[coreboot] [OpenBIOS] OpenBIOS SVN r416 breaks coreboot-v3

[Mark Cave-Ayland]

Myles Watson wrote:

> Yes.  qemu 0.9.1 works with v2+OpenBIOS and v3+OpenBIOS, but the latest qemu
> doesn't.  The latest qemu works with v2 or v3 +OpenBIOS r186, so it looks
> like an interaction between OpenBIOS and qemu.
> 
> HTH,
> Myles

Okay, I think I found out what is happening. With coreboot-v3 and 
OpenBIOS SVN then the base address for I/O devices is set to 0x400 which 
causes subsequent hardware to be mapped higher. The backtrace on the 
hw_error() line shows this:


Breakpoint 1, register_ioport_write (start=1296, length=1, size=1, 
func=0x42b105 <ne2000_asic_ioport_write>, opaque=0xc9abb8)
     at /home/build/src/qemu/trunk/vl.c:392
392                 hw_error("register_ioport_write: invalid opaque: 
(start 0x%x, length 0x%x, address 0x%x)", start, length, i);
(gdb) print/x start
$1 = 0x510
(gdb) bt
#0  register_ioport_write (start=1296, length=1, size=1, func=0x42b105 
<ne2000_asic_ioport_write>, opaque=0xc9abb8)
     at /home/build/src/qemu/trunk/vl.c:392
#1  0x000000000042bc6b in ne2000_map (pci_dev=0xc9a990, region_num=0, 
addr=1280, size=256, type=1)
     at /home/build/src/qemu/trunk/hw/ne2000.c:771
#2  0x0000000000414548 in pci_update_mappings (d=0xc9a990) at 
/home/build/src/qemu/trunk/hw/pci.c:301
#3  0x0000000000414706 in pci_default_write_config (d=0xc9a990, 
address=16, val=1281, len=4) at /home/build/src/qemu/trunk/hw/pci.c:362
#4  0x00000000004148d7 in pci_data_write (opaque=0xc281c0, 
addr=2147489808, val=1281, len=4) at /home/build/src/qemu/trunk/hw/pci.c:467
#5  0x0000000000483e31 in pci_host_data_writel (opaque=0xc281a0, 
addr=3324, val=1281) at /home/build/src/qemu/trunk/hw/pci_host.h:74
#6  0x0000000000406818 in ioport_write (index=2, address=3324, 
data=1281) at /home/build/src/qemu/trunk/vl.c:298
#7  0x0000000000406c0d in cpu_outl (env=0xc10650, addr=3324, val=1281) 
at /home/build/src/qemu/trunk/vl.c:438
#8  0x00000000005248fe in helper_outl (port=3324, data=1281) at 
/home/build/src/qemu/trunk/target-i386/op_helper.c:582
#9  0x0000000040e5d11c in ?? ()
#10 0x00000000000000f4 in ?? ()
#11 0x0000000006e64a20 in ?? ()
#12 0x0000000006f687ab in ?? ()
#13 0x0000000040e5ce30 in ?? ()
#14 0x0000000040e603c8 in ?? ()
#15 0x0000000008000000 in ?? ()
#16 0x00007fff4ef701b0 in ?? ()
#17 0x00000000004fcd9c in tb_set_jmp_target (tb=0x406670, n=0, 
addr=2361183241434822607) at ../exec-all.h:240
#18 0x000000000040c64f in main_loop () at 
/home/build/src/qemu/trunk/vl.c:3737
#19 0x000000000040f772 in main (argc=6, argv=0x7fff4ef70bf8, 
envp=0x7fff4ef70c30) at /home/build/src/qemu/trunk/vl.c:5712


So in other words, with current OpenBIOS SVN the I/O space for the 
network card requires more than 0x110 bytes from 0x400 and hence when 
qemu tries to map I/O address 0x510 (which is already mapped to the BIOS 
I/O port), qemu reports the error and panics.

My quick fix was to apply the following patch to openbios in order to 
raise the io_base further from 0x400 to 0x520 so that no devices appear 
below the BIOS_IO_PORT address of 0x510:


--- drivers/pci.c       (revision 428)
+++ drivers/pci.c       (working copy)
@@ -762,7 +762,7 @@
         mem_base = arch->mem_base;
          /* I/O ports under 0x400 are used by devices mapped at fixed
             location. */
-        io_base = arch->io_base + 0x400;
+        io_base = arch->io_base + 0x520;
         path = strdup("");
         for (bus = 0; bus<0x100; bus++) {
                 ob_scan_pci_bus(bus, &mem_base, &io_base, &path);


With this patch applied, I am pleased to report that qemu can 
successfully boot openbios once again. Can anyone with more knowledge 
comment on whether this is an adequate solution or not?


ATB,

Mark.

-- 
Mark Cave-Ayland
Sirius Corporation - The Open Source Experts
http://www.siriusit.co.uk
T: +44 870 608 0063