'const fooPtr' is the same as 'foo * const' (the pointer won't
change, but it's contents can). But in general, if an interface
is trying to be const-correct, it should be using 'const foo *'
(the pointer is to data that can't be changed).
Fix up offenders in src/conf/domain_conf, and their fallout.
Several things to note: virObjectLock() requires a non-const
argument; if this were C++, we could treat the locking field
as 'mutable' and allow locking an otherwise 'const' object, but
that is a more invasive change, so I instead dropped attempts
to be const-correct on domain lookup. virXMLPropString and
friends require a non-const xmlNodePtr - this is because libxml2
is not a const-correct library. We could make the src/util/virxml
wrappers cast away const, but I figured it was easier to not
try to mark xmlNodePtr as const. Finally, virDomainDeviceDefCopy
was a rather hard conversion - it calls virDomainDeviceDefPostParse,
which in turn in the xen driver was actually modifying the domain
outside of the current device being visited. We should not be
adding a device on the first per-device callback, but waiting until
after all per-device callbacks are complete.
* src/conf/domain_conf.h (virDomainObjListFindByID)
(virDomainObjListFindByUUID, virDomainObjListFindByName)
(virDomainObjAssignDef, virDomainObjListAdd): Drop attempt at
const.
(virDomainDeviceDefCopy): Use intended type.
(virDomainDeviceDefParse, virDomainDeviceDefPostParseCallback)
(virDomainVideoDefaultType, virDomainVideoDefaultRAM)
(virDomainChrGetDomainPtrs): Make const-correct.
* src/conf/domain_conf.c (virDomainObjListFindByID)
(virDomainObjListFindByUUID, virDomainObjListFindByName)
(virDomainDeviceDefCopy, virDomainObjListAdd)
(virDomainObjAssignDef, virDomainHostdevSubsysUsbDefParseXML)
(virDomainHostdevSubsysPciOrigStatesDefParseXML)
(virDomainHostdevSubsysPciDefParseXML)
(virDomainHostdevSubsysScsiDefParseXML)
(virDomainControllerModelTypeFromString)
(virDomainTPMDefParseXML, virDomainTimerDefParseXML)
(virDomainSoundCodecDefParseXML, virDomainSoundDefParseXML)
(virDomainWatchdogDefParseXML, virDomainRNGDefParseXML)
(virDomainMemballoonDefParseXML, virDomainNVRAMDefParseXML)
(virSysinfoParseXML, virDomainVideoAccelDefParseXML)
(virDomainVideoDefParseXML, virDomainHostdevDefParseXML)
(virDomainRedirdevDefParseXML)
(virDomainRedirFilterUsbDevDefParseXML)
(virDomainRedirFilterDefParseXML, virDomainIdMapEntrySort)
(virDomainIdmapDefParseXML, virDomainVcpuPinDefParseXML)
(virDiskNameToBusDeviceIndex, virDomainDeviceDefCopy)
(virDomainVideoDefaultType, virDomainHostdevAssignAddress)
(virDomainDeviceDefPostParseInternal, virDomainDeviceDefPostParse)
(virDomainChrGetDomainPtrs, virDomainControllerSCSINextUnit)
(virDomainSCSIDriveAddressIsUsed)
(virDomainDriveAddressIsUsedByDisk)
(virDomainDriveAddressIsUsedByHostdev): Fix fallout.
* src/openvz/openvz_driver.c (openvzDomainDeviceDefPostParse):
Likewise.
* src/libxl/libxl_domain.c (libxlDomainDeviceDefPostParse):
Likewise.
* src/qemu/qemu_domain.c (qemuDomainDeviceDefPostParse)
(qemuDomainDefaultNetModel): Likewise.
* src/lxc/lxc_domain.c (virLXCDomainDeviceDefPostParse):
Likewise.
* src/uml/uml_driver.c (umlDomainDeviceDefPostParse): Likewise.
* src/xen/xen_driver.c (xenDomainDeviceDefPostParse): Split...
(xenDomainDefPostParse): ...since per-device callback is not the
time to be adding a device.
Signed-off-by: Eric Blake <eblake@redhat.com>
virDomainChrGetDomainPtrs() required 4 levels of pointers (taking
a parameter that will be used as an output variable to return the
address of another variable that contains an array of pointers).
This is rather complex to reason about, especially when outside
of the domain_conf file, no other caller should be modifying
the resulting array of pointers directly. Changing the public
signature gives something is easier to reason with, and actually
make const-correct; which is important as it was the only function
that was blocking virDomainDeviceDefCopy from treating its source
as const.
* src/conf/domain_conf.h (virDomainChrGetDomainPtrs): Use simpler
types, and make const-correct for external users.
* src/conf/domain_conf.c (virDomainChrGetDomainPtrs): Split...
(virDomainChrGetDomainPtrsInternal): ...into an internal version
that lets us modify terms, vs. external form that is read-only.
(virDomainDeviceDefPostParseInternal, virDomainChrFind)
(virDomainChrInsert): Adjust callers.
* src/qemu/qemu_command.c (qemuGetNextChrDevIndex): Adjust caller.
(qemuDomainDeviceAliasIndex): Make const-correct.
Signed-off-by: Eric Blake <eblake@redhat.com>
Prefer using VFIO (if available) to the legacy KVM device passthrough.
With this patch a PCI passthrough device without the driver configured
will be started with VFIO if it's available on the host. If not legacy
KVM passthrough is checked and error is reported if it's not available.
Since 76b644c when the support for RAM filesystems was introduced,
libvirt accepted the following XML:
<source usage='1024' unit='KiB'/>
This was parsed correctly and internally stored in bytes, but it
was formatted as (with an extra 's'):
<source usage='1024' units='KiB'/>
When read again, this was treated as if the units were missing,
meaning libvirt was unable to parse its own XML correctly.
The usage attribute was documented as being in KiB, but it was not
scaled if the unit was missing. Transient domains still worked,
because this was balanced by an extra 'k' in the mount options.
This patch:
Changes the parser to use 'units' instead of 'unit', as the latter
was never documented (fixing persistent domains) and some programs
(libvirt-glib, libvirt-sandbox) already parse the 'units' attribute.
Removes the extra 'k' from the tmpfs mount options, which is needed
because now we parse our own XML correctly.
Changes the default input unit to KiB to match documentation, fixing:
https://bugzilla.redhat.com/show_bug.cgi?id=1015689
This resolves one of the issues in:
https://bugzilla.redhat.com/show_bug.cgi?id=1003983
This device is identical to qemu's "intel-hda" device (known as "ich6"
in libvirt), but has a different PCI device ID (which matches the ID
of the hda audio built into the ich9 chipset, of course). It's not
supported in earlier versions of qemu, so it requires a capability
bit.
The parsing of '-usb' did not check for failure of the
virDomainControllerInsert method. As a result on OOM, the
parser mistakenly attached USB disks to the IDE controller.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
qemu/KVM also supports a tftp URL while specifying the cdrom ISO image.
The xml should be as following:
<disk type='network' device='cdrom'>
<source protocol='tftp' name='/url/path'>
<host name='host.name' port='69'/>
</source>
</disk>
Signed-off-by: Aline Manera <alinefm@br.ibm.com>
The ftps protocol is another protocol supported by qemu/KVM while specifying
the cdrom ISO image.
The xml should be as following:
<disk type='network' device='cdrom'>
<source protocol='ftps' name='/url/path'>
<host name='host.name' port='990'/>
</source>
</disk>
Signed-off-by: Aline Manera <alinefm@br.ibm.com>
The https protocol is also accepted by qemu/KVM when specifying the cdrom ISO
image.
The xml should be as following:
<disk type='network' device='cdrom'>
<source protocol='https' name='/url/path'>
<host name='host.name' port='443'/>
</source>
</disk>
Signed-off-by: Aline Manera <alinefm@br.ibm.com>
The function implemented common behavior that can be reused for other
hypervisor drivers that use the virDomainObj data structures. Factor out
the core into a separate helper func.
The function implemented common behavior that can be reused for other
hypervisor drivers that use the virDomainObj data structures. Factor out
the core into a separate helper func.
Starting with qemu 1.6, the qemu-system-arm vexpress-a9 model has a
hardcoded virtio-mmio transport which enables attaching all virtio
devices.
On the command line, we have to use virtio-XXX-device rather than
virtio-XXX-pci, thankfully s390 already set the precedent here so
it's fairly straight forward.
At the XML level, this adds a new device address type virtio-mmio.
The controller and addressing don't have any subelements at the
moment because we they aren't needed for this usecase, but could
be added later if needed.
Add a test case for an ARM guest with one of every virtio device
enabled.
This corresponds to '-sd' and '-drive if=sd' on the qemu command line.
Needed for many ARM boards which don't provide any other way to
pass in storage.
Add an attribute named 'removable' to the 'target' element of disks,
which controls the removable flag. For instance, on a Linux guest it
controls the value of /sys/block/$dev/removable. This option is only
valid for USB disks (i.e. bus='usb'), and its default value is 'off',
which is the same behaviour as before.
To achieve this, 'removable=on' (or 'off') is appended to the '-device
usb-storage' parameter sent to qemu when adding a USB disk via
'-disk'. A capability flag QEMU_CAPS_USB_STORAGE_REMOVABLE was added
to keep track if this option is supported by the qemu version used.
Bug: https://bugzilla.redhat.com/show_bug.cgi?id=922495
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
When using a <interface type="network"> that points to a network with
hostdev forwarding mode a hostdev alias is created for the network. This
allias is inserted into the hostdev list, but is backed with a part of
the network object that it is connected to.
When a VM is being stopped qemuProcessStop() calls
networkReleaseActualDevice() which eventually frees the memory for the
hostdev object. Afterwards when the domain definition is being freed by
virDomainDefFree() an invalid pointer is accessed by
virDomainHostdevDefFree() and may cause a crash of the daemon.
This patch removes the entry in the hostdev list before freeing the
depending memory to avoid this issue.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1000973
<controller type='pci' index='0' model='pci-root'>
<pcihole64 unit='KiB'>1048576</pcihole64>
</controller>
It can be used to adjust (or disable) the size of the 64-bit
PCI hole. The size attribute is in kilobytes (different unit
can be specified on input), but it gets rounded up to
the nearest GB by QEMU.
Disabling it will be needed for guests that crash with the
64-bit PCI hole (like Windows XP), see:
https://bugzilla.redhat.com/show_bug.cgi?id=990418
The ftp protocol is already recognized by qemu/KVM so add this support to
libvirt as well.
The xml should be as following:
<disk type='network' device='cdrom'>
<source protocol='ftp' name='/url/path'>
<host name='host.name' port='21'/>
</source>
</disk>
Signed-off-by: Aline Manera <alinefm@br.ibm.com>
QEMU/KVM already allows a HTTP URL for the cdrom ISO image so add this support
to libvirt as well.
The xml should be as following:
<disk type='network' device='cdrom'>
<source protocol='http' name='/url/path'>
<host name='host.name' port='80'/>
</source>
</disk>
Signed-off-by: Aline Manera <alinefm@br.ibm.com>
https://bugzilla.redhat.com/show_bug.cgi?id=924153
Commit 904e05a2 (v0.9.9) added a per-<disk> seclabel element with
an attribute relabel='no' in order to try and minimize the
impact of shutdown delays when an NFS server disappears. The idea
was that if a disk is on NFS and can't be labeled in the first
place, there is no need to attempt the (no-op) relabel on domain
shutdown. Unfortunately, the way this was implemented was by
modifying the domain XML so that the optimization would survive
libvirtd restart, but in a way that is indistinguishable from an
explicit user setting. Furthermore, once the setting is turned
on, libvirt avoids attempts at labeling, even for operations like
snapshot or blockcopy where the chain is being extended or pivoted
onto non-NFS, where SELinux labeling is once again possible. As
a result, it was impossible to do a blockcopy to pivot from an
NFS image file onto a local file.
The solution is to separate the semantics of a chain that must
not be labeled (which the user can set even on persistent domains)
vs. the optimization of not attempting a relabel on cleanup (a
live-only annotation), and using only the user's explicit notation
rather than the optimization as the decision on whether to skip
a label attempt in the first place. When upgrading an older
libvirtd to a newer, an NFS volume will still attempt the relabel;
but as the avoidance of a relabel was only an optimization, this
shouldn't cause any problems.
In the ideal future, libvirt will eventually have XML describing
EVERY file in the backing chain, with each file having a separate
<seclabel> element. At that point, libvirt will be able to track
more closely which files need a relabel attempt at shutdown. But
until we reach that point, the single <seclabel> for the entire
<disk> chain is treated as a hint - when a chain has only one
file, then we know it is accurate; but if the chain has more than
one file, we have to attempt relabel in spite of the attribute,
in case part of the chain is local and SELinux mattered for that
portion of the chain.
* src/conf/domain_conf.h (_virSecurityDeviceLabelDef): Add new
member.
* src/conf/domain_conf.c (virSecurityDeviceLabelDefParseXML):
Parse it, for live images only.
(virSecurityDeviceLabelDefFormat): Output it.
(virDomainDiskDefParseXML, virDomainChrSourceDefParseXML)
(virDomainDiskSourceDefFormat, virDomainChrDefFormat)
(virDomainDiskDefFormat): Pass flags on through.
* src/security/security_selinux.c
(virSecuritySELinuxRestoreSecurityImageLabelInt): Honor labelskip
when possible.
(virSecuritySELinuxSetSecurityFileLabel): Set labelskip, not
norelabel, if labeling fails.
(virSecuritySELinuxSetFileconHelper): Fix indentation.
* docs/formatdomain.html.in (seclabel): Document new xml.
* docs/schemas/domaincommon.rng (devSeclabel): Allow it in RNG.
* tests/qemuxml2argvdata/qemuxml2argv-seclabel-*-labelskip.xml:
* tests/qemuxml2argvdata/qemuxml2argv-seclabel-*-labelskip.args:
* tests/qemuxml2xmloutdata/qemuxml2xmlout-seclabel-*-labelskip.xml:
New test files.
* tests/qemuxml2argvtest.c (mymain): Run the new tests.
* tests/qemuxml2xmltest.c (mymain): Likewise.
Signed-off-by: Eric Blake <eblake@redhat.com>
This PCI controller, named "dmi-to-pci-bridge" in the libvirt config,
and implemented with qemu's "i82801b11-bridge" device, connects to a
PCI Express slot (e.g. one of the slots provided by the pcie-root
controller, aka "pcie.0" on the qemu commandline), and provides 31
*non-hot-pluggable* PCI (*not* PCIe) slots, numbered 1-31.
Any time a machine is defined which has a pcie-root controller
(i.e. any q35-based machinetype), libvirt will automatically add a
dmi-to-pci-bridge controller if one doesn't exist, and also add a
pci-bridge controller. The reasoning here is that any useful domain
will have either an immediate (startup time) or eventual (subsequent
hot-plug) need for a standard PCI slot; since the pcie-root controller
only provides PCIe slots, we need to connect a dmi-to-pci-bridge
controller to it in order to get a non-hot-plug PCI slot that we can
then use to connect a pci-bridge - the slots provided by the
pci-bridge will be both standard PCI and hot-pluggable.
Since pci-bridge devices themselves can not be hot-plugged into a
running system (although you can hot-plug other devices into a
pci-bridge's slots), any new pci-bridge controller that is added can
(and will) be plugged into the dmi-to-pci-bridge as long as it has
empty slots available.
This patch is also changing the qemuxml2xml-pcie test from a "DO_TEST"
to a "DO_DIFFERENT_TEST". This is so that the "before" xml can omit
the automatically added dmi-to-pci-bridge and pci-bridge devices, and
the "after" xml can include it - this way we are testing if libvirt is
properly adding these devices.
This controller is implicit on q35 machinetypes. It provides 31 PCIe
(*not* PCI) slots as controller 0.
Currently there are no devices that can connect to pcie-root, and no
implicit pci controller on a q35 machine, so q35 is still
unusable. For a usable q35 system, we need to add a
"dmi-to-pci-bridge" pci controller, which can connect to pcie-root,
and provides standard pci slots that can be used to connect other
devices.
Since PCI bridges, PCIe bridges, PCIe switches, and PCIe root ports
all share the same namespace, they are all defined as controllers of
type='pci' in libvirt (but with a differing model attribute). Each of
these controllers has a certain connection type upstream, allows
certain connection types downstream, and each can either allow a
single downstream connection at slot 0, or connections from slot 1 -
31.
Right now, we only support the pci-root and pci-bridge devices, both
of which only allow PCI devices to connect, and both which have usable
slots 1 - 31. In preparation for adding other types of controllers
that have different capabilities, this patch 1) adds info to the
qemuDomainPCIAddressBus object to indicate the capabilities, 2) sets
those capabilities appropriately for pci-root and pci-bridge devices,
and 3) validates that the controller being connected to is the proper
type when allocating slots or validating that a user-selected slot is
appropriate for a device..
Having this infrastructure in place will make it much easier to add
support for the other PCI controller types.
While it would be possible to do all the necessary checking by just
storing the controller model in the qemyuDomainPCIAddressBus, it
greatly simplifies all the validation code to also keep a "flags",
"minSlot" and "maxSlot" for each - that way we can just check those
attributes rather than requiring a nearly identical switch statement
everywhere we need to validate compatibility.
You may notice many places where the flags are seemingly hard-coded to
QEMU_PCI_CONNECT_HOTPLUGGABLE | QEMU_PCI_CONNECT_TYPE_PCI
This is currently the correct value for all PCI devices, and in the
future will be the default, with small bits of code added to change to
the flags for the few devices which are the exceptions to this rule.
Finally, there are a few places with "FIXME" comments. Note that these
aren't indicating places that are broken according to the currently
supported devices, they are places that will need fixing when support
for new PCI controller models is added.
To assure that there was no regression in the auto-allocation of PCI
addresses or auto-creation of integrated pci-root, ide, and usb
controllers, a new test case (pci-bridge-many-disks) has been added to
both the qemuxml2argv and qemuxml2xml tests. This new test defines a
domain with several dozen virtio disks but no pci-root or
pci-bridges. The .args file of the new test case was created using
libvirt sources from before this patch, and the test still passes
after this patch has been applied.
The difference with already supported pool types (dir, fs, block)
is: there are two modes for iscsi pool (or network pools in future),
one can specify it either to use the volume target path (the path
showed up on host) with mode='host', or to use the remote URI qemu
supports (e.g. file=iscsi://example.org:6000/iqn.1992-01.com.example/1)
with mode='direct'.
For 'host' mode, it copies the volume target path into disk->src. For
'direct' mode, the corresponding info in the *one* pool source host def
is copied to disk->hosts[0].
There are two ways to use a iSCSI LUN as disk source for qemu.
* The LUN's path as it shows up on host, e.g.
/dev/disk/by-path/ip-$ip:3260-iscsi-$iqn-fc18:iscsi.iscsi0-lun-1
* The libiscsi URI from the storage pool source element host attribute, e.g.
iscsi://demo.org:6000/iqn.1992-01.com.example/1
For a "volume" type disk, if the specified "pool" is of iscsi
type, we should support to use the LUN in either of above 2 ways.
That's why to introduce a new XML tag "mode" for the disk source
(libvirt should support iscsi pool with libiscsi, but it's another
new feature, which should be done later).
The "mode" can be either of "host" or "direct". Use "host" to indicate
use of the LUN with the path as it shows up on host. Use "direct" to
indicate to use it with the source pool host URI (future patches may support
to use network type libvirt storage too, e.g. Ceph)
There are two levels on which a device may be hotplugged: config
and live. The config level requires just an insert or remove from
internal domain definition structure, which is exactly what this
patch does. There is currently no implementation for a chardev
update action, as there's not much to be updated. But more
importantly, the only thing that can be updated is path or socket
address by which chardevs are distinguished. So the update action
is currently not supported.
For now, only these three helpers are needed:
virDomainChrFind - to find a duplicate chardev within VM def
virDomainChrInsert - wrapper for inserting a new chardev into VM def
virDomainChrRemove - wrapper for removing chardev from VM def
There is, however, one internal helper as well:
virDomainChrGetDomainPtrs which sets given pointers to one of
vmdef->{parallels,serials,consoles,channels} based on passed
chardev type.
Convert the type of loop iterators named 'i', 'j', k',
'ii', 'jj', 'kk', to be 'size_t' instead of 'int' or
'unsigned int', also santizing 'ii', 'jj', 'kk' to use
the normal 'i', 'j', 'k' naming
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
While iterating with virDomainObjListForEach it is safe to remove
current element. But while iterating, 'doms' lock is already taken, so
can't use standard virDomainObjListRemove. So introduce
virDomainObjListRemoveLocked for this purpose.
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
This patch introduces new element <idmap> for
user namespace. for example
<idmap>
<uid start='0' target='1000' count='10'/>
<gid start='0' target='1000' count='10'/>
</idmap>
this new element is used for setting proc files
/proc/<pid>/{uid_map,gid_map}.
This patch also supports multiple uid/gid elements
setting in XML configuration.
We don't support the semi configuation, user has to
configure uid and gid both.
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Add new CPU features for HyperV:
vapic for virtual APIC support
spinlocks for setting spinlock support
<features>
<hyperv>
<vapic state='on'/>
<spinlocks state='on' retries='4096'/>
</hyperv>
</features>
https://bugzilla.redhat.com/show_bug.cgi?id=784836
https://bugzilla.redhat.com/show_bug.cgi?id=971485
As of d7f9d82753 we copy the listen
address from the qemu.conf config file in case none has been provided
via XML. But later, when migrating, we should not include such listen
address in the migratable XML as it is something autogenerated, not
requested by user. Moreover, the binding to the listen address will
likely fail, unless the address is '0.0.0.0' or its IPv6 equivalent.
This patch introduces a new boolean attribute to virDomainGraphicsListenDef
to distinguish autofilled listen addresses. However, we must keep the
attribute over libvirtd restarts, so it must be kept within status XML.
https://bugzilla.redhat.com/show_bug.cgi?id=964177
Though both libvirt and QEMU's document say RTC_CHANGE returns
the offset from the host UTC, qemu actually returns the offset
from the specified date instead when specific date is provided
(-rtc base=$date).
It's not safe for qemu to fix it in code, it worked like that
for 3 years, changing it now may break other QEMU use cases.
What qemu tries to do is to fix the document:
http://lists.gnu.org/archive/html/qemu-devel/2013-05/msg04782.html
And in libvirt side, instead of replying on the value from qemu,
this converts the offset returned from qemu to the offset from
host UTC, by:
/*
* a: the offset from qemu RTC_CHANGE event
* b: The specified date (-rtc base=$date)
* c: the host date when libvirt gets the RTC_CHANGE event
* offset: What libvirt will report
*/
offset = a + (b - c);
The specified date (-rtc base=$date) is recorded in clock's def as
an internal only member (may be useful to exposed outside?).
Internal only XML tag "basetime" is introduced to not lose the
guest's basetime after libvirt restarting/reloading:
<clock offset='variable' adjustment='304' basis='utc' basetime='1370423588'/>
This attribute is going to represent number of queues for
multique vhost network interface. This commit implements XML
extension part of the feature and add one test as well. For now,
we can only do xml2xml test as qemu command line generation code
is not adapted yet.
-vnc :5900,share=allow-exclusive
allows clients to ask for exclusive access which is
implemented by dropping other connections Connecting
multiple clients in parallel requires all clients asking
for a shared session (vncviewer: -shared switch)
-vnc :5900,share=force-shared
disables exclusive client access. Useful for shared
desktop sessions, where you don't want someone forgetting
specify -shared disconnect everybody else.
-vnc :5900,share=ignore
completely ignores the shared flag and allows everybody
connect unconditionally
Introduce use of a virDomainDefPtr in the domain lookup
APIs to simplify introduction of ACL security checks.
The virDomainPtr cannot be safely used, since the app
may have supplied mis-matching name/uuid/id fields. eg
the name points to domain X, while the uuid points to
domain Y. Resolving the virDomainPtr to a virDomainDefPtr
ensures a consistent name/uuid/id set.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
QEMU might support more values for "-drive discard", so using Bi-state
values (on/off) for it doesn't make sense.
"on" maps to "unmap", "off" maps to "ignore":
<...>
@var{discard} is one of "ignore" (or "off") or "unmap" (or "on") and
controls whether @dfn{discard} (also known as @dfn{trim} or @dfn{unmap})
requests are ignored or passed to the filesystem. Some machine types
may not support discard requests.
</...>
The following XML configuration can be used to request all domain's
memory pages to be kept locked in host's memory (i.e., domain's memory
pages will not be swapped out):
<memoryBacking>
<locked/>
</memoryBacking>
QEMU introduced "discard" option for drive since commit a9384aff53,
<...>
@var{discard} is one of "ignore" (or "off") or "unmap" (or "on") and
controls whether @dfn{discard} (also known as @dfn{trim} or @dfn{unmap})
requests are ignored or passed to the filesystem. Some machine types
may not support discard requests.
</...>
This patch exposes the support in libvirt.
QEMU supported "discard" for "-drive" since v1.5.0-rc0:
% git tag --contains a9384aff53
contains
v1.5.0-rc0
v1.5.0-rc1
So this only detects the capability bit using virQEMUCapsProbeQMPCommandLine.
Adding support for new attribute 'websocket' in the '<graphics>'
element, the attribute value is the port to listen on with '-1'
meaning auto-allocation, '0' meaning no websockets.
QEMU introduced command line "-mem-merge=on|off" (defaults to on) to
enable/disable the memory merge (KSM) at guest startup. This exposes
it by new XML:
<memoryBacking>
<nosharepages/>
</memoryBacking>
The XML tag is same with what we used internally for old RHEL.
