June 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 27 Oct '23

27 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 27 Oct '23

27 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 24 Mar '13

24 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". <span class="since">Since 0.1.8</span> + "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". <span class="since">Since 0.1.8; "aio" attribute since 0.7.7</span> </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] [PATCH 0/2] speed up qemu domain save by increasing dd blocksize
by Laine Stump 29 Oct '10

29 Oct '10

These two patches are posted together because applying the 2nd exposes the bug fixed by the first. Here are the results of tests I made with various block sizes before deciding the 1MB really was the best balance (all tests were done on a paused 512MB domain, saving to local disk on a Lenovo T61 laptop) BS M:SS save image size ----- ---- --------------- 2048K - 0:56 476135451 1024K - 0:56 475090953 512k - 1:02 474564173 256k - 1:10 474303797 128k - 1:25 474176859 512 - 3:47 474085423 - the original I didn't bother testing sizes between 512 and 128k, as there was still significant improvement from 128k to 256k.

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[libvirt] [PATCH 0/3] test cases for spoofing prevention
by gstenzel＠linux.vnet.ibm.com 14 Sep '10

14 Sep '10

The following patches add a set of test cases to verify that several spoofing attacks are prevented by the nwfilter subsystem. In order to have a well defined test machine a virtual disk is installed from scratch over the network. I am currently trying to find a suitable location for the kickstart file. -- Best regards, Gerhard Stenzel, ----------------------------------------------------------------------------------------------------------------------------------- IBM Deutschland Research & Development GmbH Vorsitzender des Aufsichtsrats: Martin Jetter Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen Registergericht: Amtsgericht Stuttgart, HRB 243294

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[libvirt] Update to libvirt-lxc driver doc page
by Serge Hallyn 24 Aug '10

24 Aug '10

Here is a new drvlxc.html.in file to make the first example work. I'll play with the second example next. thanks, -serge

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