For machinetypes with a pci-root bus (all legacy PCI), libvirt will
make a "fake" reservation for one extra slot prior to assigning
addresses to unaddressed PCI endpoint devices in the domain. This will
trigger auto-adding of a pci-bridge for the final device to be
assigned an address *if that device would have otherwise instead been
the last device on the last available pci-bridge*; thus it assures
that there will always be at least one slot left open in the domain's
bus topology for expansion (which is important both for hotplug (since
a new pci-bridge can't be added while the guest is running) as well as
for offline additions to the config (since adding a new device might
otherwise in some cases require re-addressing existing devices, which
we want to avoid)).
It's important to note that for the above case (legacy PCI), we must
check for the special case of all slots on all buses being occupied
*prior to assigning any addresses*, and avoid attempting to reserve
the extra address in that case, because there is no free address in
the existing topology, so no place to auto-add a pci-bridge for
expansion (i.e. it would always fail anyway). Since that condition can
only be reached by manual intervention, this is acceptable.
For machinetypes with pcie-root (Q35, aarch64 virt), libvirt's
methodology for automatically expanding the bus topology is different
- pcie-root-ports are plugged into slots (soon to be functions) of
pcie-root as needed, and the new endpoint devices are assigned to the
single slot in each pcie-root-port. This is done so that the devices
are, by default, hotpluggable (the slots of pcie-root don't support
hotplug, but the single slot of the pcie-root-port does). Since
pcie-root-ports can only be plugged into pcie-root, and we don't
auto-assign endpoint devices to the pcie-root slots, this means
topology expansion doesn't compete with endpoint devices for slots, so
we don't need to worry about checking for all "useful" slots being
free *prior* to assigning addresses to new endpoint devices - as a
matter of fact, if we attempt to reserve the open slots before the
used slots, it can lead to errors.
Instead this patch just reserves one slot for a "future potential"
PCIe device after doing the assignment for actual devices, but only
if the only PCI controller defined prior to starting address
assignment was pcie-root, and only if we auto-added at least one PCI
controller during address assignment. This assures two things:
1) that reserving the open slots will only be done when the domain is
initially defined, never at any time after, and
2) that if the user understands enough about PCI controllers that they
are adding them manually, that we don't mess up their plan by
adding extras - if they know enough to add one pcie-root-port, or
to manually assign addresses such that no pcie-root-ports are
needed, they know enough to add extra pcie-root-ports if they want
them (this could be called the "libguestfs clause", since
libguestfs needs to be able to create domains with as few
devices/controllers as possible).
This is set to reserve a single free port for now, but could be
increased in the future if public sentiment goes in that direction
(it's easy to increase later, but essentially impossible to decrease)
Real Q35 hardware has an ICH9 chip that includes several integrated
devices at particular addresses (see the file docs/q35-chipset.cfg in
the qemu source). libvirt already attempts to put the first two sets
of ich9 USB2 controllers it finds at 00:1D.* and 00:1A.* to match the
real hardware. This patch does the same for the ich9 "HD audio"
device.
The main inspiration for this patch is that currently the *only*
device in a reasonable "workstation" type virtual machine config that
requires a legacy PCI slot is the audio device, Without this patch,
the standard Q35 machine created by virt-manager will have a
dmi-to-pci-bridge and a pci-bridge just for the sound device; with the
patch (and if you change the sound device model from the default
"ich6" to "ich9"), the machine definition constructed by virt-manager
has absolutely no legacy PCI controllers - any legacy PCI devices
(e.g. video and sound) are on pcie-root as integrated devices.
Previously we added a set of EHCI+UHCI controllers to Q35 machines to
mimic real hardware as closely as possible, but recent discussions
have pointed out that the nec-usb-xhci (USB3) controller is much more
virtualization-friendly (uses less CPU), so this patch switches the
default for Q35 machinetypes to add an XHCI instead (if it's
supported, which it of course *will* be).
Since none of the existing test cases left out USB controllers in the
input XML, a new Q35 test case was added which has *no* devices, so
ends up with only the defaults always put in by qemu, plus those added
by libvirt.
Now the a dmi-to-pci-bridge is automatically added just as it's needed
(when a pci-bridge is being added), we no longer have any need to
force-add one to every single Q35 domain.
A few of the qemu test cases assume that a dmi-to-pci-bridge will
always be added at index 1, and so they omit it from the input data
even though a pci-bridge is present at index 2, e.g.:
<controller type='pci' index='0' model='pcie-root'/>
<controller type='pci' index='2' model='pci-bridge'/>
Support for this odd practice was discussed on libvir-list and we
decided that the complex code required to make this continue was not
worth the headache of maintaining. So instead, this patch modifies the
test cases to manually add a dmi-to-pci-bridge at index 1 (since an
upcoming patch is going to eliminate the unconditional adding of
dmi-to-pci-bridge).
Because the auto-add was placing the dmi-to-pci-bridge later in the
list (even though it has a lower index) the test output is also
updated to take account for the new order (which puts the pci
controllers in index-order)
Previously libvirt would only add pci-bridge devices automatically
when an address was requested for a device that required a legacy PCI
slot and none was available. This patch expands that support to
dmi-to-pci-bridge (which is needed in order to add a pci-bridge on a
machine with a pcie-root), and pcie-root-port (which is needed to add
a hotpluggable PCIe device). It does *not* automatically add
pcie-switch-upstream-ports or pcie-switch-downstream-ports (and
currently there are no plans for that).
Given the existing code to auto-add pci-bridge devices, automatically
adding pcie-root-ports is fairly straightforward. The
dmi-to-pci-bridge support is a bit tricky though, for a few reasons:
1) Although the only reason to add a dmi-to-pci-bridge is so that
there is a reasonable place to plug in a pci-bridge controller,
most of the time it's not the presence of a pci-bridge *in the
config* that triggers the requirement to add a dmi-to-pci-bridge.
Rather, it is the presence of a legacy-PCI device in the config,
which triggers auto-add of a pci-bridge, which triggers auto-add of
a dmi-to-pci-bridge (this is handled in
virDomainPCIAddressSetGrow() - if there's a request to add a
pci-bridge we'll check if there is a suitable bus to plug it into;
if not, we first add a dmi-to-pci-bridge).
2) Once there is already a single dmi-to-pci-bridge on the system,
there won't be a need for any more, even if it's full, as long as
there is a pci-bridge with an open slot - you can also plug
pci-bridges into existing pci-bridges. So we have to make sure we
don't add a dmi-to-pci-bridge unless there aren't any
dmi-to-pci-bridges *or* any pci-bridges.
3) Although it is strongly discouraged, it is legal for a pci-bridge
to be directly plugged into pcie-root, and we don't want to
auto-add a dmi-to-pci-bridge if there is already a pci-bridge
that's been forced directly into pcie-root.
Although libvirt will now automatically create a dmi-to-pci-bridge
when it's needed, the code still remains for now that forces a
dmi-to-pci-bridge on all domains with pcie-root (in
qemuDomainDefAddDefaultDevices()). That will be removed in a future
patch.
For now, the pcie-root-ports are added one to a slot, which is a bit
wasteful and means it will fail after 31 total PCIe devices (30 if
there are also some PCI devices), but helps keep the changeset down
for this patch. A future patch will have 8 pcie-root-ports sharing the
functions on a single slot.
The nec-usb-xhci device (which is a USB3 controller) has always
presented itself as a PCI device when plugged into a legacy PCI slot,
and a PCIe device when plugged into a PCIe slot, but libvirt has
always auto-assigned it to a legacy PCI slot.
This patch changes that behavior to auto-assign to a PCIe slot on
systems that have pcie-root (e.g. Q35 and aarch64/virt).
Since we don't yet auto-create pcie-*-port controllers on demand, this
means a config with an nec-xhci USB controller that has no PCI address
assigned will also need to have an otherwise-unused pcie-*-port
controller specified:
<controller type='pci' model='pcie-root-port'/>
<controller type='usb' model='nec-xhci'/>
(this assumes there is an otherwise-unused slot on pcie-root to accept
the pcie-root-port)
The e1000e is an emulated network device based on the Intel 82574,
present in qemu 2.7.0 and later. Among other differences from the
e1000, it presents itself as a PCIe device rather than legacy PCI. In
order to get it assigned to a PCIe controller, this patch updates the
flags setting for network devices when the model name is "e1000e".
(Note that for some reason libvirt has never validated the network
device model names other than to check that there are no dangerous
characters in them. That should probably change, but is the subject of
another patch.)
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1343094
libvirt previously assigned nearly all devices to a "hotpluggable"
legacy PCI slot even on machines with a PCIe root bus (and even though
most such machines don't even support hotplug on legacy PCI slots!)
Forcing all devices onto legacy PCI slots means that the domain will
need a dmi-to-pci-bridge (to convert from PCIe to legacy PCI) and a
pci-bridge (to provide hotpluggable legacy PCI slots which, again,
usually aren't hotpluggable anyway).
To help reduce the need for these legacy controllers, this patch tries
to assign virtio-1.0-capable devices to PCIe slots whenever possible,
by setting appropriate connectFlags in
virDomainCalculateDevicePCIConnectFlags(). Happily, when that function
was written (just a few commits ago) it was created with a
"virtioFlags" argument, set by both of its callers, which is the
proper connectFlags to set for any virtio-*-pci device - depending on
the arch/machinetype of the domain, and whether or not the qemu binary
supports virtio-1.0, that flag will have either been set to PCI or
PCIe. This patch merely enables the functionality by setting the flags
for the device to whatever is in virtioFlags if the device is a
virtio-*-pci device.
NB: the first virtio video device will be placed directly on bus 0
slot 1 rather than on a pcie-root-port due to the override for primary
video devices in qemuDomainValidateDevicePCISlotsQ35(). Whether or not
to change that is a topic of discussion, but this patch doesn't change
that particular behavior.
NB2: since the slot must be hotpluggable, and pcie-root (the PCIe root
complex) does *not* support hotplug, this means that suitable
controllers must also be in the config (i.e. either pcie-root-port, or
pcie-downstream-port). For now, libvirt doesn't add those
automatically, so if you put virtio devices in a config for a qemu
that has PCIe-capable virtio devices, you'll need to add extra
pcie-root-ports yourself. That requirement will be eliminated in a
future patch, but for now, it's simple to do this:
<controller type='pci' model='pcie-root-port'/>
<controller type='pci' model='pcie-root-port'/>
<controller type='pci' model='pcie-root-port'/>
...
Partially Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1330024
The memory device alias needs to be treated as machine ABI as qemu is
using it in the migration stream for section labels. To simplify this
generate the alias from the slot number unless an existing broken
configuration is detected.
With this patch the aliases are predictable and even certain
configurations which would not be migratable previously are fixed.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1359135
As with other devices assign the slot number right away when adding the
device. This will make the slot numbers static as we do with other
addressing elements and it will ultimately simplify allocation of the
alias in a static way which does not break with qemu.
Simplify handling of the 'dimm' address element by allowing to specify
the slot number only. This will allow libvirt to allocate slot numbers
before starting qemu.
Even though using /dev/shm/asdf as the backend, we still need to make
the mapping shared. The original patch forgot to add that parameter.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1392031
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
Propagate the selected or default level to qemu if it's supported.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1376009
Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
QEMU added support for ivshmem-plain and ivshmem-doorbell. Those are
reworked varians of legacy ivshmem that are compatible from the guest
POV, but not from host's POV and have sane specification and handling.
Details about the newer device type can be found in qemu's commit
5400c02b90bb:
http://git.qemu.org/?p=qemu.git;a=commit;h=5400c02b90bb
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
We're keeping some things at default and that's not something we want to
do intentionally. Let's save some sensible defaults upfront in order to
avoid having problems later. The details for the defaults (of the newer
implementation) can be found in qemu's commit 5400c02b90bb:
http://git.qemu.org/?p=qemu.git;a=commit;h=5400c02b90bb
Since we are merely saving the defaults it will not change the guest ABI
and thanks to the fact that we're doing it in the PostParse callback it
will not break the ABI stability checks.
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
The old ivshmem is deprecated in QEMU, so let's use the better
ivshmem-{plain,doorbell} variants instead.
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
Support for virtio disks was added in commit id 'fceeeda', but not for
SCSI drives. Add the secret for the server when hotplugging a SCSI drive.
No need to make any adjustments for unplug since that's handled during
the qemuDomainDetachDiskDevice call to qemuDomainRemoveDiskDevice in
the qemuDomainDetachDeviceDiskLive switch.
Added a test to/for the command line processing to show the command line
options when adding a SCSI drive for the guest.
Add the secret object so the 'passwordid=' can be added if the command line
if there's a secret defined in/on the host for TCP chardev TLS objects.
Preparation for the secret involves adding the secinfo to the char source
device prior to command line processing. There are multiple possibilities
for TCP chardev source backend usage.
Add test for at least a serial chardev as an example.
Add in the block I/O throttling length/duration parameter to the command
line if supported. If not supported, fail command creation.
Add the xml2argvtest for testing.
Add an optional "tls='yes|no'" attribute for a TCP chardev.
For QEMU, this will allow for disabling the host config setting of the
'chardev_tls' for a domain chardev channel by setting the value to "no" or
to attempt to use a host TLS environment when setting the value to "yes"
when the host config 'chardev_tls' setting is disabled, but a TLS environment
is configured via either the host config 'chardev_tls_x509_cert_dir' or
'default_tls_x509_cert_dir'
Signed-off-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
There was inconsistency between alias used to create tls-creds-x509
object and alias used to link that object to chardev while hotpluging.
Hotplug ends with this error:
error: Failed to detach device from channel-tcp.xml
error: internal error: unable to execute QEMU command 'chardev-add':
No TLS credentials with id 'objcharchannel3_tls0'
In XML we have for example alias "serial0", but on qemu command line we
generate "charserial0".
The issue was that code, that creates QMP command to hotplug chardev
devices uses only the second alias "charserial0" and that alias is also
used to link the tls-creds-x509 object.
This patch unifies the aliases for tls-creds-x509 to be always generated
from "charserial0".
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
The code is entirely correct, but it still managed to trip me
up when I first ran into it because I did not realize right away
that VIR_PCI_CONNECT_TYPES_ENDPOINT was not a single flag, but
rather a mask including both VIR_PCI_CONNECT_TYPE_PCI_DEVICE and
VIR_PCI_CONNECT_TYPE_PCIE_DEVICE.
In order to save the next distracted traveler in PCI Address Land
some time, document this fact with a comment. Add a test case for
the behavior as well.
https://bugzilla.redhat.com/show_bug.cgi?id=1366505
So far, this function lacked support for
VIR_DOMAIN_NET_TYPE_VHOSTUSER leaving callers to hack around the
problem by constructing the command line on their own. This is
not ideal as it blocks hot plug support.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Currently, what we do for vhost-user network is generate the
following part of command line:
-netdev type=vhost-user,id=hostnet0,chardev=charnet0
There's no need for 'type=' it is the default. Drop it.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
The idea is to have function that does some checking of the
arguments at its beginning and then have one big switch for all
the interface types it supports. Each one of them generating the
corresponding part of the command line.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
The idea is to have function that does some checking of the
arguments at its beginning and then have one big switch for all
the interface types it supports. Each one of them generating the
corresponding part of the command line.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
This improves commit 706b5b6277 in a way that we check qemu capabilities
instead of what architecture we are running on to detect whether we can
use *virtio-vga* model or not. This is not a case only for arm/aarch64.
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
This patch simplifies QEMU capabilities for QXL video device. QEMU
exposes this device as *qxl-vga* and *qxl* and they are both the same
device with the same set of parameters, the only difference is that
*qxl-vga* includes VGA compatibility.
Based on QEMU code they are tied together so it's safe to check only for
presence of only one of them.
This patch also removes an invalid test case "video-qxl-sec-nodevice"
where there is only *qxl-vga* device and *qxl* device is not present.
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
If one of QEMU_CAPS_DEVICE_QXL_VGA or QEMU_CAPS_DEVICE_QXL is set the
other one will always be set as well because both devices are tied
together in QEMU.
The change of args files is caused by the presence of capability
QEMU_CAPS_DEVICE_VIDEO_PRIMARY which means it's safe to use
"-device qxl-vga" instead of "-vga qxl", see commit (e3f2686b) and
by the fact that if QEMU_CAPS_VGA_QXL is set QEMU_CAPS_DEVICE_QXL_VGA
and QEMU_CAPS_DEVICE_QXL would be set too (since we support only qemu
with "-device" option).
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
The intel-iommu device has existed since QEMU 2.2.0, but
it was only possible to create it with -device since
QEMU 2.7.0, thanks to:
commit 621d983a1f9051f4cfc3f402569b46b77d8449fc
Author: Marcel Apfelbaum <marcel@redhat.com>
Date: Mon Jun 27 18:38:34 2016 +0300
hw/iommu: enable iommu with -device
Use the standard '-device intel-iommu' to create the IOMMU device.
The legacy '-machine,iommu=on' can still be used.
The libvirt capability check & command line formatting code
is thus broken for all QEMU versions 2.2.0 -> 2.6.0 inclusive.
This fixes it to use iommu=on instead.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
We're about to add 6 new options and it appears (from testing) one cannot
utilize both the shorthand (alias) and (much) longer names for the arguments.
So modify the command builder to use the longer name and of course alter the
test output .args to have the similarly innocuous long name.
Also utilize a macro to build that name makes it so much more visually
appealing and saves a few characters or potential cut-n-paste issues.
Signed-off-by: John Ferlan <jferlan@redhat.com>
It was missing... Also since I'm using the soft link from qemuxml2xmloutdata
to the qemuxml2argvdata file, modify the output file to have the necessary
<address> elements plus the mouse and keyboard.
Signed-off-by: John Ferlan <jferlan@redhat.com>
If this reminds you of a commit message from around a year ago, it's
41c2aa729f and yes, we're dealing with
"the same thing" again. Or f309db1f4d and
it's similar.
There is a logic in place that if there is no real need for
memory-backend-file, qemuBuildMemoryBackendStr() returns 0. However
that wasn't the case with hugepage backing. The reason for that was
that we abused the 'pagesize' variable for storing that information, but
we should rather have a separate one that specifies whether we really
need the new object for hugepage backing. And that variable should be
set only if this particular NUMA cell needs special treatment WRT
hugepages.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1372153
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
The x86 CPU driver translated each CPU definition from domain XML into
CPUID data and then back to CPU definition. This effectively sorted the
list of CPU features according to their CPUID values. Since this is
going to change, we need to reorder CPU features in a few test files to
make sure the generated QEMU command lines will not change.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Adding x86 CPU models into a list of supported CPUs for non-x86
architectures is not a very good idea. Each architecture we test needs
to maintain its own list of supported CPU models.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Most of QEMU's PCI display device models, such as:
libvirt video/model/@type QEMU -device
------------------------- ------------
cirrus cirrus-vga
vga VGA
qxl qxl-vga
virtio virtio-vga
come with a linear framebuffer (sometimes called "VGA compatibility
framebuffer"). This linear framebuffer lives in one of the PCI device's
MMIO BARs, and allows guest code (primarily: firmware drivers, and
non-accelerated OS drivers) to display graphics with direct memory access.
Due to architectural reasons on aarch64/KVM hosts, this kind of
framebuffer doesn't / can't work in
qemu-system-(arm|aarch64) -M virt
machines. Cache coherency issues guarantee a corrupted / unusable display.
The problem has been researched by several people, including kvm-arm
maintainers, and it's been decided that the best way (practically the only
way) to have boot time graphics for such guests is to consolidate on
QEMU's "virtio-gpu-pci" device.
>From <https://bugzilla.redhat.com/show_bug.cgi?id=1195176>, libvirt
supports
<devices>
<video>
<model type='virtio'/>
</video>
</devices>
but libvirt unconditionally maps @type='virtio' to QEMU's "virtio-vga"
device model. (See the qemuBuildDeviceVideoStr() function and the
"qemuDeviceVideo" enum impl.)
According to the above, this is not right for the "virt" machine type; the
qemu-system-(arm|aarch64) binaries don't even recognize the "virtio-vga"
device model (justifiedly). Whereas "virtio-gpu-pci", which is a pure
virtio device without a compatibility framebuffer, is available, and works
fine.
(The ArmVirtQemu ("AAVMF") platform of edk2 -- that is, the UEFI firmware
for "virt" -- supports "virtio-gpu-pci", as of upstream commit
3ef3209d3028. See
<https://tianocore.acgmultimedia.com/show_bug.cgi?id=66>.)
Override the default mapping of "virtio", from "virtio-vga" to
"virtio-gpu-pci", if qemuDomainMachineIsVirt() evaluates to true.
Cc: Andrea Bolognani <abologna@redhat.com>
Cc: Drew Jones <drjones@redhat.com>
Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
Cc: Martin Kletzander <mkletzan@redhat.com>
Suggested-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1372901
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Acked-by: Martin Kletzander <mkletzan@redhat.com>
The test qemuxml2argv-serial-tcp-tlsx509-chardev.args
will fail if libvirt is built with a --sysconfdir
arg that is not /etc. Fix this by setting a hardcoded
path in the test code.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
When building a chardev device string for tcp, add the necessary pieces to
access provide the TLS X.509 path to qemu. This includes generating the
'tls-creds-x509' object and then adding the 'tls-creds' parameter to the
VIR_DOMAIN_CHR_TYPE_TCP command line.
Finally add the tests for the qemu command line. This test will make use
of the "new(ish)" /etc/pki/qemu setting for a TLS certificate environment
by *not* "resetting" the chardevTLSx509certdir prior to running the test.
Also use the default "verify" option (which is "no").
Signed-off-by: John Ferlan <jferlan@redhat.com>
Add a new TLS X.509 certificate type - "chardev". This will handle the
creation of a TLS certificate capability (and possibly repository) for
properly configured character device TCP backends.
Unlike the vnc and spice there is no "listen" or "passwd" associated. The
credentials eventually will be handled via a libvirt secret provided to
a specific backend.
Make use of the default verify option as well.
Signed-off-by: John Ferlan <jferlan@redhat.com>
Add support for using the new approach to hotplug vcpus using device_add
during startup of qemu to allow sparse vcpu topologies.
There are a few limitations imposed by qemu on the supported
configuration:
- vcpu0 needs to be always present and not hotpluggable
- non-hotpluggable cpus need to be ordered at the beginning
- order of the vcpus needs to be unique for every single hotpluggable
entity
Qemu also doesn't really allow to query the information necessary to
start a VM with the vcpus directly on the commandline. Fortunately they
can be hotplugged during startup.
The new hotplug code uses the following approach:
- non-hotpluggable vcpus are counted and put to the -smp option
- qemu is started
- qemu is queried for the necessary information
- the configuration is checked
- the hotpluggable vcpus are hotplugged
- vcpus are started
This patch adds a lot of checking code and enables the support to
specify the individual vcpu element with qemu.
