Previously, snapshot code did its own permission granting (lock
manager, cgroup device controller, and security manager labeling)
inline. But now that we are adding block-commit and block-copy
which also have to change permissions, it's better to reuse
common code for the task. While snapshot should fall back to
no access if read-write access failed, block-commit will want to
fall back to read-only access. The common code doesn't know
whether failure to grant read-write access should revert to no
access (snapshot, block-copy) or read-only access (block-commit).
This code can also be used to revoke access to unused files after
block-pull.
It might be nice to clean things up in a future patch by adding
new functions to the lock manager, cgroup manager, and security
manager that takes a single file name and applies context of a
disk to that file, rather than the current semantics of applying
context to the entire chain already associated to a disk. That
way, we could avoid the games this patch plays of temporarily
swapping out the disk->src and related fields of the disk. But
that would involve more code changes, so this patch really is
the smallest hack for doing the necessary work; besides, this
patch is more or less code motion (the hack was already employed
by the snapshot creation code, we are just making it reusable).
* src/qemu/qemu_driver.c (qemuDomainSnapshotCreateSingleDiskActive)
(qemuDomainSnapshotUndoSingleDiskActive): Refactor labeling hacks...
(qemuDomainPrepareDiskChainElement): ...into new function.
Now that we can crawl the chain of backing files, we can do
argument validation and implement the 'shallow' flag. In
testing this, I discovered that it can be handy to pass the
shallow flag and an explicit base, as a means of validating
that the base is indeed the file we expected.
* src/qemu/qemu_driver.c (qemuDomainBlockCommit): Crawl through
chain to implement shallow flag.
* src/libvirt.c (virDomainBlockCommit): Relax API.
This is the bare minimum to kick off a block commit. In particular,
flags support is missing (shallow requires us to crawl the backing
chain to determine the file name to pass to the qemu monitor command;
delete requires us to track what needs to be deleted at the time
the completion event fires). Also, we are relying on qemu to do
error checking (such as validating 'top' and 'base' as being members
of the backing chain), including the fact that the current qemu code
does not support committing the active layer (although it is still
planned to add that before qemu 1.3). Since the active layer won't
change, we have it easy and do not have to alter the domain XML.
Additionally, this will fail if SELinux is enforcing, because we fail
to grant qemu proper read/write access to the files it will modify.
* src/qemu/qemu_driver.c (qemuDomainBlockCommit): New function.
(qemuDriver): Register it.
qemu 1.3 will be adding a 'block-commit' monitor command, per
qemu.git commit ed61fc1. It matches nicely to the libvirt API
virDomainBlockCommit.
* src/qemu/qemu_capabilities.h (QEMU_CAPS_BLOCK_COMMIT): New bit.
* src/qemu/qemu_capabilities.c (qemuCapsProbeQMPCommands): Set it.
* src/qemu/qemu_monitor.h (qemuMonitorBlockCommit): New prototype.
* src/qemu/qemu_monitor_json.h (qemuMonitorJSONBlockCommit):
Likewise.
* src/qemu/qemu_monitor.c (qemuMonitorBlockCommit): Implement it.
* src/qemu/qemu_monitor_json.c (qemuMonitorJSONBlockCommit):
Likewise.
(qemuMonitorJSONHandleBlockJobImpl)
(qemuMonitorJSONGetBlockJobInfoOne): Handle new event type.
We used to walk the backing file chain at least twice per disk,
once to set up cgroup device whitelisting, and once to set up
security labeling. Rather than walk the chain every iteration,
which possibly includes calls to fork() in order to open root-squashed
NFS files, we can exploit the cache of the previous patch.
* src/conf/domain_conf.h (virDomainDiskDefForeachPath): Alter
signature.
* src/conf/domain_conf.c (virDomainDiskDefForeachPath): Require caller
to supply backing chain via disk, if recursion is desired.
* src/security/security_dac.c
(virSecurityDACSetSecurityImageLabel): Adjust caller.
* src/security/security_selinux.c
(virSecuritySELinuxSetSecurityImageLabel): Likewise.
* src/security/virt-aa-helper.c (get_files): Likewise.
* src/qemu/qemu_cgroup.c (qemuSetupDiskCgroup)
(qemuTeardownDiskCgroup): Likewise.
(qemuSetupCgroup): Pre-populate chain.
Technically, we should not be re-probing any file that qemu might
be currently writing to. As such, we should cache the backing
file chain prior to starting qemu. This patch adds the cache,
but does not use it until the next patch.
Ultimately, we want to also store the chain in domain XML, so that
it is remembered across libvirtd restarts, and so that the only
kosher way to modify the backing chain of an offline domain will be
through libvirt API calls, but we aren't there yet. So for now, we
merely invalidate the cache any time we do a live operation that
alters the chain (block-pull, block-commit, external disk snapshot),
as well as tear down the cache when the domain is not running.
* src/conf/domain_conf.h (_virDomainDiskDef): New field.
* src/conf/domain_conf.c (virDomainDiskDefFree): Clean new field.
* src/qemu/qemu_domain.h (qemuDomainDetermineDiskChain): New
prototype.
* src/qemu/qemu_domain.c (qemuDomainDetermineDiskChain): New
function.
* src/qemu/qemu_driver.c (qemuDomainAttachDeviceDiskLive)
(qemuDomainChangeDiskMediaLive): Pre-populate chain.
(qemuDomainSnapshotCreateSingleDiskActive): Uncache chain before
snapshot.
* src/qemu/qemu_process.c (qemuProcessHandleBlockJob): Update
chain after block pull.
Requiring pre-allocation was an unusual idiom. It allowed iteration
over the backing chain to use fewer mallocs, but made one-shot
clients harder to read. Also, this makes it easier for a future
patch to move away from opening fds on every iteration over the chain.
* src/util/storage_file.h (virStorageFileGetMetadataFromFD): Alter
signature.
* src/util/storage_file.c (virStorageFileGetMetadataFromFD): Allocate
return value.
(virStorageFileGetMetadata): Update clients.
* src/conf/domain_conf.c (virDomainDiskDefForeachPath): Likewise.
* src/qemu/qemu_driver.c (qemuDomainGetBlockInfo): Likewise.
* src/storage/storage_backend_fs.c (virStorageBackendProbeTarget):
Likewise.
This is the last use of raw strings for disk formats throughout
the src/conf directory.
* src/conf/snapshot_conf.h (_virDomainSnapshotDiskDef): Store enum
rather than string for disk type.
* src/conf/snapshot_conf.c (virDomainSnapshotDiskDefClear)
(virDomainSnapshotDiskDefParseXML, virDomainSnapshotDefFormat):
Adjust users.
* src/qemu/qemu_driver.c (qemuDomainSnapshotDiskPrepare)
(qemuDomainSnapshotCreateSingleDiskActive): Likewise.
Express the default disk type as an enum, for easier handling.
* src/conf/capabilities.h (_virCaps): Store enum rather than
string for disk type.
* src/conf/domain_conf.c (virDomainDiskDefParseXML): Adjust
clients.
* src/qemu/qemu_driver.c (qemuCreateCapabilities): Likewise.
When an image has no backing file, using VIR_STORAGE_FILE_AUTO
for its type is a bit confusing. Additionally, a future patch
would like to reserve a default value for the case of no file
type specified in the XML, but different from the current use
of -1 to imply probing, since probing is not always safe.
Also, a couple of file types were missing compared to supported
code: libxl supports 'vhd', and qemu supports 'fat' for directories
passed through as a file system.
* src/util/storage_file.h (virStorageFileFormat): Add
VIR_STORAGE_FILE_NONE, VIR_STORAGE_FILE_FAT, VIR_STORAGE_FILE_VHD.
* src/util/storage_file.c (virStorageFileMatchesVersion): Match
documentation when version probing not supported.
(cowGetBackingStore, qcowXGetBackingStore, qcow1GetBackingStore)
(qcow2GetBackingStoreFormat, qedGetBackingStore)
(virStorageFileGetMetadataFromBuf)
(virStorageFileGetMetadataFromFD): Take NONE into account.
* src/conf/domain_conf.c (virDomainDiskDefForeachPath): Likewise.
* src/qemu/qemu_driver.c (qemuDomainGetBlockInfo): Likewise.
* src/conf/storage_conf.c (virStorageVolumeFormatFromString): New
function.
(poolTypeInfo): Use it.
Relabeling tapfd right after the tap device is created.
qemuPhysIfaceConnect is common function called both for static
netdevs and for hotplug netdevs.
Having hostuuid in migration cookie is a nice bonus since it provides an
easy way of detecting migration to the same host. However, requiring it
breaks backward compatibility with older libvirt releases.
Recently, patches were added support for (managed)saving, restoring, and
migrating domains with host USB devices. However, qemu driver would
still forbid migration of such domains because qemuMigrationIsAllowed
was not updated.
If we can't probe the architecture from QMP we parse the architecture
from the qemu binaries name. This results in the architecture being i386
instead of i686 which then results in QEMU_CAPS_PCI_MULTIBUS being unset
which gives a broken qemu command line.
This probably didn't show up earlier since most of the time there's also
a /usr/bin/qemu around which results in i686 capabilities.
When libvirt cannot find a suitable CPU model for host CPU (easily
reproducible by running libvirt in a guest), it would not provide CPU
topology in capabilities XML either. Even though CPU topology is known
and can be queried by virNodeGetInfo. With this patch, CPU topology will
always be provided in capabilities XML regardless on the presence of CPU
model.
Currently we query-spice after the main migration has completed
before moving to next state. Qemu reports this as boolean (not
enclosed within quotes). Therefore it is not correct to use
virJSONValueObjectGetString but virJSONValueObjectGetBoolean instead.
The machine in the last output line of <qemu-binary> -M ?
was always reported as default machine even if this wasn't the
actual default. Trivial fix.
Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com>
According to our recent changes (clarifications), we should be pinning
qemu's emulator processes using the <vcpu> 'cpuset' attribute in case
there is no <emulatorpin> specified. This however doesn't work
entirely as expected and this patch should resolve all the remaining
issues.
When p2p migration fails early because qemuMigrationIsAllowed or
qemuMigrationIsSafe say migration should be cancelled, we fail to clear
the migration-out async job. As a result of that, further APIs called
for the same domain may fail with Timed out during operation: cannot
acquire state change lock.
Reported by Guido Winkelmann.
It should relabel tapfd of virtual network of type VIR_DOMAIN_NET_TYPE_DIRECT
rather than VIR_DOMAIN_NET_TYPE_NETWORK and VIR_DOMAIN_NET_TYPE_BRIDGE
(commit ae368ebfcc4923d0b32e83d4ca96a6f599625785 introduced this bug)
Caution: The context of the two hunks is identical other than indentation.
Please be extremely cautious of where the patch gets applied.
BZ:https://bugzilla.redhat.com/show_bug.cgi?id=851981
When using macvtap, a character device gets first created by
kernel with name /dev/tapN, its selinux context is:
system_u:object_r:device_t:s0
Shortly, when udev gets notification when new file is created
in /dev, it will then jump in and relabel this file back to the
expected default context:
system_u:object_r:tun_tap_device_t:s0
There is a time gap happened.
Sometimes, it will have migration failed, AVC error message:
type=AVC msg=audit(1349858424.233:42507): avc: denied { read write } for
pid=19926 comm="qemu-kvm" path="/dev/tap33" dev=devtmpfs ino=131524
scontext=unconfined_u:system_r:svirt_t:s0:c598,c908
tcontext=system_u:object_r:device_t:s0 tclass=chr_file
This patch will label the tapfd device before qemu process starts:
system_u:object_r:tun_tap_device_t:MCS(MCS from seclabel->label)
This patch adds support for SUSPEND_DISK event; both lifecycle and
separated. The support is added for QEMU, machines are changed to
PMSUSPENDED, but as QEMU sends SHUTDOWN afterwards, the state changes
to shut-off. This and much more needs to be done in order for libvirt
to work with transient devices, wake-ups etc. This patch is not
aiming for that functionality.
This patch resolves:
https://bugzilla.redhat.com/show_bug.cgi?id=805071
to the extent that it can be resolved with current qemu functionality.
It attempts to detect as many situations as possible when the simple
operation of disconnecting an existing tap device from one bridge and
attaching it to another will satisfy the change requested in
virDomainUpdateDeviceFlags() for a network device. Before this patch,
that situation could only be detected if the pre-change interface
*and* the post-change interface definition were both "type='bridge'".
After this patch, it can also be detected if the before or after
interfaces are any combination of type='bridge' and type='network'
(the networks can be <forward mode='nat|route|bridge'>, as long as
they use a Linux host bridge and not macvtap connections).
This extra effort is especially useful since the recent discovery that
a netdev_del+netdev_add combo (to reconnect the network device with
completely different hostside configuration) doesn't work properly
with current qemu (1.2) unless it is accompanied by the matching
device_del+device_add - see this mailing list message for details:
http://lists.nongnu.org/archive/html/qemu-devel/2012-10/msg02355.html
(A slight modification of the patch referenced there has been prepared
to apply on top of this patch, but won't be pushed until qemu can be
made to work with it.)
* qemuDomainChangeNet needs access to the virDomainDeviceDef that
holds the new netdef (so that it can clear out the virDomainDeviceDef
if it ends up using the NetDef to replace the original), so the
virDomainNetDefPtr arg is replaced with a virDomainDeviceDefPtr.
* qemuDomainChangeNet previously checked for *some* changes to the
interface config, but this check was by no means complete. It was also
a bit disorganized.
This refactoring of the code is (I believe) complete in its check of
all NetDef attributes that might be changed, and either returns a
failure (for changes that are simply impossible), or sets one of three
flags:
needLinkStateChange - if the device link state needs to go up/down
needBridgeChange - if everything else is the same, but it needs
to be connected to a difference linux host
bridge
needReconnect - if the entire host side of the device needs
to be torn down and reconstructed (currently
non-working, as mentioned above)
Note that this function will refuse to make any change that requires
the *guest* side of the device to be detached (e.g. changing the PCI
address or mac address). Those would be disruptive enough to the guest
that it's reasonable to require an explicit detach/attach sequence
from the management application.
* As mentioned above, qemuDomainChangeNet also does its best to
understand when a simple change in attached bridge for the existing
tap device will work vs. the need to completely tear down/reconstruct
the host side of the device (including tap device).
This patch *does not* implement the "reconnect" code anyway - there is
a placeholder that turns that into an error. Rather, the purpose of
this patch is to replicate existing behavior with code that is ready
to have that functionality plugged in in a later patch.
* The expanded uses for qemuDomainChangeNetBridge meant that it needed
to be enhanced as well - it no longer replaces the original brname
string in olddev with the new brname; instead, it relies on the
caller to replace the *entire* olddev with newdev (since we've gone
to great lengths to assure they are functionally identical other
than the name of the bridge, this is now not only safe, but more
correct). Additionally, qemuDomainNetChangeBridge can now set the
bridge for type='network' interfaces as well as plain type='bridge'
interfaces. (Note that I had to make this change simultaneous to the
reorganization of qemuDomainChangeNet because the two are too
closely intertwined to separate).
The onlined vcpu pinning policy should inherit def->cpuset if
it's not specified explicitly, and the affinity should be set
in this case. Oppositely, the offlined vcpu pinning policy should
be free()'ed.
Various APIs use cgroup to either set or get the statistics of
host or guest. Hotplug or hot unplug new vcpus without creating
or removing the cgroup for the vcpus could cause problems for
those APIs. E.g.
% virsh vcpucount dom
maximum config 10
maximum live 10
current config 1
current live 1
% virsh setvcpu dom 2
% virsh schedinfo dom --set vcpu_quota=1000
Scheduler : posix
error: Unable to find vcpu cgroup for rhel6.2(vcpu: 1): No such file or
directory
This patch fixes the problem by creating cgroups for each of the
onlined vcpus, and destroying cgroups for each of the offlined
vcpus.
The comment stated that you may call qemuDomainObjBeginJobWithDriver
without passing qemud_driver to signal it's not locked.
qemuDomainObjBeginJobWithDriver still accesses the qemud_driver
structure and the lock singaling is done through a separate parameter.
Save/restore with passed through USB devices currently only works if the
USB device can be found at the same USB address where it used to be
before saving a domain. This makes sense in case a user explicitly
configure the USB address in domain XML. However, if the device was
found automatically by vendor/product identification, we should try to
search for that device when restoring the domain and use any device we
find as long as there is only one available. In other words, the USB
device can now be removed and plugged again or the host can be rebooted
between saving and restoring the domain.
Using VIR_DOMAIN_XML_MIGRATABLE flag, one can request domain's XML
configuration that is suitable for migration or save/restore. Such XML
may contain extra run-time stuff internal to libvirt and some default
configuration may be removed for better compatibility of the XML with
older libvirt releases.
This flag may serve as an easy way to get the XML that can be passed
(after desired modifications) to APIs that accept custom XMLs, such as
virDomainMigrate{,ToURI}2 or virDomainSaveFlags.
All USB device lookup functions emit an error when they cannot find the
requested device. With this patch, their caller can choose if a missing
device is an error or normal condition.
The code which looks up a USB device specified by hostdev is duplicated
in two places. This patch creates a dedicated function that can be
called in both places.
When adding variants of parameter setting APIs which accepted
flags, the existing APIs were all adapted internally to pass
VIR_DOMAIN_AFFECT_CURRENT to the new API. The QEMU impl
qemuSetSchedularParameters was an exception, which instead
used VIR_DOMAIN_AFFECT_LIVE. Change this to match other
compatibility scenarios, so that calling
virDomainSetSchedularParameters(dom, params, nparams);
Has the same semantics as
virDomainSetSchedularParametersFlags(dom, params, nparams, 0);
And
virDomainSetSchedularParametersFlags(dom, params, nparams, VIR_DOMAIN_AFFECT_CURRENT);
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
As a side effect of changes in the functions virGetUserID and
virGetGroupID, the user and group configurations for DAC in qemu.conf
are now able to accept both names and IDs, supporting a leading plus
sign to ensure that a numeric value will not be interpreted as a name.
This patch updates the comments in qemu.conf, including a description of
this new behavior.
With the recent introduction of QMP capabilities probing, libvirt failed
to detect support for QXL graphics in QEMU 1.2 and newer. In addition to
fixing that, this patch also causes libvirt to detect QXL support for
qemu-kvm-0.13.0, which doesn't advertise it in -help output but mentions
it in device list. Since qemu-kvm-0.13.0 supported -spice, it looks like
not having qxl in -help was a bug.
When both kvmclock and kvm_pv_eoi are configured (either disabled or
enabled) libvirt will generate invalid CPU specification due to the
fact that even though kvmclock causes the CPU to be specified, it
doesn't set have_cpu flag to true (and the new kvm_pv_eoi as well).
This patch fixes the issue and adds a test exactly for that to show
that it is fixed correctly (and also to keep it that way in the future
of course).
Introduced in commit 0caccb58.
CC libvirt_driver_qemu_impl_la-qemu_capabilities.lo
../../src/qemu/qemu_capabilities.c: In function 'qemuCapsInitQMP':
../../src/qemu/qemu_capabilities.c:2327:13: error: format '%d' expects argument of type 'int', but argument 8 has type 'const char *' [-Werror=format]
* src/qemu/qemu_capabilities.c (qemuCapsInitQMP): Use correct format.
Since libvirt switched to QMP capabilities probing recently, it starts
QEMU process used for this probing with -daemonize, which means
virCommandAbort can no longer reach these processes. As a result of
that, restarting libvirtd will leave several new QEMU processes behind.
Let's use QEMU's -pidfile and use it to kill the process when QMP caps
probing is done.
When doing snapshots, the filesystem freeze function used the agent
entering function that expects the qemud_driver unlocked. This might
cause a deadlock of the qemu driver if the agent does not respond.
The only call path of this function has the qemud_driver locked, so this
patch changes the entering functions to those expecting the driver
locked.
Start a QEMU process using
$QEMU -S -no-user-config -nodefaults \
-nographic -M none -qmp unix:/some/path,server,nowait
and talk QMP over stdio to discover what capabilities the
binary supports. This works for QEMU 1.2.0 or later and
for older QEMU automatically fallback to the old approach
of parsing -help and related command line args.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Some architectures provide the query-cpu-definitions command,
but are set to always return a "GenericError" from it :-(
Catch this & treat it as if there was an empty list of CPUs
returned
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
