Add dump_image_format[] to qemu.conf and support compressed dump
at virsh dump. coredump compression is important for saving disk space
in an environment where multiple guests run.
In general, "disk space for dump" is specially allocated and will be
a dead space in the system. It's used only at emergency. So, it's better
to have both of save_image_format and dump_image_format. "save" is done
in scheduled manner with enough calculated disk space for it.
This code reuses some of save_image_format[] and supports the same format.
Changelog:
- modified libvirtd_qemu.aug
- modified test_libvirtd_qemu.aug
- fixed error handling of qemudSaveCompressionTypeFromString()
When we mount any cgroup without "-o devices", we will fail to start vms:
error: Failed to start domain vm1
error: Unable to deny all devices for vm1: No such file or directory
When we mount any cgroup without "-o cpu", we will fail to get schedinfo:
Scheduler : posix
error: unable to get cpu shares tunable: No such file or directory
We should only use the cgroup controllers which are mounted on host.
So I add virCgroupMounted() for qemuCgroupControllerActive()
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
This partly reverts df90ca7661.
Don't disable the VirtualBox driver when configure can't find
VBoxXPCOMC.so, rely on detection at runtime again instead.
Keep --with-vbox=/path/to/virtualbox intact, added to for:
https://bugzilla.redhat.com/show_bug.cgi?id=609185
Detection order for VBoxXPCOMC.so:
1. VBOX_APP_HOME environment variable
2. configure provided location
3. hardcoded list of known locations
4. dynamic linker search path
Also cleanup the glue code and improve error reporting.
fix warning
CC libvirt_util_la-virtaudit.lo
cc1: warnings being treated as errors
util/virtaudit.c: In function 'virAuditEncode':
util/virtaudit.c:146: error: implicit declaration of function 'virAsprintf' [-Wimplicit-function-declaration]
util/virtaudit.c:146: error: nested extern declaration of 'virAsprintf' [-Wnested-externs]
The 2nd and 3rd hunk show the only double-closed file descriptor code part that I found while trying to clean up close(). The first hunk seems a harmless cleanup in that same file.
https://bugzilla.redhat.com/show_bug.cgi?id=638285 - when migrating
a guest, it was very easy to provoke a race where an application
could query block information on a VM that had just been migrated
away. Any time qemu code obtains a job lock, it must also check
that the VM was not taken down in the time where it was waiting
for the lock.
* src/qemu/qemu_driver.c (qemudDomainSetMemory)
(qemudDomainGetInfo, qemuDomainGetBlockInfo): Check that vm still
exists after obtaining job lock, before starting monitor action.
During virtual network startup, the iptables rule that allows tftp
traffic is only added if network->def->tftproot is non-empty, but when
the virtual network is destroyed, we had been unconditionally trying
to delete the rule. This was harmless, except that it created a bogus
error message.
This patch conditionalizes the delete command in the same manner that
the insert command is already conditionalized.
Commit 9bd3cce0d2 added virFork and
virDriverLoadModule to libvirt_private.syms, but virFork didn't have
a body on Win32 and virDriverLoadModule was already correctly
exported conditional via libvirt_driver_modules.syms.
Add auditing of all initial disk/net assignments to QEMU guests
at startup. Add auditing for all hotplug & unplug events and
disk media changes.
* src/qemu/qemu_driver.c: Add disk/net resource auditing
Add a helper API for ecscaping the value in audit log
messages
* src/util/virtaudit.h, src/util/virtaudit.c,
src/libvirt_private.syms: Add virAuditEncode
Revert most of commit a8b5f9bd27.
The audit hooks will be re-added directly in the QEMU driver code
in a future commit
* daemon/remote.c: Remove all audit logging hooks
* src/qemu/qemu_driver.c: Remove all audit logging hooks
When using 0-prefixed numbers, QEmu will interpret them as octal numbers
(as C convention says); this means that if you attach a device that has
addr > 10 (decimal) you're going to attach a different device.
Older dash mistakenly truncates regular files when using <> redirection;
this kills our use of double dd to reduce storage overhead when
saving qemu images. But qemu insists on running a command through
/bin/sh, so we work around it by having qemu run $sh -c 'real command'
when we have a replacement $sh in mind.
* configure.ac (VIR_WRAPPER_SHELL): Define to a replacement shell,
if /bin/sh is broken on <> redirection.
* src/qemu/qemu_monitor.h (VIR_WRAPPER_SHELL_PREFIX)
(VIR_WRAPPER_SHELL_SUFFIX): New macros.
* src/qemu/qemu_monitor_text.c (qemuMonitorTextMigrateToFile): Use
them.
* src/qemu/qemu_monitor_json.c (qemuMonitorJSONMigrateToFile):
Likewise.
When failing to start a virtual network, we have to cleanup,
tearing down any iptables rules. If the iptables rules were
not present yet though, this raises an error, which squashes
the original error we were handling.
* src/network/bridge_driver.c: When failing to start a virtual
network, don't squash the original error in cleanup
The network address was being set to 192.168.122.0 instead
of 192.168.122.0/24. Fix this by removing the unneccessary
'network' field from virNetworkDef and just pass the
network address and netmask into the iptables APIs directly.
* src/conf/network_conf.h, src/conf/network_conf.c: Remove
the 'network' field from virNEtworkDef.
* src/network/bridge_driver.c: Update for iptables API changes
* src/util/iptables.c, src/util/iptables.h: Require the
network address + netmask pair to be passed in
So far, readonly=on option is used when qemu supports -device. However,
there are qemu versions which support readonly option with -drive
although they don't have support for -device.
The boot server IP address is optional, so it needs to be
checked before attempting to parse it.
* src/conf/network_conf.c: Don't parse NULL ip address for
boot server
Instead of storing the IP address string in virNetwork related
structs, store the parsed virSocketAddr. This will make it
easier to add IPv6 support in the future, by letting driver
code directly check what address family is present
* src/conf/network_conf.c, src/conf/network_conf.h,
src/network/bridge_driver.c: Convert to use virSocketAddr
in virNetwork, instead of char *.
* src/util/bridge.c, src/util/bridge.h,
src/util/dnsmasq.c, src/util/dnsmasq.h,
src/util/iptables.c, src/util/iptables.h: Convert to
take a virSocketAddr instead of char * for any IP
address parameters
* src/util/network.h: Add macros to determine if an address
is set, and what address family is set.
It is useful to know where the client is connecting from,
so include the socket address in probe data.
* daemon/libvirtd.h: Use virSocketAddr for storing client
address and keep printable address handy for logging
* daemon/libvirtd.c: Include socket address in client
connect/disconnect probes
* daemon/probes.d: Add socket address to probes
* examples/systemtap/client.stp: Print socket address
* src/util/network.h: Add sockaddr_un to virSocketAddr union
The inet_pton and inet_ntop functions are obsolete, replaced
by getaddrinfo+getnameinfo with the AI_NUMERICHOST flag set.
These can be accessed via the virSocket APIs.
The bridge.c code had methods for fetching the IP address of
a bridge which used inet_ntop. Aside from the use of inet_ntop
these methods are broken, because a NIC can have multiple
addresses and this only returns one address. Since the methods
are never used, just remove them.
* src/conf/network_conf.c, src/nwfilter/nwfilter_learnipaddr.c:
Replace inet_pton and inet_ntop with virSocket APIs
* src/util/bridge.c, src/util/bridge.h: Remove unused methods
which called inet_ntop.
The addrToString functionality is now available via the
virSocketFormatAddrFull method.
* daemon/remote.c, src/remote/remote_driver.c: Remove
addrToString methods
The virSocketParse method was not doing any error reporting
which meant the true cause of the problem was lost. Remove
all error reporting from callers, and push it into virSocketParse
* src/util/network.c: Add error reporting to virSocketParse
* src/conf/domain_conf.c, src/conf/network_conf.c,
src/network/bridge_driver.c: Remove error reporting in
callers of virSocketParse
The getnameinfo() function is more flexible than inet_ntop()
avoiding the need to if/else the code based on socket family.
Also make it support UNIX socket addrs and allow inclusion
of a port (service) address. Finally do proper error reporting
via normal APIs.
* src/conf/domain_conf.c, src/nwfilter/nwfilter_ebiptables_driver.c,
src/qemu/qemu_conf.c: Fix error handling with virSocketFormat
* src/util/network.c: Rewrite virSocketFormat to use getnameinfo
and cope with UNIX socket addrs.
The nwIPAddress was simply a wrapper about virSocketAddr.
Just use the latter directly, removing all the extra field
de-references from code & helper APIs for parsing/formatting.
Also remove all the redundant casts from strong types to
void * and then immediately back to strong types.
* src/conf/nwfilter_conf.h: Remove nwIPAddress
* src/conf/nwfilter_conf.c, src/nwfilter/nwfilter_ebiptables_driver.c:
Update to use virSocketAddr and remove void * casts.
There was a typo in the IPv6 path of virSocketCheckNetmask which
caused it to never execute.
* src/util/network.c: s/AF_INET/AF_INET6/ in virSocketCheckNetmask
The virSocketParseAddr function was accepting any AF_* constant
and using that to set the ai_flags field in struct addrinfo.
This is invalid, since address families must go in the ai_family
field of the struct.
* src/util/network.c: Fix handling of address family
* src/conf/network_conf.c, src/network/bridge_driver.c: Pass
AF_UNSPEC instead of relying on it being 0.
Some operations on socket addresses need to know the length of
the sockaddr struct for the particular address family. This
info was being discarded when passing around virSocketAddr
instances. Turn it from a union into a struct containing
union+socklen_t fields, so length is always kept around.
* src/util/network.h: Add socklen_t field to virSocketAddr
* src/util/network.c, src/network/bridge_driver.c,
src/conf/domain_conf.c: Update to take account of new
struct definition.
If getnameinfo() with NI_NUMERICHOST set fails, there are no
grounds to expect inet_ntop to succeed, since these calls
are functionally equivalent. Remove useless inet_ntop code
in the getnameinfo() error path.
* daemon/remote.c, src/remote/remote_driver.c: Remove
calls to inet_ntop
* src/libvirt_private.syms: Sort by header name, then within
header, and drop duplicate virNetworkDefParseNode,
virFileLinkPointsTo and virXPathBoolean.
The QEMU 0.13 release is finally out and from testing in RHEL-6
we know that its JSON and netdev features are now good enough
for us to use by default.
* src/qemu/qemu_conf.c: Enable JSON + netdev for QEMU >= 0.13
There is no point in trying to fill params beyond the first error,
because when qemuDomainGetMemoryParameters returns -1 then the caller
cannot detect which values in params are valid.
This sets the process name to the same value as the Windows title,
but since the name is limited to 16 chars only this is kept as a
configuration option and turned off by default
* src/qemu/qemu.conf src/qemu/qemu_conf.[ch]: hceck for support in the
QEmu help output, add the option in qemu conf file and augment
qemudBuildCommandLine to add it if switched on
* src/qemu/libvirtd_qemu.aug src/qemu/test_libvirtd_qemu.aug: augment
the augeas lenses accordingly
* tests/qemuhelptest.c: cope with the extra flag being detected now
The libvirt_util.la library was mistakenly linked into libvirtd
directly. Since libvirt_util.la is already linked to libvirt.so,
this resulted in libvirtd getting two copies of the code and
more critically 2 copies of static global variables.
Testing in turn exposed a issue with loadable modules. The
gnulib replacement functions are not exported to loadable
modules. Rather than trying to figure out the name sof all
gnulib functions & export them, just linkage all loadable
modules against libgnu.la statically.
* daemon/Makefile.am: Remove linkage of libvirt_util.la
and libvirt_driver.la
* src/Makefile.am: Link driver modules against libgnu.la
* src/libvirt.c: Don't try to load modules which were
compiled out
* src/libvirt_private.syms: Export all other internal
symbols that are required by drivers
A more natural auditing point would perhaps be
SELinuxSetSecurityProcessLabel, but this happens in the child after root
permissions are dropped, so the kernel would refuse the audit record.
Most operations are audited at the libvirtd level; auditing in
src/libvirt.c would result in two audit entries per operation (one in
the client, one in libvirtd).
The only exception is a domain stopping of its own will (e.g. because
the user clicks on "shutdown" inside the interface). There can often be
no client connected at the time the domain stops, so libvirtd does not
have any virConnectPtr object on which to attach an event watch. This
patch therefore adds auditing directly inside the qemu driver (other
drivers are not supported).
Integrate with libaudit.so for auditing of important operations.
libvirtd gains a couple of config entries for auditing. By
default it will enable auditing, if its enabled on the host.
It can be configured to force exit if auditing is disabled
on the host. It will can also send audit messages via libvirt
internal logging API
Places requiring audit reporting can use the VIR_AUDIT
macro to report data. This is a no-op unless auditing is
enabled
* autobuild.sh, mingw32-libvirt.spec.in: Disable audit
on mingw
* configure.ac: Add check for libaudit
* daemon/libvirtd.aug, daemon/libvirtd.conf,
daemon/test_libvirtd.aug, daemon/libvirtd.c: Add config
options to enable auditing
* include/libvirt/virterror.h, src/util/virterror.c: Add
VIR_FROM_AUDIT source
* libvirt.spec.in: Enable audit
* src/util/virtaudit.h, src/util/virtaudit.c: Simple internal
API for auditing messages
This patch series focuses on xendConfigVersion 2 (xm_internal) and 3
(xend_internal), but leaves out changes for xenapi drivers.
See this link for more details about vcpu_avail for xm usage.
http://lists.xensource.com/archives/html/xen-devel/2009-11/msg01061.html
This relies on the fact that def->maxvcpus can be at most 32 with xen.
* src/xen/xend_internal.c (xenDaemonParseSxpr)
(sexpr_to_xend_domain_info, xenDaemonFormatSxpr): Use vcpu_avail
when current vcpus is less than maximum.
* src/xen/xm_internal.c (xenXMDomainConfigParse)
(xenXMDomainConfigFormat): Likewise.
* tests/xml2sexprdata/xml2sexpr-pv-vcpus.sexpr: New file.
* tests/sexpr2xmldata/sexpr2xml-pv-vcpus.sexpr: Likewise.
* tests/sexpr2xmldata/sexpr2xml-pv-vcpus.xml: Likewise.
* tests/xmconfigdata/test-paravirt-vcpu.cfg: Likewise.
* tests/xmconfigdata/test-paravirt-vcpu.xml: Likewise.
* tests/xml2sexprtest.c (mymain): New test.
* tests/sexpr2xmltest.c (mymain): Likewise.
* tests/xmconfigtest.c (mymain): Likewise.
* src/qemu/qemu_conf.c (qemuParseCommandLineSmp): Distinguish
between vcpus and maxvcpus, for new enough qemu.
* tests/qemuargv2xmltest.c (mymain): Add new test.
* tests/qemuxml2argvtest.c (mymain): Likewise.
* tests/qemuxml2xmltest.c (mymain): Likewise.
* tests/qemuxml2argvdata/qemuxml2argv-smp.args: New file.
Although this patch adds a distinction between maximum vcpus and
current vcpus in the XML, the values should be identical for all
drivers at this point. Only in subsequent per-driver patches will
a distinction be made.
In general, virDomainGetInfo should prefer the current vcpus.
* src/conf/domain_conf.h (_virDomainDef): Adjust vcpus to unsigned
short, to match virDomainGetInfo limit. Add maxvcpus member.
* src/conf/domain_conf.c (virDomainDefParseXML)
(virDomainDefFormat): parse and print out vcpu details.
* src/xen/xend_internal.c (xenDaemonParseSxpr)
(xenDaemonFormatSxpr): Manage both vcpu numbers, and require them
to be equal for now.
* src/xen/xm_internal.c (xenXMDomainConfigParse)
(xenXMDomainConfigFormat): Likewise.
* src/phyp/phyp_driver.c (phypDomainDumpXML): Likewise.
* src/openvz/openvz_conf.c (openvzLoadDomains): Likewise.
* src/openvz/openvz_driver.c (openvzDomainDefineXML)
(openvzDomainCreateXML, openvzDomainSetVcpusInternal): Likewise.
* src/vbox/vbox_tmpl.c (vboxDomainDumpXML, vboxDomainDefineXML):
Likewise.
* src/xenapi/xenapi_driver.c (xenapiDomainDumpXML): Likewise.
* src/xenapi/xenapi_utils.c (createVMRecordFromXml): Likewise.
* src/esx/esx_vmx.c (esxVMX_ParseConfig, esxVMX_FormatConfig):
Likewise.
* src/qemu/qemu_conf.c (qemuBuildSmpArgStr)
(qemuParseCommandLineSmp, qemuParseCommandLine): Likewise.
* src/qemu/qemu_driver.c (qemudDomainHotplugVcpus): Likewise.
* src/opennebula/one_conf.c (xmlOneTemplate): Likewise.
Note - this wrapping is completely mechanical; the old API will
function identically, since the new API validates that the exact
same flags are provided by the old API. On a per-driver basis,
it may make sense to have the old API pass a different set of flags,
but that should be done in the per-driver patch that implements
the full range of flag support in the new API.
* src/esx/esx_driver.c (esxDomainSetVcpus, escDomainGetMaxVpcus):
Move guts...
(esxDomainSetVcpusFlags, esxDomainGetVcpusFlags): ...to new
functions.
(esxDriver): Trivially support the new API.
* src/openvz/openvz_driver.c (openvzDomainSetVcpus)
(openvzDomainSetVcpusFlags, openvzDomainGetMaxVcpus)
(openvzDomainGetVcpusFlags, openvzDriver): Likewise.
* src/phyp/phyp_driver.c (phypDomainSetCPU)
(phypDomainSetVcpusFlags, phypGetLparCPUMAX)
(phypDomainGetVcpusFlags, phypDriver): Likewise.
* src/qemu/qemu_driver.c (qemudDomainSetVcpus)
(qemudDomainSetVcpusFlags, qemudDomainGetMaxVcpus)
(qemudDomainGetVcpusFlags, qemuDriver): Likewise.
* src/test/test_driver.c (testSetVcpus, testDomainSetVcpusFlags)
(testDomainGetMaxVcpus, testDomainGetVcpusFlags, testDriver):
Likewise.
* src/vbox/vbox_tmpl.c (vboxDomainSetVcpus)
(vboxDomainSetVcpusFlags, virDomainGetMaxVcpus)
(virDomainGetVcpusFlags, virDriver): Likewise.
* src/xen/xen_driver.c (xenUnifiedDomainSetVcpus)
(xenUnifiedDomainSetVcpusFlags, xenUnifiedDomainGetMaxVcpus)
(xenUnifiedDomainGetVcpusFlags, xenUnifiedDriver): Likewise.
* src/xenapi/xenapi_driver.c (xenapiDomainSetVcpus)
(xenapiDomainSetVcpusFlags, xenapiDomainGetMaxVcpus)
(xenapiDomainGetVcpusFlags, xenapiDriver): Likewise.
(xenapiError): New helper macro.
Factors common checks (such as nonzero vcpu count) up front, but
drivers will still need to do additional flag checks.
* src/libvirt.c (virDomainSetVcpusFlags, virDomainGetVcpusFlags):
New functions.
(virDomainSetVcpus, virDomainGetMaxVcpus): Refer to new API.
API agreed on in
https://www.redhat.com/archives/libvir-list/2010-September/msg00456.html,
but modified for enum names to be consistent with virDomainDeviceModifyFlags.
* include/libvirt/libvirt.h.in (virDomainVcpuFlags)
(virDomainSetVcpusFlags, virDomainGetVcpusFlags): New
declarations.
* src/libvirt_public.syms: Export new symbols.
In the table built for traffic coming from the VM going to the host make the following changes:
- don't ACCEPT the packets but do a 'RETURN' and let the host-specific firewall rules in subsequent rules evaluate whether the traffic is allowed to enter
- use the '-m state' in the rules as everywhere else
ESX(i) uses UTF-8, but a Windows based GSX server writes
Windows-1252 encoded VMX files.
Add a test case to ensure that libxml2 provides Windows-1252
to UTF-8 conversion.
Since bugs due to double-closed file descriptors are difficult to track down in a multi-threaded system, I am introducing the VIR_CLOSE(fd) macro to help avoid mistakes here.
There are lots of places where close() is being used. In this patch I am only cleaning up usage of close() in src/conf where the problems were.
I also dare to declare close() as being deprecated in libvirt code base (HACKING).
Over root-squashing nfs, when virFileOperation() is called as uid==0,
it may fail with EACCES, but also with EPERM, due to
virFileOperationNoFork()'s failed attemp to chown a writable file.
qemudDomainSaveFlag() should expect this case, too.
qemudOpenAsUID is intended to open a file with the credentials of a
specified uid. Current implementation fails if the file is accessible to
one of uid's groups but not owned by uid.
This patch replaces the supplementary group list that the child process
inherited from libvirtd with the default group list of uid.
* docs/formatdomain.html.in: Add memtune element details, added min_guarantee
* src/libvirt.c: Update virDomainGetMemoryParameters api description, make
it more clear that the user first needs to call the api to get the number
of parameters supported and then call again to get the values.
* tools/virsh.pod: Add usage of new command memtune in virsh manpage
This introduces new attribute to filesystem element
to support customizable access mode for mount type.
Valid accessmode are: passthrough, mapped and squash.
Usage:
<filesystem type='mount' accessmode='passthrough'>
<source dir='/export/to/guest'/>
<target dir='mount_tag'/>
</filesystem>
passthrough is the default model if not specified, that's
also the current behaviour.
The following filter transition from a filter allowing incoming TCP connections
<rule action='accept' direction='in' priority='401'>
<tcp/>
</rule>
<rule action='accept' direction='out' priority='500'>
<tcp/>
</rule>
to one that does not allow them
<rule action='drop' direction='in' priority='401'>
<tcp/>
</rule>
<rule action='accept' direction='out' priority='500'>
<tcp/>
</rule>
did previously not cut off existing (ssh) connections but only prevented newly initiated ones. The attached patch allows to cut off existing connections as well, thus enforcing what the filter is showing.
I had only tested with a configuration where the physical interface is connected to the bridge where the filters are applied. This patch now also solves a filtering problem where the physical interface is not connected to the bridge, but the bridge is given an IP address and the host routes between bridge and physical interface. Here the filters drop non-allowed traffic on the outgoing side on the host.
Explicitly raising a nice error in the case user tries to migrate a
guest with assigned host devices is much better than waiting for a
mysterious error with no clue for the reason.
When only some host CPUs given to cpuBaseline contain <vendor> element,
baseline CPU should not contain it. Otherwise the result would not be
compatible with the host CPUs without vendor. CPU vendors are still
taken into account when computing baseline CPU, it's just removed from
the result.
Recent CPU models were specified using invalid vendor element
<vendor>NAME</vendor>, which was silently ignored due to a bug in the
code which was parsing it.
'make -C src rpcgen' is supposed to be idempotent. But commit
f928f43b7b mistakently manually edited a generated file rather
than fixing the upstream file.
* src/remote/remote_protocol.x (remote_memory_param_value): Use
correct spelling of enum values.
* src/remote/remote_protocol.c: Regenerate.
This enables support for nested SVM using the regular CPU
model/features block. If the CPU model or features include
'svm', then the '-enable-nesting' flag will be added to the
QEMU command line. Latest out of tree patches for nested
'vmx', no longer require the '-enable-nesting' flag. They
instead just look at the cpu features. Several of the models
already include svm support, but QEMU was just masking out
the svm bit silently. So this will enable SVM on such
models
* src/qemu/qemu_conf.h: flag for -enable-nesting
* src/qemu/qemu_conf.c: Use -enable-nesting if VMX or SVM are in
the CPUID
* src/cpu/cpu.h, src/cpu/cpu.c: API to check for a named feature
* src/cpu/cpu_x86.c: x86 impl of feature check
* src/libvirt_private.syms: Add cpuHasFeature
* src/qemuhelptest.c: Add nesting flag where required
* src/xen/sexpr.c: Ensure () are escaped in sexpr2string
* tests/sexpr2xmldata/sexpr2xml-boot-grub.sexpr,
tests/sexpr2xmldata/sexpr2xml-boot-grub.xml,
tests/xml2sexprdata/xml2sexpr-boot-grub.sexpr,
tests/xml2sexprdata/xml2sexpr-boot-grub.xml: Data files to
check escaping
* tests/sexpr2xmltest.c, tests/xml2sexprtest.c: Add boot-grub
escaping test case
This is from a bug report and conversation on IRC where Soren reported that while a filter update is occurring on one or more VMs (due to a rule having been edited for example), a deadlock can occur when a VM referencing a filter is started.
The problem is caused by the two locking sequences of
qemu driver, qemu domain, filter # for the VM start operation
filter, qemu_driver, qemu_domain # for the filter update operation
that obviously don't lock in the same order. The problem is the 2nd lock sequence. Here the qemu_driver lock is being grabbed in qemu_driver:qemudVMFilterRebuild()
The following solution is based on the idea of trying to re-arrange the 2nd sequence of locks as follows:
qemu_driver, filter, qemu_driver, qemu_domain
and making the qemu driver recursively lockable so that a second lock can occur, this would then lead to the following net-locking sequence
qemu_driver, filter, qemu_domain
where the 2nd qemu_driver lock has been ( logically ) eliminated.
The 2nd part of the idea is that the sequence of locks (filter, qemu_domain) and (qemu_domain, filter) becomes interchangeable if all code paths where filter AND qemu_domain are locked have a preceding qemu_domain lock that basically blocks their concurrent execution
So, the following code paths exist towards qemu_driver:qemudVMFilterRebuild where we now want to put a qemu_driver lock in front of the filter lock.
-> nwfilterUndefine() [ locks the filter ]
-> virNWFilterTestUnassignDef()
-> virNWFilterTriggerVMFilterRebuild()
-> qemudVMFilterRebuild()
-> nwfilterDefine()
-> virNWFilterPoolAssignDef() [ locks the filter ]
-> virNWFilterTriggerVMFilterRebuild()
-> qemudVMFilterRebuild()
-> nwfilterDriverReload()
-> virNWFilterPoolLoadAllConfigs()
->virNWFilterPoolObjLoad()
-> virNWFilterPoolAssignDef() [ locks the filter ]
-> virNWFilterTriggerVMFilterRebuild()
-> qemudVMFilterRebuild()
-> nwfilterDriverStartup()
-> virNWFilterPoolLoadAllConfigs()
->virNWFilterPoolObjLoad()
-> virNWFilterPoolAssignDef() [ locks the filter ]
-> virNWFilterTriggerVMFilterRebuild()
-> qemudVMFilterRebuild()
Qemu is not the only driver using the nwfilter driver, but also the UML driver calls into it. Therefore qemuVMFilterRebuild() can be exchanged with umlVMFilterRebuild() along with the driver lock of qemu_driver that can now be a uml_driver. Further, since UML and Qemu domains can be running on the same machine, the triggering of a rebuild of the filter can touch both types of drivers and their domains.
In the patch below I am now extending each nwfilter callback driver with functions for locking and unlocking the (VM) driver (UML, QEMU) and introduce new functions for locking all registered callback drivers and unlocking them. Then I am distributing the lock-all-cbdrivers/unlock-all-cbdrivers call into the above call paths. The last shown callpath starting with nwfilterDriverStart() is problematic since it is initialize before the Qemu and UML drives are and thus a lock in the path would result in a NULL pointer attempted to be locked -- the call to virNWFilterTriggerVMFilterRebuild() is never called, so we never lock either the qemu_driver or the uml_driver in that path. Therefore, only the first 3 paths now receive calls to lock and unlock all callback drivers. Now that the locks are distributed where it matters I can remove the qemu_driver and uml_driver lock from qemudVMFilterRebuild() and umlVMFilterRebuild() and not requiring the recursive locks.
For now I want to put this out as an RFC patch. I have tested it by 'stretching' the critical section after the define/undefine functions each lock the filter so I can (easily) concurrently execute another VM operation (suspend,start). That code is in this patch and if you want you can de-activate it. It seems to work ok and operations are being blocked while the update is being done.
I still also want to verify the other assumption above that locking filter and qemu_domain always has a preceding qemu_driver lock.
* include/libvirt/libvirt.h.in: some of the function type description
were broken so they could not be automatically documented
* src/util/event.c docs/apibuild.py: event.c exports one public API
so it needs to be scanned too, avoid a few warnings
Make use of the existing <filesystem> element to support plan9fs
filesystem passthrough in the QEMU driver
<filesystem type='mount'>
<source dir='/export/to/guest'/>
<target dir='/import/from/host'/>
</filesystem>
NB, the target is not actually a directory, it is merely a arbitrary
string tag that is exported to the guest as a hint for where to mount
it.
Add proper documentation to the new VIR_DOMAIN_MEMORY_* macros in
libvirt.h.in to placate apibuild.py.
Mark args as unused in for libvirt_virDomain{Get,Set}MemoryParameters
in the Python bindings and add both to the libvirtMethods array.
Update remote_protocol-structs to placate make syntax-check.
Undo unintended modifications in vboxDomainGetInfo.
Update the function table of the VirtualBox and XenAPI drivers.
Adding parsing code for memory tunables in the domain xml file
also change the internal define structures used for domain memory
informations
Adds a new specific test
Public api to set/get memory tunables supported by the hypervisors.
dv:
* some cleanups in libvirt.c
* adding extra checks in libvirt.c new entry points
v4:
* Move exporting public API to this patch
* Add unsigned int flags to the public api for future extensions
v3:
* Add domainGetMemoryParamters and NULL in all the driver interface
v2:
* Initialize domainSetMemoryParameters to NULL in all the driver
interface structure.
Some features provided by the recently added CPU models were mentioned
twice for each model. This was a result of automatic generation of the
XML from qemu's CPU configuration file without noticing this redundancy.
