diff options
Diffstat (limited to 'hw/e1000.c')
| -rw-r--r-- | hw/e1000.c | 28 |
1 files changed, 22 insertions, 6 deletions
diff --git a/hw/e1000.c b/hw/e1000.c index 2943a1a375..0a4574cf93 100644 --- a/hw/e1000.c +++ b/hw/e1000.c @@ -631,6 +631,24 @@ e1000_can_receive(VLANClientState *nc) return (s->mac_reg[RCTL] & E1000_RCTL_EN); } +static bool e1000_has_rxbufs(E1000State *s, size_t total_size) +{ + int bufs; + /* Fast-path short packets */ + if (total_size <= s->rxbuf_size) { + return s->mac_reg[RDH] != s->mac_reg[RDT] || !s->check_rxov; + } + if (s->mac_reg[RDH] < s->mac_reg[RDT]) { + bufs = s->mac_reg[RDT] - s->mac_reg[RDH]; + } else if (s->mac_reg[RDH] > s->mac_reg[RDT] || !s->check_rxov) { + bufs = s->mac_reg[RDLEN] / sizeof(struct e1000_rx_desc) + + s->mac_reg[RDT] - s->mac_reg[RDH]; + } else { + return false; + } + return total_size <= bufs * s->rxbuf_size; +} + static ssize_t e1000_receive(VLANClientState *nc, const uint8_t *buf, size_t size) { @@ -671,17 +689,15 @@ e1000_receive(VLANClientState *nc, const uint8_t *buf, size_t size) rdh_start = s->mac_reg[RDH]; desc_offset = 0; total_size = size + fcs_len(s); + if (!e1000_has_rxbufs(s, total_size)) { + set_ics(s, 0, E1000_ICS_RXO); + return -1; + } do { desc_size = total_size - desc_offset; if (desc_size > s->rxbuf_size) { desc_size = s->rxbuf_size; } - if (s->mac_reg[RDH] == s->mac_reg[RDT] && s->check_rxov) { - /* Discard all data written so far */ - s->mac_reg[RDH] = rdh_start; - set_ics(s, 0, E1000_ICS_RXO); - return -1; - } base = ((uint64_t)s->mac_reg[RDBAH] << 32) + s->mac_reg[RDBAL] + sizeof(desc) * s->mac_reg[RDH]; cpu_physical_memory_read(base, (void *)&desc, sizeof(desc)); |