I'm running W10 Guest on Arch host in VMM. I just got the 1080ti to show up in the guest but it doesn't start, showing a little orange triangle in device manager and a status of "had a problem starting". How do I figure out what's wrong?

2/6 EDIT: I've hidden the KVM and set a vendor ID, but I still get error 43. Also I'm running a Ryzen 1800X on an ASUS PRIME X370-PRO if that matters. Here's my build:

I'm trying to hand the Waterforce off to the VM.

-07:40 GMT-
A bit of digging around with lspci -nnv reveals some interesting information:
09:00.0 VGA compatible controller [0300]: NVIDIA Corporation GP102 [GeForce GTX 1080 Ti] [10de:1b06] (rev a1) (prog-if 00 [VGA controller]) Subsystem: Gigabyte Technology Co., Ltd GP102 [GeForce GTX 1080 Ti] [1458:3751] Flags: bus master, fast devsel, latency 0, IRQ 63 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]
[virtual] Expansion ROM at 000c0000 [disabled] [size=128K] Capabilities: <access denied>
Kernel driver in use: nvidia
Kernel modules: nouveau, nvidia_drm, nvidia

0a:00.0 VGA compatible controller [0300]: NVIDIA Corporation GP102 [GeForce GTX 1080 Ti] [10de:1b06] (rev a1) (prog-if 00 [VGA controller])
        Subsystem: Gigabyte Technology Co., Ltd GP102 [GeForce GTX 1080 Ti] [1458:376a]                                                     
        Flags: fast devsel, IRQ 64                                                                                       
        Memory at f4000000 (32-bit, non-prefetchable) [size=16M]
        Memory at c0000000 (64-bit, prefetchable) [size=256M]  
        Memory at d0000000 (64-bit, prefetchable) [size=32M]   
        I/O ports at c000 [size=128] 
        Expansion ROM at f5000000 [disabled] [size=512K]
        Capabilities: <access denied>
        Kernel driver in use: vfio-pci
        Kernel modules: nouveau, nvidia_drm, nvidia   

Both cards show up, one using the nvidia driver and one using vfio-pci, which seems to confirm that it is passed to the VM properly, but I also see a nouveau module loaded in both kernels. Which is fine for the host but according to This Guy if nouveau is loaded it will break things when it gets to Windows? If I blacklist nouveau, will it also kill it for my host card?