February 2017 - Devel - libvirt List Archives

[libvirt] OSX Homebrew support note ;)
by Justin Clift 06 Feb '17

06 Feb '17

Hi all, Compiling Libvirt directly from latest git master head is now supported on OSX Homebrew. It's as simple as: $ brew install --HEAD libvirt ... $ virsh -v 3.0.0 This should make development of Libvirt and related virtualisation things much easier on OSX. :) The credit for this goes to Roman Bogorodskiy and Homebrew developer "ilovezfs" (CC-d), for adding a functional rpcgen to Homebrew so we can generate the needed RPC bindings during the build (previously missing). Thanks heaps! :) Regards and best wishes, Justin Clift

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[libvirt] [PATCH] libxl: fix dom0 autoballooning with Xen 4.8
by Jim Fehlig 03 Feb '17

03 Feb '17

xen.git commit 57f8b13c changed several of the libxl memory get/set functions to take 64 bit parameters. The libvirt libxl driver still uses uint32_t variables for these various parameters, which is particularly problematic for the libxl_set_memory_target() function. When dom0 autoballooning is enabled, libvirt (like xl) determines the memory needed to start a domain and the memory available. If memory available is less than memory needed, dom0 is ballooned down by passing a negative value to libxl_set_memory_target() 'target_memkb' parameter. Prior to xen.git commit 57f8b13c, 'target_memkb' was an int32_t. Subtracting a larger uint32 from a smaller uint32 and assigning it to int32 resulted in a negative number. After commit 57f8b13c, the same subtraction is widened to a int64, resulting in a large positive number. The simple fix taken by this patch is to assign the difference of the uint32 values to a temporary int32 variable, which is then passed to 'target_memkb' parameter of libxl_set_memory_target(). Note that it is undesirable to change libvirt to use 64 bit variables since it requires setting LIBXL_API_VERSION to 0x040800. Currently libvirt supports LIBXL_API_VERSION >= 0x040400, essentially Xen >= 4.4. Signed-off-by: Jim Fehlig <jfehlig(a)suse.com> --- src/libxl/libxl_domain.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c index a5314b0..ed73cd2 100644 --- a/src/libxl/libxl_domain.c +++ b/src/libxl/libxl_domain.c @@ -909,6 +909,7 @@ libxlDomainFreeMem(libxl_ctx *ctx, libxl_domain_config *d_config) { uint32_t needed_mem; uint32_t free_mem; + int32_t target_mem; int tries = 3; int wait_secs = 10; @@ -922,7 +923,8 @@ libxlDomainFreeMem(libxl_ctx *ctx, libxl_domain_config *d_config) if (free_mem >= needed_mem) return 0; - if (libxl_set_memory_target(ctx, 0, free_mem - needed_mem, + target_mem = free_mem - needed_mem; + if (libxl_set_memory_target(ctx, 0, target_mem, /* relative */ 1, 0) < 0) goto error; -- 2.9.2

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[libvirt] [RFC] Vhost-user backends cross-version migration support
by Maxime Coquelin 03 Feb '17

03 Feb '17

Hi, Few months ago, Michael reported a problem about migrating VMs relying on vhost-user between hosts supporting different backend versions: - Message-Id: <20161011173526-mutt-send-email-mst(a)kernel.org> - https://lists.gnu.org/archive/html/qemu-devel/2016-10/msg03026.html The goal of this thread is to draft a proposal based on the outcomes of discussions with contributors of the different parties (DPDK/OVS /libvirt/...). Problem statement: ================== When migrating a VM from one host to another, the interfaces exposed by QEMU must stay unchanged in order to guarantee a successful migration. In the case of vhost-user interface, parameters like supported Virtio feature set, max number of queues, max vring sizes,... must remain compatible. Indeed, the frontend not being re-initialized, no renegotiation happens at migration time. For example, we have a VM that runs on host A, which has its vhost-user backend advertising VIRTIO_F_RING_INDIRECT_DESC feature. Since the Guest also support this feature, it is successfully negotiated, and guest transmit packets using indirect descriptor tables, that the backend knows to handle. At some point, the VM is being migrated to host B, which runs an older version of the backend not supporting this VIRTIO_F_RING_INDIRECT_DESC feature. The migration would break, because the Guest still have the VIRTIO_F_RING_INDIRECT_DESC bit sets, and the virtqueue contains some decriptors pointing to indirect tables, that backend B doesn't know to handle. This is just an example about Virtio features compatibility, but other backend implementation details could cause other failures. What we need is to be able to query the destination host's backend to ensure migration is possible. Also, we would need to query this statically, even before the VM is started, to be sure it could be migrated elsewhere for any reason. Solution 1: Libvirt queries DPDK vhost lib: *KO* ================================================ Initial idea was to have the management tool (libvirt) to query DPDK vhost lib and get key/value pairs and check whether migration is possible. This solution doesn't work for several reasons: 1. Vhost lib API provide a way for the application to disable features at runtime (understand, not at build time). So coming back to previous example, DPDK v16.11 supports indirect descriptor features, but it could be disabled by OVS. We had a look at whether this API was mandatory, and it turns out to be, as TSO feature is supported on DPDK but not in OVS. So we cannot rely on DPDK only. 2. Some parameter may be not only DPDK specific, such as the maximum number of queues for example. Solution 2: Libvirt queries OVS for vhost backend key/value pairs: *KO* ======================================================================= Second idea was for OVS to expose its vhost backend implementation parameters as key/value pairs, for example in the DB or by a dedicated tool. For example, you could have this kind of information: - virtio-features: 0x12045694 - max-rx-queues: 1024 - max-rx-ring-size: 512 Doing this, Libvirt has the information to take decision whether migration is possible or not. The problem is that Libvirt doesn't know (and want) to interpret these values (should it be equal/lower/greater/...?), and each time a new key is introduced in OVS, Libvirt will have to be updated to handle it, adding an unwanted synchronization constraint between the projects. Solution 3: Libvirt queries OVS for vhost backend version string: *OK* ====================================================================== The idea is to have a table of supported versions, associated to key/value pairs. Libvirt could query the list of supported versions strings for each hosts, and select the first common one among all hosts. Then, libvirt would ask OVS to probe the vhost-user interfaces in the selected version (compatibility mode). For example host A runs OVS-2.7, and host B OVS-2.6. Host A's OVS-2.7 has an OVS-2.6 compatibility mode (e.g. with indirect descriptors disabled), which should be selected at vhost-user interface probe time. Advantage of doing so is that libvirt does not need any update if new keys are introduced (i.e. it does not need to know how the new keys have to be handled), all these checks remain in OVS's vhost-user implementation. Ideally, we would support per vhost-user interface compatibility mode, which may have an impact also on DPDK API, as the Virtio feature update API is global, and not per port. - Implementation: ----------------- Goal here is just to illustrate this proposal, I'm sure you will have good suggestion to improve it. In OVS vhost-user library, we would introduce a new structure, for example (neither compiled nor tested): struct vhostuser_compat { char *version; uint64_t virtio_features; uint32_t max_rx_queue_sz; uint32_t max_nr_queues; }; *version* field is the compatibility version string. It could be something like: "upstream.ovs-dpdk.v2.6" In case for example Fedora adds some more patches to its package that would break migration to upstream version, it could have a dedicated compatibility string: "fc26.ovs-dpdk.v2.6". In case OVS-v2.7 does not break compatibility with previous OVS-v2.6 version, then no need to create a new compatibility entry, just keep v2.6 one. *virtio_features* field is the Virtio features set for a given compatibility version. When an OVS tag is to be created, it would be associated to a DPDK version. The Virtio features for these version would be stored in this field. It would allow to upgrade the DPDK package for example from v16.07 to v16.11 without breaking migration. In case the distribution wants to benefit from latests Virtio features, it would have to create a new entry to ensure migration won't be broken. *max_rx_queue_sz* *max_nr_queues* fields are just here for example, don't think this is needed today. I just want to illustrate that we have to anticipate other parameters than the Virtio feature set, even if not necessary at the moment. We create a table with different compatibility versions in OVS vhost-user lib: static struct vhostuser_compat vu_compat[] = { { .version = "upstream.ovs-dpdk.v2.7", .virtio_features = 0x12045694, .max_rx_queue_sz = 512, }, { .version = "upstream.ovs-dpdk.v2.6", .virtio_features = 0x10045694, .max_rx_queue_sz = 1024, }, } At some time during installation, or system init, the table would be parsed, and compatibility version strings would be stored into the OVS database, or a new tool would be created to list these strings. Before launching the VM, libvirt will query the version strings for each hosts using for example the JSON RPC API of OVS (maybe not the best solution, looking forward for your comments on this). Libvirt would then select the first common supported version, and insert this string into the vhost-user interfaces parameters in the OVS DBs of each host. When the vhost-user connection is initiated, OVS would know in which compatibility mode to init the interface, for example by restricting the support Virtio features of the interface. Do you think this is reasonable? Or maybe you have alternative ideas that would be best fit to ensure successful migration? Cheers, Maxime

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[libvirt] [PATCH] HACKING: Update after recent change of the html file
by Peter Krempa 03 Feb '17

03 Feb '17

--- Pushed as trivial. HACKING | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/HACKING b/HACKING index ff545a8fa..fff003b9e 100644 --- a/HACKING +++ b/HACKING @@ -231,7 +231,8 @@ feature or changing the output of a program. such as adding new XML elements or fixing all but the most obscure bugs, must be (briefly) described in a release notes entry; changes that are only relevant to other libvirt developers, such as code refactoring, don't belong -in the release notes. +in the release notes. Note that "docs/news.xml" should be updated in its own +commit not to get in the way of backports. There is more on this subject, including lots of links to background reading on the subject, on Richard Jones' guide to working with open source projects -- 2.11.0

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[libvirt] [PATCH] virtlockd: fix systemd unit file dependancies
by Daniel P. Berrange 03 Feb '17

03 Feb '17

After deploying virtlogd by default we identified a number of mistakes in the systemd unit file. virtlockd's relationship to libvirtd is the same as virtlogd, so we must apply the same unit file fixes to virtlockd Signed-off-by: Daniel P. Berrange <berrange(a)redhat.com> --- daemon/libvirtd.service.in | 1 + src/locking/virtlockd.service.in | 1 + src/locking/virtlockd.socket.in | 1 + 3 files changed, 3 insertions(+) diff --git a/daemon/libvirtd.service.in b/daemon/libvirtd.service.in index bbf27da..c72dde5 100644 --- a/daemon/libvirtd.service.in +++ b/daemon/libvirtd.service.in @@ -6,6 +6,7 @@ [Unit] Description=Virtualization daemon Requires=virtlogd.socket +Requires=virtlockd.socket Before=libvirt-guests.service After=network.target After=dbus.service diff --git a/src/locking/virtlockd.service.in b/src/locking/virtlockd.service.in index 57089b0..69b568f 100644 --- a/src/locking/virtlockd.service.in +++ b/src/locking/virtlockd.service.in @@ -1,6 +1,7 @@ [Unit] Description=Virtual machine lock manager Requires=virtlockd.socket +Before=libvirtd.service Documentation=man:virtlockd(8) Documentation=http://libvirt.org diff --git a/src/locking/virtlockd.socket.in b/src/locking/virtlockd.socket.in index 9808bbb..45e0f20 100644 --- a/src/locking/virtlockd.socket.in +++ b/src/locking/virtlockd.socket.in @@ -1,5 +1,6 @@ [Unit] Description=Virtual machine lock manager socket +Before=libvirtd.service [Socket] ListenStream=@localstatedir@/run/libvirt/virtlockd-sock -- 2.9.3

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[libvirt] [PATCH] docs: Release notes should be updated in a separate commit
by Andrea Bolognani 03 Feb '17

03 Feb '17

Updating docs/news.xml in the same commit that performs the documented change makes backports needlessly complicated, both for mainteinance branches and downstream distributions, because it introduces additional potential for merge conflicts. Document in the contributor guidelines that the release notes should be updated in a separate commit instead, so that it's easy to backport just the code change. --- docs/hacking.html.in | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/docs/hacking.html.in b/docs/hacking.html.in index c7bbcbd..b1bb149 100644 --- a/docs/hacking.html.in +++ b/docs/hacking.html.in @@ -302,7 +302,8 @@ or fixing all but the most obscure bugs, must be (briefly) described in a release notes entry; changes that are only relevant to other libvirt developers, such as code refactoring, don't belong in the - release notes.</p> + release notes. Note that <code>docs/news.xml</code> should be updated + in its own commit not to get in the way of backports.</p> </li> </ol> -- 2.7.4

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[libvirt] [V2 0/5] Support cache tune in libvirt
by Eli Qiao 03 Feb '17

03 Feb '17

This series patches are for supportting CAT featues, which also called cache tune in libvirt. First to expose cache information which could be tuned in capabilites XML. Then add new domain xml element support to add cacahe bank which will apply on this libvirt domain. This series patches add a util file `resctrl.c/h`, an interface to talk with linux kernel's sys fs. There are some TODO work such as logic of supportting l3code/l3data, expose new public interface to get free cache information. Some discussion about this feature support can be found from: https://www.redhat.com/archives/libvir-list/2017-January/msg00644.html Eli Qiao (5): Resctrl: Add some utils functions Resctrl: expose cache information to capabilities Resctrl: Add new xml element to support cache tune Resctrl: Add private interface to set cachebanks Qemu: Set cache banks docs/schemas/domaincommon.rng | 41 ++ include/libvirt/virterror.h | 1 + src/Makefile.am | 1 + src/conf/capabilities.c | 56 +++ src/conf/capabilities.h | 23 + src/conf/domain_conf.c | 134 ++++++ src/conf/domain_conf.h | 18 + src/libvirt_private.syms | 10 + src/qemu/qemu_capabilities.c | 68 +++ src/qemu/qemu_driver.c | 4 + src/qemu/qemu_process.c | 10 + src/util/virerror.c | 1 + src/util/virresctrl.c | 994 ++++++++++++++++++++++++++++++++++++++++++ src/util/virresctrl.h | 135 ++++++ 14 files changed, 1496 insertions(+) create mode 100644 src/util/virresctrl.c create mode 100644 src/util/virresctrl.h -- 1.9.1

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[libvirt] [PATCH 0/2] Fix random crash in qemuhotplugtest
by Peter Krempa 02 Feb '17

02 Feb '17

First patch makes the bug 100%[1] reproducible. *[1]: Race conditions may apply. Peter Krempa (2): DON'T APPLY: Reproducer to serialize threads "correctly" tests: qemuhotplug: Don't free the monitor object as part of @vm tests/qemuhotplugtest.c | 10 +++++++++- tests/qemumonitortestutils.c | 2 ++ 2 files changed, 11 insertions(+), 1 deletion(-) -- 2.11.0

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[libvirt] [PATCH] tests: qemuhotplug: Fix memory leaks after cpu hotplug testing patches
by Peter Krempa 02 Feb '17

02 Feb '17

testQemuHotplugCpuDataFree leaked @data always and testQemuHotplugCpuPrepare leaked @prefix on success --- Pushed as trivial. tests/qemuhotplugtest.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tests/qemuhotplugtest.c b/tests/qemuhotplugtest.c index 9a203bd44..8cceb883e 100644 --- a/tests/qemuhotplugtest.c +++ b/tests/qemuhotplugtest.c @@ -377,6 +377,7 @@ testQemuHotplugCpuDataFree(struct testQemuHotplugCpuData *data) virObjectUnref(data->vm); qemuMonitorTestFree(data->mon); + VIR_FREE(data); } @@ -434,6 +435,8 @@ testQemuHotplugCpuPrepare(const char *test, if (qemuDomainRefreshVcpuInfo(&driver, data->vm, 0, false) < 0) goto error; + VIR_FREE(prefix); + return data; error: -- 2.11.0

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[libvirt] [PATCH] qemu: turn on virtlockd by default
by Daniel P. Berrange 02 Feb '17

02 Feb '17

The virtlockd daemon has existed for years now, but we have never turned it on by default, requiring explicit user opt-in. This leaves users unprotected against accidents out of the box. By turning it on by default, users will at least be protected for mistakes involving local files, and files on shared filesystems that support fcntl() (eg NFS). In turning it on the various services files are updated to have the same dependancies for virtlockd as we have for virtlogd now, since turning the latter on exposed some gaps. Signed-off-by: Daniel P. Berrange <berrange(a)redhat.com> --- daemon/libvirtd.service.in | 1 + src/locking/virtlockd.service.in | 1 + src/locking/virtlockd.socket.in | 1 + src/qemu/qemu.conf | 2 +- src/qemu/qemu_conf.c | 3 +++ 5 files changed, 7 insertions(+), 1 deletion(-) diff --git a/daemon/libvirtd.service.in b/daemon/libvirtd.service.in index bbf27da..c72dde5 100644 --- a/daemon/libvirtd.service.in +++ b/daemon/libvirtd.service.in @@ -6,6 +6,7 @@ [Unit] Description=Virtualization daemon Requires=virtlogd.socket +Requires=virtlockd.socket Before=libvirt-guests.service After=network.target After=dbus.service diff --git a/src/locking/virtlockd.service.in b/src/locking/virtlockd.service.in index 57089b0..69b568f 100644 --- a/src/locking/virtlockd.service.in +++ b/src/locking/virtlockd.service.in @@ -1,6 +1,7 @@ [Unit] Description=Virtual machine lock manager Requires=virtlockd.socket +Before=libvirtd.service Documentation=man:virtlockd(8) Documentation=http://libvirt.org diff --git a/src/locking/virtlockd.socket.in b/src/locking/virtlockd.socket.in index 9808bbb..45e0f20 100644 --- a/src/locking/virtlockd.socket.in +++ b/src/locking/virtlockd.socket.in @@ -1,5 +1,6 @@ [Unit] Description=Virtual machine lock manager socket +Before=libvirtd.service [Socket] ListenStream=@localstatedir@/run/libvirt/virtlockd-sock diff --git a/src/qemu/qemu.conf b/src/qemu/qemu.conf index a8cd369..3239f7b 100644 --- a/src/qemu/qemu.conf +++ b/src/qemu/qemu.conf @@ -535,7 +535,7 @@ # share one writable disk, libvirt offers two approaches for # locking files. The first one is sanlock, the other one, # virtlockd, is then our own implementation. Accepted values -# are "sanlock" and "lockd". +# are "sanlock", "lockd", "nop". The default is "lockd". # #lock_manager = "lockd" diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c index 6613d59..d4c6cdc 100644 --- a/src/qemu/qemu_conf.c +++ b/src/qemu/qemu_conf.c @@ -314,6 +314,9 @@ virQEMUDriverConfigPtr virQEMUDriverConfigNew(bool privileged) cfg->glusterDebugLevel = 4; cfg->stdioLogD = true; + if (VIR_STRDUP(cfg->lockManagerName, "lockd") < 0) + goto error; + if (!(cfg->namespaces = virBitmapNew(QEMU_DOMAIN_NS_LAST))) goto error; -- 2.9.3

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