See my comments below. Am 14.10.2011 12:49, schrieb Jason Wang:
Reduce spurious packet drops on RX ring empty when in c+ mode by verifying that we have at least 1 buffer ahead of the time.Signed-off-by: Jason Wang<jasow...@redhat.com> --- hw/rtl8139.c | 43 +++++++++++++++++++++++++++++-------------- 1 files changed, 29 insertions(+), 14 deletions(-) diff --git a/hw/rtl8139.c b/hw/rtl8139.c index 3753950..c654d5d 100644 --- a/hw/rtl8139.c +++ b/hw/rtl8139.c @@ -84,6 +84,19 @@ #define VLAN_TCI_LEN 2 #define VLAN_HLEN (ETHER_TYPE_LEN + VLAN_TCI_LEN) +/* w0 ownership flag */ +#define CP_RX_OWN (1<<31) +/* w0 end of ring flag */ +#define CP_RX_EOR (1<<30) +/* w0 bits 0...12 : buffer size */ +#define CP_RX_BUFFER_SIZE_MASK ((1<<13) - 1) +/* w1 tag available flag */ +#define CP_RX_TAVA (1<<16) +/* w1 bits 0...15 : VLAN tag */ +#define CP_RX_VLAN_TAG_MASK ((1<<16) - 1) +/* w2 low 32bit of Rx buffer ptr */ +/* w3 high 32bit of Rx buffer ptr */ + #if defined (DEBUG_RTL8139) # define DPRINTF(fmt, ...) \ do { fprintf(stderr, "RTL8139: " fmt, ## __VA_ARGS__); } while (0) @@ -805,6 +818,21 @@ static inline target_phys_addr_t rtl8139_addr64(uint32_t low, uint32_t high) #endif } +/* Verify that we have at least one available rx buffer */ +static int rtl8139_cp_has_rxbuf(RTL8139State *s) +{ + uint32_t val, rxdw0; + target_phys_addr_t cplus_rx_ring_desc = rtl8139_addr64(s->RxRingAddrLO, + s->RxRingAddrHI); + cplus_rx_ring_desc += 16 * s->currCPlusRxDesc; + cpu_physical_memory_read(cplus_rx_ring_desc, (uint8_t *)&val, 4);
The type cast is not needed, please remove it.
+ rxdw0 = le32_to_cpu(val); + if (rxdw0& CP_RX_OWN) + return 1; + else + return 0;
The QEMU coding conventions require braces here. Check your patch with scripts/checkpatch.pl. Regards, Stefan W.
