On 03/31/2016 11:58 AM, Moshe Levi wrote:
Thanks Laine,
Adding the driver_name o the config did the trick, thanks J
Regarding the vifo error it seem that openstack does roleback if
operation failed so that why you see the virDomainAttachDeviceFlags
Anyhow I found that the in qemu 2.1 suspend is not working (I got
error [1] ) so I upgrade to qemu 2.5 and then suspend work but it
failed on resume.
So Just to clarify vfio is not supporting “attach device” right? is
qemu going to support it?
Not at all. attach device works just fine with vfio (that's how hotplug
is done). I've just been using it myself in some testing. (note that
vfio has been supported since kernel 3.6 and libvirt 1.0.5, i.e. a "very
long time")
Now I wonder if I need to hardcode in the hostdev config to be with
driver_name=kvm…
I certainly hope not. You would be viciously attacked by the keeper of
vfio for your transgression! :-)
Seriously, there should be no reason whatsoever to force driver
name='kvm'. This was made configurable *only* as a fallback in case
errors were encountered with vfio during its early days. As a matter of
fact, I'm pretty sure that RHEL7 has legacy kvm device assignment
completely disabled. If you are needing to force legacy kvm device
assignment to make your setup work, then there is a bug somewhere that
needs to be investigated and squashed.
[1] -ERROR:qom/object.c:725:object_unref: assertion failed: (obj->ref > 0)
*From:*sendmail [mailto:justsendmailnothinge...@gmail.com] *On Behalf
Of *Laine Stump
*Sent:* Wednesday, March 30, 2016 9:25 PM
*To:* Libvirt <libvir-list@redhat.com>
*Cc:* Moshe Levi <mosh...@mellanox.com>
*Subject:* Re: [libvirt] Host device assignment driver name vfio/ kvm
On 03/29/2016 07:45 AM, Moshe Levi wrote:
Hi,
I was testing Host device assignment in OpenStack environment
where the driver name is vfio or kvm.
My setup is as follow:
1.Fedora 21
2.Libvirt 1.3.0 which I compiled
3.OpenStack master
I have also other setups with older Libvirt version and the same
OpenStack environment.
I notice that on my fedora environment the driver name is vfio
were in my old environment the driver name is kvm.
According to Libvirt documentation default is "vfio" on systems
where the VFIO driver is available and loaded, see [1]
I remove the vfio modules by removing vfio, vfio_iommu_type1,
vfio_pci but when I boot a vm the drive name is vfio
How can change the driver name to be kvm?
libvirt tries very hard to use vfio rather than legacy kvm, because
legacy kvm is old, deprecated, and "declared bad" :-). But it won't
changed it to vfio if you've explicitly said that you want to use kvm.
If you really want to use legacy kvm device assignment, manually set
that in the config. When you do that, if the system you're running on
doesn't support it, it will error out rather than switching.
Another thing that I encounter is an error when suspending VM (in
OpenStack environment) when the driver name is vfio.
In such case I am getting the following error from Libvirt:
2016-03-28 11:42:59.527 1966 ERROR oslo_messaging.rpc.dispatcher
File "/usr/lib64/python2.7/site-packages/libvirt.py", line 560, in
attachDeviceFlags
2016-03-28 11:42:59.527 1966 ERROR
oslo_messaging.rpc.dispatcher if ret == -1: raise libvirtError
('virDomainAttachDeviceFlags() failed', dom=self)
2016-03-28 11:42:59.527 1966 ERROR oslo_messaging.rpc.dispatcher
libvirtError: internal error: unable to execute QEMU command
'device_add': Device initialization failed.
I would appreciate for some pointers on what can cause this issue.
Assuming that openstack uses libvirt's virDomainSave API I would
expect suspending a guest to fail if it had an assigned device (since
libvirt implements this by "migrating to disk", and qemu doesn't allow
migration of a guest with an assigned device. But your problem is that
it's trying to *attach* a device, which I wouldn't consider to be a
part of a save or suspend or whatever operation. Is it possible to get
more information about what leads up to this?
[1] https://libvirt.org/formatdomain.html#elementsHostDev
<https://libvirt.org/formatdomain.html#elementsHostDev>
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