Re: [Qemu-devel] QEMU 0.12.3 and SCSI boot

[Kevin Wolf <kwolf@redhat.com>]

Am 27.03.2010 10:38, schrieb Gerhard Wiesinger:
> Hello,
> 
> I'm having trouble booting from SCSI adapter 53C895a and e.g. INT13h OS 
> like MS-DOS 6.22.
> 
> I downloaded and installed the option ROM with -option-rom 8xx_64.rom:
> http://www.lsi.com/DistributionSystem/AssetDocument/files/support/ssp/sdms/Bios/lsi_bios.zip
> 
> I'm seeing that Harddisks are installed well and that also "PCI boot ROM 
> succesfully installed" message appears. So that part looks good as DDIM 
> (Device Driver Initialization Model) has been implemented.
> 
> Also booting (sometimes) and sometimes access works until nearly 
> immediatly the following problems occour (repeated messages with different 
> Tags):
> lsi_scsi: error: Reselect with pending DMA
> scsi-disk: Tag 0x0 already in use
> paio_remove: aio request not found!
> 
> So it seems to me that there is some incompatibility with the ROM and the 
> SCSI emulation (busmaster DMA?) and INT 13h.
> 
> BTW: Booting Knoppix 6.2 Live CD without any option ROM and even with 
> option ROM works well with SCSI disks (at least reading from them without 
> any errors on the console, i guess because of own drivers and not INT13h 
> access).
> 
> Any ideas to fix that issue and to bugfix it?

Tried the same with current git master and it segfaults. This segfault
was introduced in af12ac98 (lsi: have lsi_request for the whole life
time of the request):

#0  0x000000000052e2d3 in lsi_command_complete (bus=0xca22f8, reason=1,
tag=0, arg=512) at /home/kwolf/source/qemu/hw/lsi53c895a.c:690
#1  0x00000000004416e7 in qcow_aio_read_cb (opaque=0xc813f0, ret=0) at
block/qcow2.c:480
#2  0x0000000000433028 in posix_aio_process_queue (opaque=<value
optimized out>) at posix-aio-compat.c:459
#3  0x00000000004330cc in posix_aio_read (opaque=0xc4bb60) at
posix-aio-compat.c:489
#4  0x000000000040ac60 in main_loop_wait (timeout=0) at
/home/kwolf/source/qemu/vl.c:3949
#5  0x000000000040ce85 in main_loop (argc=<value optimized out>,
argv=<value optimized out>, envp=<value optimized out>)
    at /home/kwolf/source/qemu/vl.c:4172
#6  main (argc=<value optimized out>, argv=<value optimized out>,
envp=<value optimized out>) at /home/kwolf/source/qemu/vl.c:6147

s->current is set to NULL by lsi_queue_command. I don't know the code
well enough to say if lsi_queue_command is wrong in setting it to NULL
or if lsi_command_complete shouldn't even try to access it (maybe it
should search in the queue for the right tag?)

Gerd, do you remember how it's supposed to work?

Kevin