This covers the case of canceling a request's I/O and still
completing it.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
The code for canceling requests upon reset is already the same. Clean
it up and move it to scsi-bus.c.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Currently the SCSIRequest structure is abstracted away and cannot accessed
directly from the driver. This requires the handler to do a lookup on
an abstract 'tag' which identifies the SCSIRequest structure.
With this patch the SCSIRequest structure is exposed to the driver. This
allows use to use it directly as an argument to the SCSIDeviceInfo
callback functions and remove the lookup.
A new callback function 'alloc_req' is introduced matching 'free
req'; unref'ing to free up resources after use is moved into the
scsi_command_complete callbacks.
This temporarily introduces a leak of requests that are cancelled,
when they are removed from the queue and not from the driver. This
is fixed later by introducing scsi_req_cancel. That patch in turn
depends on this one, because the argument to scsi_req_cancel is a
SCSIRequest.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
With the next patch, a device may hold SCSIRequest for an indefinite
time. Split a rather big patch, and protect against access errors,
by reference counting them.
There is some ugliness in scsi_send_command implementation due to
the need to unref the request when it fails. This will go away
with the next patches, which move the unref'ing to the devices.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
If a request is canceled after it has been completed, scsi_cancel_io
would pass a stale aiocb to bdrv_aio_cancel. Avoid this.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
There are more operations than a SCSI bus can handle, besides completing
commands. One example, which this series will introduce, is cleaning up
after a request is cancelled.
More long term, a "SCSI bus" can represent the LUNs attached to a
target; in this case, while all commands will ultimately reach a logical
unit, it is the target who is in charge of answering REPORT LUNs.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
This abstracts calling the command_complete callback, reducing churn
in the following patches.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
scsi-generic scsi_read_complete() should not -both- call the client
complete callback with SCSI_REASON_DATA -and- call
scsi_command_complete(). The former will cause the client to queue a
new read or write request, while the later will free the request data
structure, thus causing the new read or write request to use a
freed/stale structure when it completes.
This patch fixes the bug, fixing a crash with scsi-generic & RHEL5.5
installer.
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
This patch finally merges the EHCI host adapter aka USB 2.0 support.
Based on the ehci bits collected @ git://git.kiszka.org/qemu.git ehci
EHCI has a long out-of-tree history. Project was started by Mark
Burkley, with contributions by Niels de Vos. David S. Ahern continued
working on it. Kevin Wolf, Jan Kiszka and Vincent Palatin contributed
bugfixes.
/me (Gerd Hoffmann) picked it up where it left off, prepared the code
for merge, fixed a few bugs and added basic user docs.
Cc: David S. Ahern <daahern@cisco.com>
Cc: Jan Kiszka <jan.kiszka@web.de>
Cc: Kevin Wolf <mail@kevin-wolf.de>
Cc: Vincent Palatin <vincent.palatin_qemu@m4x.org>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Remove the cancel callback from the USBPacket struct, move it over
to USBDeviceInfo. Zap usb_defer_packet() which is obsolete now.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Add a usb_handle_packet function, put it into use everywhere.
Right now it just calls dev->info->handle_packet(), that will
change in future patches though.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
usb_msd_copy_data() may cause a recursive call to
usb_msd_command_complete() which in turn may complete
the packet, setting s->packet to NULL in case it does.
Recheck s->packet before calling usb_packet_complete()
to fix the double call.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Make the linux usb host passthrough code use the usb_generic_handle_packet()
function, rather then the curent DYI code. This removes 200 lines of almost
identical code.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
This allows using the generic usb_generic_handle_packet function from
device code which does ASYNC control requests (such as the linux host
pass through code).
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
UHCI host controller status register indicates error and
an interrupt is triggered on BABBLE and STALL errors.
Signed-off-by: Jan Vesely <jano.vesely@gmail.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
This is used for some devices that have multiple interfaces that form a logic
device. An example is Video Class, which has a Control interface and a
Streaming interface. There can be additional interfaces on the same (physical)
devices (e.g. a microphone), and Interface Association Descriptor handles this
case.
Signed-off-by: Brad Hards <bradh@frogmouth.net>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Previously we relied on the .bNumInterfaces, but that won't always be
accurate after the introduction of grouped interfaces.
Signed-off-by: Brad Hards <bradh@frogmouth.net>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
* 'ppc-next' of git://repo.or.cz/qemu/agraf:
Fix a bug in mtsr/mtsrin emulation on ppc64
pSeries: Clean up write-only variables
w32: Fix compilation and replace non-portable usage of ulong
The SDIO specification introduces new commands 52 and 53.
Handle as illegal command but do not complain on stderr,
as SDIO-aware OSes (including Linux) may legitimately use
these in their probing for presence of an SDIO card.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Remove a duplicate #include of sysbus.h.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
If pic_irq is greater than 7, the irq level is always 0 on 32bits.
Signed-off-by: TeLeMan <geleman@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
A few pieces of the pSeries emulation code have variables which are set
but never used, which causes warnings on gcc 4.6. This patch removes
these instances.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
the s390 memory detection has a 16bit field that specifies the amount of
increments. This patch adopts the memory size to always fit into that
scheme. This also fixes virtio detection for these guests, since the
descriptor page is located after the main memory.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
The s390x virtio bus keeps management information on virtio after the top
of the guest's RAM. We need to be able to tell the guest the size of its
RAM (without virtio stuff), but also be able to trap when the guest accesses
RAM outside of its scope (including virtio stuff).
So we need a variable telling us the size of the virtio stuff, so we can
calculate the highest available RAM address from that.
While at it, also increase the maximum number of virtio pages, so we play
along well with more recent kernels that spawn a ridiculous number of virtio
console adapters.
Signed-off-by: Alexander Graf <agraf@suse.de>
AHCI provides two ways of reading/writing data:
1) NCQ
2) ATA commands with the LBA in the command FIS
In the second code path, we didn't handle any LBAs that were bigger than
16 bits, so whenever a guest that used high LBA numbers wanted to access
data, the LBA got truncated down to 16 bits, giving the guest garbage.
This patch adds support for LBAs higher than 16 bits. I've tested that it
works just fine with SeaBIOS and Linux guests. This patch also unbreaks
the often reported grub errors people have seen with AHCI.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This patch makes qemu ignore unplug requests from the guest for pci
devices which are tagged as non-hotpluggable. Trouble spot is the
piix4 chipset with the ISA bridge. Requests to unplug that one will
make it go away together with all ISA bus devices, which are not
prepared to be unplugged and thus don't cleanup, leaving active
qemu timers behind in free'ed memory.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
DriveInfo is closely tied to -drive, and like -drive, it mixes
information about host and guest part of the block device. Unlike
DriveInfo, BlockDriverState should be about the host part only.
One of the remaining guest bits there is the "type hint". -drive
option media sets it, and qdevs "ide-drive", "scsi-disk" and non-qdev
IF_XEN devices check it to pick HD vs. CD.
Communicate -drive option media via new DriveInfo member media_cd
instead.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
A "scsi-disk" is either a hard disk or a CD-ROM, depending on the
associated BlockDriverState's type hint. Unclean; disk vs. CD belongs
to the guest part, not the host part.
Have separate qdevs "scsi-hd" and "scsi-cd" to model disk vs. CD in
the guest part.
Keep scsi-disk for backward compatibility.
Don't copy scsi-disk property removable to scsi-cd. It's not used and
always zero(!) there.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
An "ide-drive" is either a hard disk or a CD-ROM, depending on the
associated BlockDriverState's type hint. Unclean; disk vs. CD belongs
to the guest part, not the host part.
Have separate qdevs "ide-hd" and "ide-cd" to model disk vs. CD in
the guest part.
Keep ide-drive for backward compatibility.
"ide-disk" would perhaps be a nicer name than "ide-hd", but there's
already "scsi-disk", which is like "ide-drive", and will be likewise
split in the next commit. {ide,scsi}-{hd,cd} is the best consistent
set of names I could find within the backward compatibility
straightjacket.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
If ahci_dma_set_inactive is called a while there is still a pending BH
from a previous run, we will crash on the second run of
ahci_check_cmd_bh as it overwrites AHCIDevice::check_bh. Avoid this
broken and redundant duplicate registration.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
These printfs aren't really debug messages, but clearly indicate a bug if they
ever become effective. Noone uses DEBUG_IDE, let's re-enable the check
unconditionally and make it an assertion instead of printfs in the device
emulation.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
cppcheck report:
hw/xen_disk.c:309: style:
Variable 'len' is assigned a value that is never used
Cc: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Fix regression of 667bb59: ahci_init initializes ahci.mem, so we have to
move bar registration after it.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
* 'ppc-next' of git://repo.or.cz/qemu/agraf:
PPC: Qdev'ify e500 pci
PPC MPC7544DS: Use new TLB helper function
PPC: Implement e500 (FSL) MMU
PPC: Add another 64 bits to instruction feature mask
PPC: Add GS MSR definition
PPC: Make MPC8544DS emulation work w/o KVM
PPC: Make MPC8544DS obey -cpu switch
Fix off-by-one error in sizing pSeries hcall table
ppc64: Fix out-of-tree builds
kvm: ppc: warn user on PAGE_SIZE mismatch
kvm: ppc: detect old headers
monitor: add PPC BookE SPRs
kvm: ppc: fixes for KVM_SET_SREGS on init
ppc64: Don't try to build sPAPR RTAS on Darwin
Place pseries vty devices at addresses more similar to existing machines
Make pSeries 'model' property more closely resemble real hardware
pseries: Increase maximum CPUs to 256
The e500 PCI controller isn't qdev'ified yet. This leads to severe issues
when running with -drive.
To be able to use a virtio disk with an e500 VM, let's convert the PCI
controller over to qdev.
Reviewed-by: Paul Brook <paul@codesourcery.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Now that we have some nice helpers that can find us a TLB entry, let's
use that on the machine initialization code, so we don't need to know
about the internals of the TLB array.
Signed-off-by: Alexander Graf <agraf@suse.de>
The MPC8544DS board emulation was only used with KVM so far, so some
parts of the code didn't provide proper values for non-KVM execution.
This patch makes the machine work without KVM enabled. To actually use
this, you also need proper e500v2 MMU emulation.
Signed-off-by: Alexander Graf <agraf@suse.de>
The MPC8544DS board emulation code ignored the user defined -cpu switch.
This patch enables it to only provide a sane default, not force an e500v2
CPU inside.
Signed-off-by: Alexander Graf <agraf@suse.de>
The pSeries machine uses two tables to look up guest hcalls for emulation.
One of these is exactly one entry too small to hold all the hcalls it needs
to, leading to memory corruption.
This patch fixes the bug, and while we're at it, make both tables 'static'
since they're never used from other modules.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
Read them via KVM_GET_SREGS in kvm_arch_get_registers(),
and display them in "info registers".
Also get CR and PID from the existing KVM_GET_REGS.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Currently the qemu pseries machine numbers its virtual serial devices
from 0. However, existing pSeries machines running pHyp number them from
0x30000000.
In theory these indices are arbitrary, since everything necessary for the
kernel to find them is advertised in the device tree. However the debian
installer, at least, incorrectly looks for a device named vty@30... to
determine whether to use the hypervisor console.
Therefore this patch moves the numbers we use to match the existing pHyp
practice, in order to workaround broken userspace apps of this type.
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Currently, the qemu emulated pseries machine puts
"qemu,emulated-pSeries-LPAR" in the device tree's root level 'model'
property. Unfortunately this confuses some installers and ybin, which
expect this to start with "IBM" on pSeries machines. This patch addresses
this problem, making the property more closely resemble the pattern of
existing real hardware.
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
The original pSeries machine was limited to 32 CPUs, more or less
arbitrarily. Particularly when we get SMT KVM guests it will be
pretty easy to exceed this. Therefore, raise the max number of CPUs
in a pseries machine guest to 256.
Signed-off-by: Anton Blanchard <anton@au1.ibm.com>
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Prototype without "inline" keyword breaks the build with some gcc
versions. Noticed by Alexander Graf.
Fix this by removing the inline keywork everywhere. Some functions
can't be inlined anyway as the are referenced using function pointers.
Beside that gcc does a pretty good job on auto-inlining these days.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
The 'sense' field in the HBA status structure is misnamed, as it
actually carries the SCSI status. Rename it.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-trivial@nongnu.org
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
cppcheck report:
hw/ac97.c:1004: style:
Variable 'written' is assigned a value that is never used
hw/ac97.c:1072: style:
Variable 'written' is assigned a value that is never used
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
The code changed here is an unused data type name (evt_flush_occurred).
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Prevent a deadlock caused by leaving a map cache bucket locked by the
preceding qemu_get_ram_ptr() call.
Signed-off-By: John Baboval <john.baboval@virtualcomputer.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
On IA32 host or IA32 PAE host, at present, generally, we can't create
an HVM guest with more than 2G memory, because generally it's almost
impossible for Qemu to find a large enough and consecutive virtual
address space to map an HVM guest's whole physical address space.
The attached patch fixes this issue using dynamic mapping based on
little blocks of memory.
Each call to qemu_get_ram_ptr makes a call to qemu_map_cache with the
lock option, so mapcache will not unmap these ram_ptr.
Blocks that do not belong to the RAM, but usually to a device ROM or to
a framebuffer, are handled in a separate function. So the whole RAMBlock
can be map.
Signed-off-by: Jun Nakajima <jun.nakajima@intel.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Every set_irq call makes a Xen hypercall.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
This patch introduces Xen specific call in piix_pci.
The specific part for Xen is in write_config, set_irq and get_pirq.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
This is because there is not synchronisation of the vcpu register
between Xen and QEMU, so vmport can't work properly.
This patch introduces no_vmport parameter to pc_basic_device_init.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Introduce the Xen FV (Fully Virtualized) machine to Qemu, some more Xen
specific call will be added in further patches.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
This patch moves above_4g_mem_size and below_4g_mem_size calculation in
the caller of pc_memory_init (pc_init1). And the prototype of
pc_memory_init is changed because there is no need anymore to have
variable pointer and the ram_size parameter.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
The xenpv machine use the common init function.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
This patch updates the libxenctrl calls in Qemu to use the new interface,
otherwise Qemu wouldn't be able to build against new versions of the
library.
We check libxenctrl version in configure, from Xen 3.3.0 to Xen
unstable.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
And put braces for blocks with a single statement.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
With this new field, we can specified which accelerator use to run the
machine, if the accelerator is not already specified by either a
configuration file or the command line options.
Currently, the only use will be made in the xenfv machine.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
msi_init may fail, so we need to check on uninit if the cap was
actually installed. This also avoids that the users need to check.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The general control register is a byte register.
Add support for byte reads.
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
MDI control is a 32 bit register, but may be read or written using
8 or 16 bit access. Data is latched when the MSB is written.
Add support for byte/word read/write access.
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
pointer is a 32 bit register, but may be written using 8 or 16 bit writes.
Add support for byte/word writes.
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
port is a 32 bit register, but may be written using 8 or 16 bit writes.
Add support for byte/word writes.
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Like other Intel devices, e100 (eepro100) uses little endian byte order.
This patch was tested with these combinations:
i386 host, i386 + mipsel guests (le-le)
mipsel host, i386 guest (le-le)
i386 host, mips + ppc guests (le-be)
mips host, i386 guest (be-le)
mips and mipsel hosts were emulated machines.
v2:
Use prefix for new functions. Add the same prefix to stl_le_phys.
Fix alignment of mem (needed for word/dword reads/writes).
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
QEMU sends frames smaller than 60 bytes to ethernet nics.
Such frames are rejected by real NICs and their emulations.
To avoid this behaviour, other NIC emulations pad received
frames. This patch enables this workaround for eepro100, too.
All related code is marked with CONFIG_PAD_RECEIVED_FRAMES,
so we can drop this in case QEMU's networking code is
ever changed.
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
cppcheck reports that 'packet' is unused.
It was only used to calculate the size of the preceding data.
Removing it saves a lot of stack space (local variable rx).
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
When DEBUG_EEPRO100 was enabled, unsupported writes were logged twice.
Now logging in eepro100_write1 and eepro100_write2 is similar to the
logging in eepro100_write4 (which already was correct).
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Initialize scsi_len with zero when starting a new request, so any
stuff leftover from the previous request is cleared out. This may
happen in case the data returned by the scsi command doesn't fit
into the buffer provided by the guest.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
