I tried out your setup and still get the black screen on VM startup: RX 570 video card
IOMMU group 15:[1002:67df] 0b:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Ellesmere [Radeon RX 470/480/570/570X/580/580X/590] (rev ff)
[1002:aaf0] 0b:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Ellesmere HDMI Audio [Radeon RX 470/480 / 570/580/590] (rev ff)
cat vfio-pci.cfg
BIND="0b:00.0"
VM log ending:
2019-04-18T03:24:07.735594Z qemu-system-x86_64: -device vfio-pci,host=0b:00.0,id=hostdev0,bus=pci.7,addr=0x1: Failed to mmap 0000:0b:00.0 BAR 0. Performance may be slow
2019-04-18T03:24:08.916579Z qemu-system-x86_64: vfio: Unable to power on device, stuck in D3
2019-04-18T03:24:08.920566Z qemu-system-x86_64: vfio: Unable to power on device, stuck in D3
2019-04-18T03:24:09.442392Z qemu-system-x86_64: vfio_err_notifier_handler(0000:0b:00.1) Unrecoverable error detected. Please collect any data possible and then kill the guest
Syslog:
Apr 18 00:14:00 Jarvis kernel: pci 0000:0b:00.0: [1002:67df] type 00 class 0x030000
Apr 18 00:14:00 Jarvis kernel: pci 0000:0b:00.0: reg 0x10: [mem 0xe0000000-0xefffffff 64bit pref]
Apr 18 00:14:00 Jarvis kernel: pci 0000:0b:00.0: reg 0x18: [mem 0xf0000000-0xf01fffff 64bit pref]
Apr 18 00:14:00 Jarvis kernel: pci 0000:0b:00.0: reg 0x20: [io 0xc000-0xc0ff]
Apr 18 00:14:00 Jarvis kernel: pci 0000:0b:00.0: reg 0x24: [mem 0xfce00000-0xfce3ffff]
Apr 18 00:14:00 Jarvis kernel: pci 0000:0b:00.0: reg 0x30: [mem 0xfce40000-0xfce5ffff pref]
Apr 18 00:14:00 Jarvis kernel: pci 0000:0b:00.0: BAR 0: assigned to efifb
Apr 18 00:14:00 Jarvis kernel: pci 0000:0b:00.0: supports D1 D2
Apr 18 00:14:00 Jarvis kernel: pci 0000:0b:00.0: PME# supported from D1 D2 D3hot D3cold
Apr 18 00:14:00 Jarvis kernel: pci 0000:0b:00.1: [1002:aaf0] type 00 class 0x040300
Apr 18 00:14:00 Jarvis kernel: pci 0000:0b:00.1: reg 0x10: [mem 0xfce60000-0xfce63fff 64bit]
Apr 18 00:14:00 Jarvis kernel: pci 0000:0b:00.1: supports D1 D2