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<damo22>youpi: does qemu do pci passthrough ?

<aaabbb>damo22: yes qemu supports pci passthrough

<damo22>do i have to use vfio and iommu?

<aaabbb>yes, if you want real pci passthrough

<aaabbb>iommu should be enabled anyway. it is what vfio uses

<damo22>iommu is usually disabled on intel systems

<damo22>is there a fake pci passthrough?

<aaabbb>it may be disabled by default on linux but you can boot with intel_iommu=on to turn it on

<aaabbb>there kinda is, but it's not really passthrough, it's just exposing an emulated device

<aaabbb>overhead is higher than pci passthrough, but it'll let you expose a nic in your guest that's connected to your host's nic

<damo22>basically i want to attach mpcie wifi card to the guest

<aaabbb>for direct access? do you care about overhead?

<damo22>no it just needs to be working

<damo22>it can be emulated

<etno>> is there a fake pci passthrough?

<etno>damo22: isn't this precisely what a virtual device is ? 🤔

<damo22>well you could emulate a device and connect it to the real device on the host side

<damo22>thats not the same as passing pci access raw to the device to the guest

<etno>I fail to see the benefit of using a host device for that. Maybe for measuring perf ? But then, any intermediary layer would undo the benefit.

<damo22>to get physical link access?

<damo22>basicallly i want to test rumpnet on a wifi card

<damo22>but i dont have an emulated wifi card in qemu apparently

<damo22>not sure how that would work anyway, since the radio is physical

<youpi>damo22: does rumpnet support usb? you could pass through a usb wifi key (qemu supports that in software)

<damo22>good q

<diegonc>I'm trying to mount a newly created ext2fs image as an unprivileged user. Everything goes well until I run `settrans -a ./mnt /hurd/ext2fs test.img`. At which point the mount point changes ownership to root:root

<diegonc>I'm not sure why that happens, I'm supposed to be able to do that fully as an unprivileged user

<diegonc>this paste details the steps I did : https://paste.debian.net/1381171/

<gnucode>diegonc: I'm not sure what you are doing wrong, but I believe the last time I tried mounting an ext2fs image as a regular user, I could write files just fine.

<gnucode>try this:

<gnucode> https://darnassus.sceen.net/~hurd-web/hurd/translator/ext2fs/

<gnucode>specifically the "Create your own custom ext2fs"

<diegonc>gnucode, thanks for the link. I was missing the `-E root_owner=$UID:0` parameter to mkfs.ext2

<diegonc>that's too bad though, it means I can't mount an arbitrary image I got laying around ( for instance, some backup taken by a privileged user and then shared )

<diegonc>ah ok, google points to tune2fs for changing the root_owner

<diegonc>demo@debian:~/test-ext2fs$ /sbin/tune2fs -R root_owner=$UID:0 test.img

<diegonc>tune2fs 1.47.2 (1-Jan-2025)

<diegonc>/sbin/tune2fs: invalid option -- 'R'

<diegonc>Google AI is not very accurate :P

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2025-06-19.log