[libvirt] Supporting vhost-net and macvtap in libvirt for QEMU
by Anthony Liguori
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
6 months, 2 weeks
Re: [libvirt] question about rdma migration
by Michael R. Hines
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
>
>
7 years, 6 months
[libvirt] Qemu: create empty cdrom
by Gromak Yuriy
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.
7 years, 6 months
[libvirt] [libvirt-glib/libvirt-gconfig 00/17] Graphics: Introduce the new Remote and Local classes (and also implement a few missing methods).
by Fabiano Fidêncio
While trying to use libvirt-gobject and libvirt-gconfig for accessing VMs
and looking at their config, instead of using libvirt and parsing XML
directly, I found out that a few methods have been missing and that
libvirt-gconfig is not exactly thought for the "reading their config" use
case (see more explanations on the 10th and 14th commits.
This series, unfortunately, introduces an ABI breakage.
Fabiano Fidêncio (17):
gconfig: Implement gvir_config_domain_graphics_vnc_get_autoport()
gconfig: Implement gvir_config_domain_graphics_spice_get_autoport()
gconfig: Implement gvir_config_domain_graphics_rdp_get_autoport()
gconfig: Implement gvir_config_domain_graphics_sdl_get_display()
gconfig: Implement gvir_config_domain_graphics_sdl_get_fullscreen()
gconfig: Implement gvir_config_domain_graphics_spice_get_tls_port()
gconfig: Implement gvir_config_domain_graphics_spice_{get,set}_host()
gconfig: Implement gvir_config_domain_graphics_vnc_{get,set}_host()
gconfig: Implement gvir_config_domain_graphics_rdp_{get,set}_host()
gconfig: Add GVirCofigDomainGraphicsRemote class
gconfig: Adapt GVirConfigDomainGraphicsSpice to
GVirConfigDomainGraphicsRemote
gconfig: Adapt GVirConfigDomainGraphicsRdp to
GVirConfigDomainGraphicsRemote
gconfig: Adapt GVirConfigDomainGraphicsVnc to
GVirConfigDomainGraphicsRemote
gconfig: Add GVirCofigDomainGraphicsLocal class
gconfig: Adapt GVirConfigDomainGraphicsSdl to
GVirConfigDomainGraphicsLocal
gconfig: Adapt GVirConfigDomainGraphicsDesktop to
GVirConfigDomainGraphicsLocal
gconfig,graphics: Avoid crash when gvir_config_object_new_from_xml()
returns NULL
libvirt-gconfig/Makefile.am | 4 +
.../libvirt-gconfig-domain-graphics-desktop.c | 14 ++-
.../libvirt-gconfig-domain-graphics-desktop.h | 4 +-
.../libvirt-gconfig-domain-graphics-local.c | 97 +++++++++++++++++++
.../libvirt-gconfig-domain-graphics-local.h | 68 ++++++++++++++
.../libvirt-gconfig-domain-graphics-rdp.c | 32 ++++++-
.../libvirt-gconfig-domain-graphics-rdp.h | 9 +-
.../libvirt-gconfig-domain-graphics-remote.c | 103 +++++++++++++++++++++
.../libvirt-gconfig-domain-graphics-remote.h | 70 ++++++++++++++
.../libvirt-gconfig-domain-graphics-sdl.c | 19 +++-
.../libvirt-gconfig-domain-graphics-sdl.h | 6 +-
.../libvirt-gconfig-domain-graphics-spice.c | 40 +++++++-
.../libvirt-gconfig-domain-graphics-spice.h | 10 +-
.../libvirt-gconfig-domain-graphics-vnc.c | 32 ++++++-
.../libvirt-gconfig-domain-graphics-vnc.h | 9 +-
libvirt-gconfig/libvirt-gconfig.h | 2 +
libvirt-gconfig/libvirt-gconfig.sym | 20 ++++
po/POTFILES.in | 2 +
18 files changed, 513 insertions(+), 28 deletions(-)
create mode 100644 libvirt-gconfig/libvirt-gconfig-domain-graphics-local.c
create mode 100644 libvirt-gconfig/libvirt-gconfig-domain-graphics-local.h
create mode 100644 libvirt-gconfig/libvirt-gconfig-domain-graphics-remote.c
create mode 100644 libvirt-gconfig/libvirt-gconfig-domain-graphics-remote.h
--
2.5.0
7 years, 8 months
[libvirt] [RFC PATCH 0/2] nodeinfo: PPC64: Fix topology and siblings info on capabilities and nodeinfo
by Shivaprasad G Bhat
The nodeinfo output was fixed earlier to reflect the actual cpus available in
KVM mode on PPC64. The earlier fixes covered the aspect of not making a host
look overcommitted when its not. The current fixes are aimed at helping the
users make better decisions on the kind of guest cpu topology that can be
supported on the given sucore_per_core setting of KVM host and also hint the
way to pin the guest vcpus efficiently.
I am planning to add some test cases once the approach is accepted.
With respect to Patch 2:
The second patch adds a new element to the cpus tag and I need your inputs on
if that is okay. Also if there is a better way. I am not sure if the existing
clients have RNG checks that might fail with the approach. Or if the checks
are not enoforced on the elements but only on the tags.
With my approach if the rng checks pass, the new element "capacity" even if
ignored by many clients would have no impact except for PPC64.
To the extent I looked at code, the siblings changes dont affect existing
libvirt functionality. Please do let me know otherwise.
---
Shivaprasad G Bhat (2):
nodeinfo: Reflect guest usable host topology on PPC64
Introduce capacity to virCapsHostNUMACellCPU to help vcpu pinning decisions
src/conf/capabilities.c | 3 +
src/conf/capabilities.h | 1
src/nodeinfo.c | 51 ++++++++++++++++++++++--
tests/vircaps2xmldata/vircaps-basic-4-4-2G.xml | 32 ++++++++-------
tests/vircaps2xmltest.c | 1
5 files changed, 67 insertions(+), 21 deletions(-)
--
Signature
7 years, 9 months
[libvirt] Bump tar format?
by Andrea Bolognani
Hi everyone,
commit cc3d52e[1] has apparently broken 'make dist' for at least some
platforms: Fedora 20 is fine[2], but both Fedora 21 and rawhide[3][4]
are currently failing. My laptop is running Fedora 22 and can make
dist just fine, which is of course very confusing.
The issue is caused by the following tar error:
tar: libvirt-1.2.18/tests/nodeinfodata/linux-deconfigured-cpus/ \
node/node0/cpu16/topology/core_siblings_list: \
link name is too long; not dumped
There seem to be basically two ways to solve the failure:
1. rename the test case, making it shorter;
2. bump tar format from ustar, which has limitations on the length
of file names, to posix/pax, which has no such limitations.
I'm not a fan of the former option because short names are usually very
opaque, see tests/nodeinfodata/linux-test[0-8] for some perfect
examples.
On the other hand, I'm not sure whether bumping the tar version would
affect portability in a significant way: the automake documentation[5]
reports that
this format is very young and should probably be restricted to
packages that target only very modern platforms
but the GNU tar documentation[6], while containing some warnings as
well, suggest that this format is going to become the default.
Any suggestions on how to proceed?
Cheers.
[1] https://www.redhat.com/archives/libvir-list/2015-July/msg00662.html
[2] https://ci.centos.org/view/libvirt-project/job/libvirt-daemon
-rpm/systems=libvirt-fedora-20/327/
[3] https://ci.centos.org/view/libvirt-project/job/libvirt-daemon
-rpm/systems=libvirt-fedora-21/327/
[4] https://ci.centos.org/view/libvirt-project/job/libvirt-daemon
-rpm/systems=libvirt-fedora-rawhide/327/
[5] https://www.gnu.org/software/automake/manual/html_node/List-of
-Automake-options.html
[6] http://www.gnu.org/software/tar/manual/html_chapter/tar_8.html
--
Andrea Bolognani
Software Engineer - Virtualization Team
7 years, 10 months
[libvirt] Libvirt multi queue support
by Naor Shlomo
Hello experts,
Could anyone please tell me if Multi Queue it fully supported in Libvirt and if so what version contains it?
Thanks,
Naor
7 years, 10 months
[libvirt] [PATCH] xen: Also add sub-type for driver=tap2 in xen-xm
by Philipp Hahn
tap2 only handles 'aio', but not 'raw', which must be explicitly given:
| $ virsh domxml-to-native yyy.xml > yyy.xm
| $ xm new yyy.xm
| Error: tap:/srv/xen/xxx.img not a valid disk type
| $ sed -i -e 's/tap2:/&aio:/' yyy.xm
| $ xm new yyy.xm
Fix reading and writing "xen-xm" format for "tap2" by handling it the
same as "tap".
---
src/xenconfig/xen_xm.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/src/xenconfig/xen_xm.c b/src/xenconfig/xen_xm.c
index e09d97e..6556886 100644
--- a/src/xenconfig/xen_xm.c
+++ b/src/xenconfig/xen_xm.c
@@ -196,7 +196,8 @@ xenParseXMDisk(virConfPtr conf, virDomainDefPtr def)
}
/* And the sub-type for tap:XXX: type */
- if (STREQ_NULLABLE(virDomainDiskGetDriver(disk), "tap")) {
+ if (STREQ_NULLABLE(virDomainDiskGetDriver(disk), "tap") ||
+ STREQ_NULLABLE(virDomainDiskGetDriver(disk), "tap2")) {
char *driverType;
if (!(tmp = strchr(src, ':')))
@@ -298,7 +299,7 @@ xenFormatXMDisk(virConfValuePtr list,
else
type = virStorageFileFormatTypeToString(format);
virBufferAsprintf(&buf, "%s:", driver);
- if (STREQ(driver, "tap"))
+ if (STREQ(driver, "tap") || STREQ(driver, "tap2"))
virBufferAsprintf(&buf, "%s:", type);
} else {
switch (virDomainDiskGetType(disk)) {
--
2.1.4
7 years, 11 months
[libvirt] KVM Forum 2016: Call For Participation
by Paolo Bonzini
=================================================================
KVM Forum 2016: Call For Participation
August 24-26, 2016 - Westin Harbor Castle - Toronto, Canada
(All submissions must be received before midnight May 1, 2016)
=================================================================
KVM Forum is an annual event that presents a rare opportunity
for developers and users to meet, discuss the state of Linux
virtualization technology, and plan for the challenges ahead.
We invite you to lead part of the discussion by submitting a speaking
proposal for KVM Forum 2016.
At this highly technical conference, developers driving innovation
in the KVM virtualization stack (Linux, KVM, QEMU, libvirt) can
meet users who depend on KVM as part of their offerings, or to
power their data centers and clouds.
KVM Forum will include sessions on the state of the KVM
virtualization stack, planning for the future, and many
opportunities for attendees to collaborate. As we celebrate ten years
of KVM development in the Linux kernel, KVM continues to be a
critical part of the FOSS cloud infrastructure.
This year, KVM Forum is joining LinuxCon and ContainerCon in Toronto,
Canada. Selected talks from KVM Forum will be presented on Wednesday
August 24 to the full audience of LinuxCon and ContainerCon. Also,
attendees of KVM Forum will have access to all of the LinuxCon and
ContainerCon talks on Wednesday.
http://events.linuxfoundation.org/cfp
Suggested topics:
KVM and Linux
* Scaling and optimizations
* Nested virtualization
* Linux kernel performance improvements
* Resource management (CPU, I/O, memory)
* Hardening and security
* VFIO: SR-IOV, GPU, platform device assignment
* Architecture ports
QEMU
* Management interfaces: QOM and QMP
* New devices, new boards, new architectures
* Scaling and optimizations
* Desktop virtualization and SPICE
* Virtual GPU
* virtio and vhost, including non-Linux or non-virtualized uses
* Hardening and security
* New storage features
* Live migration and fault tolerance
* High availability and continuous backup
* Real-time guest support
* Emulation and TCG
* Firmware: ACPI, UEFI, coreboot, u-Boot, etc.
* Testing
Management and infrastructure
* Managing KVM: Libvirt, OpenStack, oVirt, etc.
* Storage: glusterfs, Ceph, etc.
* Software defined networking: Open vSwitch, OpenDaylight, etc.
* Network Function Virtualization
* Security
* Provisioning
* Performance tuning
===============
SUBMITTING YOUR PROPOSAL
===============
Abstracts due: May 1, 2016
Please submit a short abstract (~150 words) describing your presentation
proposal. Slots vary in length up to 45 minutes. Also include the proposal
type -- one of:
- technical talk
- end-user talk
Submit your proposal here:
http://events.linuxfoundation.org/cfp
Please only use the categories "presentation" and "panel discussion"
You will receive a notification whether or not your presentation proposal
was accepted by May 27, 2016.
Speakers will receive a complimentary pass for the event. In the instance
that your submission has multiple presenters, only the primary speaker for a
proposal will receive a complementary event pass. For panel discussions, all
panelists will receive a complimentary event pass.
TECHNICAL TALKS
A good technical talk should not just report on what has happened over
the last year; it should present a concrete problem and how it impacts
the user and/or developer community. Whenever applicable, focus on
work that needs to be done, difficulties that haven't yet been solved,
and on decisions that other developers should be aware of. Summarizing
recent developments is okay but it should not be more than a small
portion of the overall talk.
END-USER TALKS
One of the big challenges as developers is to know what, where and how
people actually use our software. We will reserve a few slots for end
users talking about their deployment challenges and achievements.
If you are using KVM in production you are encouraged submit a speaking
proposal. Simply mark it as an end-user talk. As an end user, this is a
unique opportunity to get your input to developers.
HANDS-ON / BOF SESSIONS
We will reserve some time for people to get together and discuss
strategic decisions as well as other topics that are best solved within
smaller groups.
These sessions will be announced during the event. If you are interested
in organizing such a session, please add it to the list at
http://www.linux-kvm.org/page/KVM_Forum_2016_BOF
Let people you think might be interested know about it, and encourage
them to add their names to the wiki page as well. Please try to
add your ideas to the list before KVM Forum starts.
PANEL DISCUSSIONS
If you are proposing a panel discussion, please make sure that you list
all of your potential panelists in your abstract. We will request full
biographies if a panel is accepted.
===============
HOTEL / TRAVEL
===============
This year's event will take place at the Westin Harbour Castle Toronto.
For information on discounted room rates for conference attendees
and on other hotels close to the conference, please visit
http://events.linuxfoundation.org/events/kvm-forum/attend/hotel-travel.
As of March 15, 2016, non-US citizens need either a visa or an Electronic
Travel Authorization (eTA) in order to enter Canada. Detailed information
on the travel documentation required for your country of origin can
be found at http://www.cic.gc.ca/english/visit/visas.asp and
http://events.linuxfoundation.org/events/kvm-forum/attend/hotel-travel.
** We urge you to start this process as quickly as possible to ensure
** receipt of appropriate travel documentation in time for your conference
** travel to Canada. For processing times for visa applications, please visit
** http://www.cic.gc.ca/english/information/times/.
===============
IMPORTANT DATES
===============
Notification: May 27, 2015
Schedule announced: June 3, 2015
Event dates: August 24-26, 2016
Thank you for your interest in KVM. We're looking forward to your
submissions and seeing you at the KVM Forum 2016 in August!
-your KVM Forum 2016 Program Committee
Please contact us with any questions or comments at
kvm-forum-2016-pc(a)redhat.com
7 years, 11 months
