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[Qemu-devel] [PATCH 04/13] eepro100: Fix network hang when rx buffers ru
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PATCH 04/13] eepro100: Fix network hang when rx buffers run out |
Date: |
Fri, 14 Sep 2012 09:46:51 +0100 |
From: Bo Yang <address@hidden>
This is reported by QA. When installing os with pxe, after the initial
kernel and initrd are loaded, the procedure tries to copy files from install
server to local harddisk, the network becomes stall because of running out of
receive descriptor.
[Whitespace fixes and removed qemu_notify_event() because Paolo's
earlier net patches have moved it into qemu_flush_queued_packets().
Additional info:
I can reproduce the network hang with a tap device doing a iPXE HTTP
boot as follows:
$ qemu -enable-kvm -m 1024 \
-netdev tap,id=netdev0,script=no,downscript=no \
-device i82559er,netdev=netdev0,romfile=80861209.rom \
-drive if=virtio,cache=none,file=test.img
iPXE> ifopen net0
iPXE> config # set static network configuration
iPXE> kernel
http://mirror.bytemark.co.uk/fedora/linux/releases/17/Fedora/x86_64/os/images/pxeboot/vmlinuz
I needed a vanilla iPXE ROM to get to the iPXE prompt. I think the boot
prompt has been disabled in the ROMs that ship with QEMU to reduce boot
time.
During the vmlinuz HTTP download there is a network hang. hw/eepro100.c
has reached the end of the rx descriptor list. When the iPXE driver
replenishes the rx descriptor list we don't kick the QEMU net subsystem
and event loop, thereby leaving the tap netdev without its file
descriptor in select(2).
Stefan Hajnoczi <address@hidden>]
Signed-off-by: Bo Yang <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
hw/eepro100.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/hw/eepro100.c b/hw/eepro100.c
index 50d117e..5b23116 100644
--- a/hw/eepro100.c
+++ b/hw/eepro100.c
@@ -1036,6 +1036,7 @@ static void eepro100_ru_command(EEPRO100State * s,
uint8_t val)
}
set_ru_state(s, ru_ready);
s->ru_offset = e100_read_reg4(s, SCBPointer);
+ qemu_flush_queued_packets(&s->nic->nc);
TRACE(OTHER, logout("val=0x%02x (rx start)\n", val));
break;
case RX_RESUME:
@@ -1770,7 +1771,8 @@ static ssize_t nic_receive(NetClientState *nc, const
uint8_t * buf, size_t size)
if (rfd_command & COMMAND_EL) {
/* EL bit is set, so this was the last frame. */
logout("receive: Running out of frames\n");
- set_ru_state(s, ru_suspended);
+ set_ru_state(s, ru_no_resources);
+ eepro100_rnr_interrupt(s);
}
if (rfd_command & COMMAND_S) {
/* S bit is set. */
--
1.7.10.4
- [Qemu-devel] [PULL 00/13] Net patches, Stefan Hajnoczi, 2012/09/14
- [Qemu-devel] [PULL 00/13] Net patches, Stefan Hajnoczi, 2012/09/14
- [Qemu-devel] [PATCH 02/13] e1000: flush queue whenever can_receive can go from false to true, Stefan Hajnoczi, 2012/09/14
- [Qemu-devel] [PATCH 01/13] net: notify iothread after flushing queue, Stefan Hajnoczi, 2012/09/14
- [Qemu-devel] [PATCH 03/13] xen: flush queue when getting an event, Stefan Hajnoczi, 2012/09/14
- [Qemu-devel] [PATCH 04/13] eepro100: Fix network hang when rx buffers run out,
Stefan Hajnoczi <=
- [Qemu-devel] [PATCH 05/13] net: add receive_disabled logic to iov delivery path, Stefan Hajnoczi, 2012/09/14
- [Qemu-devel] [PATCH 07/13] net: add -netdev options to man page, Stefan Hajnoczi, 2012/09/14
- [Qemu-devel] [PATCH 08/13] net: clean up usbnet_receive(), Stefan Hajnoczi, 2012/09/14
- [Qemu-devel] [PATCH 06/13] net: do not report queued packets as sent, Stefan Hajnoczi, 2012/09/14
- [Qemu-devel] [PATCH 11/13] net: asynchronous send/receive infrastructure for net/socket.c, Stefan Hajnoczi, 2012/09/14
- [Qemu-devel] [PATCH 09/13] net: fix usbnet_receive() packet drops, Stefan Hajnoczi, 2012/09/14
- [Qemu-devel] [PATCH 12/13] net: EAGAIN handling for net/socket.c UDP, Stefan Hajnoczi, 2012/09/14
- [Qemu-devel] [PATCH 10/13] net: broadcast hub packets if at least one port can receive, Stefan Hajnoczi, 2012/09/14
- [Qemu-devel] [PATCH 13/13] net: EAGAIN handling for net/socket.c TCP, Stefan Hajnoczi, 2012/09/14
- Re: [Qemu-devel] [PULL 00/13] Net patches, Anthony Liguori, 2012/09/17