Commit graph

48 commits

Author SHA1 Message Date
Paolo Bonzini
1288844e7c iscsi: reorganize iscsi_readcapacity_sync
Avoid the goto, and use the same retry logic for the 10- and 16-
byte versions.

Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-06-18 12:43:03 +02:00
Paolo Bonzini
f0d2a4d4d6 iscsi: simplify freeing of tasks
Always free them in the iscsi_aio_*_acb functions and remove the
checks in their callers.  Remove ifs when the task struct was
previously dereferenced (spotted by Coverity).

Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-06-18 12:43:03 +02:00
Kevin Wolf
56d1b4d21d block: Remove filename parameter from .bdrv_file_open()
It is unused now in all block drivers.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2013-04-22 11:34:35 +02:00
Kevin Wolf
60beb3412d iscsi: Use bdrv_open options instead of filename
This is only to convert the internal interface that is used for passing
the "filename" to be parsed, but converting to actual fine grained
options is left for another day, as it doesn't look trivial.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2013-04-22 10:27:59 +02:00
Paolo Bonzini
0d09e41a51 hw: move headers to include/
Many of these should be cleaned up with proper qdev-/QOM-ification.
Right now there are many catch-all headers in include/hw/ARCH depending
on cpu.h, and this makes it necessary to compile these files per-target.
However, fixing this does not belong in these patches.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-04-08 18:13:10 +02:00
Kevin Wolf
787e4a8500 block: Add options QDict to bdrv_file_open() prototypes
The new parameter is unused yet.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2013-03-22 17:51:31 +01:00
Peter Lieven
cb1b83e740 iscsi: add iscsi_truncate support
this patch adds iscsi_truncate which effectively allows for
online resizing of iscsi volumes. for this to work you have
to resize the volume on your storage and then call
block_resize command in qemu which will issue a
readcapacity16 to update the capacity.

v4:
  - factor out complete readcapacity logic into a separate function
  - handle capacity change check condition in readcapacity function
    (this happens if the block_resize cmd is the first iscsi task
    executed after a resize on the storage)

v3:
  - remove switch statement in iscsi_open
  - create separate patch for brdv_drain_all() in bdrv_truncate()

v2:
  - add a general bdrv_drain_all() before bdrv_truncate() to avoid
    in-flight AIOs while the device is truncated
  - since no AIOs are in flight we can use a sync libiscsi call
    to re-read the capacity
  - factor out the readcapacity16 logic as it is redundant
    to iscsi_open() and iscsi_truncate().

Signed-off-by: Peter Lieven <pl@kamp.de>
[allow any type of unit attention check condition in iscsi_readcapacity_sync(),
 as in Message-ID: <51263A2A.6070304@dlhnet.de> - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-03-05 17:51:51 +01:00
Peter Lieven
1dde716ed6 iscsi: retry read, write, flush and unmap on unit attention check conditions
the storage might return a check condition status for various reasons.
(e.g. bus reset, capacity change, thin-provisioning info etc.)

currently all these informative status responses lead to an I/O error
which is populated to the guest. this patch introduces a retry mechanism
to avoid this.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-03-05 17:51:50 +01:00
Peter Lieven
7371d56fb2 iscsi: add support for iovectors
This patch adds support for directly passing the iovec
array from QEMUIOVector if libiscsi supports it (1.8.0
or newer).

Signed-off-by: Peter Lieven <pl@kamp.de>
[Preserve the improvements from commit 4cc841b, iscsi: partly
 avoid iovec linearization in iscsi_aio_writev, 2012-11-19 - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-01-24 15:37:55 +01:00
Paolo Bonzini
4790b03d30 iscsi: do not leak acb->buf when commands are aborted
acb->buf is freed in the WRITE(16) callback, but this may not
get called at all when commands are aborted.  Add another
free in the ABORT TASK callback, which requires setting acb->buf
to NULL everywhere.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-01-24 15:37:55 +01:00
Anthony Liguori
177f7fc688 Merge remote-tracking branch 'bonzini/scsi-next' into staging
# By Peter Lieven (3) and others
# Via Paolo Bonzini
* bonzini/scsi-next:
  scsi: Drop useless null test in scsi_unit_attention()
  lsi: use qbus_reset_all to reset SCSI bus
  scsi: fix segfault with 0-byte disk
  iscsi: add support for iSCSI NOPs [v2]
  iscsi: partly avoid iovec linearization in iscsi_aio_writev
  iscsi: add iscsi_create support
2013-01-23 09:08:54 -06:00
Peter Lieven
5b5d34ec98 iscsi: add support for iSCSI NOPs [v2]
This patch will send NOP-Out PDUs every 5 seconds to the iSCSI target.
If a consecutive number of NOP-In replies fail a reconnect is initiated.
iSCSI NOPs help to ensure that the connection to the target is still operational.
This should not, but in reality may be the case even if the TCP connection is still
alive if there are bugs in either the target or the initiator implementation.

v2:
 - track the NOPs inside libiscsi so libiscsi can reset the counter
   in case it initiates a reconnect.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-01-22 15:07:03 +01:00
Peter Lieven
4cc841b57c iscsi: partly avoid iovec linearization in iscsi_aio_writev
libiscsi expects all write16 data in a linear buffer. If the
iovec only contains one buffer we can skip the linearization
step as well as the additional malloc/free and pass the
buffer directly.

Reported-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-01-22 15:07:03 +01:00
Peter Lieven
de8864e5ae iscsi: add iscsi_create support
This patch adds support for bdrv_create. This allows e.g.
to use qemu-img to convert from any supported device to
an iscsi backed storage as destination.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-01-22 15:07:03 +01:00
Paolo Bonzini
4d4545743f qemu-option: move standard option definitions out of qemu-config.c
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-01-12 17:17:53 +01:00
Paolo Bonzini
1de7afc984 misc: move include files to include/qemu/
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-12-19 08:32:39 +01:00
Paolo Bonzini
737e150e89 block: move include files to include/block/
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-12-19 08:31:31 +01:00
Paolo Bonzini
077805fa92 janitor: do not rely on indirect inclusions of or from qemu-char.h
Various header files rely on qemu-char.h including qemu-config.h or
main-loop.h, but they really do not need qemu-char.h at all (particularly
interesting is the case of the block layer!).  Clean this up, and also
add missing inclusions of qemu-char.h itself.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-12-19 08:29:52 +01:00
Peter Lieven
f807ecd574 iscsi: do not assume device is zero initialized
Without any complex checks we can't assume that an
iscsi target is initialized to zero.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-11-28 12:51:58 +01:00
Peter Lieven
e829b0bb05 iscsi: fix deadlock during login
If the connection is interrupted before the first login is successfully
completed qemu-kvm is waiting forever in qemu_aio_wait().

This is fixed by performing an sync login to the target. If the
connection breaks after the first successful login errors are
handled internally by libiscsi.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-11-28 12:50:56 +01:00
Peter Lieven
8da1e18b0c iscsi: fix segfault in url parsing
If an invalid URL is specified iscsi_get_error(iscsi) is called
with iscsi == NULL.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-11-28 12:46:13 +01:00
Stefan Hajnoczi
d7331bed11 aio: rename AIOPool to AIOCBInfo
Now that AIOPool no longer keeps a freelist, it isn't really a "pool"
anymore.  Rename it to AIOCBInfo and make it const since it no longer
needs to be modified.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-11-14 18:19:21 +01:00
Anthony Liguori
444dbc381b Merge remote-tracking branch 'kwolf/for-anthony' into staging
* kwolf/for-anthony:
  block: remove keep_read_only flag from BlockDriverState struct
  block: convert bdrv_commit() to use bdrv_reopen()
  block: vpc image file reopen
  block: vdi image file reopen
  block: vmdk image file reopen
  block: qcow image file reopen
  block: qcow2 image file reopen
  block: qed image file reopen
  block: raw image file reopen
  block: raw-posix image file reopen
  block: purge s->aligned_buf and s->aligned_buf_size from raw-posix.c
  block: use BDRV_O_NOCACHE instead of s->aligned_buf in raw-posix.c
  block: do not parse BDRV_O_CACHE_WB in block drivers
  block: move open flag parsing in raw block drivers to helper functions
  block: move aio initialization into a helper function
  block: Framework for reopening files safely
  block: make bdrv_set_enable_write_cache() modify open_flags
  block: correctly set the keep_read_only flag
  blockdev: preserve readonly and snapshot states across media changes
2012-09-25 16:06:16 -05:00
Jeff Cody
39c9fb9565 block: do not parse BDRV_O_CACHE_WB in block drivers
Block drivers should ignore BDRV_O_CACHE_WB in .bdrv_open flags,
and in the bs->open_flags.

This patch removes the code, leaving the behaviour behind as if
BDRV_O_CACHE_WB was set.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-09-24 15:15:11 +02:00
Ronnie Sahlberg
40a13ca8d2 iSCSI: We dont need to explicitely call qemu_notify_event() any more
We no longer need to explicitely call qemu_notify_event() any more
since this is now done automatically any time the filehandles we listen
to change.

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-09-21 16:12:33 +02:00
Ronnie Sahlberg
f1a12821d7 iSCSI: We need to support SG_IO also from iscsi_ioctl()
We need to support SG_IO from the synchronous iscsi_ioctl() since
scsi-block uses this to do an INQ to the device to discover its properties
This patch makes scsi-block work with iscsi.

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-09-21 16:05:51 +02:00
Ronnie Sahlberg
135b908878 iscsi: Set number of blocks to 0 for blank CDROM devices
The number of blocks of the device is used to compute the device size
in bdrv_getlength()/iscsi_getlength().
For MMC devices, the ReturnedLogicalBlockAddress in the READCAPACITY10
has a special meaning when it is 0.
In this case it does not mean that LBA 0 is the last accessible LBA,
and thus the device has 1 readable block, but instead it means that the
disc is blank and there are no readable blocks.

This change ensures that when the iSCSI LUN is loaded with a blank
DVD-R disk or similar that bdrv_getlength() will return the correct
size of the device as 0 bytes.

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
2012-08-28 14:50:08 +02:00
Paolo Bonzini
1bd075f29e iscsi: fix races between task completion and abort
This patch fixes two main issues with block/iscsi.c:

1) iscsi_task_mgmt_abort_task_async calls iscsi_scsi_task_cancel which
was also directly called in iscsi_aio_cancel

2) a race between task completion and task abortion could happen cause
the scsi_free_scsi_task were done before iscsi_schedule_bh has finished.
To fix this, all the freeing of IscsiTasks and releasing of the AIOCBs
is centralized in iscsi_bh_cb, independent of whether the SCSI command
has completed or was cancelled.

3) iscsi_aio_cancel was not synchronously waiting for the end of the
command.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-08-20 15:58:47 +02:00
Paolo Bonzini
cfb3f5064a iscsi: simplify iscsi_schedule_bh
It is always used with the same callback, remove the argument.  And
its return value is never used, assume allocation succeeds.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-08-20 15:58:47 +02:00
Paolo Bonzini
27cbd828c6 iscsi: move iscsi_schedule_bh and iscsi_readv_writev_bh_cb
Put these functions at the beginning, to avoid forward references
in the next patches.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-08-20 15:58:47 +02:00
Paolo Bonzini
b209091957 Revert "iscsi: Fix NULL dereferences / races between task completion and abort"
This reverts commit 64e69e8092.  The commit
returned immediately from iscsi_aio_cancel, risking corruption in case the
following happens:

    guest                  qemu                 target
  =========================================================================
    send write 1 -------->
                           send write 1 -------->
    cancel write 1 ------>
                           cancel write 1 ------>
       <------------------ cancellation processed
    send write 2 -------->
                           send write 2 -------->
                               <---------------- completed write 2
       <------------------ completed write 2
                               <---------------- completed write 1
                               <---------------- cancellation not done

Here, the guest would see write 2 superseding write 1, when in fact the
outcome could have been the opposite.  The right behavior is to return
only after the target says whether the cancellation was done or not, and
it will be implemented by the next three patches.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-08-20 15:50:45 +02:00
Stefan Priebe
64e69e8092 iscsi: Fix NULL dereferences / races between task completion and abort
Signed-off-by: Stefan Priebe <s.priebe@profihost.ag>
Acked-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-08-15 13:16:22 +02:00
Ronnie Sahlberg
31459f463a iscsi: Pick default initiator-name based on the name of the VM
This patch updates the iscsi layer to automatically pick a 'unique'
initiator-name based on the name of the vm in case the user has not set
an explicit iqn-name to use.

Create a new function qemu_get_vm_name() that returns the name of the VM,
if specified.

This way we can thus create default names to use as the initiator name
based on the guest session.

If the VM is not named via the '-name' command line argument, the iscsi
initiator-name used wiull simply be

    iqn.2008-11.org.linux-kvm

If a name for the VM was specified with the '-name' option, iscsi will
use a default initiatorname of

    iqn.2008-11.org.linux-kvm:<name>

These names are just the default iscsi initiator name that qemu will
generate/use only when the user has not set an explicit initiator name
via the commandlines or config files.

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
2012-08-09 15:04:09 +02:00
Paolo Bonzini
f2ef4a6dd9 iscsi: reorganize code for parse_initiator_name
Merge the occurrences of the "iqn.2008-11.org.linux-kvm" string
to avoid duplication.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-08-08 14:51:59 +02:00
Paolo Bonzini
b93c94f7ec iscsi: do not leak initiator_name
The argument of iscsi_create_context is never freed by libiscsi,
which in fact calls strdup on it.  Avoid a leak.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-08-08 14:51:59 +02:00
Anthony Liguori
23797df3d9 Merge remote-tracking branch 'mjt/mjt-iov2' into staging
* mjt/mjt-iov2:
  rewrite iov_send_recv() and move it to iov.c
  cleanup qemu_co_sendv(), qemu_co_recvv() and friends
  export iov_send_recv() and use it in iov_send() and iov_recv()
  rename qemu_sendv to iov_send, change proto and move declarations to iov.h
  change qemu_iovec_to_buf() to match other to,from_buf functions
  consolidate qemu_iovec_copy() and qemu_iovec_concat() and make them consistent
  allow qemu_iovec_from_buffer() to specify offset from which to start copying
  consolidate qemu_iovec_memset{,_skip}() into single function and use existing iov_memset()
  rewrite iov_* functions
  change iov_* function prototypes to be more appropriate
  virtio-serial-bus: use correct lengths in control_out() message

Conflicts:
	tests/Makefile

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-07-09 12:35:06 -05:00
Ronnie Sahlberg
622695a458 ISCSI: force use of sg for SMC and SSC devices
If the device we open is a SMC or SSC device, then force the use of sg. We
dont have any medium changer or tape emulation so only passthrough via
real sg or scsi-generic via iscsi would work anyway.

Forcing sg also makes qemu skip trying to read from the device to guess
the image format by reading from the device (find_image_format()).
SMC devices do not implement READ6/10/12/16 so it is not possible to
read from them (SSC have different CDBs).

With this patch I can successfully manage a SMC device wiht iscsi in
passthrough mode.

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
[Added TYPE_TAPE handling - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-07-02 10:18:41 +02:00
Ronnie Sahlberg
983924532f ISCSI: Add SCSI passthrough via scsi-generic to libiscsi
Update iscsi to allow passthrough of SG_IO scsi commands when the iscsi
device is forced to be scsi-generic.

Implement both bdrv_ioctl() and bdrv_aio_ioctl() in the iscsi backend,
emulate the SG_IO ioctl and pass the SCSI commands across to the
iscsi target.

This allows end-to-end passthrough of SCSI all the way from the guest,
to qemu, via scsi-generic, then libiscsi all the way to the iscsi target.

To activate this you need to specify that the iscsi lun should be treated
as a scsi-generic device.

Example:
    -device lsi -device scsi-generic,drive=MyISCSI \
    -drive file=iscsi://10.1.1.125/iqn.ronnie.test/1,if=none,id=MyISCSI

Note, you can currently not boot a qemu guest from a scsi device.

Note,
This only works when the host is linux, since the emulation relies on
definitions of SG_IO from the scsi-generic implementation in the
linux kernel.
It should be fairly easy to re-implement some structures similar enough
for non-linux hosts to do the same style of passthrough via a fake
scsi generic layer and libiscsi if need be.

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-07-02 10:18:41 +02:00
Michael Tokarev
d5e6b1619c change qemu_iovec_to_buf() to match other to,from_buf functions
It now allows specifying offset within qiov to start from and
amount of bytes to copy.  Actual implementation is just a call
to iov_to_buf().

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2012-06-11 23:12:11 +04:00
Ronnie Sahlberg
f4dfa67f04 ISCSI: Switch to using READ16/WRITE16 for I/O to the LUN
This allows using LUNs bigger than 2TB.  Keep using READ10 for other
device types such as MMC.

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
2012-05-28 14:04:16 +02:00
Ronnie Sahlberg
6bcd1346bb ISCSI: Only call READCAPACITY16 for SBC devices, use READCAPACITY10 for MMC
Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
2012-05-28 14:04:15 +02:00
Ronnie Sahlberg
dbfff6d776 ISCSI: get device type at connection time
This is needed to avoid READ CAPACITY(16) for MMC devices.

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-05-28 14:04:14 +02:00
Paolo Bonzini
c7b4a95202 ISCSI: change num_blocks to 64-bit
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-05-28 14:04:14 +02:00
Ronnie Sahlberg
c9b9f6824f ISCSI: redo how we set up the events
Call qemu_notify_event() after updating events.  Otherwise, If we add
an event for -is-writeable but the socket is already writeable there
may be a delay before the event callback is actually triggered.

Those delays would in particular hurt performance during BIOS boot and
when the GRUB bootloader reads the kernel and initrd.

But first call out to the socket write functions directly, and only set up
the write event if the socket is full.  This will happen very rarely and
this improves performance.

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
2012-05-28 14:04:06 +02:00
Ronnie Sahlberg
fa6acb0c2f ISCSI: Add support for thin-provisioning via discard/UNMAP and bigger LUNs
Update the configure test for libiscsi support to detect version 1.3
or later.  Version 1.3 of libiscsi provides both READCAPACITY16 as well
as UNMAP commands.

Update the iscsi block layer to use READCAPACITY16 to detect the size of
the LUN instead of READCAPACITY10. This allows support for LUNs larger
than 2TB.

Update to implement bdrv_aio_discard() using the UNMAP command.
This allows us to use thin-provisioned LUNs from TGTD and other iSCSI
targets that support thin-provisioning.

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
[squashed in subsequent patch from Ronnie to fix off-by-one in LBA count]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-05-04 10:39:18 +02:00
Paolo Bonzini
bafbd6a1c6 aio: remove process_queue callback and qemu_aio_process_queue
Both unused after the previous patch.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-19 16:37:53 +02:00
Ronnie Sahlberg
f9dadc9855 iSCSI: add configuration variables for iSCSI
This patch adds configuration variables for iSCSI to set
initiator-name to use when logging in to the target,
which type of header-digest to negotiate with the target
and username and password for CHAP authentication.

This allows specifying a initiator-name either from the command line
-iscsi initiator-name=iqn.2004-01.com.example:test
or from a configuration file included with -readconfig
    [iscsi]
      initiator-name = iqn.2004-01.com.example:test
      header-digest = CRC32C|CRC32C-NONE|NONE-CRC32C|NONE
      user = CHAP username
      password = CHAP password

If you use several different targets, you can also configure this on a per
target basis by using a group name:
    [iscsi "iqn.target.name"]
    ...

The configuration file can be read using -readconfig.
Example :
qemu-system-i386 -drive file=iscsi://127.0.0.1/iqn.ronnie.test/1
 -readconfig iscsi.conf

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-02-09 16:17:50 +01:00
Ronnie Sahlberg
c589b24972 iSCSI block driver
This provides built-in support for iSCSI to QEMU.

This has the advantage that the iSCSI devices need not be made visible to the host, which is useful if you have very many virtual machines and very many iscsi devices.
It also has the benefit that non-root users of QEMU can access iSCSI devices across the network without requiring root privilege on the host.

This driver interfaces with the multiplatform posix library for iscsi initiator/client access to iscsi devices hosted at
    git://github.com/sahlberg/libiscsi.git

The patch adds the driver to interface with the iscsi library.
It also updated the configure script to
* by default, probe is libiscsi is available and if so, build
  qemu against libiscsi.
* --enable-libiscsi
  Force a build against libiscsi. If libiscsi is not available
  the build will fail.
* --disable-libiscsi
  Do not link against libiscsi, even if it is available.

When linked with libiscsi, qemu gains support to access iscsi resources such as disks and cdrom directly, without having to make the devices visible to the host.

You can specify devices using a iscsi url of the form :
iscsi://[<username>[:<password>@]]<host>[:<port]/<target-iqn-name>/<lun>
When using authentication, the password can optionally be set with
LIBISCSI_CHAP_PASSWORD="password" to avoid it showing up in the process list

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-28 19:25:48 +02:00