Re: Issue with PCI passthrough ("swiotlb buffer is full") after Debian Dom0 kernel update to 5.10.178-3

[zithro <slack@xxxxxxxxx>]

On 05 May 2023 21:32, Paul Leiber wrote:
> Hi list,
>
> Since a Debian update of package linux-image-amd64 to version 5.10.0-22 
> (kernel 5.10.178-3), I am experiencing an issue with PCI passthrough.
You lucky, I can't even BOOT dom0 with this kernel !
(and no serial console avail for now, so dunno where it is bugging ...).

Also, I found a few users having problems with the new kernel and 
virtualization on the debian-users mailing list.
Maybe the kernel is ill-fated ?

Quick notes:
- did you try swiotlb buffer==64k (swiotlb=65536) ? (from memory it 
helped for a WLAN NIC, as I told you in our previous exchanges)
- most of the updates you linked are about APIC, so you may try adding 
in Xen cmdline : "apic_verbosity=debug"
- another one, not sure about the syntax but I et more info with 
"iommu=debug,verbose" (maybe in your case "iommu=debug,verbose,soft" ?)
- you have "permissive=1" in your domU config for the PCI device, is 
that normal ? I've never needed that and iirc is not recommended (check 
man pages though, corrupted brain memory here ^^)
As for the rest of your post, I need some rest :p
(if I ever make some sense from it ^^)