Re: [Qemu-devel] [PATCH] pci: add standard bridge device

[Wen Congyang <wency@cn.fujitsu.com>]

At 08/17/2011 04:37 PM, Wen Congyang Write:
> At 07/04/2011 05:43 PM, Michael S. Tsirkin Write:
>> This adds support for a standard pci to pci bridge,
>> enabling support for more than 32 PCI devices in the system.
>> To use, specify the device id as a 'bus' option.
>> Example:
>> 	-device pci-bridge,id=bridge1 \
>> 	-netdev user,id=u \
>> 	-device ne2k_pci,id=net2,bus=bridge1,netdev=u
>>
>> TODO: device hotplug support.
> 
> I try this patch, and found that when I use pci bridge, qemu will core dump.
> 
> Here is my command line:
> /usr/local2/bin/qemu-system-x86_64 -M pc-0.14 -enable-kvm -m 512 -name vm1 -drive file=/var/lib/libvirt/images/vm1.img,if=none,id=drive-ide0-0-0,format=qcow2,cache=writethrough -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 -vnc 0.0.0.0:1 -device pci-bridge,id=bridge1,bus=pci.0,addr=0x08.0x0 -netdev user,id=u -device ne2k_pci,id=net2,bus=bridge1,netdev=u
> 
> Here is the backtrace:
> Core was generated by `/usr/local2/bin/qemu-system-x86_64 -M pc-0.14 -enable-kvm -m 512 -name vm1 -dri'.
> Program terminated with signal 11, Segmentation fault.
> #0  0x0000000000438e34 in memory_region_add_subregion_common (mr=0x0, offset=49152, subregion=0x1de5d58) at /home/wency/source/qemu/memory.c:1152
> 1152	    QTAILQ_FOREACH(other, &mr->subregions, subregions_link) {
> Missing separate debuginfos, use: debuginfo-install SDL-1.2.14-2.el6.x86_64 celt051-0.5.1.3-0.el6.x86_64 cyrus-sasl-gssapi-2.1.23-8.el6.x86_64 cyrus-sasl-lib-2.1.23-8.el6.x86_64 cyrus-sasl-md5-2.1.23-8.el6.x86_64 cyrus-sasl-plain-2.1.23-8.el6.x86_64 db4-4.7.25-16.el6.x86_64 glib2-2.22.5-6.el6.x86_64 glibc-2.12-1.25.el6.x86_64 keyutils-libs-1.4-1.el6.x86_64 krb5-libs-1.9-9.el6.x86_64 libX11-1.3-2.el6.x86_64 libXau-1.0.5-1.el6.x86_64 libaio-0.3.107-10.el6.x86_64 libattr-2.4.44-4.el6.x86_64 libcom_err-1.41.12-7.el6.x86_64 libcurl-7.19.7-26.el6.x86_64 libgcrypt-1.4.5-5.el6.x86_64 libgpg-error-1.7-3.el6.x86_64 libidn-1.18-2.el6.x86_64 libjpeg-6b-46.el6.x86_64 libpng-1.2.44-1.el6.x86_64 libselinux-2.0.94-5.el6.x86_64 libssh2-1.2.2-7.el6.x86_64 libtasn1-2.3-3.el6.x86_64 libuuid-2.17.2-12.el6.x86_64 libxcb-1.5-1.el6.x86_64 ncurses-libs-5.7-3.20090208.el6.x86_64 nspr-4.8.7-1.el6.x86_64 nss-3.12.9-9.el6.x86_64 nss-softokn-freebl-3.12.9-3.el6.x86_64 nss-util-3.12.9-1.el6.x86_64 openld

ap
> -2.4.23-15.el6.x86_64 openssl-1.0.0-10.el6.x86_64 pixman-0.18.4-1.el6_0.1.x86_64 spice-server-0.8.0-1.el6.x86_64 zlib-1.2.3-25.el6.x86_64
> (gdb) bt
> #0  0x0000000000438e34 in memory_region_add_subregion_common (mr=0x0, offset=49152, subregion=0x1de5d58) at /home/wency/source/qemu/memory.c:1152
> #1  0x0000000000439090 in memory_region_add_subregion_overlap (mr=0x0, offset=49152, subregion=0x1de5d58, priority=1) at /home/wency/source/qemu/memory.c:1194
> #2  0x00000000005c55fe in pci_update_mappings (d=0x1de5900) at /home/wency/source/qemu/hw/pci.c:1063
> #3  0x00000000005c5982 in pci_default_write_config (d=0x1de5900, addr=4, val=0, l=2) at /home/wency/source/qemu/hw/pci.c:1121
> #4  0x00000000005cbfbf in pci_host_config_write_common (pci_dev=0x1de5900, addr=4, limit=256, val=1, len=2) at /home/wency/source/qemu/hw/pci_host.c:54
> #5  0x00000000005cc0d1 in pci_data_write (s=0x1da2b90, addr=2147549188, val=1, len=2) at /home/wency/source/qemu/hw/pci_host.c:75
> #6  0x00000000005cc2b1 in pci_host_data_write (handler=0x1da2b60, addr=3324, val=1, len=2) at /home/wency/source/qemu/hw/pci_host.c:125
> #7  0x000000000042c884 in ioport_simple_writew (opaque=0x1da2b60, addr=3324, value=1) at /home/wency/source/qemu/rwhandler.c:50
> #8  0x0000000000499e85 in ioport_write (index=1, address=3324, data=1) at ioport.c:81
> #9  0x000000000049a8e1 in cpu_outw (addr=3324, val=1) at ioport.c:280
> #10 0x0000000000433c5d in kvm_handle_io (port=3324, data=0x7f0b30f86000, direction=1, size=2, count=1) at /home/wency/source/qemu/kvm-all.c:837
> #11 0x00000000004341c8 in kvm_cpu_exec (env=0x1b7fc70) at /home/wency/source/qemu/kvm-all.c:976
> #12 0x000000000040da99 in cpu_exec_all () at /home/wency/source/qemu/cpus.c:1102
> #13 0x00000000005b60c4 in main_loop () at /home/wency/source/qemu/vl.c:1392
> #14 0x00000000005baa49 in main (argc=20, argv=0x7ffffa6b5a38, envp=0x7ffffa6b5ae0) at /home/wency/source/qemu/vl.c:3356
> 
> If I do not attach any device on bus bridge1, qemu can work nice.
> 
> Thanks
> Wen Congyang
> 

The following patch can fix this problem, but I'm not sure whether it is right.

>From 3ce0000e5a14f0ff7aeac148f9416eac6fa7c6ca Mon Sep 17 00:00:00 2001
From: Wen Congyang <wency@cn.fujitsu.com>
Date: Thu, 18 Aug 2011 09:33:19 +0800
Subject: [PATCH] PCI_Bridge: use parent bus's address space

The pci device may call pci_register_bar() to use PCI bus's address space.
But we forget to init PCI bus's address space if it is not bus 0. It will
cause qemu crashed.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>

---
 hw/pci_bridge.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/hw/pci_bridge.c b/hw/pci_bridge.c
index 464d897..df16faa 100644
--- a/hw/pci_bridge.c
+++ b/hw/pci_bridge.c
@@ -246,6 +246,8 @@ int pci_bridge_initfn(PCIDevice *dev)
                         br->bus_name);
     sec_bus->parent_dev = dev;
     sec_bus->map_irq = br->map_irq;
+    sec_bus->address_space_mem = parent->address_space_mem;
+    sec_bus->address_space_io = parent->address_space_io;
 
     QLIST_INIT(&sec_bus->child);
     QLIST_INSERT_HEAD(&parent->child, sec_bus, sibling);
-- 
1.7.1