$subject says all. First cut.
It's a pure UAS (usb attached scsi) emulation, without BOT (bulk-only
transport) compatibility. If your guest can't handle it use usb-storage
instead.
The emulation works like any other scsi hba emulation (eps, lsi, virtio,
megasas, ...). It provides just the HBA where you can attach scsi
devices as you like using '-device'. A single scsi target with up to
256 luns is supported.
For now only usb 2.0 transport is supported. This will change in the
future though as I plan to use this as playground when codeing up &
testing usb 3.0 transport and streams support in the qemu usb core and
the xhci emulation.
No migration support yet. I'm planning to add usb 3.0 support first as
this probably requires saving additional state.
Special thanks go to Paolo for bringing the qemu scsi emulation into
shape, so this can be added nicely without having to touch a single line
of scsi code.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
All transports can use the same event handler for the irqfd, though the
exact mechanics of the assignment will be specific. Note that there
are three states: handled by the kernel, handled in userspace, disabled.
This also lets virtio use event_notifier_set_handler.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
All transports can use the same event handler for the ioeventfd, though
the exact setup (address/memory region) will be specific.
This lets virtio use event_notifier_set_handler.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Under Win32, EventNotifiers will not have event_notifier_get_fd, so we
cannot call it in common code such as hw/virtio-pci.c. Pass a pointer to
the notifier, and only retrieve the file descriptor in kvm-specific code.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
All of ivshmem's usage of eventfd now has a corresponding API in
EventNotifier. Simplify the code by using it, and also use the
memory API consistently to set up and tear down the ioeventfds.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Add a missing cast to avoid gcc complaining about format string
errors when printing an expression based on a target_phys_addr_t.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter Chubb <peter.chubb@nicta.com.au>
Most device models have a simple lifecycle for the hba_private field
and they can free it when a request is completed or cancelled.
However, in some cases it may be simpler to tie the lifetime
of hba_private to that of the included SCSIRequest. This patch
adds a free_request callback to SCSIBusInfo that lets an HBA
device model do exactly that.
Normally, device models use req->hba_private == NULL to flag requests
that have been completed already. Device models that use free_request
will still need to track this using a flag. This is the reason why
"converting" existing HBAs to use free_request adds complexity and
makes little sense. It is simply an additional convenience that is
provided by the SCSI layer. USB-attached storage will be the first
user.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
KVM performs TPR raising asynchronously to QEMU, specifically outside
QEMU's global lock. When an interrupt is injected into the APIC and TPR
is checked to decide if this can be delivered, a stale TPR value may be
used, causing spurious interrupts in the end.
Fix this by deferring apic_update_irq to the context of the target VCPU.
We introduce a new interrupt flag for this, CPU_INTERRUPT_POLL. When it
is set, the VCPU calls apic_poll_irq before checking for further pending
interrupts. To avoid special-casing KVM, we also implement this logic
for TCG mode.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
When the guest modifies the LVT_LINT0 register, we need to check if some
pending PIC interrupt can now be delivered.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Commit d96e173769 refactored the reinjection of pending PIC interrupts.
However, it missed the potential loop of apic_update_irq ->
apic_deliver_pic_intr -> apic_local_deliver -> apic_set_irq ->
apic_update_irq that /could/ occur if LINT0 is injected as APIC_DM_FIXED
and that vector is currently blocked via TPR.
Resolve this by reinjecting only where it matters: inside
apic_get_interrupt. This function may clear a vector while a
PIC-originated reason still exists.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
* 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>
* kwolf/for-anthony: (24 commits)
block: Factor bdrv_read_unthrottled() out of guess_disk_lchs()
qtest: Tidy up temporary files properly
fdc: Drop broken code for user-defined floppy geometry
fdc_test: introduce test_sense_interrupt
fdc_test: update media_change test
fdc: fix interrupt handling
fdc: rewrite seek and DSKCHG bit handling
block: introduce bdrv_swap, implement bdrv_append on top of it
block: copy over job and dirty bitmap fields in bdrv_append
raw: hook into blkdebug
blkdebug: optionally tie errors to a specific sector
blkdebug: store list of active rules
blkdebug: pass getlength to underlying file
blkdebug: tiny cleanup
blkdebug: remove sync i/o events
sheepdog: traverse pending_list from the first for each time
sheepdog: split outstanding list into inflight and pending
sheepdog: make sure we don't free aiocb before sending all requests
sheepdog: use coroutine based socket functions in coroutine context
sheepdog: restart I/O when socket becomes ready in do_co_req()
...
* kraxel/usb.55:
usb-host: add trace events for iso xfers
usb: fix interface initialization
usb: split endpoint init and reset
usb-redir: Correctly handle the usb_redir_babble usbredir status
ehci: Kick async schedule on wakeup in the non companion case
usb-ehci: Fix an assert whenever isoc transfers are used
ehci: don't flush cache on doorbell rings.
ehci: fix td writeback
ehci: fix ehci_qh_do_overlay
* bonzini/scsi-next:
scsi: Fix transfer length for READ POSITION commands.
scsi: Add basic support for SCSI media changer commands.
scsi: Ensure command and transfer lengths are set for all SCSI devices
scsi: Fix LOAD_UNLOAD
scsi: Fix data length == SCSI_SENSE_BUF_SIZE
virtio-scsi: do not crash on adding buffers to the event queue
megasas: LSI Megaraid SAS HBA emulation
megasas: Add header file
ISCSI: force use of sg for SMC and SSC devices
ISCSI: Add SCSI passthrough via scsi-generic to libiscsi
scsi-disk: implement READ DISC INFORMATION
atapi: implement READ DISC INFORMATION
scsi: add a qdev property for the disk's WWN
scsi: simplify handling of the VPD page length field
bdrv_get_floppy_geometry_hint() fails to store through its parameter
drive when bs has a geometry hint. Makes fd_revalidate() assign
random crap to drv->drive.
Has been broken that way for ages. Harmless, because:
* The only way to set a geometry hint is -drive if=none,cyls=...
Since commit c219331e, probably unintentional.
* The only use of drv->drive is as argument to another
bdrv_get_floppy_geometry_hint(). Which doesn't use it, since the
geometry hint is still there.
Drop the broken code, ignore -drive parameter cyls, heads and secs for
floppies even with if=none, just like before commit c219331e. Matches
-help, which explains cyls, heads, secs as "hard disk physical
geometry".
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
If you call the SENSE INTERRUPT STATUS command while there is no interrupt
waiting you get as result unknown command.
Fixed status0 register handling for read/write/format commands.
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This bit is cleared on every successful seek to a different track (cylinder).
The seek is also called on revalidate or on read/write/format commands which
also clear the DSKCHG bit.
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Replace iso transfer fprintf's with trace points. Also rename existing
tracepoints so they all match usb_host_iso_*.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Create a new usb_ep_reset() function to reset endpoint state, without
re-initialiting the queues, so we don't unlink in-flight packets just
because usb-host has to re-parse the descriptor tables.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Commit 0f588df8b3, added code
to ehci_wakeup to kick the async schedule on wakeup, but the else
was positioned wrong making it trigger for devices which are routed
to the companion rather then to the ehci controller itself.
This patch fixes this. Note that the "programming style" with using the
return at the end of the companion block matches how the companion case
is handled in the other ports ops, and is done this way for consistency.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
hcd-ehci.c is missing an usb_packet_init() call for the ipacket UsbPacket
it uses for isoc transfers, triggering an assert (taking the entire vm down)
in usb_packet_setup as soon as any isoc transfers are done by a high speed
USB device.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Commit 4be23939ab makes ehci instantly
zap any unlinked queue heads when the guest rings the doorbell.
While hacking up uas support this turned out to be a problem. The linux
kernel can unlink and instantly relink the very same queue head, thereby
killing any async packets in flight. That alone isn't an issue yet, the
packet will canceled and resubmitted and everything is fine. We'll run
into trouble though in case the async packet is completed already, so we
can't cancel it any more. The transaction is simply lost then.
usb_ehci_qh_ptrs q (nil) - QH @ 39c4f000: next 39c4f122 qtds 00000000,00000001,39c50000
usb_ehci_qh_fields QH @ 39c4f000 - rl 0, mplen 0, eps 0, ep 0, dev 0
usb_ehci_qh_ptrs q 0x7f95feba90a0 - QH @ 39c4f000: next 39c4f122 qtds 00000000,00000001,39c50000
usb_ehci_qh_fields QH @ 39c4f000 - rl 0, mplen 0, eps 0, ep 0, dev 0
usb_ehci_qh_ptrs q 0x7f95fe515210 - QH @ 39c4f120: next 39c4f0c2 qtds 29dbce40,29dbc4e0,00000009
usb_ehci_qh_fields QH @ 39c4f120 - rl 4, mplen 512, eps 2, ep 1, dev 2
usb_ehci_packet_action q 0x7f95fe515210 p 0x7f95fdec32a0: alloc
usb_packet_state_change bus 0, port 2, ep 1, packet 0x7f95fdec32e0, state undef -> setup
usb_ehci_packet_action q 0x7f95fe515210 p 0x7f95fdec32a0: process
usb_uas_command dev 2, tag 0x2, lun 0, lun64 00000000-00000000
scsi_req_parsed target 0 lun 0 tag 2 command 42 dir 2 length 16384
scsi_req_parsed_lba target 0 lun 0 tag 2 command 42 lba 5933312
scsi_req_alloc target 0 lun 0 tag 2
scsi_req_continue target 0 lun 0 tag 2
scsi_req_data target 0 lun 0 tag 2 len 16384
usb_uas_scsi_data dev 2, tag 0x2, bytes 16384
usb_uas_write_ready dev 2, tag 0x2
usb_packet_state_change bus 0, port 2, ep 1, packet 0x7f95fdec32e0, state setup -> complete
usb_ehci_packet_action q 0x7f95fe515210 p 0x7f95fdec32a0: free
usb_ehci_qh_ptrs q 0x7f95fdec3210 - QH @ 39c4f0c0: next 39c4f002 qtds 29dbce40,00000001,00000009
usb_ehci_qh_fields QH @ 39c4f0c0 - rl 4, mplen 512, eps 2, ep 2, dev 2
usb_ehci_queue_action q 0x7f95fe5152a0: free
usb_packet_state_change bus 0, port 2, ep 2, packet 0x7f95feba9170, state async -> complete
^^^ async packets completes.
usb_ehci_packet_action q 0x7f95fdec3210 p 0x7f95feba9130: wakeup
usb_ehci_qh_ptrs q (nil) - QH @ 39c4f000: next 39c4f122 qtds 00000000,00000001,39c50000
usb_ehci_qh_fields QH @ 39c4f000 - rl 0, mplen 0, eps 0, ep 0, dev 0
usb_ehci_qh_ptrs q 0x7f95feba90a0 - QH @ 39c4f000: next 39c4f122 qtds 00000000,00000001,39c50000
usb_ehci_qh_fields QH @ 39c4f000 - rl 0, mplen 0, eps 0, ep 0, dev 0
usb_ehci_qh_ptrs q 0x7f95fe515210 - QH @ 39c4f120: next 39c4f002 qtds 29dbc4e0,29dbc8a0,00000009
usb_ehci_qh_fields QH @ 39c4f120 - rl 4, mplen 512, eps 2, ep 1, dev 2
usb_ehci_queue_action q 0x7f95fdec3210: free
usb_ehci_packet_action q 0x7f95fdec3210 p 0x7f95feba9130: free
^^^ endpoint #2 queue head removed from schedule, doorbell makes ehci zap the queue,
the (completed) usb packet is freed too and gets lost.
usb_ehci_qh_ptrs q (nil) - QH @ 39c4f000: next 39c4f0c2 qtds 00000000,00000001,39c50000
usb_ehci_qh_fields QH @ 39c4f000 - rl 0, mplen 0, eps 0, ep 0, dev 0
usb_ehci_qh_ptrs q 0x7f95feba90a0 - QH @ 39c4f000: next 39c4f0c2 qtds 00000000,00000001,39c50000
usb_ehci_qh_fields QH @ 39c4f000 - rl 0, mplen 0, eps 0, ep 0, dev 0
usb_ehci_queue_action q 0x7f9600dff570: alloc
usb_ehci_qh_ptrs q 0x7f9600dff570 - QH @ 39c4f0c0: next 39c4f122 qtds 29dbce40,00000001,00000009
usb_ehci_qh_fields QH @ 39c4f0c0 - rl 4, mplen 512, eps 2, ep 2, dev 2
usb_ehci_packet_action q 0x7f9600dff570 p 0x7f95feba9130: alloc
usb_packet_state_change bus 0, port 2, ep 2, packet 0x7f95feba9170, state undef -> setup
usb_ehci_packet_action q 0x7f9600dff570 p 0x7f95feba9130: process
usb_packet_state_change bus 0, port 2, ep 2, packet 0x7f95feba9170, state setup -> async
usb_ehci_packet_action q 0x7f9600dff570 p 0x7f95feba9130: async
^^^ linux kernel relinked the queue head, ehci creates a new usb packet,
but we should have delivered the completed one instead.
usb_ehci_qh_ptrs q 0x7f95fe515210 - QH @ 39c4f120: next 39c4f002 qtds 29dbc4e0,29dbc8a0,00000009
usb_ehci_qh_fields QH @ 39c4f120 - rl 4, mplen 512, eps 2, ep 1, dev 2
So instead of instantly zapping the queue we'll set a flag that the
queue needs revalidation in case we'll see it again in the schedule.
ehci then checks that the queue head fields addressing / describing the
endpoint and the qtd pointer match the cached content before reusing it.
Cc: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Only write back the dwords the hc is supposed to update. Should not
make a difference in theory as the guest must not touch the td while
it is active to avoid races. But it is still more correct.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
BARs are registered in init functions from memory regions created
by the drivers. Exit functions destroy those memory regions.
By unregistering the io regions after exit(), we're calling
memory_region_del_subregion on freed memory. Don't do that. The
option rom comes along for the ride because it's more symmetric
to how it's created.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Not a single driver has any possibility of failure on their
exit function, let's keep it that way.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Make the state fields rx_desc_addr and tx_desc_addr uint32_t;
this matches the VMStateDescription, and also conforms to how
hardware works: the registers don't magically become larger
if the device is attached to a CPU with a larger physical
address size. It also fixes a compile failure if the
target_phys_addr_t type is changed to 64 bits.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter A. G. Crosthwaite <peter.crosthwaite@petalogix.com>
Board support for Kyoto Micro's KZM-ARM11-01, an evaluation board built
around the Freescale i.MX31.
Signed-off-by: Philip O'Sullivan <philipo@ok-labs.com>
Signed-off-by: Peter Chubb <peter.chubb@nicta.com.au>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Implement the Freescale i.MX31 advanced vectored interrupt controller, at least
to the extent it is used by Linux 3.x
Vectors are not implemented.
Signed-off-by: Philip O'Sullivan <philipo@ok-labs.com>
Signed-off-by: Peter Chubb <peter.chubb@nicta.com.au>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Implement the timers on the Freescale i.MX31 SoC.
This is not a complete implementation, but gives enough for
Linux to boot and run. In particular external triggers, which are
not useful under QEMU, are not implemented.
Signed-off-by: Philip O'Sullivan <philipo@ok-labs.com>
Signed-off-by: Peter Chubb <peter.chubb@nicta.com.au>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
For Linux to be able to work out how fast its clocks are going, so
that timer ticks come approximately at the right time, it needs to
be able to query the clock control module (CCM).
This is the start of a CCM implementation. It currently knows only about
the MCU, HSP and IPG clocks --- i.e., the ones used to feed the periodic
and general purpose timers.
Signed-off-by: Peter Chubb <peter.chubb@nicta.com.au>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Implement the Freescale i.MX UART. This uart is used in a variety of
SoCs, including some by Motorola, as well as in the Freescale i.MX
series.
This patch gives only a `bare-bones' implementation, enough to run Linux
or OKL4, but that's about it.
Signed-off-by: Philip O'Sullivan <philipo@ok-labs.com>
Signed-off-by: Peter Chubb <peter.chubb@nicta.com.au>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
We want to mirror whole IROM and should pass zero instead of
EXYNOS4210_IROM_BASE_ADDR (though it equals to zero too) since
memory_region_init_alias takes an offset within an original
region as an argument.
Signed-off-by: Evgeny Voevodin <e.voevodin@samsung.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
START/STOP bit was not cleaned correctly.
Signed-off-by: Evgeny Voevodin <e.voevodin@samsung.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
After some long period of time Linux kernel hanged due to
ptimer_get_count may return 0 before timer interrupt occurs,
thus, causing FRC to jump back in time
Signed-off-by: Evgeny Voevodin <e.voevodin@samsung.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
The transfer length depends on the specific service action
code, as defined in the SCSI stream commands spec section 7.7.
Up to now only the extended form was supported.
Signed-off-by: Christian Hoff <christian.hoff@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This adds basic support for SCSI media changer commands.
Not all commands are supported as of now, but enough to cover
basic functionality.
Signed-off-by: Christian Hoff <christian.hoff@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
scsi-generic relies on those values to be correct, so it is important that
those values are initialized properly for all device types.
Reported-by: Christian Hoff <christian.hoff@de.ibm.com>
Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Change operation code of LOAD_UNLOAD command to 0x1b as described in
section 7.3 of the SCSI Stream Commands spec.
Signed-off-by: Christian Hoff <christian.hoff@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Fix the edge case where the sense data length is exactly the same
as SCSI_SENSE_BUF_SIZE.
This makes SCSI requests work that use all of the available 95 byte
sense data.
Signed-off-by: Christian Hoff <christian.hoff@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The event queue is not supported yet and the handler does not
have to do much anyway when buffers are added. However, the
handler is called unconditionally by the virtio layer, and this
results in a crash as soon as buffers are added to the event
queue because we pass NULL.
Reported-by: Bryan Venteicher <bryanv@daemoninthecloset.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This patch adds an emulation for the LSI Megaraid SAS 8708EM2 HBA.
I've tested it to work with Linux, Windows Vista, and Windows7.
Signed-off-by: Hannes Reinecke <hare@suse.de>
[ Squashed trivial changes from Andreas Faerber, rebased over IOMMU
and QBus changes - Paolo ]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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>
This command is not necessary for CD-ROM and DVD-ROM, but some versions of
udev trip on its absence.
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This command is not necessary for CD-ROM and DVD-ROM, but some versions of
udev trip on its absence.
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
