April 2010 - Devel - libvirt List Archives

[libvirt] [PATCH] Fix python error reporting for some storage operations
by Cole Robinson 07 Mar '25

07 Mar '25

In the python bindings, all vir* classes expect to be passed a virConnect object when instantiated. Before the storage stuff, these classes were only instantiated in virConnect methods, so the generator is hardcoded to pass 'self' as the connection instance to these classes. Problem is there are some methods that return pool or vol instances which aren't called from virConnect: you can lookup a storage volume's associated pool, and can lookup volumes from a pool. In these cases passing 'self' doesn't give the vir* instance a connection, so when it comes time to raise an exception crap hits the fan. Rather than rework the generator to accomodate this edge case, I just fixed the init functions for virStorage* to pull the associated connection out of the passed value if it's not a virConnect instance. Thanks, Cole diff --git a/python/generator.py b/python/generator.py index 01a17da..c706b19 100755 --- a/python/generator.py +++ b/python/generator.py @@ -962,8 +962,12 @@ def buildWrappers(): list = reference_keepers[classname] for ref in list: classes.write(" self.%s = None\n" % ref[1]) - if classname in [ "virDomain", "virNetwork", "virStoragePool", "virStorageVol" ]: + if classname in [ "virDomain", "virNetwork" ]: classes.write(" self._conn = conn\n") + elif classname in [ "virStorageVol", "virStoragePool" ]: + classes.write(" self._conn = conn\n" + \ + " if not isinstance(conn, virConnect):\n" + \ + " self._conn = conn._conn\n") classes.write(" if _obj != None:self._o = _obj;return\n") classes.write(" self._o = None\n\n"); destruct=None

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[libvirt] [PATCH] web docs -- macvtap mode explanation
by Stefan Berger 26 Oct '23

26 Oct '23

This adds more information about the different macvtap device modes. Regards, Stefan

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[libvirt] Supporting vhost-net and macvtap in libvirt for QEMU
by Anthony Liguori 26 Oct '23

26 Oct '23

Disclaimer: I am neither an SR-IOV nor a vhost-net expert, but I've CC'd people that are who can throw tomatoes at me for getting bits wrong :-) I wanted to start a discussion about supporting vhost-net in libvirt. vhost-net has not yet been merged into qemu but I expect it will be soon so it's a good time to start this discussion. There are two modes worth supporting for vhost-net in libvirt. The first mode is where vhost-net backs to a tun/tap device. This is behaves in very much the same way that -net tap behaves in qemu today. Basically, the difference is that the virtio backend is in the kernel instead of in qemu so there should be some performance improvement. Current, libvirt invokes qemu with -net tap,fd=X where X is an already open fd to a tun/tap device. I suspect that after we merge vhost-net, libvirt could support vhost-net in this mode by just doing -net vhost,fd=X. I think the only real question for libvirt is whether to provide a user visible switch to use vhost or to just always use vhost when it's available and it makes sense. Personally, I think the later makes sense. The more interesting invocation of vhost-net though is one where the vhost-net device backs directly to a physical network card. In this mode, vhost should get considerably better performance than the current implementation. I don't know the syntax yet, but I think it's reasonable to assume that it will look something like -net tap,dev=eth0. The effect will be that eth0 is dedicated to the guest. On most modern systems, there is a small number of network devices so this model is not all that useful except when dealing with SR-IOV adapters. In that case, each physical device can be exposed as many virtual devices (VFs). There are a few restrictions here though. The biggest is that currently, you can only change the number of VFs by reloading a kernel module so it's really a parameter that must be set at startup time. I think there are a few ways libvirt could support vhost-net in this second mode. The simplest would be to introduce a new tag similar to <source network='br0'>. In fact, if you probed the device type for the network parameter, you could probably do something like <source network='eth0'> and have it Just Work. Another model would be to have libvirt see an SR-IOV adapter as a network pool whereas it handled all of the VF management. Considering how inflexible SR-IOV is today, I'm not sure whether this is the best model. Has anyone put any more thought into this problem or how this should be modeled in libvirt? Michael, could you share your current thinking for -net syntax? -- Regards, Anthony Liguori

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[libvirt] [PATCH 0/4] Multiple problems with saving to block devices
by Daniel P. Berrange 23 Mar '13

23 Mar '13

This patch series makes it possible to save to a block device, instead of a plain file. There were multiple problems - WHen save failed, we might de-reference a NULL pointer - When save failed, we unlinked the device node !! - The approach of using >> to append, doesn't work with block devices - CGroups was blocking QEMU access to the block device when enabled One remaining problem is not in libvirt, but rather QEMU. The QEMU exec: based migration often fails to detect failure of the command and will thus hang forever attempting a migration that'll never succeed! Fortunately you can now work around this in libvirt using the virsh domjobabort command

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[libvirt] website: API reference for virterror contains libvirt API also
by Matthias Bolte 17 Jan '11

17 Jan '11

The API reference website [1] for virterror contains the API reference for virterror as expected. But the complete libvirt API reference, that is already found at [2], is appended too. I looked into the XSLT process that generates those two HTML files from the libvirt-api.xml to understand why this happens, but I couldn't locate the problem. [1] http://www.libvirt.org/html/libvirt-virterror.html [2] http://www.libvirt.org/html/libvirt-libvirt.html Matthias

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[libvirt] [PATCH v2] Support for qemu aio drive option
by Matthias Dahl 04 Jan '11

04 Jan '11

Revised patch against libvirt 0.7.6 to support qemu's aio option. qemu allows the user to choose what io storage api should be used, either the default (threads) or native (linux aio) which in the latter case can result in better performance. This patch exposes this functionality through libvirt. Thanks a lot to Eric Blake and Matthias Bolte for their comments. --- docs/formatdomain.html.in | 4 +++- docs/schemas/domain.rng | 13 +++++++++++-- src/conf/domain_conf.c | 23 +++++++++++++++++++++++ src/conf/domain_conf.h | 10 ++++++++++ src/qemu/qemu_conf.c | 14 ++++++++++++++ src/qemu/qemu_conf.h | 2 ++ 6 files changed, 63 insertions(+), 3 deletions(-) diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in index ce49f7d..ec85ef3 100644 --- a/docs/formatdomain.html.in +++ b/docs/formatdomain.html.in @@ -478,7 +478,9 @@ attribute is the primary backend driver name, while the optional <code>type</code> attribute provides the sub-type. The optional <code>cache</code> attribute controls the cache mechanism, possible values are "default", "none", - "writethrough" and "writeback". Since 0.1.8 + "writethrough" and "writeback". Specific to KVM guests is the optional <code>aio</code> + attribute which controls what storage api is used for io operations, its possible + values are "threads" and "native". Since 0.1.8; "aio" attribute since 0.7.7 </dd> <dt><code>encryption</code></dt> <dd>If present, specifies how the volume is encrypted. See diff --git a/docs/schemas/domain.rng b/docs/schemas/domain.rng index bb6d00d..5d2dafe 100644 --- a/docs/schemas/domain.rng +++ b/docs/schemas/domain.rng @@ -499,8 +499,9 @@ <ref name="driverCache"/> </group> </choice> - <empty/> - </element> + <optional> + <ref name="driverAIO"/> + </optional> </define> <define name="driverFormat"> <attribute name="name"> @@ -521,6 +522,14 @@ </choice> </attribute> </define> + <define name="driverAIO"> + <attribute name="aio"> + <choice> + <value>threads</value> + <value>native</value> + </choice> + </attribute> + </define> <define name="controller"> <element name="controller"> <optional> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 766993c..8bee7b8 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -120,6 +120,11 @@ VIR_ENUM_IMPL(virDomainDiskCache, VIR_DOMAIN_DISK_CACHE_LAST, "writethrough", "writeback") +VIR_ENUM_IMPL(virDomainDiskAIO, VIR_DOMAIN_DISK_AIO_LAST, + "default", + "native", + "threads") + VIR_ENUM_IMPL(virDomainController, VIR_DOMAIN_CONTROLLER_TYPE_LAST, "ide", "fdc", @@ -1228,6 +1233,7 @@ virDomainDiskDefParseXML(virConnectPtr conn, char *target = NULL; char *bus = NULL; char *cachetag = NULL; + char *aiotag = NULL; char *devaddr = NULL; virStorageEncryptionPtr encryption = NULL; char *serial = NULL; @@ -1293,6 +1299,7 @@ virDomainDiskDefParseXML(virConnectPtr conn, driverName = virXMLPropString(cur, "name"); driverType = virXMLPropString(cur, "type"); cachetag = virXMLPropString(cur, "cache"); + aiotag = virXMLPropString(cur, "aio"); } else if (xmlStrEqual(cur->name, BAD_CAST "readonly")) { def->readonly = 1; } else if (xmlStrEqual(cur->name, BAD_CAST "shareable")) { @@ -1409,6 +1416,13 @@ virDomainDiskDefParseXML(virConnectPtr conn, goto error; } + if (aiotag && + (def->aiomode = virDomainDiskAIOTypeFromString(aiotag)) < 0) { + virDomainReportError(conn, VIR_ERR_INTERNAL_ERROR, + _("unknown disk aio mode '%s'"), aiotag); + goto error; + } + if (devaddr) { if (sscanf(devaddr, "%x:%x:%x", &def->info.addr.pci.domain, @@ -1450,6 +1464,7 @@ cleanup: VIR_FREE(driverType); VIR_FREE(driverName); VIR_FREE(cachetag); + VIR_FREE(aiotag); VIR_FREE(devaddr); VIR_FREE(serial); virStorageEncryptionFree(encryption); @@ -4565,6 +4580,7 @@ virDomainDiskDefFormat(virConnectPtr conn, const char *device = virDomainDiskDeviceTypeToString(def->device); const char *bus = virDomainDiskBusTypeToString(def->bus); const char *cachemode = virDomainDiskCacheTypeToString(def->cachemode); + const char *aiomode = virDomainDiskAIOTypeToString(def->aiomode); if (!type) { virDomainReportError(conn, VIR_ERR_INTERNAL_ERROR, @@ -4586,6 +4602,11 @@ virDomainDiskDefFormat(virConnectPtr conn, _("unexpected disk cache mode %d"), def->cachemode); return -1; } + if (!aiomode) { + virDomainReportError(conn, VIR_ERR_INTERNAL_ERROR, + _("unexpected disk aio mode %d"), def->aiomode); + return -1; + } virBufferVSprintf(buf, " <disk type='%s' device='%s'>\n", @@ -4597,6 +4618,8 @@ virDomainDiskDefFormat(virConnectPtr conn, virBufferVSprintf(buf, " type='%s'", def->driverType); if (def->cachemode) virBufferVSprintf(buf, " cache='%s'", cachemode); + if (def->aiomode) + virBufferVSprintf(buf, " aio='%s'", aiomode); virBufferVSprintf(buf, "/>\n"); } diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h index 0b79e88..07805a6 100644 --- a/src/conf/domain_conf.h +++ b/src/conf/domain_conf.h @@ -141,6 +141,14 @@ enum virDomainDiskCache { VIR_DOMAIN_DISK_CACHE_LAST }; +enum virDomainDiskAIO { + VIR_DOMAIN_DISK_AIO_DEFAULT, + VIR_DOMAIN_DISK_AIO_NATIVE, + VIR_DOMAIN_DISK_AIO_THREADS, + + VIR_DOMAIN_DISK_AIO_LAST +}; + /* Stores the virtual disk configuration */ typedef struct _virDomainDiskDef virDomainDiskDef; typedef virDomainDiskDef *virDomainDiskDefPtr; @@ -154,6 +162,7 @@ struct _virDomainDiskDef { char *driverType; char *serial; int cachemode; + int aiomode; unsigned int readonly : 1; unsigned int shared : 1; virDomainDeviceInfo info; @@ -897,6 +906,7 @@ VIR_ENUM_DECL(virDomainDisk) VIR_ENUM_DECL(virDomainDiskDevice) VIR_ENUM_DECL(virDomainDiskBus) VIR_ENUM_DECL(virDomainDiskCache) +VIR_ENUM_DECL(virDomainDiskAIO) VIR_ENUM_DECL(virDomainController) VIR_ENUM_DECL(virDomainFS) VIR_ENUM_DECL(virDomainNet) diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c index 3d83a8f..fd3a670 100644 --- a/src/qemu/qemu_conf.c +++ b/src/qemu/qemu_conf.c @@ -83,6 +83,12 @@ VIR_ENUM_IMPL(qemuDiskCacheV2, VIR_DOMAIN_DISK_CACHE_LAST, "writethrough", "writeback"); +VIR_ENUM_DECL(qemuDiskAIO) +VIR_ENUM_IMPL(qemuDiskAIO, VIR_DOMAIN_DISK_AIO_LAST, + "default", + "native", + "threads"); + VIR_ENUM_DECL(qemuVideo) VIR_ENUM_IMPL(qemuVideo, VIR_DOMAIN_VIDEO_TYPE_LAST, @@ -1137,6 +1143,8 @@ static unsigned int qemudComputeCmdFlags(const char *help, flags |= QEMUD_CMD_FLAG_DRIVE_CACHE_V2; if (strstr(help, "format=")) flags |= QEMUD_CMD_FLAG_DRIVE_FORMAT; + if (strstr(help, "aio=threads|native")) + flags |= QEMUD_CMD_FLAG_DRIVE_AIO; } if (strstr(help, "-vga") && !strstr(help, "-std-vga")) flags |= QEMUD_CMD_FLAG_VGA; @@ -2340,6 +2348,12 @@ qemuBuildDriveStr(virDomainDiskDefPtr disk, virBufferAddLit(&opt, ",cache=off"); } + if (disk->aiomode && (qemuCmdFlags & QEMUD_CMD_FLAG_DRIVE_AIO)) { + const char * mode = qemuDiskAIOTypeToString(disk->aiomode); + + virBufferVSprintf(&opt, ",aio=%s", mode); + } + if (virBufferError(&opt)) { virReportOOMError(NULL); goto error; diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h index 101f187..780ae6e 100644 --- a/src/qemu/qemu_conf.h +++ b/src/qemu/qemu_conf.h @@ -82,6 +82,8 @@ enum qemud_cmd_flags { QEMUD_CMD_FLAG_SDL = (1 << 27), /* Is the new -sdl arg available */ QEMUD_CMD_FLAG_SMP_TOPOLOGY = (1 << 28), /* Is sockets=s,cores=c,threads=t available for -smp? */ QEMUD_CMD_FLAG_NETDEV = (1 << 29), /* The -netdev flag & netdev_add/remove monitor commands */ + + QEMUD_CMD_FLAG_DRIVE_AIO = (1 << 30), /* Is -drive aio= avail */ }; /* Main driver state */ -- 1.7.0.4

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[libvirt] process= support for 'qemu-kvm -name' [Bug 576950]
by John Morrissey 16 Nov '10

16 Nov '10

I wrote (attached here, and to the bug) a quick patch that sets the process name to the same value as the window title. I'm unsure where to go from here. Should I add support for converting "native" QEMU command lines to libvirt XML? What would that look like, since I'm not modifying the libvirt format? Should it just drop any ,process= from the QEMU command line it's parsing? I also imagine the test cases will need updating. If someone could give me some high-level guidance, I'd be happy to keep going on this. john -- John Morrissey _o /\ ---- __o jwm(a)horde.net _-< \_ / \ ---- < \, www.horde.net/ __(_)/_(_)________/ \_______(_) /_(_)__

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[libvirt] inability to open local read-only connection
by Tavares, John 20 Aug '10

20 Aug '10

I have been experimenting with using libvirt (0.3.3) on a variety of systems (RHEL, CentOS and Oracle VM). I have run into an issue when I try to open a local read-only connection to the hypervisor that is failing only on Oracle VM server release 2.2.0. I have created a root owned setuid executable that is effectively running as root, but even so, still cannot open the local read-only connection of the hypervisor. It only works if I run it directly as root. This is not an option. I do not understand why it works as is on my RHEL and CentOS machines, but not my Oracle machine. It would seem as thought it is not checking if the effective uid is root, just the uid. Has anyone run into a similar issue or have any suggestions of what I might try to fix this issue or can tell me that this is a defect that needs (is) fixed?? Thanks.

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Re: [libvirt] Documentation for synchronous hooks
by Jintao Yang 02 Jul '10

02 Jul '10

hi DV, I saw the changelog of 0.7.8, which told the hooks scripts are supported. but is it took away in 0.8.0-4? [root@dhcp-66-70 libvirt]# rpm -ql libvirt | grep etc /etc/libvirt /etc/libvirt/libvirtd.conf /etc/libvirt/lxc.conf /etc/libvirt/nwfilter /etc/libvirt/nwfilter/allow-arp.xml /etc/libvirt/nwfilter/allow-dhcp-server.xml /etc/libvirt/nwfilter/allow-dhcp.xml /etc/libvirt/nwfilter/allow-incoming-ipv4.xml /etc/libvirt/nwfilter/allow-ipv4.xml /etc/libvirt/nwfilter/clean-traffic.xml /etc/libvirt/nwfilter/no-arp-spoofing.xml /etc/libvirt/nwfilter/no-ip-multicast.xml /etc/libvirt/nwfilter/no-ip-spoofing.xml /etc/libvirt/nwfilter/no-mac-broadcast.xml /etc/libvirt/nwfilter/no-mac-spoofing.xml /etc/libvirt/nwfilter/no-other-l2-traffic.xml /etc/libvirt/qemu /etc/libvirt/qemu.conf /etc/libvirt/qemu/networks /etc/libvirt/qemu/networks/autostart /etc/logrotate.d/libvirtd.lxc /etc/logrotate.d/libvirtd.qemu /etc/rc.d/init.d/libvirtd /etc/sysconfig/libvirtd [root@dhcp-66-70 libvirt]# rpm -q libvirt libvirt-0.8.0-4.el6.x86_64 Regards osier ----- Original Message ----- From: "Daniel Veillard" <veillard(a)redhat.com> To: libvir-list(a)redhat.com Sent: Monday, April 12, 2010 11:16:27 PM GMT +08:00 Beijing / Chongqing / Hong Kong / Urumqi Subject: [libvirt] Documentation for synchronous hooks Was still missing from main commits and would be needed for 0.8.0 Add documentation for synchronous hooks * docs/sitemap.html.in: add in navigation under Documentation/Deployment/Hooks * docs/hooks.html.in: new doc describing current support for 0.8.0 diff --git a/docs/hooks.html.in b/docs/hooks.html.in new file mode 100644 index 0000000..4ebeec3 --- /dev/null +++ b/docs/hooks.html.in @@ -0,0 +1,71 @@ +<?xml version="1.0"?> +<html> + <body> + <h1>Hooks for specific system management</h1> + Libvirt includes synchronous hooks starting from version 0.8.0, + this is a way to tie specific tailored system actions at specific + time. This is based on scripts being called on the Host where the + hypervisor is running, if the script is present when the libvirtd + daemon is doing some significant actions. + The scripts are expected to execute quickly, return a zero exit + status if all conditions are set for the daemon to continue the + action (non zero will be considered a failure which may + be ignored but in general will stops the ongoing operation). + The script also should not call back into libvirt as the daemon + is waiting for the script exit and deadlock is likely to occur + otherwise. + The scripts are stored in the directory <code>/etc/libvirt/hooks/</code> + when using a standard installation path + (<code>$SYSCONF_DIR/libvirt/hook/</code> in general). + The scripts gets arguments as parameter on their command line: + <ul> + <li> the first argument is the name of the object involved in the + operation or '-' if there is none. + <li> the second argument is the name of the operation. + <li> the third argument is a suboperation indication like 'start' + 'end' or '-' if there is none. + <li> the last argument is an extra argument string or '-' if there + is none. + </ul> + There is currently scripts for 3 domains of operation: + <ul> + <li><code>/etc/libvirt/hooks/daemon</code> script if + present is called at 3 points in time: + at daemon startup, typically started with the following + arguments: + <pre>/etc/libvirt/hooks/daemon - start - start</pre> + at daemon shutdown when it is about to exit, with the following + arguments: + <pre>/etc/libvirt/hooks/daemon - shutdown - shutdown</pre> + When the daemon is asked to reload its driver state when + receiving the SIGHUP signal, arguments are: + <pre>/etc/libvirt/hooks/daemon - reload begin SIGHUP</pre> + </li> + <li><code>/etc/libvirt/hooks/qemu</code> script and + <code>/etc/libvirt/hooks/lxc</code> to associate hooks for domain + operation on the respective QEmu/KVM and LXC drivers. + The domain related hooks also receive the full XML description + for the concerned domain on their stdin, which allows to get + all the informations from the domain, including UUID or storage + if that is needed for the script operation. + Currently only domain startup and domain end operations + involve the hook, the first one just before the domain gets + created. + For example if starting a QEmu domain named <code>test</code> + the following script will get called: + <pre>/etc/libvirt/hooks/qemu test start begin -</pre> + note that a non-zero return value from the script will abort the + domain startup operation, and if an error string is passed on + stderr by the hook script, it will be provided back to the user + at the libvirt API level. + For domain shutdown, the script will be called just after the + domain has finished execution, and the script will get: + <pre>/etc/libvirt/hooks/qemu test stopped end -</pre> + It is expected that other operation will be associated to hooks + but at the time of 0.8.0 only those 2 are associated to domains + lifecycle + </li> + </ul> + + </body> +</html> diff --git a/docs/sitemap.html.in b/docs/sitemap.html.in index 0c3f0c3..0117c8d 100644 --- a/docs/sitemap.html.in +++ b/docs/sitemap.html.in @@ -50,6 +50,10 @@ <a href="logging.html">Logging</a> The library and the daemon logging support </li> + <li> + <a href="hooks.html">Hooks</a> + Hooks for system specific management + </li> </ul> </li> <li> -- Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/ daniel(a)veillard.com | Rpmfind RPM search engine http://rpmfind.net/ http://veillard.com/ | virtualization library http://libvirt.org/ -- libvir-list mailing list libvir-list(a)redhat.com https://www.redhat.com/mailman/listinfo/libvir-list

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[libvirt] Live Migration with non-shared storage for kvm
by Kenneth Nagin 27 Jun '10

27 Jun '10

On Wed Apr 07 I sent an email with a patch titled Live Migration with non-shared storage for kvm. What is the status on the patch? Kenneth Nagin Ph: +972-4-8296227 Cell: 054-6976227 Fx: +972-4- 8296113 "Do not look back in anger, or forward in fear, but around in awareness." --James Thurber

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