dcavalca / rpms / qemu

Forked from rpms/qemu a year ago
Clone

Blame 0189-eepro100-Fix-network-hang-when-rx-buffers-run-out.patch

5544c1
From 154f1e30c09d261b12937c385632c05474989b02 Mon Sep 17 00:00:00 2001
5544c1
From: Bo Yang <boyang@suse.com>
5544c1
Date: Wed, 29 Aug 2012 19:26:11 +0800
5544c1
Subject: [PATCH] eepro100: Fix network hang when rx buffers run out
5544c1
5544c1
This is reported by QA. When installing os with pxe, after the initial
5544c1
kernel and initrd are loaded, the procedure tries to copy files from install
5544c1
server to local harddisk, the network becomes stall because of running out of
5544c1
receive descriptor.
5544c1
5544c1
[Whitespace fixes and removed qemu_notify_event() because Paolo's
5544c1
earlier net patches have moved it into qemu_flush_queued_packets().
5544c1
5544c1
Additional info:
5544c1
5544c1
I can reproduce the network hang with a tap device doing a iPXE HTTP
5544c1
boot as follows:
5544c1
5544c1
  $ qemu -enable-kvm -m 1024 \
5544c1
    -netdev tap,id=netdev0,script=no,downscript=no \
5544c1
    -device i82559er,netdev=netdev0,romfile=80861209.rom \
5544c1
    -drive if=virtio,cache=none,file=test.img
5544c1
  iPXE> ifopen net0
5544c1
  iPXE> config # set static network configuration
5544c1
  iPXE> kernel http://mirror.bytemark.co.uk/fedora/linux/releases/17/Fedora/x86_64/os/images/pxeboot/vmlinuz
5544c1
5544c1
I needed a vanilla iPXE ROM to get to the iPXE prompt.  I think the boot
5544c1
prompt has been disabled in the ROMs that ship with QEMU to reduce boot
5544c1
time.
5544c1
5544c1
During the vmlinuz HTTP download there is a network hang.  hw/eepro100.c
5544c1
has reached the end of the rx descriptor list.  When the iPXE driver
5544c1
replenishes the rx descriptor list we don't kick the QEMU net subsystem
5544c1
and event loop, thereby leaving the tap netdev without its file
5544c1
descriptor in select(2).
5544c1
5544c1
Stefan Hajnoczi <stefanha@gmail.com>]
5544c1
5544c1
Signed-off-by: Bo Yang <boyang@suse.com>
5544c1
Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
5544c1
(cherry picked from commit 1069985fb132cd4324fc02d371f1e61492a1823f)
5544c1
5544c1
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
5544c1
---
5544c1
 hw/eepro100.c | 4 +++-
5544c1
 1 file changed, 3 insertions(+), 1 deletion(-)
5544c1
5544c1
diff --git a/hw/eepro100.c b/hw/eepro100.c
5544c1
index 50d117e..5b23116 100644
5544c1
--- a/hw/eepro100.c
5544c1
+++ b/hw/eepro100.c
5544c1
@@ -1036,6 +1036,7 @@ static void eepro100_ru_command(EEPRO100State * s, uint8_t val)
5544c1
         }
5544c1
         set_ru_state(s, ru_ready);
5544c1
         s->ru_offset = e100_read_reg4(s, SCBPointer);
5544c1
+        qemu_flush_queued_packets(&s->nic->nc);
5544c1
         TRACE(OTHER, logout("val=0x%02x (rx start)\n", val));
5544c1
         break;
5544c1
     case RX_RESUME:
5544c1
@@ -1770,7 +1771,8 @@ static ssize_t nic_receive(NetClientState *nc, const uint8_t * buf, size_t size)
5544c1
     if (rfd_command & COMMAND_EL) {
5544c1
         /* EL bit is set, so this was the last frame. */
5544c1
         logout("receive: Running out of frames\n");
5544c1
-        set_ru_state(s, ru_suspended);
5544c1
+        set_ru_state(s, ru_no_resources);
5544c1
+        eepro100_rnr_interrupt(s);
5544c1
     }
5544c1
     if (rfd_command & COMMAND_S) {
5544c1
         /* S bit is set. */
5544c1
-- 
5544c1
1.7.12.1
5544c1