Maxime Coquelin <maxime.coque...@redhat.com> writes:
> This patch implements support for the Virtio MTU feature.
> When negotiated, the host shares its maximum supported MTU,
> which is used as initial MTU and as maximum MTU the application
> can set.
>
> Signed-off-by: Maxime Coquelin <maxime.coque...@redhat.com>
> ---
> doc/guides/nics/features/virtio.ini | 1 +
> drivers/net/virtio/virtio_ethdev.c | 22 ++++++++++++++++++++--
> drivers/net/virtio/virtio_ethdev.h | 3 ++-
> drivers/net/virtio/virtio_pci.h | 3 +++
> 4 files changed, 26 insertions(+), 3 deletions(-)
>
> diff --git a/doc/guides/nics/features/virtio.ini
> b/doc/guides/nics/features/virtio.ini
> index 5164937..7bea075 100644
> --- a/doc/guides/nics/features/virtio.ini
> +++ b/doc/guides/nics/features/virtio.ini
> @@ -24,3 +24,4 @@ ARMv8 = Y
> x86-32 = Y
> x86-64 = Y
> Usage doc = Y
> +MTU update = Y
> diff --git a/drivers/net/virtio/virtio_ethdev.c
> b/drivers/net/virtio/virtio_ethdev.c
> index d1ff234..ad3e6e1 100644
> --- a/drivers/net/virtio/virtio_ethdev.c
> +++ b/drivers/net/virtio/virtio_ethdev.c
> @@ -721,10 +721,13 @@ virtio_mtu_set(struct rte_eth_dev *dev, uint16_t mtu)
> uint32_t ether_hdr_len = ETHER_HDR_LEN + VLAN_TAG_LEN +
> hw->vtnet_hdr_size;
> uint32_t frame_size = mtu + ether_hdr_len;
> + uint32_t max_frame_size = hw->max_mtu + ether_hdr_len;
>
> - if (mtu < ETHER_MIN_MTU || frame_size > VIRTIO_MAX_RX_PKTLEN) {
> + max_frame_size = RTE_MIN(max_frame_size, VIRTIO_MAX_RX_PKTLEN);
> +
> + if (mtu < ETHER_MIN_MTU || frame_size > max_frame_size) {
> PMD_INIT_LOG(ERR, "MTU should be between %d and %d",
> - ETHER_MIN_MTU, VIRTIO_MAX_RX_PKTLEN - ether_hdr_len);
> + ETHER_MIN_MTU, max_frame_size - ether_hdr_len);
> return -EINVAL;
> }
> return 0;
> @@ -1392,6 +1395,21 @@ virtio_init_device(struct rte_eth_dev *eth_dev,
> uint64_t req_features)
>
> hw->max_queue_pairs = config->max_virtqueue_pairs;
>
> + if (vtpci_with_feature(hw, VIRTIO_NET_F_MTU)) {
> + vtpci_read_dev_config(hw,
> + offsetof(struct virtio_net_config, mtu),
> + &config->mtu,
> + sizeof(config->mtu));
I think we need to check the value here against the min mtu, right?
> + hw->max_mtu = config->mtu;
> + /* Set initial MTU to maximum one supported by vhost */
> + eth_dev->data->mtu = config->mtu;
> +
> + } else {
> + hw->max_mtu = VIRTIO_MAX_RX_PKTLEN - ETHER_HDR_LEN -
> + VLAN_TAG_LEN - hw->vtnet_hdr_size;
> + }
> +
> PMD_INIT_LOG(DEBUG, "config->max_virtqueue_pairs=%d",
> config->max_virtqueue_pairs);
> PMD_INIT_LOG(DEBUG, "config->status=%d", config->status);
> diff --git a/drivers/net/virtio/virtio_ethdev.h
> b/drivers/net/virtio/virtio_ethdev.h
> index 777a14b..aa78adc 100644
> --- a/drivers/net/virtio/virtio_ethdev.h
> +++ b/drivers/net/virtio/virtio_ethdev.h
> @@ -51,7 +51,7 @@
> #define VIRTIO_MAX_TX_QUEUES 128U
> #define VIRTIO_MAX_MAC_ADDRS 64
> #define VIRTIO_MIN_RX_BUFSIZE 64
> -#define VIRTIO_MAX_RX_PKTLEN 9728
> +#define VIRTIO_MAX_RX_PKTLEN 9728U
>
> /* Features desired/implemented by this driver. */
> #define VIRTIO_PMD_DEFAULT_GUEST_FEATURES \
> @@ -66,6 +66,7 @@
> 1u << VIRTIO_NET_F_HOST_TSO4 | \
> 1u << VIRTIO_NET_F_HOST_TSO6 | \
> 1u << VIRTIO_NET_F_MRG_RXBUF | \
> + 1u << VIRTIO_NET_F_MTU | \
> 1u << VIRTIO_RING_F_INDIRECT_DESC | \
> 1ULL << VIRTIO_F_VERSION_1 | \
> 1ULL << VIRTIO_F_IOMMU_PLATFORM)
> diff --git a/drivers/net/virtio/virtio_pci.h b/drivers/net/virtio/virtio_pci.h
> index 59e45c4..771f5b1 100644
> --- a/drivers/net/virtio/virtio_pci.h
> +++ b/drivers/net/virtio/virtio_pci.h
> @@ -106,6 +106,7 @@ struct virtnet_ctl;
> /* The feature bitmap for virtio net */
> #define VIRTIO_NET_F_CSUM 0 /* Host handles pkts w/ partial csum */
> #define VIRTIO_NET_F_GUEST_CSUM 1 /* Guest handles pkts w/
> partial csum */
> +#define VIRTIO_NET_F_MTU 3 /* Initial MTU advice. */
> #define VIRTIO_NET_F_MAC 5 /* Host has given MAC address. */
> #define VIRTIO_NET_F_GUEST_TSO4 7 /* Guest can handle TSOv4 in. */
> #define VIRTIO_NET_F_GUEST_TSO6 8 /* Guest can handle TSOv6 in. */
> @@ -251,6 +252,7 @@ struct virtio_hw {
> uint64_t req_guest_features;
> uint64_t guest_features;
> uint32_t max_queue_pairs;
> + uint16_t max_mtu;
> uint16_t vtnet_hdr_size;
> uint8_t vlan_strip;
> uint8_t use_msix;
> @@ -296,6 +298,7 @@ struct virtio_net_config {
> /* See VIRTIO_NET_F_STATUS and VIRTIO_NET_S_* above */
> uint16_t status;
> uint16_t max_virtqueue_pairs;
> + uint16_t mtu;
> } __attribute__((packed));
>
> /*
