[PATCH 0/1] linux-user: Add support for SG_IO and SG_GET_VERSION_NUM raw SCSI ioctls

From: Leif N Huhn <leif.n.huhn@gmail.com>
To: qemu-devel@nongnu.org
Cc: Leif N Huhn <leif.n.huhn@gmail.com>
Subject: [PATCH 0/1] linux-user: Add support for SG_IO and SG_GET_VERSION_NUM raw SCSI ioctls
Date: Wed, 29 Jul 2020 21:55:47 -0500	[thread overview]
Message-ID: <20200730025548.237905-1-leif.n.huhn@gmail.com> (raw)

Hi. This is my first time trying to contribute to qemu. This patch
works correctly for architectures with the same bit-width, for example
32bit arm host and i386 user binary. Here is an example with the sg_simple2
executable from https://github.com/hreinecke/sg3_utils

32-bit ARM native:

  strace -e trace=ioctl ./sg_simple2 /dev/sg0
  ioctl(3, SG_GET_VERSION_NUM, [30536])   = 0
  ioctl(3, SG_IO, {interface_id='S', dxfer_direction=SG_DXFER_FROM_DEV, cmd_len=6, cmdp="\x12\x00\x00\x00\x60\x00", mx_sb_len=32, iovec_count=0, dxfer_len=96, timeout=20000, flags=0, dxferp="\x05\x80\x00\x32\x5b\x00\x00\x00\x48\x4c\x2d\x44\x54\x2d\x53\x54\x42\x44\x2d\x52\x45\x20\x20\x57\x48\x31\x36\x4e\x53\x34\x30\x20"..., status=0, masked_status=0, msg_status=0, sb_len_wr=0, sbp="", host_status=0, driver_status=0, resid=0, duration=3, info=0}) = 0
  Some of the INQUIRY command's results:
      HL-DT-ST  BD-RE  WH16NS40   1.05  [wide=0 sync=0 cmdque=0 sftre=0]
  ioctl(3, SG_IO, {interface_id='S', dxfer_direction=SG_DXFER_NONE, cmd_len=6, cmdp="\x00\x00\x00\x00\x00\x00", mx_sb_len=32, iovec_count=0, dxfer_len=0, timeout=20000, flags=0, status=0, masked_status=0, msg_status=0, sb_len_wr=0, sbp="", host_status=0, driver_status=0, resid=0, duration=4, info=0}) = 0
  Test Unit Ready successful so unit is ready!
  +++ exited with 0 +++

i386 binary on 32-bit arm host:

  strace -f -e trace=ioctl qemu/build/i386-linux-user/qemu-i386 sg3_utils/examples/sg_simple2 /dev/sg0
  strace: Process 690 attached
  [pid   689] ioctl(3, SG_GET_VERSION_NUM, [30536]) = 0
  [pid   689] ioctl(3, SG_IO, {interface_id='S', dxfer_direction=SG_DXFER_FROM_DEV, cmd_len=6, cmdp="\x12\x00\x00\x00\x60\x00", mx_sb_len=32, iovec_count=0, dxfer_len=96, timeout=20000, flags=0, dxferp="\x05\x80\x00\x32\x5b\x00\x00\x00\x48\x4c\x2d\x44\x54\x2d\x53\x54\x42\x44\x2d\x52\x45\x20\x20\x57\x48\x31\x36\x4e\x53\x34\x30\x20"..., status=0, masked_status=0, msg_status=0, sb_len_wr=0, sbp="", host_status=0, driver_status=0, resid=0, duration=3, info=0}) = 0
  Some of the INQUIRY command's results:
      HL-DT-ST  BD-RE  WH16NS40   1.05  [wide=0 sync=0 cmdque=0 sftre=0]
  [pid   689] ioctl(3, SG_IO, {interface_id='S', dxfer_direction=SG_DXFER_NONE, cmd_len=6, cmdp="\x00\x00\x00\x00\x00\x00", mx_sb_len=32, iovec_count=0, dxfer_len=0, timeout=20000, flags=0, status=0, masked_status=0, msg_status=0, sb_len_wr=0, sbp="", host_status=0, driver_status=0, resid=0, duration=3, info=0}) = 0
  Test Unit Ready successful so unit is ready!
  [pid   690] +++ exited with 0 +++
  +++ exited with 0 +++

However when I try i386 guest on x86_64 host, the cmdp bytes in the
first SG_IO call are zero, incorrectly. I assume that is because I need
to write a special ioctl handler. Is that correct? Should I be calling
lock_user(VERIFY_WRITE...) to copy the buffers over?

Also, is the current patch acceptable as is, or does it need to be
reworked until the ioctl works with different architecture bit-widths?

Thanks!

Leif N Huhn (1):
  linux-user: Add support for SG_IO and SG_GET_VERSION_NUM raw SCSI
    ioctls

 linux-user/ioctls.h        |  2 ++
 linux-user/syscall.c       |  1 +
 linux-user/syscall_defs.h  | 33 +++++++++++++++++++++++++++++++++
 linux-user/syscall_types.h |  5 +++++
 4 files changed, 41 insertions(+)

-- 
2.28.0