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Re: [PATCH 1/1] linux-user: Add support for SG_IO and SG_GET_VERSION_NUM
From: |
Filip Bozuta |
Subject: |
Re: [PATCH 1/1] linux-user: Add support for SG_IO and SG_GET_VERSION_NUM raw SCSI ioctls |
Date: |
Fri, 31 Jul 2020 12:23:23 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 |
On 30.7.20. 04:55, Leif N Huhn wrote:
This patch implements functionalities of following ioctls:
SG_GET_VERSION_NUM - Returns SG driver version number
The sg version numbers are of the form "x.y.z" and the single number given
by the SG_GET_VERSION_NUM ioctl() is calculated by
(x * 10000 + y * 100 + z).
SG_IO - Permits user applications to send SCSI commands to a device
It is logically equivalent to a write followed by a read.
Implementation notes:
For SG_GET_VERSION_NUM the value is an int and the implementation is
straightforward.
For SG_IO, the generic thunk mechanism is used, and works correctly when
the host and guest architecture have the same pointer size. A special ioctl
handler may be needed in other situations and is not covered in this
implementation.
Signed-off-by: Leif N Huhn <leif.n.huhn@gmail.com>
---
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(+)
diff --git a/linux-user/ioctls.h b/linux-user/ioctls.h
index 0713ae1311..92e2f65e05 100644
--- a/linux-user/ioctls.h
+++ b/linux-user/ioctls.h
@@ -333,6 +333,8 @@
IOCTL(CDROM_DRIVE_STATUS, 0, TYPE_NULL)
IOCTL(CDROM_DISC_STATUS, 0, TYPE_NULL)
IOCTL(CDROMAUDIOBUFSIZ, 0, TYPE_INT)
I think there should be a space between ioctls of different groups (in
this case CDROM and SG).
+ IOCTL(SG_GET_VERSION_NUM, 0, TYPE_INT)
SG_GET_VERSION_NUM reads the SG driver version number which means it is of
type IOC_R. The 0 is used only for ioctl types that don't have the third
argument. Also,
the third argument is a pointer to a 'TYPE_INT' since it is used for
reading. I tried
your patch with sg_simple1 and I get the different version number with
native and
cross execution so I think this needs to be corrected. The IOCTL(...)
definition should be:
IOCTL(SG_GET_VERSION_NUM, IOC_R, MK_PTR(TYPE_INT))
After this, the 'SG_GET_VERSION_NUM' works fine.
+ IOCTL(SG_IO, IOC_RW, MK_PTR(MK_STRUCT(STRUCT_sg_io_hdr)))
#if 0
IOCTL(SNDCTL_COPR_HALT, IOC_RW, MK_PTR(TYPE_INT))
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 945fc25279..d846ef1af2 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -115,6 +115,7 @@
#ifdef HAVE_DRM_H
#include <libdrm/drm.h>
#endif
+#include <scsi/sg.h>
#include "linux_loop.h"
#include "uname.h"
diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
index 3c261cff0e..0e3004eb31 100644
--- a/linux-user/syscall_defs.h
+++ b/linux-user/syscall_defs.h
@@ -2774,4 +2774,37 @@ struct target_statx {
/* 0x100 */
};
+/* from kernel's include/scsi/sg.h */
+
+#define TARGET_SG_GET_VERSION_NUM 0x2282 /* Example: version 2.1.34 yields
20134 */
+/* synchronous SCSI command ioctl, (only in version 3 interface) */
+#define TARGET_SG_IO 0x2285 /* similar effect as write() followed by read()
*/
+
+struct target_sg_io_hdr
+{
+ int interface_id; /* [i] 'S' for SCSI generic (required) */
+ int dxfer_direction; /* [i] data transfer direction */
+ unsigned char cmd_len; /* [i] SCSI command length */
+ unsigned char mx_sb_len; /* [i] max length to write to sbp */
+ unsigned short iovec_count; /* [i] 0 implies no scatter gather */
+ unsigned int dxfer_len; /* [i] byte count of data transfer */
+ abi_ulong dxferp; /* [i], [*io] points to data transfer memory
+ or scatter gather list */
+ abi_ulong cmdp; /* [i], [*i] points to command to perform */
+ abi_ulong sbp; /* [i], [*o] points to sense_buffer memory */
+ unsigned int timeout; /* [i] MAX_UINT->no timeout (unit: millisec) */
+ unsigned int flags; /* [i] 0 -> default, see SG_FLAG... */
+ int pack_id; /* [i->o] unused internally (normally) */
+ abi_ulong usr_ptr; /* [i->o] unused internally */
+ unsigned char status; /* [o] scsi status */
+ unsigned char masked_status;/* [o] shifted, masked scsi status */
+ unsigned char msg_status; /* [o] messaging level data (optional) */
+ unsigned char sb_len_wr; /* [o] byte count actually written to sbp */
+ unsigned short host_status; /* [o] errors from host adapter */
+ unsigned short driver_status;/* [o] errors from software driver */
+ int resid; /* [o] dxfer_len - actual_transferred */
+ unsigned int duration; /* [o] time taken by cmd (unit: millisec) */
+ unsigned int info; /* [o] auxiliary information */
+}; /* 64 bytes long (on i386) */
+
This target structure is defined, but is not used anywhere. It should be
used
in a special ioctl handling function for SG_IO to convert the values of
'sg_io_hdr'
between host and target.
#endif
diff --git a/linux-user/syscall_types.h b/linux-user/syscall_types.h
index 3f1f033464..3752d217e2 100644
--- a/linux-user/syscall_types.h
+++ b/linux-user/syscall_types.h
@@ -59,6 +59,11 @@ STRUCT(cdrom_read_audio,
TYPE_CHAR, TYPE_CHAR, TYPE_CHAR, TYPE_CHAR, TYPE_CHAR, TYPE_INT,
TYPE_PTRVOID,
TYPE_NULL)
+STRUCT(sg_io_hdr,
+ TYPE_INT, TYPE_INT, TYPE_CHAR, TYPE_CHAR, TYPE_SHORT, TYPE_INT,
TYPE_PTRVOID,
+ TYPE_PTRVOID, TYPE_PTRVOID, TYPE_INT, TYPE_INT, TYPE_INT, TYPE_PTRVOID,
TYPE_CHAR,
+ TYPE_CHAR, TYPE_CHAR, TYPE_CHAR, TYPE_SHORT, TYPE_SHORT, TYPE_INT,
TYPE_INT, TYPE_INT)
+
I think a nicer and cleaner way to define the thunk types is to write
the types in separate lines
followed by a tail comment which describes the field type. Something like:
STRUCT(sg_io_hdr,
TYPE_INT, /* interface_id */
TYPE_INT, /* dxfer_direction */
TYPE_CHAR, /* cmd_len */
...
This way it is less likely that an issue can ocurr (i.e. to forget a
field) and it makes the
code more reviewable. You can check out other examples from
'syscall_types.h' (i.e. snd_timer_id,
loop_info).
Best regards,
Filip
STRUCT(hd_geometry,
TYPE_CHAR, TYPE_CHAR, TYPE_SHORT, TYPE_ULONG)