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[virtio] Use host-specified MTU when available
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Signed-off-by: Michael Brown <mcb30@ipxe.org>
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@mcb30
mcb30 committed Jan 23, 2017
1 parent de85336 commit 4e85b27
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Showing 2 changed files with 37 additions and 13 deletions.
40 changes: 27 additions & 13 deletions src/drivers/net/virtio-net.c
View file
Expand Up @@ -77,13 +77,8 @@ enum {
QUEUE_NB
};

enum {
/** Max number of pending rx packets */
NUM_RX_BUF = 8,

/** Max Ethernet frame length, including FCS and VLAN tag */
RX_BUF_SIZE = 1522,
};
/** Max number of pending rx packets */
#define NUM_RX_BUF 8

struct virtnet_nic {
/** Base pio register address */
Expand Down Expand Up @@ -160,20 +155,21 @@ static void virtnet_enqueue_iob ( struct net_device *netdev,
*/
static void virtnet_refill_rx_virtqueue ( struct net_device *netdev ) {
struct virtnet_nic *virtnet = netdev->priv;
size_t len = ( netdev->max_pkt_len + 4 /* VLAN */ );

while ( virtnet->rx_num_iobufs < NUM_RX_BUF ) {
struct io_buffer *iobuf;

/* Try to allocate a buffer, stop for now if out of memory */
iobuf = alloc_iob ( RX_BUF_SIZE );
iobuf = alloc_iob ( len );
if ( ! iobuf )
break;

/* Keep track of iobuf so close() can free it */
list_add ( &iobuf->list, &virtnet->rx_iobufs );

/* Mark packet length until we know the actual size */
iob_put ( iobuf, RX_BUF_SIZE );
iob_put ( iobuf, len );

virtnet_enqueue_iob ( netdev, RX_INDEX, iobuf );
virtnet->rx_num_iobufs++;
Expand Down Expand Up @@ -237,7 +233,8 @@ static int virtnet_open_legacy ( struct net_device *netdev ) {

/* Driver is ready */
features = vp_get_features ( ioaddr );
vp_set_features ( ioaddr, features & ( 1 << VIRTIO_NET_F_MAC ) );
vp_set_features ( ioaddr, features & ( ( 1 << VIRTIO_NET_F_MAC ) |
( 1 << VIRTIO_NET_F_MTU ) ) );
vp_set_status ( ioaddr, VIRTIO_CONFIG_S_DRIVER | VIRTIO_CONFIG_S_DRIVER_OK );
return 0;
}
Expand All @@ -260,6 +257,7 @@ static int virtnet_open_modern ( struct net_device *netdev ) {
}
vpm_set_features ( &virtnet->vdev, features & (
( 1ULL << VIRTIO_NET_F_MAC ) |
( 1ULL << VIRTIO_NET_F_MTU ) |
( 1ULL << VIRTIO_F_VERSION_1 ) |
( 1ULL << VIRTIO_F_ANY_LAYOUT ) ) );
vpm_add_status ( &virtnet->vdev, VIRTIO_CONFIG_S_FEATURES_OK );
Expand Down Expand Up @@ -389,7 +387,7 @@ static void virtnet_process_rx_packets ( struct net_device *netdev ) {
virtnet->rx_num_iobufs--;

/* Update iobuf length */
iob_unput ( iobuf, RX_BUF_SIZE );
iob_unput ( iobuf, iob_len ( iobuf ) );
iob_put ( iobuf, len - sizeof ( struct virtio_net_hdr ) );

DBGC2 ( virtnet, "VIRTIO-NET %p rx complete iobuf %p len %zd\n",
Expand Down Expand Up @@ -461,6 +459,7 @@ static int virtnet_probe_legacy ( struct pci_device *pci ) {
struct net_device *netdev;
struct virtnet_nic *virtnet;
u32 features;
u16 mtu;
int rc;

/* Allocate and hook up net device */
Expand All @@ -480,14 +479,20 @@ static int virtnet_probe_legacy ( struct pci_device *pci ) {
adjust_pci_device ( pci );
vp_reset ( ioaddr );

/* Load MAC address */
/* Load MAC address and MTU */
features = vp_get_features ( ioaddr );
if ( features & ( 1 << VIRTIO_NET_F_MAC ) ) {
vp_get ( ioaddr, offsetof ( struct virtio_net_config, mac ),
netdev->hw_addr, ETH_ALEN );
DBGC ( virtnet, "VIRTIO-NET %p mac=%s\n", virtnet,
eth_ntoa ( netdev->hw_addr ) );
}
if ( features & ( 1ULL << VIRTIO_NET_F_MTU ) ) {
vp_get ( ioaddr, offsetof ( struct virtio_net_config, mtu ),
&mtu, sizeof ( mtu ) );
DBGC ( virtnet, "VIRTIO-NET %p mtu=%d\n", virtnet, mtu );
netdev->max_pkt_len = ( mtu + ETH_HLEN );
}

/* Register network device */
if ( ( rc = register_netdev ( netdev ) ) != 0 )
Expand Down Expand Up @@ -517,6 +522,7 @@ static int virtnet_probe_modern ( struct pci_device *pci, int *found_dev ) {
struct net_device *netdev;
struct virtnet_nic *virtnet;
u64 features;
u16 mtu;
int rc, common, isr, notify, config, device;

common = virtio_pci_find_capability ( pci, VIRTIO_PCI_CAP_COMMON_CFG );
Expand Down Expand Up @@ -583,7 +589,7 @@ static int virtnet_probe_modern ( struct pci_device *pci, int *found_dev ) {
vpm_add_status ( &virtnet->vdev, VIRTIO_CONFIG_S_ACKNOWLEDGE );
vpm_add_status ( &virtnet->vdev, VIRTIO_CONFIG_S_DRIVER );

/* Load MAC address */
/* Load MAC address and MTU */
if ( device ) {
features = vpm_get_features ( &virtnet->vdev );
if ( features & ( 1ULL << VIRTIO_NET_F_MAC ) ) {
Expand All @@ -593,6 +599,14 @@ static int virtnet_probe_modern ( struct pci_device *pci, int *found_dev ) {
DBGC ( virtnet, "VIRTIO-NET %p mac=%s\n", virtnet,
eth_ntoa ( netdev->hw_addr ) );
}
if ( features & ( 1ULL << VIRTIO_NET_F_MTU ) ) {
vpm_get ( &virtnet->vdev,
offsetof ( struct virtio_net_config, mtu ),
&mtu, sizeof ( mtu ) );
DBGC ( virtnet, "VIRTIO-NET %p mtu=%d\n", virtnet,
mtu );
netdev->max_pkt_len = ( mtu + ETH_HLEN );
}
}

/* We need a valid MAC address */
Expand Down
10 changes: 10 additions & 0 deletions src/drivers/net/virtio-net.h
View file
Expand Up @@ -4,6 +4,7 @@
/* 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_GSO 6 /* Host handles pkts w/ any GSO type */
#define VIRTIO_NET_F_GUEST_TSO4 7 /* Guest can handle TSOv4 in. */
Expand All @@ -25,6 +26,15 @@ struct virtio_net_config
{
/* The config defining mac address (if VIRTIO_NET_F_MAC) */
u8 mac[6];
/* See VIRTIO_NET_F_STATUS and VIRTIO_NET_S_* above */
u16 status;
/* Maximum number of each of transmit and receive queues;
* see VIRTIO_NET_F_MQ and VIRTIO_NET_CTRL_MQ.
* Legal values are between 1 and 0x8000
*/
u16 max_virtqueue_pairs;
/* Default maximum transmit unit advice */
u16 mtu;
} __attribute__((packed));

/* This is the first element of the scatter-gather list. If you don't
Expand Down

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