100% cpu usage when booting vm with pcie passthrough

[Bm1170]

When I start a vm with a gpu passed through the cores I have assigned to the vm stick at 100% usage till the vm starts. Startup of the vm takes a very long time but eventually it does start. I also noticed the more ram the vm has assigned the longer it takes to start (and the less ram the quicker it starts).

Anyone got a solution or something I can try?

 

Thanks in advance.

[bastl]

First of all, don't use all available cores for your VM and especially not the core 0 and it's HT. Unraid always uses these core for itself to manage stuff in the background. Second thing, you have 2x 6core Xeons in your system, try it first to ONLY use the cores from a single CPU. 1-5 + HT or 6-11 + HT or even less and don't mix the cores from the different CPUs. 

[Bm1170]

Tried cores from one cpu and tried just one core

same issue seems to maybe be slightly faster to start with one core but i'm not sure of it.

Edited July 14, 2021 by Bm1170

[startsomewhere]

Hi, I have the same issue when trying to passthrough a USB PCIe card.   1 thread hangs at 99-100% and Windows get's stuck at booting page.  Never starts.   VM works perfectly when I'm not passing the card through.  Let me know if you find something,  I'll continue deep diving this issue.

 

Here's my XML in case anyone looks at this : 

 

    <hostdev mode='subsystem' type='pci' managed='yes'>
      <driver name='vfio'/>
      <source>
        <address domain='0x0000' bus='0x03' slot='0x00' function='0x0'/>
      </source>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x08' function='0x0'/>
    </hostdev>

 

 

[ghost82]

VL805/806 seems a nogo because of broken firmware, sorry. I would suggest a 20$/Eur usb card like the inateck with fresco fl1100 controller.

[RERLTuna]

@Bm1170 sorry for the necro everyone but I'm facing the same issue. Did you ever find a solution to this? When I first start unraids and start a windows VM it boots almost instantly but it seems the longer I have unraids running the slower the boot becomes for the VM, sometimes taking around 3 minutes. I've noticed core 0 shoots to 100% while it's booting then drops back down to normal usage once the VM starts up, and I'm isolating cores 2-14 (ht 3-15) for the VM on a 13900k. Everything else seems to work fine just an inconvenience so I was wondering if you figured it out.