Greetings,
I've been trying to get VFIO GPU passthrough working with direct kernel
boot but haven't been able to figure it out.
I can successfully boot without attaching the VFIO device and I can attach
a VFIO device without direct kernal boot but when I try to combine them the
VM seems to start but there's no console output or any other sign that it's
booted successfully.
I'm wondering if it's even possible to get this to work now since direct
boot is skipping OVMF/UEFI and PCI passthrough is enabled by OVMF?
I've included the QEMU command I'm using below, just removing the 2 vfio
devices is enough to get it to work. Sorry about the verbosity - it was
generated by virsh!
Thanks for your time,
Callan
qemu-system-x86_64 -name guest=gbeast,debug-threads=on -machine
pc-q35-6.2,usb=off,vmport=off,dump-guest-core=off,memory-backend=pc.ram,hpet=off,acpi=on
-accel kvm -cpu
host,migratable=on,hv-time=on,hv-relaxed=on,hv-vapic=on,hv-spinlocks=0x1fff,hv-vpindex=on,hv-synic=on,hv-stimer=on,hv-reset=on,hv-vendor-id=randomid,kvm=off
-m size=32768000k -object
'{"qom-type":"memory-backend-file","id":"pc.ram","mem-path":"/dev/hugepages/libvirt/qemu/-1-gbeast","x-use-canonical-path-for-ramblock-id":false,"prealloc":true,"size":33554432000}'
-overcommit mem-lock=off -smp
24,sockets=1,dies=1,clusters=1,cores=12,threads=2 -uuid
14a09575-a9f7-4009-a518-4f2c63fb5988 -display none -no-user-config
-nodefaults -rtc base=localtime,driftfix=slew -global
kvm-pit.lost_tick_policy=delay -no-shutdown -boot strict=on -kernel
/nix/store/mijjaxkbrhag85l4im8j19mx4vq15bdk-nixos-system-gbeast-24.11.20250120.ae584d9/kernel
-initrd
/nix/store/xm6yln4hs5lysqaw20x2xmi6pkm49i2f-initrd-linux-6.6.72/initrd
-append 'loglevel=7 initcall_blacklist=sysfb_init net.ifnames=0
init=/nix/store/mijjaxkbrhag85l4im8j19mx4vq15bdk-nixos-system-gbeast-24.11.20250120.ae584d9/init
regInfo=/nix/store/gabjc36vvhng6r40cvrnyj4cp01nvzcp-closure-info/registration
console=ttyS0,115200n8' -device
'{"driver":"pcie-root-port","port":8,"chassis":1,"id":"pci.1","bus":"pcie.0","multifunction":true,"addr":"0x1"}'
-device
'{"driver":"pcie-root-port","port":9,"chassis":2,"id":"pci.2","bus":"pcie.0","addr":"0x1.0x1"}'
-device
'{"driver":"pcie-root-port","port":10,"chassis":3,"id":"pci.3","bus":"pcie.0","addr":"0x1.0x2"}'
-device
'{"driver":"pcie-root-port","port":11,"chassis":4,"id":"pci.4","bus":"pcie.0","addr":"0x1.0x3"}'
-device
'{"driver":"pcie-root-port","port":12,"chassis":5,"id":"pci.5","bus":"pcie.0","addr":"0x1.0x4"}'
-device
'{"driver":"pcie-root-port","port":13,"chassis":6,"id":"pci.6","bus":"pcie.0","addr":"0x1.0x5"}'
-device
'{"driver":"pcie-root-port","port":14,"chassis":7,"id":"pci.7","bus":"pcie.0","addr":"0x1.0x6"}'
-device
'{"driver":"pcie-root-port","port":15,"chassis":8,"id":"pci.8","bus":"pcie.0","addr":"0x1.0x7"}'
-device
'{"driver":"pcie-root-port","port":17,"chassis":9,"id":"pci.9","bus":"pcie.0","addr":"0x2.0x1"}'
-device
'{"driver":"pcie-root-port","port":16,"chassis":10,"id":"pci.10","bus":"pcie.0","multifunction":true,"addr":"0x2"}'
-device '{"driver":"qemu-xhci","id":"usb","bus":"pci.3","addr":"0x0"}'
-fsdev local,security_model=passthrough,id=fsdev-fs0,path=/nix/store
-device
'{"driver":"virtio-9p-pci","id":"fs0","fsdev":"fsdev-fs0","mount_tag":"nix-store","bus":"pci.1","addr":"0x0"}'
-chardev pty,id=charserial0 -serial stdio -device
'{"driver":"isa-serial","chardev":"charserial0","id":"serial0","index":0}'
-audiodev '{"id":"audio1","driver":"none"}' -global ICH9-LPC.noreboot=off
-watchdog-action reset -device
'{"driver":"vfio-pci","host":":01:00.1","id":"hostdev0","bus":"pci.5","addr":"0x0"}'
-device
'{"driver":"vfio-pci","host":":01:00.0","id":"hostdev1","bus":"pci.4","addr":"0x0"}'
-device
'{"driver":"virtio-balloon-pci","id":"balloon0","bus":"pci.6","addr":"0x0"}'
-sandbox
on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny
-msg timestamp=on
