int
vmbus_chan_recv(struct vmbus_channel *chan, void *data, int *dlen0,
uint64_t *xactid)
{
struct vmbus_chanpkt_hdr pkt;
int error, dlen, hlen;
error = vmbus_rxbr_peek(&chan->ch_rxbr, &pkt, sizeof(pkt));
if (error)
return error;
hlen = VMBUS_CHANPKT_GETLEN(pkt.cph_hlen);
dlen = VMBUS_CHANPKT_GETLEN(pkt.cph_tlen) - hlen;
if (*dlen0 < dlen) {
/* Return the size of this packet's data. */
*dlen0 = dlen;
return ENOBUFS;
}
*xactid = pkt.cph_xactid;
*dlen0 = dlen;
/* Skip packet header */
error = vmbus_rxbr_read(&chan->ch_rxbr, data, dlen, hlen);
KASSERT(!error, ("vmbus_rxbr_read failed"));
return 0;
}
int
vmbus_chan_recv_pkt(struct vmbus_channel *chan,
struct vmbus_chanpkt_hdr *pkt0, int *pktlen0)
{
struct vmbus_chanpkt_hdr pkt;
int error, pktlen;
error = vmbus_rxbr_peek(&chan->ch_rxbr, &pkt, sizeof(pkt));
if (error)
return error;
pktlen = VMBUS_CHANPKT_GETLEN(pkt.cph_tlen);
if (*pktlen0 < pktlen) {
/* Return the size of this packet. */
*pktlen0 = pktlen;
return ENOBUFS;
}
*pktlen0 = pktlen;
/* Include packet header */
error = vmbus_rxbr_read(&chan->ch_rxbr, pkt0, pktlen, 0);
KASSERT(!error, ("vmbus_rxbr_read failed"));
return 0;
}
static int vmbus_read_and_signal(struct vmbus_channel *chan,
void *data, size_t dlen, size_t skip)
{
struct vmbus_br *rbr = &chan->rxbr;
uint32_t write_sz, pending_sz, bytes_read;
int error;
/* Record where host was when we started read (for debug) */
rbr->windex = rbr->vbr->windex;
/* Read data and skip packet header */
error = vmbus_rxbr_read(rbr, data, dlen, skip);
if (error)
return error;
/* No need for signaling on older versions */
if (!rbr->vbr->feature_bits.feat_pending_send_sz)
return 0;
/* Make sure reading of pending happens after new read index */
rte_mb();
pending_sz = rbr->vbr->pending_send;
if (!pending_sz)
return 0;
rte_smp_rmb();
write_sz = vmbus_br_availwrite(rbr, rbr->vbr->windex);
bytes_read = dlen + skip + sizeof(uint64_t);
/* If there was space before then host was not blocked */
if (write_sz - bytes_read > pending_sz)
return 0;
/* If pending write will not fit */
if (write_sz <= pending_sz)
return 0;
vmbus_set_event(chan->device, chan);
return 0;
}