This adds the scsi-generic device into the device controller's
whitelist, so that it's allowed to used by the qemu process.
Signed-off-by: Han Cheng <hanc.fnst@cn.fujitsu.com>
Signed-off-by: Osier Yang <jyang@redhat.com>
I must have looked at this a couple dozen times before I noticed it
had "!=" instead of "==". Not doing this setup prevented qemu from
doing anything with the vfio group device.
The source code base needs to be adapted as well. Some files
include virutil.h just for the string related functions (here,
the include is substituted to match the new file), some include
virutil.h without any need (here, the include is removed), and
some require both.
The USB-specific cgroup setup had been inserted inline in
qemuDomainAttachHostUsbDevice and qemuSetupCgroup, but now there is a
common cgroup setup function called for all hostdevs, so it makes sens
to put the usb-specific setup there and just rely on that function
being called.
The one thing I'm uncertain of here (and a reason for not pushing
until after release) is that previously hostdev->missing was checked
only when starting a domain (and cgroup setup for the device skipped
if missing was true), but with this consolidation, it is now checked
in the case of hotplug as well. I don't know if this will have any
practical effect (does it make sense to hotplug a "missing" usb
device?)
PCIO device assignment using VFIO requires read/write access by the
qemu process to /dev/vfio/vfio, and /dev/vfio/nn, where "nn" is the
VFIO group number that the assigned device belongs to (and can be
found with the function virPCIDeviceGetVFIOGroupDev)
/dev/vfio/vfio can be accessible to any guest without danger
(according to vfio developers), so it is added to the static ACL.
The group device must be dynamically added to the cgroup ACL for each
vfio hostdev in two places:
1) for any devices in the persistent config when the domain is started
(done during qemuSetupCgroup())
2) at device attach time for any hotplug devices (done in
qemuDomainAttachHostDevice)
The group device must be removed from the ACL when a device it
"hot-unplugged" (in qemuDomainDetachHostDevice())
Note that USB devices are already doing their own cgroup setup and
teardown in the hostdev-usb specific function. I chose to make the new
functions generic and call them in a common location though. We can
then move the USB-specific code (which is duplicated in two locations)
to this single location. I'll be posting a followup patch to do that.
The change in commit aed4986322
was incomplete, missing a couple of cases of /system. This
caused failure to start VMs.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
After discussions with systemd developers it was decided that
a better default policy for resource partitions is to have
3 default partitions at the top level
/system - system services
/machine - virtual machines / containers
/user - user login session
This ensures that the default policy isolates guest from
user login sessions & system services, so a mis-behaving
guest can't consume 100% of CPU usage if other things are
contending for it.
Thus we change the default partition from /system to
/machine
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The virCgroupNewDriver method had a 'bool privileged' param.
If a false value was ever passed in, it would simply not
work, since non-root users don't have any privileges to create
new cgroups. Just delete this broken code entirely and make
the QEMU driver skip cgroup setup in non-privileged mode
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Historically QEMU/LXC guests have been placed in a cgroup layout
that is
$LOCATION-OF-LIBVIRTD/libvirt/{qemu,lxc}/$VMNAME
This is bad for a number of reasons
- The cgroup hierarchy gets very deep which seriously
impacts kernel performance due to cgroups scalability
limitations.
- It is hard to setup cgroup policies which apply across
services and virtual machines, since all VMs are underneath
the libvirtd service.
To address this the default cgroup location is changed to
be
/system/$VMNAME.{lxc,qemu}.libvirt
This puts virtual machines at the same level in the hierarchy
as system services, allowing consistent policy to be setup
across all of them.
This also honours the new resource partition location from the
XML configuration, for example
<resource>
<partition>/virtualmachines/production</partitions>
</resource>
will result in the VM being placed at
/virtualmachines/production/$VMNAME.{lxc,qemu}.libvirt
NB, with the exception of the default, /system, path which
is intended to always exist, libvirt will not attempt to
auto-create the partitions in the XML. It is the responsibility
of the admin/app to configure the partitions. Later libvirt
APIs will provide a way todo this.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
A resource partition is an absolute cgroup path, ignoring the
current process placement. Expose a virCgroupNewPartition API
for constructing such cgroups
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Rename all the virCgroupForXXX methods to use the form
virCgroupNewXXX since they are all constructors. Also
make sure the output parameter is the last one in the
list, and annotate all pointers as non-null. Fix up
all callers, and make sure they use true/false not 0/1
for the boolean parameters
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Instead of calling virCgroupForDomain every time we need
the virCgrouPtr instance, just do it once at Vm startup
and cache a reference to the object in qemuDomainObjPrivatePtr
until shutdown of the VM. Removing the virCgroupPtr from
the QEMU driver state also means we don't have stale mount
info, if someone mounts the cgroups filesystem after libvirtd
has been started
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Some refactoring for virDomainChrSourceDef type of devices so
we can use common code.
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-by: Corey Bryant <coreyb@linux.vnet.ibm.com>
Tested-by: Corey Bryant <coreyb@linux.vnet.ibm.com>
The virCgroupMounted method is badly named, since a controller can be
mounted, but disabled in the current object. Rename the method to be
virCgroupHasController. Also make it tolerant to a NULL virCgroupPtr
and out-of-range controller index, to avoid duplication of these
checks in all callers
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Currently when getting an instance of virCgroupPtr we will
create the path in all cgroup controllers. Only at the virt
driver layer are we attempting to filter controllers. This
is bad because the mere act of creating the dirs in the
controllers can have a functional impact on the kernel,
particularly for performance.
Update the virCgroupForDriver() method to accept a bitmask
of controllers to use. Only create dirs in the controllers
that are requested. When creating cgroups for domains,
respect the active controller list from the parent cgroup
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Intend to reduce the redundant code,use virNumaSetupMemoryPolicy
to replace virLXCControllerSetupNUMAPolicy and
qemuProcessInitNumaMemoryPolicy.
This patch also moves the numa related codes to the
file virnuma.c and virnuma.h
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
The QEMU driver has a list of devices nodes that are whitelisted
for all guests. The kernel has recently started returning an
error if you try to whitelist a device which does not exist.
This causes a warning in libvirt logs and an audit error for
any missing devices. eg
2013-02-27 16:08:26.515+0000: 29625: warning : virDomainAuditCgroup:451 : success=no virt=kvm resrc=cgroup reason=allow vm="vm031714" uuid=9d8f1de0-44f4-a0b1-7d50-e41ee6cd897b cgroup="/sys/fs/cgroup/devices/libvirt/qemu/vm031714/" class=path path=/dev/kqemu rdev=? acl=rw
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The code for putting the emulator threads in a separate cgroup
would spam the logs with warnings
2013-02-27 16:08:26.731+0000: 29624: warning : virCgroupMoveTask:887 : no vm cgroup in controller 3
2013-02-27 16:08:26.731+0000: 29624: warning : virCgroupMoveTask:887 : no vm cgroup in controller 4
2013-02-27 16:08:26.732+0000: 29624: warning : virCgroupMoveTask:887 : no vm cgroup in controller 6
This is because it has only created child cgroups for 3 of the
controllers, but was trying to move the processes from all the
controllers. The fix is to only try to move threads in the
controllers we actually created. Also remove the warning and
make it return a hard error to avoid such lazy callers in the
future.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
https://bugzilla.redhat.com/show_bug.cgi?id=896685 points out
a regression caused by commit 38c4a9c - libvirt only labels
the backing chain if the backing chain cache is populated, but
the code to populate the cache was only conditionally performed
if cgroup labeling was necessary.
* src/qemu/qemu_cgroup.c (qemuSetupCgroup): Hoist cache setup...
* src/qemu/qemu_process.c (qemuProcessStart): ...earlier into
caller, where it is now unconditional.
When iterating over USB host devices to setup cgroups, the
usbDevice object was leaked in both LXC and QEMU driers
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Currently the virQEMUDriverPtr struct contains an wide variety
of data with varying access needs. Move all the static config
data into a dedicated virQEMUDriverConfigPtr object. The only
locking requirement is to hold the driver lock, while obtaining
an instance of virQEMUDriverConfigPtr. Once a reference is held
on the config object, it can be used completely lockless since
it is immutable.
NB, not all APIs correctly hold the driver lock while getting
a reference to the config object in this patch. This is safe
for now since the config is never updated on the fly. Later
patches will address this fully.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
While OOM can have knock-on effects that trash a system, generally
the first symptom is one of memory thrashing.
* src/qemu/qemu_cgroup.c (qemuSetupCgroup): Reword slightly.
Currently, if there's no hard memory limit defined for a domain,
libvirt tries to calculate one, based on domain definition and magic
equation and set it upon the domain startup. The rationale behind was,
if there's a memory leak or exploit in qemu, we should prevent the
host system trashing. However, the equation was too tightening, as it
didn't reflect what the kernel counts into the memory used by a
process. Since many hosts do have a swap, nobody hasn't noticed
anything, because if hard memory limit is reached, process can
continue allocating memory on a swap. However, if there is no swap on
the host, the process gets killed by OOM killer. In our case, the qemu
process it is.
To prevent this, we need to relax the hard RSS limit. Moreover, we
should reflect more precisely the kernel way of accounting the memory
for process. That is, even the kernel caches are counted within the
memory used by a process (within cgroups at least). Hence the magic
equation has to be changed:
limit = 1.5 * (domain memory + total video memory) + (32MB for cache
per each disk) + 200MB
To bring in line with new naming practice, rename the=
src/util/cgroup.{h,c} files to vircgroup.{h,c}
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
When LXC labels USB devices during hotplug, it is running in
host context, so it needs to pass in a vroot path to the
container root.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Remove the obsolete 'qemud' naming prefix and underscore
based type name. Introduce virQEMUDriverPtr as the replacement,
in common with LXC driver naming style
The libvirt coding standard is to use 'function(...args...)'
instead of 'function (...args...)'. A non-trivial number of
places did not follow this rule and are fixed in this patch.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
When the cpu placement model is "auto", it sets the affinity for
domain process with the advisory nodeset from numad, however,
creating cgroup for the domain process (called emulator thread
in some contexts) later overrides that with pinning it to all
available pCPUs.
How to reproduce:
* Configure the domain with "auto" placement for <vcpu>, e.g.
<vcpu placement='auto'>4</vcpu>
* % virsh start dom
* % cat /proc/$dompid/status
Though the emulator cgroup cause conflicts, but we can't simply
prohibit creating it, as other tunables are still useful, such
as "emulator_period", which is used by API
virDomainSetSchedulerParameter. So this patch doesn't prohibit
creating the emulator cgroup, but inherit the nodeset from numad,
and reset the affinity for domain process.
* src/qemu/qemu_cgroup.h: Modify definition of qemuSetupCgroupForEmulator
to accept the passed nodenet
* src/qemu/qemu_cgroup.c: Set the affinity with the passed nodeset
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.
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.
https://www.gnu.org/licenses/gpl-howto.html recommends that
the 'If not, see <url>.' phrase be a separate sentence.
* tests/securityselinuxhelper.c: Remove doubled line.
* tests/securityselinuxtest.c: Likewise.
* globally: s/; If/. If/
This is another fix for the emulator-pin series. When going through
the cputune pinning settings, the current code is trying to pin all
the CPUs, even when not all of them are specified. This causes error
in the subsequent function which, of course, cannot find the cpu to
pin. Since it's enough to pass the correct VCPU ID to the function,
the fix is trivial.
When domain XML contains any of the elements for setting up CPU
scheduling parameters (period, quota, emulator_period, or
emulator_quota) we need cpu cgroup to enforce the configuration.
However, the existing code would just ignore silently such settings if
either cgroups were not available at all cpu cgroup was not available.
Moreover, APIs for manipulating CPU scheduler parameters were already
failing if cpu cgroup was not available. This patch makes cpu cgroup
mandatory for all domains that use CPU scheduling elements in their XML.
If cgroups are enabled in general but cpu cgroup is disabled in
qemu.conf or not mounted at all, libvirt would refuse to start any
domain even though scheduler parameters are not set in domain XML.
This patch makes cpu cgroup mandatory only for domains that actually
want to use it.
Commit 4b03d59167 changed the pinning
behavior in a way that makes some machines non-startable.
The comment mentioning that we cannot control each vcpu when there is
not VCPU<-> PID mapping available is true, however, this isn't
necessarily an error, because this can be caused by old QEMU without
support for "query-cpus" command as well as a software emulated
machines that don't create more than one process.
This patch introduces support of setting emulator's period and
quota to limit cpu bandwidth when the vm starts. Also updates
XML Schema for new entries and docs.
This patch changes the behaviour of xml element cputune.period
and cputune.quota to limit cpu bandwidth only for vcpus, and no
longer limit cpu bandwidth for the whole guest.
The reasons to do this are:
- This matches docs of cputune.period and cputune.quota.
- The other parts excepting vcpus are treated as "emulator",
and there are separate period/quota settings for emulator
in the subsequent patches
Introduce qemuSetupCgroupEmulatorPin() function to add emulator
threads pin info to cpuset cgroup, the same as vcpupin.
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
vcpu threads pin are implemented using sched_setaffinity(), but
not controlled by cgroup. This patch does the following things:
1) enable cpuset cgroup
2) reflect all the vcpu threads pin info to cgroup
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
Create a new cgroup and move all emulator threads to the new cgroup.
And then we can do the other things:
1. limit only vcpu usage rather than the whole qemu
2. limit for emulator threads(include vhost-net threads)
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
