The previous optimizations lead to some follow-on cleanups.
* src/conf/domain_conf.c (virDomainSnapshotForEachChild)
(virDomainSnapshotForEachDescendant): Drop dead parameter.
(virDomainSnapshotActOnDescendant)
(virDomainSnapshotObjListNumFrom)
(virDomainSnapshotObjListGetNamesFrom): Update callers.
* src/qemu/qemu_driver.c (qemuDomainSnapshotNumChildren)
(qemuDomainSnapshotListChildrenNames, qemuDomainSnapshotDelete):
Likewise.
* src/conf/domain_conf.h: Update prototypes.
Maintain the parent/child relationships of all qemu snapshots.
* src/qemu/qemu_driver.c (qemuDomainSnapshotLoad): Populate
relationships after loading.
(qemuDomainSnapshotCreateXML): Set relations on creation; tweak
redefinition to reuse existing object.
(qemuDomainSnapshotReparentChildren, qemuDomainSnapshotDelete):
Clear relations on delete.
To date, JSON disk snapshots worked by accident, as they were always
using hmp fallback due to a typo in commit e702b5b not picking up
on the (intentional) difference in command names between the two
monitor protocols.
* src/qemu/qemu_monitor_json.c (qemuMonitorJSONDiskSnapshot):
Spell QMP command correctly.
Reported by Luiz Capitulino.
Not too hard to wire up. The trickiest part is realizing that
listing children of a snapshot cannot use SNAPSHOT_LIST_ROOTS,
and that we overloaded that bit to also mean SNAPSHOT_LIST_DESCENDANTS;
we use that bit to decide which iteration to use, but don't want
the existing counting/listing functions to see that bit.
* src/conf/domain_conf.h (virDomainSnapshotObjListNumFrom)
(virDomainSnapshotObjListGetNamesFrom): New prototypes.
* src/conf/domain_conf.c (virDomainSnapshotObjListNumFrom)
(virDomainSnapshotObjListGetNamesFrom): New functions.
* src/libvirt_private.syms (domain_conf.h): Export them.
* src/qemu/qemu_driver.c (qemuDomainSnapshotNumChildren)
(qemuDomainSnapshotListChildrenNames): New functions.
If parsing qemu command line fails (e.g. because of non-existing
process number supplied), we jump to cleanup label where we free
pidfile. Therefore it needs to be initialized. Otherwise we free
random pointer.
Coverity complained that 4 out of 5 callers to virJSONValueObjectGetBoolean
checked for errors. But we documented that we don't care in this case.
* src/qemu/qemu_monitor_json.c (qemuMonitorJSONGetBlockInfo): Use
ignore_value.
Previously libvirt's disk device XML only had a single attribute,
error_policy, to control both read and write error policy, but qemu
has separate options for controlling read and write. In one case
(enospc) a policy is allowed for write errors but not read errors.
This patch adds a separate attribute that sets only the read error
policy. If just error_policy is set, it will apply to both read and
write error policy (previous behavior), but if the new rerror_policy
attribute is set, it will override error_policy for read errors only.
Possible values for rerror_policy are "stop", "report", and "ignore"
("report" is the qemu-controlled default for rerror_policy when
error_policy isn't specified).
For consistency, the value "report" has been added to the possible
values for error_policy as well.
commit 12062ab set rerror=ignore when error_policy="enospace" was
selected (since the rerror option in qemu doesn't accept "enospc", as
the werror option does).
After that patch was already pushed, Paolo Bonzini noticed it and
commented that leaving rerror at the default ("report") would be a
better choice. This patch corrects the problem - if error_policy =
"enospace" is given, rerror is left off the qemu commandline,
effectively setting it to "report". For other values, rerror is still
set to match werror.
Additionally, the parsing of error_policy was changed to no longer
erroneously allow "default" as a choice - as with most other
attributes, if you want the default setting, just don't specify an
error_policy.
Finally, two ommissions in the first patch were corrected - a
long-dormant qemuxml2argv test for enospace was enabled, and fixed to
pass, and the argv2xml parser in qemu_command.c was updated to
recognize the different spelling on the qemu commandline.
Now that RHEL 6.2 Beta is out, it would be nice to test multifunction
devices on that platform. This changes things so that the multifunction
cap bit can be set in two different ways: by version comparison (needed
for qemu 0.13 which lacked a -device query), and by -device query
(provided by qemu.git and backported to the RHEL beta build of
qemu-kvm which still claims to be a modified 0.12, and therefore needed
for RHEL).
* src/qemu/qemu_capabilities.c (qemuCapsParseDeviceStr): Allow
second method of setting multifunction cap bit.
* tests/qemuhelptest.c (mymain): Test it.
* tests/qemuhelpdata/qemu-kvm-0.12.1.2-rhel62-beta: New file.
* tests/qemuhelpdata/qemu-kvm-0.12.1.2-rhel62-beta-device: Likewise.
Implements the documentation for snapshot revert vs. force.
Part of the patch tightens existing behavior (previously, reverting
to an old snapshot without <domain> was blindly attempted, now it
requires force), while part of it relaxes behavior (previously, it
was not possible to revert an active domain to an ABI-incompatible
active snapshot, now force allows this transition).
* src/qemu/qemu_driver.c (qemuDomainRevertToSnapshot): Check for
risky situations, and allow force to get past them.
Once we know which set of disks belong to a snapshot, reverting or
deleting that snapshot should visit just those disks, rather than
also visiting disks that were hot-plugged in the meantime or
skipping disks that were hot-unplugged in the meantime.
* src/qemu/qemu_domain.c (qemuDomainSnapshotForEachQcow2): Use
snapshot domain details when available. Avoid NULL deref.
Qemu driver tries to update balloon data in virDomainGetInfo and if it
can't do so because there is another monitor job running, it just
reports what's known in domain def. However, if there was no job running
but getting the data from qemu fails, we would fail the whole API. This
doesn't make sense. Let's make the failure nonfatal.
This resolves:
https://bugzilla.redhat.com/show_bug.cgi?id=730909
When support for setting the qemu disk error policy to "enospc" was
added, it was inadvertently spelled "enospace". This patch corrects
that on the qemu commandline (while retaining the "enospace" spelling
for libvirt's XML).
Also, while examining the qemu source, I found that "enospc" is not
allowed for the read error policy, only for write error policy (makes
sense). Since libvirt currently only has a single error policy
setting, when "enospace" is selected, the read error policy is set to
"ignore".
Destination libvirtd remembers the original name in the prepare phase
and clears it in the finish phase. The original name is used when
comparing domain name in migration cookie.
When support for was added for PCI multifunction cards (in commit
9f8baf, first included in libvirt 0.9.3), it was done by always
turning on the multifunction bit for all PCI devices. Since that time
it has been realized that this is not an ideal solution, and that the
multifunction bit must be selectively turned on. For example, see
https://bugzilla.redhat.com/show_bug.cgi?id=728174
and the discussion before and after
https://www.redhat.com/archives/libvir-list/2011-September/msg01036.html
This patch modifies multifunction support so that the multifunction=on
option is only added to the qemu commandline for a device if its PCI
<address> definition has the attribute "multifunction='on'", e.g.:
<address type='pci' domain='0x0000' bus='0x00'
slot='0x04' function='0x0' multifunction='on'/>
In practice, the multifunction bit should only be turned on if
function='0' AND other functions will be used in the same slot - it
usually isn't needed for functions 1-7 (although there are apparently
some exceptions, e.g. the Intel X53 according to the QEMU source
code), and should never be set if only function 0 will be used in the
slot. The test cases have been changed accordingly to illustrate.
With this patch in place, if a user attempts to assign multiple
functions in a slot without setting the multifunction bit for function
0, libvirt will issue an error when the domain is defined, and the
define operation will fail. In the future, we may decide to detect
this situation and automatically add multifunction=on to avoid the
error; even then it will still be useful to have a manual method of
turning on multifunction since, as stated above, there are some
devices that excpect it to be turned on for all functions in a slot.
A side effect of this patch is that attempts to use the same PCI
address for two different devices will now log an error (previously
this would cause the domain define operation to fail, but there would
be no log message generated). Because the function doing this log was
almost completely rewritten, I didn't think it worthwhile to make a
separate patch for that fix (the entire patch would immediately be
obsoleted).
Currently, qemuDomainGetXMLDesc and qemudDomainGetInfo check for
outstanding synchronous job before (eventual) monitor entering.
However, there can be already async job set, e.g. migration.
If the daemon is restarted so we reconnect to monitor, cdrom media
can be ejected. In that case we don't want to show it in domain xml,
or require it on migration destination.
To check for disk status use 'info block' monitor command.
* src/qemu/qemu_migration.c: if 'vmdef' is NULL, the function
virDomainSaveConfig still dereferences it, it doesn't make
sense, so should add return value check to make sure 'vmdef'
is non-NULL before calling virDomainSaveConfig, in addition,
in order to debug later, also should record error information
into log.
Signed-off-by: Alex Jia <ajia@redhat.com>
First hypervisor implementation of the new API.
Allows 'virsh snapshot-list --tree' to be more efficient.
* src/qemu/qemu_driver.c (qemuDomainSnapshotGetParent): New
function.
If a domain started with -no-shutdown shuts down while libvirtd is not
running, it will be seen as paused when libvirtd reconnects to it. Use
the paused reason to detect if a domain was stopped because of shutdown
and finish the process just as if a SHUTDOWN event is delivered from
qemu.
This patch was made in response to:
https://bugzilla.redhat.com/show_bug.cgi?id=738095
In short, qemu's default for the rombar setting (which makes the
firmware ROM of a PCI device visible/not on the guest) was previously
0 (not visible), but they recently changed the default to 1
(visible). Unfortunately, there are some PCI devices that fail in the
guest when rombar is 1, so the setting must be exposed in libvirt to
prevent a regression in behavior (it will still require explicitly
setting <rom bar='off'/> in the guest XML).
rombar is forced on/off by adding:
<rom bar='on|off'/>
inside a <hostdev> element that defines a PCI device. It is currently
ignored for all other types of devices.
At the moment there is no clean method to determine whether or not the
rombar option is supported by QEMU - this patch uses the advice of a
QEMU developer to assume support for qemu-0.12+. There is currently a
patch in the works to put this information in the output of "qemu-kvm
-device pci-assign,?", but of course if we switch to keying off that,
we would lose support for setting rombar on all the versions of qemu
between 0.12 and whatever version gets that patch.
SIGTERM handling for -no-shutdown is already fixed in qemu git and
libvirt can safely use it. The downside is that 0.15.50 version of qemu
can be any qemu compiled from git, even that without the fix for
SIGTERM. However, I think this patch is worth it since excluding 0.15.50
from the check makes testing current qemu with libvirt much easier and
someone running qemu from git should be able to rebuild fixed qemu from
git if they hit the problem with a hang on shutdown.
QEMU 0.13 introduced cache=unsafe for -drive, this patch exposes
it in the libvirt layer.
* Introduced a new QEMU capability flag ($prefix_CACHE_UNSAFE),
as even if $prefix_CACHE_V2 is set, we can't know if unsafe
is supported.
* Improved the reliability of qemu cache type detection.
If a domain has inactive XML we want to transfer it to destination
when migrating with VIR_MIGRATE_PERSIST_DEST. In order to harm
the migration protocol as least as possible, a optional cookie was
chosen.
The previous patch removed all snapshots, but not the directory
where the snapshots lived, which is still a form of stale data.
* src/qemu/qemu_domain.c (qemuDomainRemoveInactive): Wipe any
snapshot directory.
Commit 282fe1f0 documented that transient domains will auto-delete
any snapshot metadata when the last reference to the domain is
removed, and that management apps are in charge of grabbing any
snapshot metadata prior to that point. However, this was not
actually implemented for qemu until now.
* src/qemu/qemu_driver.c (qemudDomainCreate)
(qemuDomainDestroyFlags, qemuDomainSaveInternal)
(qemudDomainCoreDump, qemuDomainRestoreFlags, qemudDomainDefine)
(qemuDomainUndefineFlags, qemuDomainMigrateConfirm3)
(qemuDomainRevertToSnapshot): Clean up snapshot metadata.
* src/qemu/qemu_migration.c (qemuMigrationPrepareAny)
(qemuMigrationPerformJob, qemuMigrationPerformPhase)
(qemuMigrationFinish): Likewise.
* src/qemu/qemu_process.c (qemuProcessHandleMonitorEOF)
(qemuProcessReconnect, qemuProcessReconnectHelper)
(qemuProcessAutoDestroyDom): Likewise.
This patch is mostly code motion - moving some functions out
of qemu_driver and into qemu_domain so they can be reused by
multiple qemu_* files (since qemu_driver.h must not grow).
It also adds a new helper function, qemuDomainRemoveInactive,
which will be used in the next patch.
* src/qemu/qemu_domain.h (qemuFindQemuImgBinary)
(qemuDomainSnapshotWriteMetadata, qemuDomainSnapshotForEachQcow2)
(qemuDomainSnapshotDiscard, qemuDomainSnapshotDiscardAll)
(qemuDomainRemoveInactive): New prototypes.
(struct qemu_snap_remove): New struct.
* src/qemu/qemu_domain.c (qemuDomainRemoveInactive)
(qemuDomainSnapshotDiscardAllMetadata): New functions.
(qemuFindQemuImgBinary, qemuDomainSnapshotWriteMetadata)
(qemuDomainSnapshotForEachQcow2, qemuDomainSnapshotDiscard)
(qemuDomainSnapshotDiscardAll): Move here...
* src/qemu/qemu_driver.c (qemuFindQemuImgBinary)
(qemuDomainSnapshotWriteMetadata, qemuDomainSnapshotForEachQcow2)
(qemuDomainSnapshotDiscard, qemuDomainSnapshotDiscardAll): ...from
here.
(qemuDomainUndefineFlags): Update caller.
* src/conf/domain_conf.c (virDomainRemoveInactive): Doc fixes.
Commit 19f8c98 introduced VIR_DOMAIN_UNDEFINE_SNAPSHOTS_METADATA,
with the intent that omitting the flag makes undefine fail, and
including the flag deletes metadata. But it used the wrong logic.
Also, hoist the transient domain sooner, so that we don't
accidentally remove metadata of a transient domain.
* src/qemu/qemu_driver.c (qemuDomainUndefineFlags): Check correct
flag value.
* src/qemu/qemu_process.c: Taking if (qemuDomainObjEndJob(driver, obj) == 0)
true branch then 'obj' is NULL, virDomainObjIsActive(obj) and
virDomainObjUnref(obj) will dereference NULL pointer.
Signed-off-by: Alex Jia <ajia@redhat.com>
Once virDomainReboot is called for a domain, guest OS initiated shutdown
would always result in reboot instead of shutdown. Only
virDomainShutdown would actually shutd such domain down. That's because
we forgot to reset fakeReboot flag once we asked the domain to reboot.
The commit that prevents disk corruption on domain shutdown
(96fc478417) causes regression with QEMU
0.14.* and 0.15.* because of a regression bug in QEMU that was fixed
only recently in QEMU git. The affected versions of QEMU do not quit on
SIGTERM if started with -no-shutdown, which we use to implement fake
reboot. Since -no-shutdown tells QEMU not to quit automatically on guest
shutdown, domains started using the affected QEMU cannot be shutdown
properly and stay in a paused state.
This patch disables fake reboot feature on such QEMU by not using
-no-shutdown, which makes shutdown work as expected. However,
virDomainReboot will not work in this case and it will report "Requested
operation is not valid: Reboot is not supported with this QEMU binary".
gcc warns when building libvirt 0.9.5 on a 32-bit machine:
qemu/qemu_migration.c: In function 'qemuMigrationToFile':
qemu/qemu_migration.c:2727:38: error: large integer implicitly truncated to unsigned type [-Woverflow]
* src/qemu/qemu_domain.h (QEMU_DOMAIN_FILE_MIG_BANDWIDTH_MAX): Cap
to long when building for 32-bit platform.
Virsh man page lists driver types to be used with attach-device
command, but does not specify that those are usable only with the XEN
Hypervisor.
This patch adds statement, that those options specified are applicable
only on the Xen hypervisor and adds option usable with qemu emulator.
This patch also changes type of error returned by QEMU driver if the
user specifies incompatible driver type from VIR_ERR_INTERNAL_ERROR to
VIR_ERR_CONFIG_UNSUPPORTED.
For all types of disks other than qcow2, we were requesting that
SELinux labeling visit the new file as if it were qcow2, which
means labeling would try to find the backing files of an empty file.
And for a pre-existing qcow2 disk, we were passing NULL, which meant
that labelling tried to probe the file type (and if probing is
disabled, per the default qemu.conf, this made snapshots fail).
What we really want is to make SELinux labeling visit the new
file as raw; it will later be converted to qcow2 if qemu successfully
made the snapshot.
* src/qemu/qemu_driver.c
(qemuDomainSnapshotCreateSingleDiskActive): Force SELinux labeling
to avoid probe of new file.
For external snapshots to be useful on persistent domains, we must
alter the persistent definition alongside the running definition.
Thanks to the possibility of disk hotplug as well as of edits that
only affect the persistent xml, we can't assume that vm->def and
vm->newDef have the same disk at the same index, so we can only
update the persistent copy if the device destination matches up.
* src/qemu/qemu_driver.c (qemuDomainSnapshotCreateDiskActive)
(qemuDomainSnapshotCreateSingleDiskActive): Also affect newDef, if
present.
Qemu sends STOP event as part of the shutdown process. Detect such STOP
event and consider shutdown to be reason of emitting such event. That's
the best we can do until qemu provides us the reason directly in STOP
event. This allows us to report shutdown reason for paused state so that
apps can detect domains that failed to finish the shutdown process
(e.g., because qemu is buggy and doesn't exit on SIGTERM or it is
blocked in flushing disk buffers).
Ever since we introduced fake reboot, we call qemuProcessKill as a
reaction to SHUTDOWN event. Unfortunately, qemu doesn't guarantee it
flushed all internal buffers before sending SHUTDOWN, in which case
killing the process forcibly may result in (virtual) disk corruption.
By sending just SIGTERM without SIGKILL we give qemu time to to flush
all buffers and exit. Once qemu exits, we will see an EOF on monitor
connection and tear down the domain. In case qemu ignores SIGTERM or
just hangs there, the process stays running but that's not any different
from a possible hang anytime during the shutdown process so I think it's
just fine.
Also qemu (since 0.14 until it's fixed) has a bug in SIGTERM processing
which causes it not to exit but instead send new SHUTDOWN event and keep
waiting. I think the best we can do is to ignore duplicate SHUTDOWN
events to avoid a SHUTDOWN-SIGTERM loop and leave the domain in paused
state.
When a domain is rebooted using libvirt API, we use fake reboot
consisting of shutting down and resetting the domain. Thus we see a
SHUTDOWN event and set gotShutdown flag. But we never reset it back and
if the domain crashes after it was rebooted this way, we consider it was
a normal shutdown and not a crash.
Commit 4454a9efc7 changed shutoff reason
from VIR_DOMAIN_SHUTOFF_CRASHED to VIR_DOMAIN_SHUTOFF_FAILED in case we
see an unexpected EOF on monitor connection. But FAILED reason is
dedicated for domains that fail to start. CRASHED reason is the right
one to use in this situation.
This patch fixes the bug shown in bugzilla 738778. It's not an nwfilter problem but a connection sharing / closure issue.
https://bugzilla.redhat.com/show_bug.cgi?id=738778
Depending on the speed / #CPUs of the machine you are using you may not see this bug all the time.
Adjust qemuMigrationRun() to use migMaxBandwidth in qemuDomainObjPrivate
structure when setting qemu migration speed. Caller-specified 'resource'
parameter overrides migMaxBandwidth.
The qemu migration speed default is 32MiB/s as defined in migration.c
/* Migration speed throttling */
static int64_t max_throttle = (32 << 20);
There's no need to throttle migration when targeting a file, so set migration
speed to unlimited prior to migration, and restore to libvirt default value
after migration.
Default units is MB for migrate_set_speed monitor command, so
(INT64_MAX / (1024 * 1024)) is used for unlimited migration speed.
Tested with both json and text monitors.
Now that migration speed is stored in qemuDomainObjPrivate structure,
save the new value when invoking qemuDomainMigrateSetMaxSpeed().
Allow setting migration speed on inactive domain too.
The maximum bandwidth that can be consumed when migrating a domain
is better classified as an operational vs configuration parameter of
the dommain. As such, store this parameter in qemuDomainObjPrivate
structure.
Commit 498d783 cleans up some of virtual file names for parsing strings
in memory. This patch cleans up (hopefuly) the rest forgotten by the
first patch.
This patch also changes all of the previously modified "filenames" to
valid URI's replacing spaces for underscores.
Changes to v1:
- Replace all spaces for underscores, so that the strings form valid
URI's
- Replace spaces in places changed by commit 498d783
Regression introduced in commit 3881a470, due to an improper rebase
of a cleanup written beforehand but only applied after a rebased of
a refactoring that created a new function in commit 25fb3ef.
Also avoids passing NULL to printf %s.
* src/qemu/qemu_driver.c: In qemuDomainSnapshotForEachQcow2()
it free up the memory of qemu_driver->qemuImgBinary in the
cleanup tag which leads to the garbage value of qemuImgBinary
in qemu_driver struct and libvirtd crash when running
"virsh snapshot-create" command a second time.
Signed-off-by: Eric Blake <eblake@redhat.com>
Regression introduced in commit 89b6284fd, due to an incorrect
conversion to the new means of converting disk names back to
the correct object.
* src/qemu/qemu_driver.c (qemuDomainGetBlockInfo): Avoid NULL deref.
This patch enables modifying network device configuration using the
virUpdateDeviceFlags API method. Matching of devices is accomplished
using MAC addresses.
While updating live configuration of a running domain, the user is
allowed only to change link state of the interface. Additional
modifications may be added later. For now the code checks for
unsupported changes and thereafter changes the link state, if
applicable.
When updating persistent configuration of guest's network interface the
whole configuration (except for the MAC address) may be modified and
is stored for the next startup.
* src/qemu/qemu_driver.c - Add dispatching of virUpdateDevice for
network devices update (live/config)
* src/qemu/qemu_hotplug.c - add setting of initial link state on live
device addition
- add function to change network device
configuration. By now it supports only
changing of link state
* src/qemu/qemu_hotplug.h - Headers to above functions
* src/qemu/qemu_process.c - set link states before virtual machine
start. Qemu does not support setting of
this on the command line.
This patch adds handlers for modification of guest's interface
link state. Both HMP and QMP commands are supported, but as the
link state functionality is from the beginning supported in QMP
the HMP code will probably never be used.
The mainly changes are:
1) Update qemuMonitorGetBlockStatsInfo and it's children (Text/JSON)
functions to return the value of new latency fields.
2) Add new function qemuMonitorGetBlockStatsParamsNumber, which is
to count how many parameters the underlying QEMU supports.
3) Update virDomainBlockStats in src/qemu/qemu_driver.c to be
compatible with the changes by 1).
If libvirt daemon gets restarted and there is (at least) one
unresponsive qemu, the startup procedure hangs up. This patch creates
one thread per vm in which we try to reconnect to monitor. Therefore,
blocking in one thread will not affect other APIs.
This patch creates an optional BeginJob queue size limit. When
active, all other attempts above level will fail. To set this
feature assign desired value to max_queued variable in qemu.conf.
Setting it to 0 turns it off.
This patch annotates APIs with low or high priority.
In low set MUST be all APIs which might eventually access monitor
(and thus block indefinitely). Other APIs may be marked as high
priority. However, some must be (e.g. domainDestroy).
For high priority calls (HPC), there are some high priority workers
(HPW) created in the pool. HPW can execute only HPC, although normal
worker can process any call regardless priority. Therefore, only those
APIs which are guaranteed to end in reasonable small amount of time
can be marked as HPC.
The size of this HPC pool is static, because HPC are expected to end
quickly, therefore jobs assigned to this pool will be served quickly.
It can be configured in libvirtd.conf via prio_workers variable.
Default is set to 5.
To mark API with low or high priority, append priority:{low|high} to
it's comment in src/remote/remote_protocol.x. This is similar to
autogen|skipgen. If not marked, the generator assumes low as default.
With this, it is now possible to create external snapshots even
when SELinux is enforcing, and to protect the new file with a
lock manager.
* src/qemu/qemu_driver.c
(qemuDomainSnapshotCreateSingleDiskActive): Create and register
new file with proper permissions and locks.
(qemuDomainSnapshotCreateDiskActive): Update caller.
Lots of earlier patches led up to this point - the qemu snapshot_blkdev
monitor command can now be controlled by libvirt! Well, insofar as
SELinux doesn't prevent qemu from open(O_CREAT) on the files. There's
still some followup work before things work with SELinux enforcing,
but this patch is big enough to post now.
There's still room for other improvements, too (for example, taking a
disk snapshot of an inactive domain, by using qemu-img for both internal
and external snapshots; wiring up delete and revert control, including
additional flags from my RFC; supporting active QED disk snapshots;
supporting per-storage-volume snapshots such as LVM or btrfs snapshots;
etc.). But this patch is the one that proves the new XML works!
* src/qemu/qemu_driver.c (qemuDomainSnapshotCreateXML): Wire in
active disk snapshots.
(qemuDomainSnapshotDiskPrepare)
(qemuDomainSnapshotCreateDiskActive)
(qemuDomainSnapshotCreateSingleDiskActive): New functions.
No one uses this yet, but it will be important once
virDomainSnapshotCreateXML learns a VIR_DOMAIN_SNAPSHOT_DISK_ONLY
flag, and the xml allows passing in the new file names.
* src/qemu/qemu_monitor.h (qemuMonitorDiskSnapshot): New prototype.
* src/qemu/qemu_monitor_text.h (qemuMonitorTextDiskSnapshot):
Likewise.
* src/qemu/qemu_monitor_json.h (qemuMonitorJSONDiskSnapshot):
Likewise.
* src/qemu/qemu_monitor.c (qemuMonitorDiskSnapshot): New
function.
* src/qemu/qemu_monitor_json.c (qemuMonitorJSONDiskSnapshot):
Likewise.
Snapshots alter the set of disk image files opened by qemu, so
they must be audited. But they don't involve a full disk definition
structure, just the new filename. Make the next patch easier by
refactoring the audit routines to just operate on file name.
* src/conf/domain_audit.h (virDomainAuditDisk): Update prototype.
* src/conf/domain_audit.c (virDomainAuditDisk): Act on strings,
not definition structures.
(virDomainAuditStart): Update caller.
* src/qemu/qemu_hotplug.c (qemuDomainChangeEjectableMedia)
(qemuDomainAttachPciDiskDevice, qemuDomainAttachSCSIDisk)
(qemuDomainAttachUsbMassstorageDevice)
(qemuDomainDetachPciDiskDevice, qemuDomainDetachDiskDevice):
Likewise.
My RFC for snapshot support [1] proposes several rules for when it is
safe to delete or revert to an external snapshot, predicated on
the existence of new API flags. These will be incrementally added
in future patches, but until then, blindly mishandling a disk
snapshot risks corrupting internal state, so it is better to
outright reject the attempts until the other pieces are in place,
thus incrementally relaxing the restrictions added in this patch.
[1] https://www.redhat.com/archives/libvir-list/2011-August/msg00361.html
* src/qemu/qemu_driver.c (qemuDomainSnapshotCountExternal): New
function.
(qemuDomainUndefineFlags, qemuDomainSnapshotDelete): Use it to add
safety valve.
(qemuDomainRevertToSnapshot, qemuDomainSnapshotCreateXML): Add safety
valve.
Prior to this patch, <domainsnapshot>/<disks> was ignored. This
changes it to be an error unless an explicit disk snapshot is
requested (a future patch may relax things if it turns out to
be useful to have a <disks> specification alongside a system
checkpoint).
* include/libvirt/libvirt.h.in
(VIR_DOMAIN_SNAPSHOT_CREATE_DISK_ONLY): New flag.
* src/libvirt.c (virDomainSnapshotCreateXML): Document it.
* src/esx/esx_driver.c (esxDomainSnapshotCreateXML): Disk
snapshots not supported yet.
* src/vbox/vbox_tmpl.c (vboxDomainSnapshotCreateXML): Likewise.
* src/qemu/qemu_driver.c (qemuDomainSnapshotCreateXML): Likewise.
I got confused when 'virsh domblkinfo dom disk' required the
path to a disk (which can be ambiguous, since a single file
can back multiple disks), rather than the unambiguous target
device name that I was using in disk snapshots. So, in true
developer fashion, I went for the best of both worlds - all
interfaces that operate on a disk (aka block) now accept
either the target name or the unambiguous path to the backing
file used by the disk.
* src/conf/domain_conf.h (virDomainDiskIndexByName): Add
parameter.
(virDomainDiskPathByName): New prototype.
* src/libvirt_private.syms (domain_conf.h): Export it.
* src/conf/domain_conf.c (virDomainDiskIndexByName): Also allow
searching by path, and decide whether ambiguity is okay.
(virDomainDiskPathByName): New function.
(virDomainDiskRemoveByName, virDomainSnapshotAlignDisks): Update
callers.
* src/qemu/qemu_driver.c (qemudDomainBlockPeek)
(qemuDomainAttachDeviceConfig, qemuDomainUpdateDeviceConfig)
(qemuDomainGetBlockInfo, qemuDiskPathToAlias): Likewise.
* src/qemu/qemu_process.c (qemuProcessFindDomainDiskByPath):
Likewise.
* src/libxl/libxl_driver.c (libxlDomainAttachDeviceDiskLive)
(libxlDomainDetachDeviceDiskLive, libxlDomainAttachDeviceConfig)
(libxlDomainUpdateDeviceConfig): Likewise.
* src/uml/uml_driver.c (umlDomainBlockPeek): Likewise.
* src/xen/xend_internal.c (xenDaemonDomainBlockPeek): Likewise.
* docs/formatsnapshot.html.in: Update documentation.
* tools/virsh.pod (domblkstat, domblkinfo): Likewise.
* docs/schemas/domaincommon.rng (diskTarget): Tighten pattern on
disk targets.
* docs/schemas/domainsnapshot.rng (disksnapshot): Update to match.
* tests/domainsnapshotxml2xmlin/disk_snapshot.xml: Update test.
Since a snapshot is fully recoverable, it is useful to have a
snapshot as a means of hibernating a guest, then reverting to
the snapshot to wake the guest up. This mode of usage is
similar to 'virsh save/virsh restore', except that virsh
save uses an external file while virsh snapshot keeps the
vm state internal to a qcow2 file. However, it only works on
persistent domains.
In the usage pattern of snapshot/revert for hibernating a guest,
there is no need to keep the guest running between the two points
in time, especially since that would generate runtime state that
would just be discarded. Add a flag to make it possible to
stop the domain after the snapshot has completed.
* include/libvirt/libvirt.h.in (VIR_DOMAIN_SNAPSHOT_CREATE_HALT):
New flag.
* src/libvirt.c (virDomainSnapshotCreateXML): Document it.
* src/qemu/qemu_driver.c (qemuDomainSnapshotCreateXML)
(qemuDomainSnapshotCreateActive): Implement it.
Reverting to a state prior to an external snapshot risks
corrupting any other branches in the snapshot hierarchy that
were using the snapshot as a read-only backing file. So
disk snapshot code will default to preventing reverting to
a snapshot that has any children, meaning that deleting just
the children of a snapshot becomes a useful operation in
preparing that snapshot for being a future reversion target.
The code for the new flag is simple - it's one less deletion,
plus a tweak to keep the current snapshot correct.
* include/libvirt/libvirt.h.in
(VIR_DOMAIN_SNAPSHOT_DELETE_CHILDREN_ONLY): New flag.
* src/libvirt.c (virDomainSnapshotDelete): Document it, and
enforce mutual exclusion.
* src/qemu/qemu_driver.c (qemuDomainSnapshotDelete): Implement
it.
The previous patch introduced new config, but if a hypervisor does
not support that new config, someone can write XML that does not
behave as documented. This prevents some of those cases by
explicitly rejecting transient disks for several hypervisors.
Disk snapshots will require a new flag to actually affect a snapshot
creation, so there's not much to reject there.
* src/qemu/qemu_command.c (qemuBuildDriveStr): Reject transient
disks for now.
* src/libxl/libxl_conf.c (libxlMakeDisk): Likewise.
* src/xenxs/xen_sxpr.c (xenFormatSxprDisk): Likewise.
* src/xenxs/xen_xm.c (xenFormatXMDisk): Likewise.
When reverting to a snapshot, the inactive domain configuration
has to be rolled back to what it was at the time of the snapshot.
Additionally, if the VM is active and the snapshot was active,
this now adds a failure if the two configurations are ABI
incompatible, rather than risking qemu confusion.
A future patch will add a VIR_DOMAIN_SNAPSHOT_FORCE flag, which
will be required for two risky code paths - reverting to an
older snapshot that lacked full domain information, and reverting
from running to a live snapshot that requires starting a new qemu
process. Any reverting that stops a running vm is also a form
of data loss (discarding the current running state to go back in
time), but as that is what reversion usually implies, it is
probably not worth requiring a force flag.
* src/qemu/qemu_driver.c (qemuDomainSnapshotCreateXML): Copy out
domain.
(qemuDomainSnapshotCreateXML, qemuDomainRevertToSnapshot): Perform
ABI compatibility checks.
Just like VM saved state images (virsh save), snapshots MUST
track the inactive domain xml to detect any ABI incompatibilities.
The indentation is not perfect, but functionality comes before form.
Later patches will actually supply a full domain; for now, this
wires up the storage to support one, but doesn't ever generate one
in dumpxml output.
Happily, libvirt.c was already rejecting use of VIR_DOMAIN_XML_SECURE
from read-only connections, even though before this patch, there was
no information to be secured by the use of that flag.
And while we're at it, mark the libvirt snapshot metadata files
as internal-use only.
* src/libvirt.c (virDomainSnapshotGetXMLDesc): Document flag.
* src/conf/domain_conf.h (_virDomainSnapshotDef): Add member.
(virDomainSnapshotDefParseString, virDomainSnapshotDefFormat):
Update signature.
* src/conf/domain_conf.c (virDomainSnapshotDefFree): Clean up.
(virDomainSnapshotDefParseString): Optionally parse domain.
(virDomainSnapshotDefFormat): Output full domain.
* src/esx/esx_driver.c (esxDomainSnapshotCreateXML)
(esxDomainSnapshotGetXMLDesc): Update callers.
* src/vbox/vbox_tmpl.c (vboxDomainSnapshotCreateXML)
(vboxDomainSnapshotGetXMLDesc): Likewise.
* src/qemu/qemu_driver.c (qemuDomainSnapshotCreateXML)
(qemuDomainSnapshotLoad, qemuDomainSnapshotGetXMLDesc)
(qemuDomainSnapshotWriteMetadata): Likewise.
* docs/formatsnapshot.html.in: Rework doc example.
Based on a patch by Philipp Hahn.
Migration is another case of stranding metadata. And since
snapshot metadata is arbitrarily large, there's no way to
shoehorn it into the migration cookie of migration v3.
This patch consolidates two existing locations for migration
validation into one helper function, then enhances that function
to also do the new checks. If we could always trust the source
to validate migration, then the destination would not have to
do anything; but since older servers that did not do checking
can migrate to newer destinations, we have to repeat some of
the same checks on the destination; meanwhile, we want to
detect failures as soon as possible. With migration v2, this
means that validation will reject things at Prepare on the
destination if the XML exposes the problem, otherwise at Perform
on the source; with migration v3, this means that validation
will reject things at Begin on the source, or if the source
is old and the XML exposes the problem, then at Prepare on the
destination.
This patch is necessarily over-strict. Once a later patch
properly handles auto-cleanup of snapshot metadata on the
death of a transient domain, then the only time we actually
need snapshots to prevent migration is when using the
--undefinesource flag on a persistent source domain.
It is possible to recreate snapshot metadata on the destination
with VIR_DOMAIN_SNAPSHOT_CREATE_REDEFINE and
VIR_DOMAIN_SNAPSHOT_CREATE_CURRENT. But for now, that is limited,
since if we delete the snapshot metadata prior to migration,
then we won't know the name of the current snapshot to pass
along; and if we delete the snapshot metadata after migration
and use the v3 migration cookie to pass along the name of the
current snapshot, then we need a way to bypass the fact that
this patch refuses migration with snapshot metadata present.
So eventually, we may have to introduce migration protocol v4
that allows feature negotiation and an arbitrary number of
handshake exchanges, so as to pass as many rpc calls as needed
to transfer all the snapshot xml hierarchy.
But all of that is thoughts for the future; for now, the best
course of action is to quit early, rather than get into a
funky state of stale metadata; then relax restrictions later.
* src/qemu/qemu_migration.h (qemuMigrationIsAllowed): Make static.
* src/qemu/qemu_migration.c (qemuMigrationIsAllowed): Alter
signature, and allow checks for both outgoing and incoming.
(qemuMigrationBegin, qemuMigrationPrepareAny)
(qemuMigrationPerformJob): Update callers.
A nice benefit of deleting all snapshots at undefine time is that
you don't have to do any reparenting or subtree identification - since
everything goes, this is an O(n) process, whereas using multiple
virDomainSnapshotDelete calls would be O(n^2) or worse. But it is
only doable for snapshot metadata, where we are in control of the
data being deleted; for the actual snapshots, there's too much
likelihood of something going wrong, and requiring even more API
calls to figure out what failed in the meantime, so callers are
better off deleting the snapshot data themselves one snapshot at
a time where they can deal with failures as they happen.
* src/qemu/qemu_driver.c (qemuDomainUndefineFlags): Honor new flags.
As more clients start to want to know this information, doing
a PATH stat walk and malloc for every client adds up.
We are only caching the location, not the capabilities, so even
if qemu-img is updated in the meantime, it will still probably
live in the same location. So there is no need to worry about
clearing this particular cache.
* src/qemu/qemu_conf.h (qemud_driver): Add member.
* src/qemu/qemu_driver.c (qemudShutdown): Cleanup.
(qemuFindQemuImgBinary): Add an argument, and cache result.
(qemuDomainSnapshotForEachQcow2, qemuDomainSnapshotDiscard)
(qemuDomainSnapshotCreateInactive, qemuDomainSnapshotRevertInactive)
(qemuDomainSnapshotCreateXML, qemuDomainRevertToSnapshot): Update
callers.
Just as leaving managed save metadata behind can cause problems
when creating a new domain that happens to collide with the name
of the just-deleted domain, the same is true of leaving any
snapshot metadata behind. For safety sake, extend the semantic
change of commit b26a9fa9 to also cover snapshot metadata as a
reason to reject undefining an inactive domain. A future patch
will make sure that shutdown of a transient domain automatically
deletes snapshot metadata (whether by destroy, shutdown, or
guest-initiated action). Management apps of transient domains
should take care to capture xml of snapshots, if it is necessary
to recreate the snapshot metadata on a later transient domain
with the same name and uuid.
This also documents a new flag that hypervisors can choose to
support as a shortcut for taking care of the metadata as part of
the undefine process; however, nontrivial driver support for these
flags will be deferred to future patches.
Note that ESX and VBox can never be transient; therefore, they
do not have to worry about automatic cleanup after shutdown
(the persistent domain still remains); likewise they never
store snapshot metadata, so the undefine flag is trivial.
The nontrivial work remaining is thus in the qemu driver.
* include/libvirt/libvirt.h.in
(VIR_DOMAIN_UNDEFINE_SNAPSHOTS_METADATA): New flag.
* src/libvirt.c (virDomainUndefine, virDomainUndefineFlags):
Document new limitations and flag.
* src/esx/esx_driver.c (esxDomainUndefineFlags): Trivial
implementation.
* src/vbox/vbox_tmpl.c (vboxDomainUndefineFlags): Likewise.
* src/qemu/qemu_driver.c (qemuDomainUndefineFlags): Enforce
the limitations.
Redefining a qemu snapshot requires a bit of a tweak to the common
snapshot parsing code, but the end result is quite nice.
Be careful that redefinitions do not introduce circular parent
chains. Also, we don't want to allow conversion between online
and offline existing snapshots. We could probably do some more
validation for snapshots that don't already exist to make sure
they are even feasible, by parsing qemu-img output, but that
can come later.
* src/conf/domain_conf.h (virDomainSnapshotParseFlags): New
internal flags.
* src/conf/domain_conf.c (virDomainSnapshotDefParseString): Alter
signature to take internal flags.
* src/esx/esx_driver.c (esxDomainSnapshotCreateXML): Update caller.
* src/vbox/vbox_tmpl.c (vboxDomainSnapshotCreateXML): Likewise.
* src/qemu/qemu_driver.c (qemuDomainSnapshotCreateXML): Support
new public flags.
Supporting NO_METADATA on snapshot creation is interesting - we must
still return a valid opaque snapshot object, but the user can't get
anything out of it (unless we add a virDomainSnapshotGetName()),
since it is no longer registered with the domain.
Also, virsh now tries to query for secure xml, in anticipation of
when we store <domain> xml inside <domainsnapshot>; for now, we
can trivially support it, since we have nothing secure.
* src/qemu/qemu_driver.c (qemuDomainSnapshotCreateXML): Support
new flag.
(qemuDomainSnapshotGetXMLDesc): Trivially support VIR_DOMAIN_XML_SECURE.
To make it easier to know when undefine will fail because of existing
snapshot metadata, we need to know how many snapshots have metadata.
Also, it is handy to filter the list of snapshots to just those that
have no parents; document that flag now, but implement it in later patches.
* include/libvirt/libvirt.h.in (VIR_DOMAIN_SNAPSHOT_LIST_ROOTS)
(VIR_DOMAIN_SNAPSHOT_LIST_METADATA): New flags.
* src/libvirt.c (virDomainSnapshotNum)
(virDomainSnapshotListNames): Document them.
* src/esx/esx_driver.c (esxDomainSnapshotNum)
(esxDomainSnapshotListNames): Implement trivial flag.
* src/vbox/vbox_tmpl.c (vboxDomainSnapshotNum)
(vboxDomainSnapshotListNames): Likewise.
* src/qemu/qemu_driver.c (qemuDomainSnapshotNum)
(qemuDomainSnapshotListNames): Likewise.
Adding this was trivial compared to the previous patch for fixing
qemu snapshot deletion in the first place.
* src/qemu/qemu_driver.c (qemuDomainSnapshotDiscard): Add
parameter.
(qemuDomainSnapshotDiscardDescendant, qemuDomainSnapshotDelete):
Update callers.
Similar to the last patch in isolating the filtering from the
client actions, so that clients don't have to reinvent the
filtering.
* src/conf/domain_conf.h (virDomainSnapshotForEachChild): New
prototype.
* src/libvirt_private.syms (domain_conf.h): Export it.
* src/conf/domain_conf.c (virDomainSnapshotActOnChild)
(virDomainSnapshotForEachChild): New functions.
(virDomainSnapshotCountChildren): Delete.
(virDomainSnapshotHasChildren): Simplify.
* src/qemu/qemu_driver.c (qemuDomainSnapshotReparentChildren)
(qemuDomainSnapshotDelete): Likewise.
Deleting a snapshot and all its descendants had problems with
tracking the current snapshot. The deletion does not necessarily
proceed in depth-first order, so a parent could be deleted
before a child, wreaking havoc on passing the notion of the
current snapshot to the parent. Furthermore, even if traversal
were depth-first, doing multiple file writes to pass current up
the chain one snapshot at a time is wasteful, comparing to a
single update to the current snapshot at the end of the algorithm.
* src/qemu/qemu_driver.c (snap_remove): Add field.
(qemuDomainSnapshotDiscard): Add parameter.
(qemuDomainSnapshotDiscardDescendant): Adjust accordingly.
(qemuDomainSnapshotDelete): Properly reset current.
This one's nasty. Ever since we fixed virHashForEach to prevent
nested hash iterations for safety reasons (commit fba550f6),
virDomainSnapshotDelete with VIR_DOMAIN_SNAPSHOT_DELETE_CHILDREN
has been broken for qemu: it deletes children, while leaving
grandchildren intact but pointing to a no-longer-present parent.
But even before then, the code would often appear to succeed to
clean up grandchildren, but risked memory corruption if you have
a large and deep hierarchy of snapshots.
For acting on just children, a single virHashForEach is sufficient.
But for acting on an entire subtree, it requires iteration; and
since we declared recursion as invalid, we have to switch to a
while loop. Doing this correctly requires quite a bit of overhaul,
so I added a new helper function to isolate the algorithm from the
actions, so that callers do not have to reinvent the iteration.
Note that this _still_ does not handle CHILDREN correctly if one
of the children is the current snapshot; that will be next.
* src/conf/domain_conf.h (_virDomainSnapshotDef): Add mark.
(virDomainSnapshotForEachDescendant): New prototype.
* src/libvirt_private.syms (domain_conf.h): Export it.
* src/conf/domain_conf.c (virDomainSnapshotMarkDescendant)
(virDomainSnapshotActOnDescendant)
(virDomainSnapshotForEachDescendant): New functions.
* src/qemu/qemu_driver.c (qemuDomainSnapshotDiscardChildren):
Replace...
(qemuDomainSnapshotDiscardDescenent): ...with callback that
doesn't nest hash traversal.
(qemuDomainSnapshotDelete): Use new function.
For a system checkpoint of a running or paused domain, it's fairly
easy to honor new flags for altering which state to use after the
revert. For an inactive snapshot, the revert has to be done while
there is no qemu process, so do back-to-back transitions; this also
lets us revert to inactive snapshots even for transient domains.
* src/qemu/qemu_driver.c (qemuDomainRevertToSnapshot): Support new
flags.
Commit 5e47785 broke reverts to offline system checkpoint snapshots
with older qemu, since there is no longer any code path to use
qemu -loadvm on next boot. Meanwhile, reverts to offline system
checkpoints have been broken for newer qemu, both before and
after that commit, since -loadvm no longer works to revert to
disk state without accompanying vm state. Fix both of these by
using qemu-img to revert disk state.
Meanwhile, consolidate the (now 3) clients of a qemu-img iteration
over all disks of a VM into one function, so that any future
algorithmic fixes to the FIXMEs in that function after partial
loop iterations are dealt with at once. That does mean that this
patch doesn't handle partial reverts very well, but we're not
making the situation any worse in this patch.
* src/qemu/qemu_driver.c (qemuDomainRevertToSnapshot): Use
qemu-img rather than 'qemu -loadvm' to revert to offline snapshot.
(qemuDomainSnapshotRevertInactive): New helper.
(qemuDomainSnapshotCreateInactive): Factor guts...
(qemuDomainSnapshotForEachQcow2): ...into new helper.
(qemuDomainSnapshotDiscard): Use it.
If you take a checkpoint snapshot of a running domain, then pause
qemu, then restore the snapshot, the result should be a running
domain, but the code was leaving things paused. Furthermore, if
you take a checkpoint of a paused domain, then run, then restore,
there was a brief but non-deterministic window of time where the
domain was running rather than paused. Fix both of these
discrepancies by always pausing before restoring.
Also, check that the VM is active every time lock is dropped
between two monitor calls.
Finally, straighten out the events that get emitted on each
transition.
* src/qemu/qemu_driver.c (qemuDomainRevertToSnapshot): Always
pause before reversion, and improve events.
Implement the new running/paused overrides for saved state management.
Unfortunately, for virDomainSaveImageDefineXML, the saved state
updates are write-only - I don't know of any way to expose a way
to query the current run/pause setting of an existing save image
file to the user without adding a new API or modifying the domain
xml of virDomainSaveImageGetXMLDesc to include a new element to
reflect the state bit encoded into the save image. However, I
don't think this is a show-stopper, since the API is designed to
leave the state bit alone unless an explicit flag is used to
change it.
* src/qemu/qemu_driver.c (qemuDomainSaveInternal)
(qemuDomainSaveImageOpen): Adjust signature.
(qemuDomainSaveFlags, qemuDomainManagedSave)
(qemuDomainRestoreFlags, qemuDomainSaveImageGetXMLDesc)
(qemuDomainSaveImageDefineXML, qemuDomainObjRestore): Adjust
callers.
There are two classes of management apps that track events - one
that only cares about on/off (and only needs to track EVENT_STARTED
and EVENT_STOPPED), and one that cares about paused/running (also
tracks EVENT_SUSPENDED/EVENT_RESUMED). To keep both classes happy,
any transition that can go from inactive to paused must emit two
back-to-back events - one for started and one for suspended (since
later resuming of the domain will only send RESUMED, but the first
class isn't tracking that).
This also fixes a bug where virDomainCreateWithFlags with the
VIR_DOMAIN_START_PAUSED flag failed to start paused when restoring
from a managed save image.
* include/libvirt/libvirt.h.in (VIR_DOMAIN_EVENT_SUSPENDED_RESTORED)
(VIR_DOMAIN_EVENT_SUSPENDED_FROM_SNAPSHOT)
(VIR_DOMAIN_EVENT_RESUMED_FROM_SNAPSHOT): New sub-events.
* src/qemu/qemu_driver.c (qemuDomainRevertToSnapshot): Use them.
(qemuDomainSaveImageStartVM): Likewise, and add parameter.
(qemudDomainCreate, qemuDomainObjStart): Send suspended event when
starting paused.
(qemuDomainObjRestore): Add parameter.
(qemuDomainObjStart, qemuDomainRestoreFlags): Update callers.
* examples/domain-events/events-c/event-test.c
(eventDetailToString): Map new detail strings.
QEMU uses USB bus name "usb.0" when using the legacy -usb argument.
If we want to allow USB devices to specify their addresses with legacy
-usb, we should either in case of legacy bus name drop the 0 from the
address bus, or just drop the 0 from device id. This patch does the
later.
Another solution would be to permit addressing on non-legacy USB
controllers only.
