The current BDC VPD page (page 0xb1) is too short. This can be
seen running sg_utils:

$ sg_vpd --page=bdc /dev/sda
Block device characteristics VPD page (SBC):
Block device characteristics VPD page length too short=8

By the SCSI spec, the expected size of the SBC page is 0x40.
There is no telling how the guest will behave with a shorter
message - it can ignore it, or worse, make (wrong)
assumptions.

This patch fixes the emulation by setting the size to 0x40.
This is the output of the previous sg_vpd command after
applying it:

$ sg_vpd --page=bdc /dev/sda -v
    inquiry cdb: 12 01 b1 00 fc 00
Block device characteristics VPD page (SBC):
   [PQual=0  Peripheral device type: disk]
  Medium rotation rate is not reported
  Product type: Not specified
  WABEREQ=0
  WACEREQ=0
  Nominal form factor not reported
  FUAB=0
  VBULS=0

To improve readability, this patch also adds the VBULS value
explictly and add comments on the existing fields we're
setting.
Signed-off-by: NDaniel Henrique Barboza <danielhb413@gmail.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This reverts commit b0083267.

Hold off removing this for one more QEMU release (current libvirt
release still uses it.)
Signed-off-by: NCornelia Huck <cohuck@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

It eases code review, unit is explicit.

Patch generated using:

  $ git grep -E '(1024|2048|4096|8192|(<<|>>).?(10|20|30))' hw/ include/hw/

and modified manually.
Signed-off-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20180625124238.25339-10-f4bug@amsat.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The VPD Block Limits Inquiry page is optional, allowing SCSI devices
to not implement it. This is the case for devices like the MegaRAID
SAS 9361-8i and Microsemi PM8069.

In case of SCSI passthrough, the response of this request is used by
the QEMU SCSI layer to set the max_io_sectors that the guest
device will support, based on the value of the max_sectors_kb that
the device has set in the host at that time. Without this response,
the guest kernel is free to assume any value of max_io_sectors
for the SCSI device. If this value is greater than the value from
the host, SCSI Sense errors will occur because the guest will send
read/write requests that are larger than the underlying host device
is configured to support. An example of this behavior can be seen
in [1].

A workaround is to set the max_sectors_kb host value back in the guest
kernel (a process that can be automated using rc.local startup scripts
and the like), but this has several drawbacks:

- it can be troublesome if the guest has many passthrough devices that
needs this tuning;

- if a change in max_sectors_kb is made in the host side, manual change
in the guests will also be required;

- during an OS install it is difficult, and sometimes not possible, to
go to a terminal and change the max_sectors_kb prior to the installation.
This means that the disk can't be used during the install process. The
easiest alternative here is to roll back to scsi-hd, install the guest
and then go back to SCSI passthrough when the installation is done and
max_sectors_kb can be set.

An easier way would be to QEMU handle the absence of the Block Limits
VPD device response, setting max_io_sectors accordingly and allowing
the guest to use the device without the hassle.

This patch adds emulation of the Block Limits VPD response for
SCSI passthrough devices of type TYPE_DISK that doesn't support
it. The following changes were made:

- scsi_handle_inquiry_reply will now check the available VPD
pages from the Inquiry EVPD reply. In case the device does not

- a new function called scsi_generic_set_vpd_bl_emulation,
that is called during device realize,  was created to set a
new flag 'needs_vpd_bl_emulation' of the device. This function
retrieves the Inquiry EVPD response of the device to check for
VPD BL support.

- scsi_handle_inquiry_reply will now check the available VPD
pages from the Inquiry EVPD reply in case the device needs
VPD BL emulation, adding the Block Limits page (0xb0) to
the list. This will make the guest kernel aware of the
support that we're now providing by emulation.

- a new function scsi_emulate_block_limits creates the
emulated Block Limits response. This function is called
inside scsi_read_complete in case the device requires
Block Limits VPD emulation and we detected a SCSI Sense
error in the VPD Block Limits reply that was issued
from the guest kernel to the device. This error is
expected: we're reporting support from our side, but
the device isn't aware of it.

With this patch, the guest now queries the Block Limits
page during the device configuration because it is being
advertised in the Supported Pages response. It will either
receive the Block Limits page from the hardware, if it supports
it, or will receive an emulated response from QEMU. At any rate,
the guest now has the information to set the max_sectors_kb
parameter accordingly, sparing the user of SCSI sense errors
that would happen without the emulated response and in the
absence of Block Limits support from the hardware.

[1] https://bugzilla.redhat.com/show_bug.cgi?id=1566195

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1566195Reported-by: NDac Nguyen <dacng@us.ibm.com>
Signed-off-by: NDaniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20180627172432.11120-4-danielhb413@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

For the VPD Block Limits emulation with SCSI passthrough,
we'll issue an Inquiry request with EVPD set to retrieve
the available VPD pages of the device. This would be done in
a way similar of what scsi_generic_read_device_identification
does: create a SCSI command and a reply buffer, fill in the
sg_io_hdr_t structure, call blk_ioctl, check if an error
occurred, process the response.

This same process is done in other 2 functions, get_device_type
and get_stream_blocksize. They differ in the command/reply
buffer and post-processing, everything else is almost a
copy/paste.

Instead of adding a forth copy/pasted-ish code when adding
the passthrough VPD BL emulation, this patch extirpates
this repetition of those 3 functions and put it into
a new one called scsi_SG_IO_FROM_DEV. Any future code that
wants to execute an SG_DXFER_FROM_DEV to the device can
use it, avoiding filling sg_io_hdr_t again and et cetera.
Signed-off-by: NDaniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20180627172432.11120-3-danielhb413@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

To add support for the emulation of Block Limits VPD page
for passthrough devices, a few adjustments in the current code
base is required to avoid repetition and improve clarity.

In scsi-generic.c, detach the Inquiry handling from
scsi_read_complete and put it into a new function called
scsi_handle_inquiry_reply. This change aims to avoid
cluttering of scsi_read_complete when we more logic in the
Inquiry response handling is added in the next patches,
centralizing the changes in the new function.

In scsi-disk.c, take the build of all emulated VPD pages
from scsi_disk_emulate_inquiry and make it available to
other files into a non-static function called
scsi_disk_emulate_vpd_page. Making it public will allow
the future VPD BL emulation code for passthrough devices
to use it from scsi-generic.c, avoiding copy/pasting this
code solely for that purpose. It also has the advantage of
providing emulation of all VPD pages in case we need to
emulate other pages in other scenarios. As a bonus,
scsi_disk_emulate_inquiry got tidier.
Signed-off-by: NDaniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20180627172432.11120-2-danielhb413@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The -drive option serial was deprecated in QEMU 2.10. It's time to
remove it.

Tests need to be updated to set the serial number with -global instead
of using the -drive option.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NJeff Cody <jcody@redhat.com>

QEMU SCSI code makes assumptions about how the PROTECT and BYTCHK
works in the protocol, denying support for PI (Protection
Information) in case the guest OS requests it. However, in SCSI versions 2
and older, there is no PI concept in the protocol.

This means that when dealing with such devices:

- there is no PROTECT bit in byte 5 of the standard INQUIRY response. The
whole byte is marked as "Reserved";

- there is no RDPROTECT in byte 2 of READ. We have 'Logical Unit Number'
in this field instead;

- there is no VRPROTECT in byte 2 of VERIFY. We have 'Logical Unit Number'
in this field instead. This also means that the BYTCHK bit in this case
is not related to PI.

Since QEMU does not consider these changes, a SCSI passthrough using
a SCSI-2 device will not work. It will mistake these fields with
PI information and return Illegal Request SCSI SENSE thinking
that the driver is asking for PI support.

This patch fixes it by adding a new attribute called 'scsi_version'
that is read from the standard INQUIRY response of passthrough
devices. This allows for a version verification before applying
conditions related to PI that doesn't apply for older versions.
Reported-by: NDac Nguyen <dacng@us.ibm.com>
Signed-off-by: NDaniel Henrique Barboza <danielhb@linux.vnet.ibm.com>
Message-Id: <20180327211451.14647-1-danielhb@linux.vnet.ibm.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

We would like to have different behavior for passthrough devices
depending on the SCSI version they expose.  To prepare for that,
allow the user of emulated devices to specify the desired SCSI
level, and adjust the emulation according to the property value.
The next patch will set the level for scsi-block and scsi-generic
devices.

Based on a patch by Daniel Henrique Barboza
<danielhb@linux.vnet.ibm.com>.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Some backends report big max_io_sectors. Making min_io_size the same
value in this case will make it impossible for guest to align memory,
therefore the disk may not be usable at all.

Do not enlarge them when they are zero.
Reported-by: NDavid Gibson <dgibson@redhat.com>
Signed-off-by: NFam Zheng <famz@redhat.com>

Message-Id: <20180327164141.19075-1-famz@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

If the user does not have permissions to send ioctls to the device (due to
SELinux or cgroups, for example), the output can look like

qemu-kvm: -device scsi-block,drive=disk: cannot get SG_IO version number:
  Operation not permitted.  Is this a SCSI device?

but this is confusing because the ioctl was blocked _before_ the device
even received the SG_GET_VERSION_NUM ioctl.  Therefore, for EPERM errors
the suggestion should be eliminated.  To make that simpler, change the
code to use error_append_hint.
Reported-by: NAla Hino <ahino@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

A NDOB bit set to one specifies that the disk shall not transfer data
from the data-out buffer and shall process the command as if the data-out
buffer contained user data set to all zeroes.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The calculation of the max_transfer atribute of BlockDriverState
makes considerations such as max_segments and transfer_length via
the BLKSECTGET ioctl (if available).

However, bl->max_transfer isn't considered when emulating the INQUIRY
'Block Limit' response to the scsi-hd devices. This leads to situations
where the declared max_sectors from the INQUIRY response is inconsistent
with the block limits, which isn't ideal. It can also be misleading to the
user that sets /sys/block/<dev>/queue/max_sectors_kb to a certain
value, then finds a different value in the guest OS for the same disk.

Following the same logic scsi_read_complete from scsi-generic.c does
when patching the response of the Block Limits VPD back to the guest,
change the max_io_sectors value of the emulated Block Limits VPD
response by considering the blk_get_max_transfer of the related
BlockDriverState. Use MIN_NOT_ZERO to be sure that the minimal
value is chosen.

Given that we're changing max_io_sectors, consider that min_io_sectors
and opt_io_sectors can't be greater than the new calculated value.
Signed-off-by: NDaniel Henrique Barboza <danielhb@linux.vnet.ibm.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Message-Id: <20180306154411.18462-1-danielhb@linux.vnet.ibm.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

scsi_write_same_complete() can retry the write if the request was
unaligned.  Make sure to release the AioContext when that code path is
taken!

This patch fixes a hang when QEMU terminates after an unaligned WRITE
SAME request has been processed with dataplane.  The hang occurs because
iothread_stop_all() cannot acquire the AioContext lock that was leaked
by the IOThread in scsi_write_same_complete().

Fixes: b9e413dd ("block: explicitly acquire aiocontext in aio callbacks that need it").
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-stable@nongnu.org
Reported-by: NCong Li <coli@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20180104142502.15175-1-stefanha@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Scsi-block doesn't use the DEFINE_BLOCK_PROPERTIES() macro so it didn't
gain the share-rw back when it was added to all other storage devices.
This option is meaningful here, and need to be used when attaching a
shared storage to guest.
Signed-off-by: NFam Zheng <famz@redhat.com>
Message-Id: <20171205071928.30242-1-famz@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

[Drop virtio_blk_data_plane_create() change that misinterprets return
value when the virtio transport does not support dataplane.
--Stefan]

Cc: John Snow <jsnow@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Max Reitz <mreitz@redhat.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Markus Armbruster <armbru@redhat.com>
Signed-off-by: NMao Zhongyi <maozy.fnst@cn.fujitsu.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Message-id: e77848d3735ba590f23ffbf8094379c646c33d79.1511317952.git.maozy.fnst@cn.fujitsu.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Logical block size of a SCSI disk should never be larger than
physical block size. From an ATA/SCSI perspective, it makes no sense
to have the logical block size greater than the physical block size,
and it cannot even be effectively expressed in the command set. The
whole point of adding the physical block size to the ATA/SCSI command
set was to communicate a desire for a larger block size (than logical),
while maintaining backwards compatibility with legacy 512 byte block
size.

When setting logical_block_size > physical_block_size, QEMU cannot express
it in READ CAPACITY(16) output, and all it can do is set the physical
block exponent to 0 (i.e. logical_block_size == physical_block_size).
Reporting the error properly, however, is better.
Signed-off-by: NMark Kanda <mark.kanda@oracle.com>
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Message-Id: <1508185024-5840-1-git-send-email-mark.kanda@oracle.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The Linux kernel will query the SCSI "Block device characteristics"
VPD to determine the rotations per minute of the disk. If this has
the value 1, it is taken to be an SSD and so Linux sets the
'rotational' flag to 0 for the I/O queue and will stop using that
disk as a source of random entropy. Other operating systems may
also take into account rotation rate when setting up default
behaviour.

Mgmt apps should be able to set the rotation rate for virtualized
block devices, based on characteristics of the host storage in use,
so that the guest OS gets sensible behaviour out of the box. This
patch thus adds a 'rotation-rate' parameter for 'scsi-hd' and
'scsi-block' device types. For the latter, this parameter will be
ignored unless the host device has TYPE_DISK.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Message-Id: <20171004114008.14849-2-berrange@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Complete the transition by renaming this header, which was
shared by block/iscsi.c and the SCSI emulation code.
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

util/scsi.c includes some SCSI code that is shared by block/iscsi.c and
hw/scsi, but the introduction of the persistent reservation helper
will add many more instances of this.  There is also include/block/scsi.h,
which actually is not part of the core block layer.

The persistent reservation manager will also need a home.  A scsi/
directory provides one for both the aforementioned shared code and
the PR manager code.
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

After introducing the scsi/ subdirectory, there will be a scsi_build_sense
function that is the same as scsi_req_build_sense but without needing
a SCSIRequest.  The existing scsi_build_sense function gets in the way,
remove it.
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This makes the werror/rerror options available on the scsi-block device,
to allow user specify error handling policy similar to scsi-hd.
Signed-off-by: NFam Zheng <famz@redhat.com>
Message-Id: <20170821141008.19383-5-famz@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

If no drive=... option is passed (for an empty drive), we don't only
lack the BlockBackend normally created by parse_drive(), but we also
need to manually call blk_attach_dev().

This fixes at least a segfault when unplugging such devices, the bug
that they didn't show up in query-block, and probably some more
problems.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NJohn Snow <jsnow@redhat.com>

This makes all device emulations with a qdev drive property request
permissions on their BlockBackend. The only thing we block at this point
is resizing images for some devices that can't support it.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Acked-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

Some devices allow a media change between read-only and read-write
media. They need to adapt the permissions in their .change_media_cb()
implementation, which can fail. So add an Error parameter to the
function.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Acked-by: NFam Zheng <famz@redhat.com>

We want every user to be specific about the permissions it needs, so
we'll pass the initial permissions as parameters to blk_new(). A user
only needs to call blk_set_perm() if it wants to change the permissions
after the fact.

The permissions are stored in the BlockBackend and applied whenever a
BlockDriverState should be attached in blk_insert_bs().

This does not include actually choosing the right set of permissions
everywhere yet. Instead, the usual FIXME comment is added to each place
and will be addressed in individual patches.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Acked-by: NFam Zheng <famz@redhat.com>

Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NDaniel P. Berrange <berrange@redhat.com>
Message-id: 20170213135235.12274-16-pbonzini@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Commit 166dbda7 added some extra cases to a switch() such
that the existing code is intended to fall through the new
case statements. It's clear from the commit that this is
intentional, but less clear to subsequent readers of the
code, and not clear at all to static analysis tools like
Coverity. Add a /* fall through */ comment to indicate the
intent. (Fixes CID 1368287.)
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

The direction is wrong; scsi_block_is_passthrough returns
false for commands that *can* use sglists.
Reported-by: NZhang Qian <zhangqian@sangfor.com.cn>
Fixes: 8fdc7839
Cc: qemu-stable@nongnu.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

When a scsi-disk object receives VERIFY command with BYTCHK bit being zero,
scsi_block_is_passthrough returns false and finally makes req being proceeded
by scsi_block_dma_command. Because scsi_block_dma_command has removed process
of VERIFY, QEMU will abort in this function.
Reported-by: NJunlian Bell <zhongjun@sangfor.com.cn>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The hard-coded default alignment is BDRV_SECTOR_SIZE, however this is not
necessarily the case for all platforms. Use this as the default alignment for
all current callers.
Signed-off-by: NMark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: NEric Blake <eblake@redhat.com>
Acked-by: NJohn Snow <jsnow@redhat.com>
Message-id: 1476445266-27503-2-git-send-email-mark.cave-ayland@ilande.co.uk
Signed-off-by: NJohn Snow <jsnow@redhat.com>

Even if tray is not open, it can be empty (blk_is_inserted() == false).
Handle both cases correctly by replacing the s->tray_open checks with
blk_is_available(), which is an AND of the two.

Also simplify successive checks of them into blk_is_available(), in a
couple cases.
Signed-off-by: NFam Zheng <famz@redhat.com>
Message-Id: <1473848224-24809-2-git-send-email-famz@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Openstack Cinder assigns volume a 36 characters uuid as serial.
QEMU will shrinks the uuid to 20 characters, which does not match
the original uuid.

Note that there is no limit to the length of the serial number in
the SCSI spec.  20 was copy-pasted from virtio-blk which in turn was
copy-pasted from ATA; 36 is even more arbitrary.  However, bumping it
up too much might cause issues (e.g. 252 seems to make sense because
then the maximum amount of returned data is 256; but who knows there's
no off-by-one somewhere for such a nicely rounded number).
Signed-off-by: NRony Weng <ronyweng@synology.com>
Message-Id: <1472457138-23386-1-git-send-email-ronyweng@synology.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This allows the creation of an empty scsi-cd device without manually
creating a BlockBackend.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Change sector-based blk_discard(), blk_co_discard(), and
blk_aio_discard() to instead be byte-based blk_pdiscard(),
blk_co_pdiscard(), and blk_aio_pdiscard().  NBD gets a lot
simpler now that ignoring the unaligned portion of a
byte-based discard request is handled under the hood by
the block layer.
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Message-id: 1468624988-423-6-git-send-email-eblake@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

The rerror/werror policies are implemented in the devices, so that's
where they should be configured. In comparison to the old options in
-drive, the qdev properties are only added to those devices that
actually support them.

If the option isn't given (or "auto" is specified), the setting of the
BlockBackend is used for compatibility with the old options. For block
jobs, "auto" is the same as "enospc".
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

As cache.writeback is a BlockBackend property and as such more related
to the guest device than the BlockDriverState, we already removed it
from the blockdev-add interface. This patch adds the new way to set it,
as a qdev property of the corresponding guest device.

For example: -drive if=none,file=test.img,node-name=img
             -device ide-hd,drive=img,write-cache=off
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

Some source code analyzers like cppcheck spill out a warning if
the sign of the argument does not match the format string.

Ticket: https://bugs.launchpad.net/qemu/+bug/1589564Signed-off-by: NThomas Huth <thuth@redhat.com>
Message-Id: <1465805418-15906-1-git-send-email-thuth@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Suggested-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>