179 lines
4.4 KiB
C
179 lines
4.4 KiB
C
#ifndef _NETFRONT_H
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#define _NETFRONT_H
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/** @file
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*
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* Xen netfront driver
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*
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*/
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FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
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#include <ipxe/xen.h>
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#include <xen/io/netif.h>
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/** Number of transmit ring entries */
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#define NETFRONT_NUM_TX_DESC 16
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/** Number of receive ring entries */
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#define NETFRONT_NUM_RX_DESC 32
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/** Receive ring fill level
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*
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* The xen-netback driver from kernels 3.18 to 4.2 inclusive have a
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* bug (CA-163395) which prevents packet reception if fewer than 18
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* receive descriptors are available. This was fixed in upstream
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* kernel commit d5d4852 ("xen-netback: require fewer guest Rx slots
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* when not using GSO").
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*
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* We provide 18 receive descriptors to avoid unpleasant silent
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* failures on these kernel versions.
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*/
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#define NETFRONT_RX_FILL 18
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/** Grant reference indices */
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enum netfront_ref_index {
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/** Transmit ring grant reference index */
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NETFRONT_REF_TX_RING = 0,
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/** Transmit descriptor grant reference base index */
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NETFRONT_REF_TX_BASE,
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/** Receive ring grant reference index */
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NETFRONT_REF_RX_RING = ( NETFRONT_REF_TX_BASE + NETFRONT_NUM_TX_DESC ),
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/** Receive descriptor grant reference base index */
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NETFRONT_REF_RX_BASE,
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/** Total number of grant references required */
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NETFRONT_REF_COUNT = ( NETFRONT_REF_RX_BASE + NETFRONT_NUM_RX_DESC )
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};
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/** A netfront descriptor ring */
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struct netfront_ring {
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/** Shared ring */
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union {
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/** Transmit shared ring */
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netif_tx_sring_t *tx;
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/** Receive shared ring */
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netif_rx_sring_t *rx;
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/** Raw pointer */
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void *raw;
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} sring;
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/** Shared ring grant reference key */
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const char *ref_key;
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/** Shared ring grant reference */
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grant_ref_t ref;
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/** Maximum number of used descriptors */
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size_t count;
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/** I/O buffers, indexed by buffer ID */
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struct io_buffer **iobufs;
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/** I/O buffer grant references, indexed by buffer ID */
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grant_ref_t *refs;
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/** Buffer ID ring */
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uint8_t *ids;
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/** Buffer ID ring producer counter */
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unsigned int id_prod;
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/** Buffer ID ring consumer counter */
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unsigned int id_cons;
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};
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/**
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* Initialise descriptor ring
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*
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* @v ring Descriptor ring
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* @v ref_key Shared ring grant reference key
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* @v ref Shared ring grant reference
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* @v count Maxium number of used descriptors
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* @v iobufs I/O buffers
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* @v refs I/O buffer grant references
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* @v ids Buffer IDs
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*/
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static inline __attribute__ (( always_inline )) void
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netfront_init_ring ( struct netfront_ring *ring, const char *ref_key,
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grant_ref_t ref, unsigned int count,
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struct io_buffer **iobufs, grant_ref_t *refs,
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uint8_t *ids ) {
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ring->ref_key = ref_key;
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ring->ref = ref;
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ring->count = count;
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ring->iobufs = iobufs;
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ring->refs = refs;
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ring->ids = ids;
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}
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/**
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* Calculate descriptor ring fill level
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*
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* @v ring Descriptor ring
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* @v fill Fill level
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*/
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static inline __attribute__ (( always_inline )) unsigned int
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netfront_ring_fill ( struct netfront_ring *ring ) {
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unsigned int fill_level;
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fill_level = ( ring->id_prod - ring->id_cons );
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assert ( fill_level <= ring->count );
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return fill_level;
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}
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/**
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* Check whether or not descriptor ring is full
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*
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* @v ring Descriptor ring
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* @v is_full Ring is full
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*/
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static inline __attribute__ (( always_inline )) int
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netfront_ring_is_full ( struct netfront_ring *ring ) {
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return ( netfront_ring_fill ( ring ) >= ring->count );
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}
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/**
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* Check whether or not descriptor ring is empty
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*
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* @v ring Descriptor ring
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* @v is_empty Ring is empty
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*/
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static inline __attribute__ (( always_inline )) int
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netfront_ring_is_empty ( struct netfront_ring *ring ) {
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return ( netfront_ring_fill ( ring ) == 0 );
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}
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/** A netfront NIC */
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struct netfront_nic {
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/** Xen device */
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struct xen_device *xendev;
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/** Grant references */
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grant_ref_t refs[NETFRONT_REF_COUNT];
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/** Transmit ring */
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struct netfront_ring tx;
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/** Transmit front ring */
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netif_tx_front_ring_t tx_fring;
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/** Transmit I/O buffers */
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struct io_buffer *tx_iobufs[NETFRONT_NUM_TX_DESC];
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/** Transmit I/O buffer IDs */
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uint8_t tx_ids[NETFRONT_NUM_TX_DESC];
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/** Receive ring */
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struct netfront_ring rx;
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/** Receive front ring */
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netif_rx_front_ring_t rx_fring;
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/** Receive I/O buffers */
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struct io_buffer *rx_iobufs[NETFRONT_NUM_RX_DESC];
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/** Receive I/O buffer IDs */
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uint8_t rx_ids[NETFRONT_NUM_RX_DESC];
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/** Event channel */
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struct evtchn_send event;
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};
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/** Transmit shared ring field */
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#define tx_sring tx.sring.tx
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/** Receive shared ring field */
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#define rx_sring rx.sring.rx
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#endif /* _NETFRONT_H */
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