On 2020/3/24 上午10:04, Li Qiang wrote:
P J P <[email protected] <mailto:[email protected]>> 于2020年3月23日周一 下午8:25写道：From: Prasad J Pandit <[email protected] <mailto:[email protected]>> Define .can_receive routine to do sanity checks before receiving packet data. And call qemu_flush_queued_packets to flush queued packets once they are read in tulip_receive(). Suggested-by: Jason Wang <[email protected] <mailto:[email protected]>> Signed-off-by: Prasad J Pandit <[email protected] <mailto:[email protected]>> --- hw/net/tulip.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) Update v6: merge earlier patch 2 & 3 into one -> https://lists.gnu.org/archive/html/qemu-devel/2020-03/msg06868.html diff --git a/hw/net/tulip.c b/hw/net/tulip.c index fbe40095da..8d8c9519e7 100644 --- a/hw/net/tulip.c +++ b/hw/net/tulip.c @@ -229,6 +229,18 @@ static bool tulip_filter_address(TULIPState *s, const uint8_t *addr) return ret; } +static int +tulip_can_receive(NetClientState *nc) +{ + TULIPState *s = qemu_get_nic_opaque(nc); + + if (s->rx_frame_len || tulip_rx_stopped(s)) { + return false; + } + + return true; +} + static ssize_t tulip_receive(TULIPState *s, const uint8_t *buf, size_t size) { struct tulip_descriptor desc; @@ -236,7 +248,7 @@ static ssize_t tulip_receive(TULIPState *s, const uint8_t *buf, size_t size) trace_tulip_receive(buf, size); if (size < 14 || size > sizeof(s->rx_frame) - 4 - || s->rx_frame_len || tulip_rx_stopped(s)) { + || !tulip_can_receive(s->nic->ncs)) { return 0; } @@ -275,6 +287,8 @@ static ssize_t tulip_receive(TULIPState *s, const uint8_t *buf, size_t size) tulip_desc_write(s, s->current_rx_desc, &desc); tulip_next_rx_descriptor(s, &desc); } while (s->rx_frame_len); + + qemu_flush_queued_packets(qemu_get_queue(s->nic)); Hi Prasad ans Jason, I want to know why here we need call 'qemu_flush_queued_packets'. AFAICS, the other networking card emulation need no this.
Right, I thought we need this because rx_frame_len is checked in tulip_can_receive().
But not I think it's unnecessary. According to kernel driver code, the rx is not necessarily stopped when rx buffer is overrun, e.g, tulip_rx_refill() only toggle the doorbell when chip is LC82C168. But own emulation did DC21143.
This means using can_receive() is wrong. So I think we can drop this patch. Thanks for the checking and sorry for the wrong suggestion.
Thanks, Li Qiang return size; } @@ -288,6 +302,7 @@ static NetClientInfo net_tulip_info = { .type = NET_CLIENT_DRIVER_NIC, .size = sizeof(NICState), .receive = tulip_receive_nc, + .can_receive = tulip_can_receive, }; static const char *tulip_reg_name(const hwaddr addr)-- 2.25.1
