[ovirt-users] Re: Viewing and hopefully, modifying the VM's qemu command line
Hello,
Many thanks for the prompt reply.
On Mon, Nov 8, 2021 at 8:52 PM Nir Soffer <nsoffer(a)redhat.com> wrote:
On Mon, Nov 8, 2021 at 5:47 PM Gilboa Davara
<gilboad(a)gmail.com> wrote:
>
> Hello all,
>
> I'm setting up a fairly (?) complex oVirt over Gluster setup built
around 3 Xeon servers-turned-into-workstations, each doubling as oVirt node
+ one primary Fedora VM w/ a dedicated passthrough GPU (+audio and a couple
of USB root devices).
> One of the servers seems to have some weird issue w/ the passthrough
nVidia GPU that seems to require me to edit the VM iommu (1) and
passthrough device (2) command line.
> I tried using the qemu-cmdline addon to add the missing parameters, but
it seems that qemu treats the added parameters as an additional device /
iommu instead of editing the existing parameters.
>
> So:
> 1. How can I view the VM qemu command line?
less /var/log/libvirt/qemu/vm-name.log
Found it, thanks!
> 2. Can I somehow manually edit the qemu command line, either
directly or
by somehow adding parameters in the HE XML file?
I think this should be possible via vdsm hook, but hooks are bad.
Can you explain what do you want to change?
Nir
1. IOMMU:
-device intel-iommu,intremap=on,eim=on
To (Add: caching-mode=on, per qemu log message)
-device intel-iommu,intremap=on,eim=on,caching-mode=on
(2021-11-05T18:42:36.651191Z qemu-kvm: We need to set caching-mode=on for
intel-iommu to enable device assignment with IOMMU protection.)
2. Device:
-device
vfio-pci,host=0000:84:00.0,id=ua-c774115b-c0ee-43a5-97c8-12ac73cb6f3a,bus=pci.10,addr=0x0
-device
vfio-pci,host=0000:84:00.1,id=ua-3c7d3b66-57aa-470b-afc8-78383ac9a025,bus=pci.8,addr=0x0
To (Attach hdmi sound as function of GPU, possibly add x-vga=on):
-device
vfio-pci,host=0000:84:00.0,id=ua-c774115b-c0ee-43a5-97c8-12ac73cb6f3a,bus=pci.8.0,x-vga=on,addr=0x0
-device
vfio-pci,host=0000:84:00.1,id=ua-3c7d3b66-57aa-470b-afc8-78383ac9a025,bus=pci.8.1,addr=0x0
3. I'm facing some odd memory allocation issues (only if the VM is Q35, all
works well if the VM is configured as i440fx), which may req
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