PVE 7.2 / kernel 5.15 and PCI passthrough (GPU vs NIC)

sbellon

New Member
Oct 12, 2021
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Hi all,

I read a lot of reports here that GPU passthrough or RAID systems do not work any more with PVE 7.2 and kernel 5.15 when using intel_iommu=on and the advice is to go back to kernel 5.13 or turn intel_iommu=off - iI understood all the posts correctly.

i have however not seen a posting with the same issue and NIC passthrough, therefore I wonder, is this issue really limited to GPU passthrough (and RAID?), but does not affect NIC passthrough, or is NIC passthrough just not used that often and nobody reported yet?

I'd like to know before upgrading as otherwise I do not have internet any more to fix it (my virtualized OPNsense depends on two NICs for WAN and LAN being passed through).

TIA.
 

leesteken

Famous Member
May 31, 2020
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It appears to occur when the GPU is used by the machine POST and Proxmox boot. With the new kernel version, the boot framebuffer claims some of the GPU memory and the usual work-arounds to prevent this don't seem to work. Virtually disconnecting the GPU and rescanning the PCIe bus appears to be the new work-around.
A NIC should not have this issue in the first place. The new work-around, which you shouldn't need, should be applicable to NICs and you can use (the PVE 7.1) kernel version 5.13 with PVE 7.2 (for a while). So I think you'll be fine.
 

sbellon

New Member
Oct 12, 2021
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But understanding from your post, I *will* have to make sure that it boots up with kernel 5.13 instead of 5.15 the first time I reboot after upgrading?
 

leesteken

Famous Member
May 31, 2020
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But understanding from your post, I *will* have to make sure that it boots up with kernel 5.13 instead of 5.15 the first time I reboot after upgrading?
I did not intend to give that impression. Just upgrade. You won't have that GPU issue with a NIC. An even if you do there are multiple work-arounds. But you won't have that issue.

EDIT: If you really want to test beforehand, you can apt install pve-kernel-5.15 on PVE 7.1 and see if that breaks anything before doing a apt dist-upgrade to 7.2.
 
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