From a71b6050a88402c3f388b8f13afed51e6ba6f41a Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Thu, 9 Aug 2012 16:45:56 +0200
Subject: [PATCH] e1000: flush queue whenever can_receive can go from false to
 true

When the guests replenish the receive ring buffer, the network device
should flush its queue of pending packets.  This is done with
qemu_flush_queued_packets.

e1000's can_receive can go from false to true when RCTL or RDT are
modified.

Reported-by: Luigi Rizzo <rizzo@iet.unipi.it>
Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Cc: Jan Kiszka <jan.kiszka@siemens.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Amos Kong <akong@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
(cherry picked from commit e8b4c680b41bd960ecccd9ff076b7b058e0afcd4)

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 hw/e1000.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/e1000.c b/hw/e1000.c
index ae8a6c5..ec3a7c4 100644
--- a/hw/e1000.c
+++ b/hw/e1000.c
@@ -295,6 +295,7 @@ set_rx_control(E1000State *s, int index, uint32_t val)
     s->rxbuf_min_shift = ((val / E1000_RCTL_RDMTS_QUAT) & 3) + 1;
     DBGOUT(RX, "RCTL: %d, mac_reg[RCTL] = 0x%x\n", s->mac_reg[RDT],
            s->mac_reg[RCTL]);
+    qemu_flush_queued_packets(&s->nic->nc);
 }
 
 static void
@@ -926,6 +927,9 @@ set_rdt(E1000State *s, int index, uint32_t val)
 {
     s->check_rxov = 0;
     s->mac_reg[index] = val & 0xffff;
+    if (e1000_has_rxbufs(s, 1)) {
+        qemu_flush_queued_packets(&s->nic->nc);
+    }
 }
 
 static void