Okay, I started looking into how to handle scsi-generic I/O in the
new world order.
I think the best is to use the SG_IO ioctl instead of the read/write
interface as that allows us to support scsi passthrough on disk/cdrom
devices, too. See Hannes patch on the kvm list from August for an
example.
Now that we always do ioctls we don't need another abstraction than
bdrv_ioctl for the synchronous requests for now, and for asynchronous
requests I've added a aio_ioctl abstraction keeping it simple.
Long-term we might want to move the ops to a higher-level abstraction
and let the low-level code fill out the request header, but I'm lazy
enough to leave that to the people trying to support scsi-passthrough
on a non-Linux OS.
Tested lightly by issuing various sg_ commands from sg3-utils in a guest
to a host CDROM device.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6895 c046a42c-6fe2-441c-8c8c-71466251a162
When a scsi device is backed by a scsi generic device instead of an
ordinary host block device, the block API is abused in a couple of annoying
ways:
- nb_sectors is negative, and specifies a byte count instead of a sector count
- offset is ignored, since scsi-generic is essentially a packet protocol
This overloading makes hacking the block layer difficult. Remove it by
introducing a new explicit API for scsi-generic devices. The new API
is still backed by the old implementation, but at least the users are
insulated.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6822 c046a42c-6fe2-441c-8c8c-71466251a162
this patch allows to fully use a tape device connected to qemu through
the scsi-generic interface.
Previous patch introduced tape SCSI commands management, this one
improve error case management:
- the SCSI controller command completion must be called with the status
value, not the sense value. In the case of scsi-generic, the SCSI status
is given by the field status of sg_io_hdr_t (the value is left shifted
by one regarding status codes defined in /usr/include/scsi/scsi.h)
- when a read is aborted due to a mark/EOF/EOD/EOM, the len reported to
controller can be 0. LSI controller emulation doesn't know how to manage
this. A workaround found is to call the completion routine with
SCSI_REASON_DONE just after calling it with SCSI_REASON_DATA with len=0.
This patch also manages correctly the block size of the tape device.
This patch has been tested with a real tape device "HP C5683A", linux
guest (debian etch) and tools like "mt", "tar" and "btape".
Windows guest is not better supported than before...
Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5497 c046a42c-6fe2-441c-8c8c-71466251a162
This patch allows to use a "real" SCSI tape with qemu using
"-drive /dev/sgX,if=scsi".
It allows to decode correctly transfer length when the type of the
device is a tape.
Some issues remain when the application reading the tape tries to go
beyond the end of the stream (but they must be corrected at the SCSI
controller level).
Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5305 c046a42c-6fe2-441c-8c8c-71466251a162
According to SCSI documentation, for 6 bytes commands (READ(6),
WRITE(6)), if transfer length is 0 it specifies 256 blocks.
Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5292 c046a42c-6fe2-441c-8c8c-71466251a162
void *memset(void *s, int c, size_t n);
DESCRIPTION
The memset() function fills the first n bytes of the
memory area
pointed to by s with the constant byte c."
Reported by Dietmar Maurer.
Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5291 c046a42c-6fe2-441c-8c8c-71466251a162
This patch fixes two spurious `may be used uninitialised' warnings
when compiling with some compilers.
Signed-off-by: Andre Przywara <andre.przywara@amd.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5127 c046a42c-6fe2-441c-8c8c-71466251a162
