Re: [dpdk-dev] [PATCH 1/2] net/vhost: support TSO disabling

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 6/19/19 8:13 AM, Noa Ezra wrote:
> TSO (TCP Segmentation Offload) is enabled by default on vhost.
> Add the ability to disable TSO on vhost.
> The user should also disable the feature on the virtual machine's xml.

For TSO, I think it make sense to have the option to disable it,
as it requires the application to support it.

I even wonder whether it should not be disabled by default.
Any thoughts?

Also, next time, please add other maintainers as recipients,
it can be done by checking the MAINTAINERS file, or even by
using the get_maintainers.sh script.

Thanks,
Maxime

> Signed-off-by: Noa Ezra <noae@mellanox.com>
> Reviewed-by: Matan Azrad <matan@mellanox.com>
> ---
>   doc/guides/nics/vhost.rst         |  5 +++++
>   drivers/net/vhost/rte_eth_vhost.c | 30 +++++++++++++++++++++++++++---
>   2 files changed, 32 insertions(+), 3 deletions(-)
> 
> diff --git a/doc/guides/nics/vhost.rst b/doc/guides/nics/vhost.rst
> index 23f2e87..8cfda4d 100644
> --- a/doc/guides/nics/vhost.rst
> +++ b/doc/guides/nics/vhost.rst
> @@ -76,6 +76,11 @@ The user can specify below arguments in `--vdev` option.
>       It is used to enable postcopy live-migration support in vhost library.
>       (Default: 0 (disabled))
>   
> +#.  ``tso``:
> +
> +    It is used to disable tso support in vhost library.
> +    (Default: 1 (enabled))
> +
>   Vhost PMD event handling
>   ------------------------
>   
> diff --git a/drivers/net/vhost/rte_eth_vhost.c b/drivers/net/vhost/rte_eth_vhost.c
> index b2cda04..a38c235 100644
> --- a/drivers/net/vhost/rte_eth_vhost.c
> +++ b/drivers/net/vhost/rte_eth_vhost.c
> @@ -31,6 +31,7 @@
>   #define ETH_VHOST_DEQUEUE_ZERO_COPY	"dequeue-zero-copy"
>   #define ETH_VHOST_IOMMU_SUPPORT		"iommu-support"
>   #define ETH_VHOST_POSTCOPY_SUPPORT	"postcopy-support"
> +#define ETH_VHOST_VIRTIO_NET_F_HOST_TSO "tso"
>   #define VHOST_MAX_PKT_BURST 32
>   
>   static const char *valid_arguments[] = {
> @@ -40,6 +41,7 @@
>   	ETH_VHOST_DEQUEUE_ZERO_COPY,
>   	ETH_VHOST_IOMMU_SUPPORT,
>   	ETH_VHOST_POSTCOPY_SUPPORT,
> +	ETH_VHOST_VIRTIO_NET_F_HOST_TSO,
>   	NULL
>   };
>   
> @@ -1200,7 +1202,8 @@ struct vhost_xstats_name_off {
>   
>   static int
>   eth_dev_vhost_create(struct rte_vdev_device *dev, char *iface_name,
> -	int16_t queues, const unsigned int numa_node, uint64_t flags)
> +	int16_t queues, const unsigned int numa_node, uint64_t flags,
> +	uint64_t disable_flags)
>   {
>   	const char *name = rte_vdev_device_name(dev);
>   	struct rte_eth_dev_data *data;
> @@ -1272,6 +1275,11 @@ struct vhost_xstats_name_off {
>   	if (rte_vhost_driver_register(iface_name, flags))
>   		goto error;
>   
> +	if (disable_flags) {
> +		if (rte_vhost_driver_disable_features(iface_name, disable_flags))
> +			goto error;
> +	}
> +
>   	if (rte_vhost_driver_callback_register(iface_name, &vhost_ops) < 0) {
>   		VHOST_LOG(ERR, "Can't register callbacks\n");
>   		goto error;
> @@ -1334,10 +1342,12 @@ struct vhost_xstats_name_off {
>   	char *iface_name;
>   	uint16_t queues;
>   	uint64_t flags = 0;
> +	uint64_t disable_flags = 0;
>   	int client_mode = 0;
>   	int dequeue_zero_copy = 0;
>   	int iommu_support = 0;
>   	int postcopy_support = 0;
> +	int tso = 1;
>   	struct rte_eth_dev *eth_dev;
>   	const char *name = rte_vdev_device_name(dev);
>   
> @@ -1419,11 +1429,24 @@ struct vhost_xstats_name_off {
>   			flags |= RTE_VHOST_USER_POSTCOPY_SUPPORT;
>   	}
>   
> +	if (rte_kvargs_count(kvlist, ETH_VHOST_VIRTIO_NET_F_HOST_TSO) == 1) {
> +		ret = rte_kvargs_process(kvlist,
> +				ETH_VHOST_VIRTIO_NET_F_HOST_TSO,
> +				&open_int, &tso);
> +		if (ret < 0)
> +			goto out_free;
> +
> +		if (tso == 0) {
> +			disable_flags |= (1ULL << VIRTIO_NET_F_HOST_TSO4);
> +			disable_flags |= (1ULL << VIRTIO_NET_F_HOST_TSO6);
> +		}
> +	}
> +
>   	if (dev->device.numa_node == SOCKET_ID_ANY)
>   		dev->device.numa_node = rte_socket_id();
>   
>   	eth_dev_vhost_create(dev, iface_name, queues, dev->device.numa_node,
> -		flags);
> +		flags, disable_flags);
>   
>   out_free:
>   	rte_kvargs_free(kvlist);
> @@ -1470,7 +1493,8 @@ struct vhost_xstats_name_off {
>   	"client=<0|1> "
>   	"dequeue-zero-copy=<0|1> "
>   	"iommu-support=<0|1> "
> -	"postcopy-support=<0|1>");
> +	"postcopy-support=<0|1> "
> +	"tso=<0|1>");
>   
>   RTE_INIT(vhost_init_log)
>   {
>