Re: [dpdk-dev] [PATCH v1] net/virtio: wait device ready during reset

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

On 9/15/21 12:21 PM, Xueming Li wrote:
> According to virtio spec, the device MUST reset when 0 is written to
> device_status, and present 0 in device_status once reset is done.
> 
> This patch waits status value to be 0 during reset operation, if
> timeout in 3 seconds, log and continue.

I have no strong opinion on timeout.

> 
> Signed-off-by: Xueming Li <xuemingl@nvidia.com>
> Cc: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> ---
>  drivers/net/virtio/virtio.c | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio.c b/drivers/net/virtio/virtio.c
> index 7e1e77797f..f865b27b65 100644
> --- a/drivers/net/virtio/virtio.c
> +++ b/drivers/net/virtio/virtio.c
> @@ -3,7 +3,10 @@
>   * Copyright(c) 2020 Red Hat, Inc.
>   */
>  
> +#include <unistd.h>
> +
>  #include "virtio.h"
> +#include "virtio_logs.h"
>  
>  uint64_t
>  virtio_negotiate_features(struct virtio_hw *hw, uint64_t host_features)
> @@ -38,9 +41,17 @@ virtio_write_dev_config(struct virtio_hw *hw, size_t offset,
>  void
>  virtio_reset(struct virtio_hw *hw)
>  {
> +	uint32_t retry = 0;
> +
>  	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 max 3 seconds. */
> +	while (VIRTIO_OPS(hw)->get_status(hw) != VIRTIO_CONFIG_STATUS_RESET) {
> +		if (retry++ > 3000) {
> +			PMD_INIT_LOG(WARNING, "device reset timeout");

I think it would be very useful to log ethdev port ID here.

> +			break;
> +		}
> +		usleep(1000L);
> +	}
>  }
>  
>  void
>