Nvidia Driver v376.33 Fails to Install - Windows Reverts back to Generic Display Driver

It installed fine on my system, not sure what exactly is going to be different between us.

###Software Debian Sid
QEMU 2.8
libvirt 2.5.0

###System specs i5-4960K, overclocked to 4GHz
32B Ram
Geforce 1070
Windows 10 64bit.

I've got no drivers loaded of any kind on the linux side (nouveau or proprietary). You should be able to check if that driver is doing anything by doing lspci -v and looking for the driver in use to be vfio-pci (this is with the VM running)

02:00.0 VGA compatible controller: NVIDIA Corporation GP104 [GeForce GTX 1070] (rev a1) (prog-if 00 [VGA controller])
        Subsystem: eVga.com. Corp. GP104 [GeForce GTX 1070]
        Flags: bus master, fast devsel, latency 0, IRQ 33
        Memory at f6000000 (32-bit, non-prefetchable) [size=16M]
        Memory at e0000000 (64-bit, prefetchable) [size=256M]
        Memory at f0000000 (64-bit, prefetchable) [size=32M]
        I/O ports at d000 [size=128]
        Expansion ROM at f7000000 [disabled] [size=512K]
        Capabilities: <access denied>
        Kernel driver in use: vfio-pci
        Kernel modules: nouveau

02:00.1 Audio device: NVIDIA Corporation GP104 High Definition Audio Controller (rev a1)
        Subsystem: eVga.com. Corp. GP104 High Definition Audio Controller
        Flags: bus master, fast devsel, latency 0, IRQ 34
        Memory at f7080000 (32-bit, non-prefetchable) [size=16K]
        Capabilities: <access denied>
        Kernel driver in use: vfio-pci
        Kernel modules: snd_hda_intel

My XML file for libvirt, I do most of this through virt-manager so I don't know what some of it does exactly but at the least it might help you spot something. Take special care looking at 02:00:* in mine as those are the graphics card and it's hdmi audio being passed through. You might also need to check that you've got the vendor id set in <hyperv>

<!--
WARNING: THIS IS AN AUTO-GENERATED FILE. CHANGES TO IT ARE LIKELY TO BE
OVERWRITTEN AND LOST. Changes to this xml configuration should be made using:
  virsh edit win10-clone
or other application using the libvirt API.
-->

<domain type='kvm'>
  <name>win10-clone</name>
  <uuid>112939e7-96d8-4446-91ca-c723a2fda6df</uuid>
  <memory unit='KiB'>12582912</memory>
  <currentMemory unit='KiB'>12582912</currentMemory>
  <vcpu placement='static'>4</vcpu>
  <os>
    <type arch='x86_64' machine='pc-q35-2.6'>hvm</type>
    <loader readonly='yes' type='pflash'>/usr/share/OVMF/OVMF_CODE.fd</loader>
    <nvram>/var/lib/libvirt/qemu/nvram/win10_VARS.fd</nvram>
  </os>
  <features>
    <acpi/>
    <apic/>
    <hyperv>
      <relaxed state='on'/>
      <vapic state='on'/>
      <spinlocks state='on' retries='8191'/>
      <vendor_id state='on' value='fucknvidia'/>
    </hyperv>
    <kvm>
      <hidden state='on'/>
    </kvm>
  </features>
  <cpu mode='host-passthrough'>
    <topology sockets='1' cores='2' threads='2'/>
  </cpu>
  <clock offset='localtime'>
    <timer name='hypervclock' present='yes'/>
    <timer name='rtc' tickpolicy='catchup'/>
    <timer name='pit' tickpolicy='delay'/>
    <timer name='hpet' present='no'/>
  </clock>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>restart</on_crash>
  <pm>
    <suspend-to-mem enabled='yes'/>
    <suspend-to-disk enabled='yes'/>
  </pm>
  <devices>
    <emulator>/usr/bin/qemu-kvm</emulator>
    <disk type='file' device='cdrom'>
      <driver name='qemu' type='raw'/>
      <source file='/mnt/media/virts/Win10_1607_English_x64.iso'/>
      <target dev='sda' bus='sata'/>
      <readonly/>
      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
    </disk>
    <disk type='file' device='disk'>
      <driver name='qemu' type='qcow2'/>
      <source file='/mnt/media/virts/win10-clone.qcow2'/>
      <target dev='sdc' bus='scsi'/>
      <boot order='1'/>
      <address type='drive' controller='0' bus='0' target='0' unit='2'/>
    </disk>
    <controller type='usb' index='0' model='ich9-ehci1'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x7'/>
    </controller>
    <controller type='usb' index='0' model='ich9-uhci1'>
      <master startport='0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0' multifunction='on'/>
    </controller>
    <controller type='usb' index='0' model='ich9-uhci2'>
      <master startport='2'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x1'/>
    </controller>
    <controller type='usb' index='0' model='ich9-uhci3'>
      <master startport='4'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x2'/>
    </controller>
    <controller type='pci' index='0' model='pcie-root'/>
    <controller type='pci' index='1' model='dmi-to-pci-bridge'>
      <model name='i82801b11-bridge'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x1e' function='0x0'/>
    </controller>
    <controller type='pci' index='2' model='pci-bridge'>
      <model name='pci-bridge'/>
      <target chassisNr='2'/>
      <address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
    </controller>
    <controller type='sata' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x1f' function='0x2'/>
    </controller>
    <controller type='virtio-serial' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
    </controller>
    <controller type='scsi' index='0' model='virtio-scsi'>
      <address type='pci' domain='0x0000' bus='0x02' slot='0x01' function='0x0'/>
    </controller>
    <interface type='network'>
      <mac address='52:54:00:86:6e:e1'/>
      <source network='vmnetwork'/>
      <model type='virtio'/>
      <address type='pci' domain='0x0000' bus='0x02' slot='0x04' function='0x0'/>
    </interface>
    <interface type='bridge'>
      <mac address='52:54:00:28:3f:6f'/>
      <source bridge='br0'/>
      <model type='virtio'/>
      <address type='pci' domain='0x0000' bus='0x02' slot='0x05' function='0x0'/>
    </interface>
    <serial type='pty'>
      <target port='0'/>
    </serial>
    <console type='pty'>
      <target type='serial' port='0'/>
    </console>
    <input type='mouse' bus='ps2'/>
    <input type='keyboard' bus='ps2'/>
    <graphics type='spice' autoport='yes'>
      <listen type='address'/>
    </graphics>
    <sound model='ich6'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
    </sound>
    <video>
      <model type='cirrus' vram='16384' heads='1' primary='yes'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x0'/>
    </video>
    <hostdev mode='subsystem' type='pci' managed='yes'>
      <source>
        <address domain='0x0000' bus='0x02' slot='0x00' function='0x0'/>
      </source>
      <address type='pci' domain='0x0000' bus='0x02' slot='0x02' function='0x0'/>
    </hostdev>
    <hostdev mode='subsystem' type='pci' managed='yes'>
      <source>
        <address domain='0x0000' bus='0x02' slot='0x00' function='0x1'/>
      </source>
      <address type='pci' domain='0x0000' bus='0x02' slot='0x03' function='0x0'/>
    </hostdev>
    <redirdev bus='usb' type='spicevmc'>
      <address type='usb' bus='0' port='2'/>
    </redirdev>
    <redirdev bus='usb' type='spicevmc'>
      <address type='usb' bus='0' port='3'/>
    </redirdev>
    <memballoon model='virtio'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x09' function='0x0'/>
    </memballoon>
  </devices>
</domain>

I know you've already fixed it but, tried this?

Also the PCI bridge being in the IOMMU group is normal (and is required!). as stated here I have a near identical setup as yours(6700k, GTX 1070) but I didn't need to apply the ACS patch.

Out of curiousity why were you running Bumblebee? I thought that was only intended for optimus laptops and served little benefit on desktop machines? Your issue sounds a bit odd with your solution.

Why NVIDIA drivers didn't install properly for my Win10 but fine for my Win8.1

TL;DR: Use the latest official ISO from Microsofts website.
Anyway, out of interest for you or others. I've had a similar issue specifically with Win 10, 8.1 worked perfectly. Turned out that the original ISO I had(Win 10 with updates pre-applied) had something shady about it and wouldn't install properly on UEFI VM. Tried an ISO of the Win 10 media from release which installed and updated fine but still refused my GPU drivers. Found out that Microsoft actuall supplies a download of their Win 10 OS as an ISO officially on their website, an updated version from their original release media. Drivers installed on this official/updated ISO no problem.

You didn't share how you handled the pass-through but mentioned that you had trouble with the host claiming your GPU which required ACS to let your VM attach it. Not sure how you approached this prior, thought I'd share what I do as an alternative that probably works just as well without ACS.

3 Simple steps to passthrough on the host side

• Update grub with line below(with your hardware ids instead of course)
• Uninstall NVIDIA drivers
• Switch your primary GPU in BIOS

/etc/default/grub:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash modprobe.blacklist=nouveau,nvidia,nvidia_drm intel_iommu=on iommu=pt modules-load=vfio,vfio_iommu_type1,vfio_pci_vfio_virqfd vfio-pci.ids=10de:1b81,10de:10f0"

That single line will blacklist drivers on my Manjaro host, enable IOMMU and handle the VFIO binding. No additional files required. It's important to remove the nvidia drivers from the host and replace them with the Intel iGPU drivers instead(Manjaro handles this by default by uninstalling NVIDIA drivers from memory). Other than that to switch I just need to change my primary GPU in the BIOS at boot.

Going to take a wild guess that your approach was one of the more outdated ways(I'm not sure if any guides actually mention the way I do it with a single line) or you made a slight mistake somewhere(did you passthrough both the GPU and it's audio device, or only the GPU?).

I had similar problems getting a EVGA GTX 660 ti working, turned out I needed to flash the card with EFI rom. Once this was done it worked right away.

I used rom-parser from here to determine that my card needed to be flashed: http://vfio.blogspot.co.uk/2014/08/does-my-graphics-card-rom-support-efi.html

Before:

root@bumblebee:~/rom-parser# ./rom-parser BACKUP.rom
Valid ROM signature found @400h, PCIR offset 190h
    PCIR: type 0 (x86 PC-AT), vendor: 10de, device: 1183, class: 030000
    PCIR: revision 0, vendor revision: 1
    Last image

After:

root@bumblebee:~/rom-parser# ./rom-parser BACKUP_NEW.rom
Valid ROM signature found @400h, PCIR offset 190h
    PCIR: type 0 (x86 PC-AT), vendor: 10de, device: 1183, class: 030000
    PCIR: revision 0, vendor revision: 1
Valid ROM signature found @10000h, PCIR offset 1ch
    PCIR: type 3 (EFI), vendor: 10de, device: 1183, class: 030000
    PCIR: revision 3, vendor revision: 0
        EFI: Signature Valid, Subsystem: Boot, Machine: X64
    Last image

You can dump the bios using NVFlash found here (also useful to backup): https://www.techpowerup.com/downloads/Utilities/BIOS_Flashing/NVIDIA/

./nvflash --index=0 --save BACKUP.rom

I had to enable UEFI settings in my bios after I had flashed it, without that the card wouldn't show up as a pci device in lspci.

Hopefully this helps someone else googling :)