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<div class="moz-cite-prefix">On 10/15/2012 06:29 PM, Radhika
Niranjan wrote:<br>
</div>
<blockquote
cite="mid:CAKXQXMDVPN-jHgB7zbamdrRVg23LrMiHWhuRhQL=Uncm+7pgow@mail.gmail.com"
type="cite">Hi,
<div><br>
</div>
<div>I've been using libvirt (versions 0.9.11.5, and recently
upgraded to 0.10.2), and have been attaching an SR-IOV VF to my
VM with the following device configuration:</div>
<div>
<div><hostdev mode='subsystem' type='pci' managed='yes'></div>
<div> <source></div>
<div> <address domain='0x0000' bus='0x07' slot='0x10'
function='0x0'/></div>
<div> </source></div>
<div> <address type='pci' domain='0x0000' bus='0x00'
slot='0x05' function='0x0'/></div>
<div> </hostdev></div>
</div>
<div><br>
</div>
<div>I had no problems with bringing up the VM and using the VF
with this configuration.</div>
<div><br>
</div>
<div>Recently I noticed that I would be able to assign a mac
address to the SR-IOV VF if I used the interface configuration
and changed over to using:</div>
<div>
<div><interface type='hostdev'></div>
</div>
</blockquote>
<br>
Since your <hostdev> used managed='yes', you should use it
here too:<br>
<br>
<interface type='hostdev' managed='yes'><br>
<br>
<blockquote
cite="mid:CAKXQXMDVPN-jHgB7zbamdrRVg23LrMiHWhuRhQL=Uncm+7pgow@mail.gmail.com"
type="cite">
<div>
<div> <mac address='52:54:00:d3:23:4f'/></div>
<div> <source></div>
<div> <address type='pci' domain='0x0000' bus='0x07'
slot='0x10' function='0x0'/></div>
<div> </source></div>
<div> <model type='virtio'/></div>
</div>
</blockquote>
<br>
<model> is unused for interface type='hostdev', so that line
is harmless, but also meaningless.<br>
(actually it should probably log an error when it sees that, but
currently just ignores it).<br>
<br>
<blockquote
cite="mid:CAKXQXMDVPN-jHgB7zbamdrRVg23LrMiHWhuRhQL=Uncm+7pgow@mail.gmail.com"
type="cite">
<div>
<div> <address type='pci' domain='0x0000' bus='0x00'
slot='0x03' function='0x0'/></div>
<div> </interface></div>
</div>
<div><br>
</div>
<div>My VM fails to start up with this interface configuration.
The error reported is:</div>
<div>error: Failed to start domain exp85-1</div>
<div>error: An error occurred, but the cause is unknown</div>
</blockquote>
<br>
This is a bit odd. It means that some code path has returned an
error without logging an error message. I tried removing
"managed='yes'" and adding <model type='virtio'/> to a similar
interface definition on the one machine where I have an SR-IOV card,
and it failed to start, but gave a slightly less meaningless
message:<br>
<br>
error: Unable to read from monitor: Connection reset by peer<br>
<br>
(This is less meaningless because that generally indicates that the
qemu-kvm process encountered an error and exited, so I know I can
look in /var/log/libvirt/qemu/$guest.log for an error. And indeed,
when I look there I see this:<br>
<br>
Failed to assign device "hostdev0" : Device or resource busy<br>
qemu-kvm: -device
pci-assign,host=03:10.1,id=hostdev0,configfd=32,bus=pci.0,addr=0x7:
Device 'pci-assign' could not be initialized<br>
<br>
which makes sense.<br>
<br>
<blockquote
cite="mid:CAKXQXMDVPN-jHgB7zbamdrRVg23LrMiHWhuRhQL=Uncm+7pgow@mail.gmail.com"
type="cite">
<div><br>
</div>
<div>When I look into /var/log/messages I see the following
messages:</div>
<div><br>
</div>
<div>
<div>Oct 15 15:25:48 dcswitch85 libvirtd[17709]: 2012-10-15
22:25:48.145+0000: 17713: error : virFileReadAll:457 : Failed
to open file '/var/run/libvirt/qemu/p1p1_vf0': No such file or
directory</div>
</div>
</blockquote>
<br>
That file is used to save the previous MAC address and vlan tag of
the VF for restoration when the guest is finished with it. I'm not
sure why that error wasn't propogated back to virsh. (btw, this
error isn't the root error anyway - it would only be issued if a
failure happened while attempting to save the old MAC address/vlan
of the VF. Perhaps there's a failure in that bit of code that fails
without logging an error.)<br>
<br>
How handy are you at running gdb? If you could install the debuginfo
for libvirt, then attach gdb and set a breakpoint on the function
qemuDomainHostdevNetConfigReplace then single step, I'm pretty sure
whatever failure you're encountering is somewhere within one of the
functions called by that function. Otherwise we can probably find it
by manual examination, but that will take *much* more effort/time.<br>
<br>
<blockquote
cite="mid:CAKXQXMDVPN-jHgB7zbamdrRVg23LrMiHWhuRhQL=Uncm+7pgow@mail.gmail.com"
type="cite">
<div>
<div>Oct 15 15:25:48 dcswitch85 libvirtd[17709]: 2012-10-15
22:25:48.146+0000: 17713: error : qemuRemoveCgroup:740 :
internal error Unable to find cgroup for exp85-1</div>
<div>Oct 15 15:25:48 dcswitch85 libvirtd[17709]: 2012-10-15
22:25:48.146+0000: 17713: warning : qemuProcessStop:4136 :
Failed to remove cgroup for exp85-1</div>
</div>
<div><br>
</div>
<div>I was wondering if anyone else has faced this problem or has
a solution to this.</div>
<div><br>
</div>
<div>I'm using Fedora17, KVM, and an 82599EB Intel NIC.</div>
<div><br>
</div>
<div>Thanks much in advance.</div>
<div><br>
</div>
<div>With best regards</div>
<div>Radhika</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<br>
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</blockquote>
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