"
>  
>  uint64_t
> @@ -39,8 +41,9 @@ void
>  virtio_reset(struct virtio_hw *hw)
>  {
>  	VIRTIO_OPS(hw)->set_status(hw, VIRTIO_CONFIG_STATUS_RESET);
> -	/* flush status write */
> -	VIRTIO_OPS(hw)->get_status(hw);
> +	/* Flush status write and wait device ready. */
> +	while (VIRTIO_OPS(hw)->get_status(hw) != VIRTIO_CONFIG_STATUS_RESET)
> +		usleep(1000L);

Don't we need a protection against forever loop here?

>  }
>  
>  void
>