July 2016 - 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] Fix compile error for stable 1.2.9
by Yang hongyang 26 Oct '23

26 Oct '23

Seems a backport miss. An extra member is passed to struct virLXCBasicMountInfo. Signed-off-by: Yang hongyang <hongyang.yang(a)easystack.cn> --- src/lxc/lxc_container.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/src/lxc/lxc_container.c b/src/lxc/lxc_container.c index 28dabec..1c65fa9 100644 --- a/src/lxc/lxc_container.c +++ b/src/lxc/lxc_container.c @@ -760,7 +760,7 @@ typedef struct { static const virLXCBasicMountInfo lxcBasicMounts[] = { { "proc", "/proc", "proc", MS_NOSUID|MS_NOEXEC|MS_NODEV, false, false }, - { "/proc/sys", "/proc/sys", NULL, MS_BIND|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, false, false, false }, + { "/proc/sys", "/proc/sys", NULL, MS_BIND|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, false, false }, { "sysfs", "/sys", "sysfs", MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, false, false }, { "securityfs", "/sys/kernel/security", "securityfs", MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, true, true }, #if WITH_SELINUX -- 1.7.1

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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 v2 0/1] storage: vstorage support
by Olga Krishtal 21 Dec '16

21 Dec '16

The patch supports pool and volume managment using Vistuozzo Storage (vstorage) as a backend. To define pool use: virsh -c qemu+unix:///system pool-define-as --name VZ --type vstorage --source-name vz7-vzstorage --target /vzstorage_pool The resulting XML: <pool type='vstorage'> <name>VZ</name> <uuid>5f45665b-66fa-4b18-84d1-248774cff3a1</uuid> <capacity unit='bytes'>107374182400</capacity> <allocation unit='bytes'>1441144832</allocation> <available unit='bytes'>105933037568</available> <source> <name>vz7-vzstorage</name> </source> <target> <path>/vzstorage_pool</path> <permissions> <mode>0700</mode> <owner>0</owner> <group>0</group> </permissions> </target> </pool> For the vstorage pool the only obligatory parameter, which stores cluster name, is --source-name. v2: - maximum code reusage - fixed name issue - we use vstorage - simplified findPoolSources Olga Krishtal (1): storage: vz storage pool support configure.ac | 28 ++++++++++ docs/schemas/storagepool.rng | 13 +++++ include/libvirt/libvirt-storage.h | 1 + src/conf/storage_conf.c | 16 +++++- src/conf/storage_conf.h | 4 +- src/storage/storage_backend.c | 3 + src/storage/storage_backend_fs.c | 114 ++++++++++++++++++++++++++++++++++++-- src/storage/storage_backend_fs.h | 3 + src/storage/storage_driver.c | 2 + tools/virsh-pool.c | 2 + tools/virsh.c | 3 + 11 files changed, 181 insertions(+), 8 deletions(-) -- 1.8.3.1

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[libvirt] [PATCH 0/2] qemu_cgroup: allow access to /dev/dri/render*
by Ján Tomko 14 Dec '16

14 Dec '16

Technically a v2, but v1 is already pushed. This version is based on the <gl enable> in <spice> instead of accel3d="yes" in <video><model type="virtio". It also only allows access to the render* devices, instead of all of them. https://bugzilla.redhat.com/show_bug.cgi?id=1337290 Ján Tomko (2): Revert "qemu_cgroup: allow access to /dev/dri for virtio-vga" qemu_cgroup: allow access to /dev/dri/render* src/qemu/qemu_cgroup.c | 71 ++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 57 insertions(+), 14 deletions(-) -- 2.7.3

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[libvirt] RFC: add recreate option to domain events conf
by Nikolay Shirokovskiy 09 Dec '16

09 Dec '16

Hi, all. Does it make sense to anybody else that rebooting and resetting a persistent domain from outside or from inside should bring upon pending configuration changes? For this purpose we can add another option to on_reboot and other events, say 'recreate'. From technical POV qemu has enough capabilities, namely -no-reboot option. Nikolay

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Re: [libvirt] question about rdma migration
by Michael R. Hines 25 Oct '16

25 Oct '16

Hi Roy, On 02/09/2016 03:57 AM, Roy Shterman wrote: > Hi, > > I tried to understand the rdma-migration in qemu code and i have two > questions about it: > > 1. I'm working with qemu-kvm using libvirt and i'm getting > > MEMLOCK max locked-in-memory address space 65536 65536 bytes > > in qemu process so I don't understand how can you use rdma-pin-all > with such low MEMLOCK. > > I found a solution in libvirt to lock all vm memory in advance and to > enlarge MEMLOCK. > It uses memoryBacking locking and memory tuning hard_limit of vm > memory but I couldn't find a usage of this in rdma-migration code. > You're absolutey right, the RDMA migration code itself doesn't set this lock limit explicitly because there are system-wide restrictions in both appArmour, /etc/security, as well as SELINUX that restrict applications from arbitrarily setting their maximum memory lock limits. The other problem is CGROUPS: If someone sets a cgroup control for maximum memory and forgets about that mlock() limits, then there will be a conflict. So, libvirt must have a policy to deal with all of these possibilities, not just handle a special case for RDMA migration. The only way "simple" way (without patching the problems above) to apply a higher lock limit to QEMU is to set the ulimit for libvirt (or for QEMU if starting QEMU manually) in your environment or the command line with $ ulimit # before attempting the migration, then the RDMA subsystem will be able to lock the memory successfully. The other option is to use /etc/security/limits.conf and set the option for a specific libvirt process user and make sure your libvirt/qemu are not running as root. QEMU itself also has a "mlock" option built into the command line, but it also suffers from the same problem --- you have to find a way (currently) to increase the limit before using the option. > 2. Do you have any comparison of IOPS and bandwidth between TCP > migration and rdma migration? > Yes, lots of comparisons. http://wiki.qemu.org/Features/RDMALiveMigration http://www.canturkisci.com/ETC/papers/IBMJRD2011/preprint.pdf > Regards, > Roy > >

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[libvirt] Qemu: create empty cdrom
by Gromak Yuriy 18 Oct '16

18 Oct '16

Hello. Qemu is latest from master branch. Tryingto start a domain, which is connected toa blankcdrom: <disk type='file' device='cdrom'> <driver name='qemu' type='raw'/> <target dev='sdb' bus='scsi'/> <readonly/> <address type='drive' controller='0' target='1' bus='0' unit='0'/> </disk> But I get an error: qemu-system-x86_64: -drive if=none,id=drive-scsi0-0-1-0,readonly=on,format=raw: Can't use 'raw' as a block driver for the protocol level.

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[libvirt] [PATCHv2] qemu: agent: Fix QEMU guest agent is not available due to an error
by Xiubo Li 21 Sep '16

21 Sep '16

These days, we experienced one qemu guest agent is not available error. Then the guest agent couldn't be used forever before rebooting the libvirtd daemon or reboot the qemu-guest-agent in the VM(you can also reboot the VM) to clear the priv->agentError. This is one bug for a long time in many verisons of libvirtd: https://bugzilla.redhat.com/show_bug.cgi?id=1090551 And there is one python script to reproduce this bug from the bugzilla: https://github.com/aspirer/study/blob/master/qemu-guest-agent/test2.py Just set the timeout to 0 at Line26, you can reproduce it very quickly: rsp = libvirt_qemu.qemuAgentCommand(dom, cmd, 1, 0) // 1 -> 0 The reason why this could happen is that: In case we received something like {"return": {}} for example, it is likely that somebody: 1) Started GA thread which sent one "guest-ping" command with seconds equals to VIR_DOMAIN_QEMU_AGENT_COMMAND_NOWAIT(0) makes this function return immediately without waiting, but after updating the events, it will sleep in virCondWait() or virCondWaitUntil(). 2) While in AgentIO thread the "guest-ping" command is sent successfully, with updating the events it will wait for reply. 3) Then the GA thread is woken up and the mon->msg is set to NULL and exit. 4) At last the AgentIO thread receives the reply of "guest-ping" command with the mon->msg == NULL. This case could be adapt to all the GA commands, including guest-sync, etc. This patch will check if this is the case and don't report an error but return silently. Signed-off-by: Xiubo Li <lixiubo(a)cmss.chinamobile.com> Signed-off-by: Zhuoyu Zhang <zhangzhuoyu(a)cmss.chinamobile.com> Signed-off-by: Wei Tang <tangwei(a)cmss.chinamobile.com> Signed-off-by: Yaowei Bai <baiyaowei(a)cmss.chinamobile.com> Signed-off-by: Qide Chen <chenqide(a)cmss.chinamobile.com> --- Changes in V2: - check value type instead of object type. src/qemu/qemu_agent.c | 37 ++++++++++++++++++++++++++++--------- src/util/virjson.h | 7 +++++++ 2 files changed, 35 insertions(+), 9 deletions(-) diff --git a/src/qemu/qemu_agent.c b/src/qemu/qemu_agent.c index eeede6b..f5408cc 100644 --- a/src/qemu/qemu_agent.c +++ b/src/qemu/qemu_agent.c @@ -308,7 +308,6 @@ qemuAgentIOProcessLine(qemuAgentPtr mon, { virJSONValuePtr obj = NULL; int ret = -1; - unsigned long long id; VIR_DEBUG("Line [%s]", line); @@ -333,16 +332,36 @@ qemuAgentIOProcessLine(qemuAgentPtr mon, obj = NULL; ret = 0; } else { - /* If we've received something like: - * {"return": 1234} - * it is likely that somebody started GA - * which is now processing our previous - * guest-sync commands. Check if this is - * the case and don't report an error but + virJSONValuePtr val; + + /* In case we received something like: + * {"return": {}} for example, + * it is likely that somebody: + * + * 1) Started GA thread which sent one "guest-ping" command + * with seconds equals to VIR_DOMAIN_QEMU_AGENT_COMMAND_NOWAIT(0) + * makes this function return immediately without waiting, but + * after updating the events, it will sleep in virCondWait() or + * virCondWaitUntil(). + * + * 2) While in AgentIO thread the "guest-ping" command is sent + * successfully, with updating the events it will wait for reply. + * + * 3) Then the GA thread is woken up and the mon->msg is set + * to NULL and exit. + * + * 4) At last the AgentIO thread receives the reply of "guest-ping" + * command with the mon->msg == NULL. + * + * This case could be adapt to all the GA commands, including + * guest-sync, etc. + * + * Check if this is the case and don't report an error but * return silently. */ - if (virJSONValueObjectGetNumberUlong(obj, "return", &id) == 0) { - VIR_DEBUG("Ignoring delayed reply to guest-sync: %llu", id); + val = virJSONValueObjectGet(obj, "return"); + if (val && virJSONValueTypeIsValid(val)) { + VIR_DEBUG("Ignoring delayed command reply"); ret = 0; goto cleanup; } diff --git a/src/util/virjson.h b/src/util/virjson.h index 66ed48a..cb1d973 100644 --- a/src/util/virjson.h +++ b/src/util/virjson.h @@ -80,6 +80,13 @@ struct _virJSONValue { } data; }; +static inline bool +virJSONValueTypeIsValid(virJSONValuePtr value) +{ + return ((value->type >= VIR_JSON_TYPE_OBJECT) && + (value->type <= VIR_JSON_TYPE_BOOLEAN)); +} + void virJSONValueFree(virJSONValuePtr value); int virJSONValueObjectCreate(virJSONValuePtr *obj, ...) -- 1.8.3.1

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