[Qemu-devel] Debug Qemu dhcpd

[Adnan Khaleel]

I'm using Isaku Yamahata's q35 chipset model in Qemu0.14 and I'm trying to figure out why the Qemu dhcpd server is not responding back to the nic device in the guest OS when used with user mode networking.

The guest OS sees the network device and initialises it but I think the Qemu DHCP server/firewall never gets back, since the network device doesn't even get a 10.0.2.15 ip address during bootup and the guest dhcp client never gets an ip address, 

eth0   device: Intel Corporation 82540EM Gigabit Ethernet Controller (rev 03)

eth0   Starting DHCP4 client. . . . . . . .

eth0   DHCP4 continues in background 

eth0   device: Intel Corporation 82540EM Gigabit Ethernet Controller (rev 03)

eth0   DHCP4 client (dhcpcd) is running

eth0   . . . but is still waiting for data

eth0   interface could not be set up until now

So doing an ifconfig later on just shows

eth0     Link encap:Ethernet  HWaddr 52:54:00:12:34:56

         UP BROADCAST MULTICAST  MTU:1500  Metric:1

         RX packets:0 errors:0 dropped:0 overruns:0 frame:0

         TX packets:0 errors:0 dropped:0 overruns:0 carrier:0

         collisions:0 txqueuelen:1000

         RX bytes:0 (0.0 b)   TX bytes:0 (0.0 b)

lo       Link encap:Local loopback  

         inet addr:127.0.0.1  Mask:255.0.0.0

         inet6 addr: ::1/128 Scope:Host

         UP LOOPBACK RUNING  MTU:16436  Metric:1

         RX packets:0 errors:0 dropped:0 overruns:0 frame:0

         TX packets:0 errors:0 dropped:0 overruns:0 carrier:0

         collisions:0 txqueuelen:1000

         RX bytes:0 (0.0 b)   TX bytes:0 (0.0 b)

The NIC device is an Intel e1000 however, even if I use a pci ne2k, I get the same result. I've enabled debugging in the hw/e1000.c and in comparing the good debug output with the bad debug output, I noticed the point of deviation. The two traces are identical up till that point. Given that the problem is not the e1000 model itself, I doubt these traces are anything but symptomatic of the underlying problem in the Qemu portion that handles network traffic. 

Any ideas on what I can check next to see where the underlying problem might be?

-AK

This is a trace of the e1000.c debug messages from boot up for the good case on the left (where networking works) and the bad case on the right (where it doesn't).

Good - Debug out                                                          Bad - Debug out

================                                                          ===============

e1000: e1000_ioport_map addr=0xc040 size=0x00000040                          

e1000: e1000_ioport_map addr=0xc040 size=0x00000040  

e1000: RCTL: 0, mac_reg[RCTL] = 0x0  

e1000: tx disabled  

e1000: RCTL: 0, mac_reg[RCTL] = 0x0                                          

e1000: tx disabled  

e1000: MMIO unknown write addr=0x00005800,val=0x00000000  

e1000: tx disabled  

e1000: MMIO unknown write addr=0x00000030,val=0x00008808  

e1000: MMIO unknown write addr=0x0000002c,val=0x00000100  

e1000: MMIO unknown write addr=0x00000028,val=0x00c28001  

e1000: MMIO unknown write addr=0x00000170,val=0x00000680  

e1000: MMIO unknown write addr=0x00002160,val=0x00000000  

e1000: MMIO unknown write addr=0x00002168,val=0x00000000  

e1000: MMIO unknown read addr=0x00004014  

e1000: MMIO unknown read addr=0x00004018  

e1000: MMIO unknown read addr=0x0000401c  

e1000: MMIO unknown read addr=0x00004020  

:                                                                            

e1000: MMIO unknown read addr=0x000040b4  

e1000: MMIO unknown read addr=0x000040b8  

e1000: MMIO unknown read addr=0x000040bc  

e1000: MMIO unknown write addr=0x00000458,val=0x00000000  

e1000: RCTL: 0, mac_reg[RCTL] = 0x40000  

e1000: tx disabled  

e1000: MMIO unknown write addr=0x00000410,val=0x00602008  

e1000: MMIO unknown write addr=0x00003820,val=0x00000008  

e1000: MMIO unknown write addr=0x0000382c,val=0x00000020  

e1000: tx disabled  

e1000: tx disabled  

e1000: RCTL: 0, mac_reg[RCTL] = 0x48002  

e1000: RCTL: 0, mac_reg[RCTL] = 0x48000  

e1000: MMIO unknown write addr=0x00002820,val=0x00000000  

e1000: MMIO unknown write addr=0x0000282c,val=0x00000008  

e1000: MMIO unknown write addr=0x000000c4,val=0x000000c3  

e1000: MMIO unknown read addr=0x00005000  

e1000: MMIO unknown write addr=0x00005000,val=0x00000200         

e1000: RCTL: 0, mac_reg[RCTL] = 0x48002 e1000: RCTL: 0, mac_reg[RCTL] = 0x48002                              

e1000: MMIO unknown write addr=0x000000c4,val=0x000003d0 e1000: RCTL: 254, mac_reg[RCTL] = 0x48002 <= Point at which 1st difference appears

e1000: RCTL: 254, mac_reg[RCTL] = 0x48002 e1000: RCTL: 254, mac_reg[RCTL] = 0x48002

e1000: tx disabled e1000: RCTL: 254, mac_reg[RCTL] = 0x48002

e1000: MMIO unknown read addr=0x00004088 e1000: RCTL: 254, mac_reg[RCTL] = 0x48002

e1000: MMIO unknown read addr=0x0000408c e1000: RCTL: 254, mac_reg[RCTL] = 0x48002

e1000: MMIO unknown read addr=0x00004078 e1000: RCTL: 254, mac_reg[RCTL] = 0x48002

e1000: MMIO unknown read addr=0x0000407c e1000: RCTL: 254, mac_reg[RCTL] = 0x48002

e1000: MMIO unknown read addr=0x000040ac e1000: RCTL: 254, mac_reg[RCTL] = 0x0

e1000: MMIO unknown read addr=0x0000405c e1000: tx disabled

e1000: MMIO unknown read addr=0x00004060 e1000: MMIO unknown write addr=0x00005800,val=0x00000000

e1000: MMIO unknown read addr=0x00004064 e1000: tx disabled

e1000: MMIO unknown read addr=0x00004068 e1000: MMIO unknown write addr=0x00000030,val=0x00008808

                                                                        e1000: MMIO unknown write addr=0x0000002c,val=0x00000100

                                                                        e1000: MMIO unknown write addr=0x00000028,val=0x00c28001

                                                                        e1000: MMIO unknown write addr=0x00000170,val=0x00000680

                                                                        e1000: MMIO unknown write addr=0x00002160,val=0x00000000