Apologies, the title of this bug might be very misleading. I've made a huge assumption that PCI-E GFX card pass-through was triggering the bug, purely because a Debian Stretch guest VM on the same host, using the same build of QEMU, which uses virtio-vga for graphics and the same version of OVMF firmware, boots up fine.
-- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1721221 Title: PCI-E passthrough of Nvidia GTX GFX card to Win 10 guest fails with "kvm_set_phys_mem: error registering slot: Invalid argument" Status in QEMU: New Bug description: Problem: Passthrough of a PCI-E Nvidia GTX 970 GFX card to a Windows 10 guest from a Debian Stretch host fails after recent changes to kvm in QEMU master/trunk. Before this recent commit, everything worked as expected. QEMU Version: Master/trunk pulled from github 4/10/17 ( git reflog: d147f7e815 HEAD@{0} ) Host: Debian Stretch kernel SMP Debian 4.9.30-2+deb9u5 (2017-09-19) x86_64 GNU/Linux Guest: Windows 10 Professional Issue is with this commit: https://github.com/qemu/qemu/commit/f357f564be0bd45245b3ccfbbe20ace08fe83ca8 Subsequent commit does not help: https://github.com/qemu/qemu/commit/3110cdbd8a4845c5b5fb861b0a664c56d993dd3c#diff-7b7a17f6e8ba4195198dd685073f43cb Error output from qemu: (qemu) kvm_set_phys_mem: error registering slot: Invalid argument QEMU commandline used: ./sources/qemu/x86_64-softmmu/qemu-system-x86_64 -machine q35,accel=kvm -serial none -parallel none -name Windows \ -enable-kvm -cpu host,kvm=off,hv_vendor_id=sugoidesu,-hypervisor -smp 6,sockets=1,cores=3,threads=2 \ -m 8G -mem-path /dev/hugepages -mem-prealloc -balloon none \ -drive if=pflash,format=raw,readonly,file=vms/ovmf-x64/ovmf-x64/OVMF_CODE-pure-efi.fd \ -drive if=pflash,format=raw,file=vms/ovmf-x64/ovmf-x64/OVMF_VARS-pure-efi.fd \ -rtc clock=host,base=localtime \ -readconfig ./vms/q35-virtio-graphical.cfg \ -object iothread,id=iothread0 -object iothread,id=iothread1 -object iothread,id=iothread2 -object iothread,id=iothread3 \ -device virtio-scsi-pci,iothread=iothread0,id=scsi0 -device virtio-scsi-pci,iothread=iothread1,id=scsi1 -device virtio-scsi-pci,iothread=iothread2,id=scsi2 -device virtio-scsi-pci,iothread=iothread3,id=scsi3 \ -device scsi-hd,bus=scsi0.0,drive=drive0,bootindex=1 -device scsi-hd,bus=scsi1.0,drive=drive1 -device scsi-hd,bus=scsi2.0,drive=drive2 -device scsi-hd,bus=scsi3.0,drive=drive3 -device scsi-hd,bus=scsi1.0,drive=drive4 -device scsi-hd,bus=scsi2.0,drive=drive5 -device scsi-hd,bus=scsi3.0,drive=drive6 -device scsi-hd,bus=scsi1.0,drive=drive7 -device scsi-hd,bus=scsi2.0,drive=drive8 -device scsi-hd,bus=scsi3.0,drive=drive9 \ -drive if=none,id=drive0,file=vms/w10p64.qcow2,format=qcow2,cache=none,discard=unmap \ -drive if=none,id=drive1,file=vms/w10p64-2.qcow2,format=qcow2,cache=none,discard=unmap \ -drive if=none,id=drive2,file=/dev/mapper/w10p64-3,format=raw,cache=none \ -drive if=none,id=drive3,file=vms/w10p64-4.qcow2,format=qcow2,cache=none \ -drive if=none,id=drive4,file=vms/w10p64-5.qcow2,format=qcow2,cache=none \ -drive if=none,id=drive5,file=vms/w10p64-6.qcow2,format=qcow2,cache=none,discard=unmap \ -drive if=none,id=drive6,file=/dev/mapper/w10p64-7,format=raw,cache=none \ -drive if=none,id=drive7,file=vms/w10p64-8.qcow2,format=qcow2,cache=none,discard=unmap \ -device vfio-pci,host=01:00.0,multifunction=on,x-vga=on \ -device vfio-pci,host=01:00.1,multifunction=on \ -netdev type=tap,id=net1,ifname=tap1,script=no,downscript=no,vhost=on \ -device virtio-net-pci,netdev=net1,mac=52:54:00:18:32:c9,bus=pcie.2,addr=00.0,ioeventfd=on \ -device usb-host,bus=usb.0,hostbus=3,hostport=2.1 \ -device usb-host,hostbus=3,hostport=2.2 \ -device usb-host,bus=ich9-ehci-1.0,hostbus=3,hostport=2.4 \ -object input-linux,id=kbd1,evdev=/dev/input/event0,grab_all=yes,repeat=on \ -drive if=none,id=drive8,file=vms/w10p64.qcow2-9,format=qcow2,discard=unmap \ -drive if=none,id=drive9,file=vms/w10p64-10.qcow2,format=qcow2,cache=none,discard=unmap \ -device usb-host,bus=usb.0,hostbus=3,hostport=9 \ -monitor stdio To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1721221/+subscriptions
