From guest VM that booted quickly, has 52 physbits/57 virtual bits, and in which GPU driver does not work since `pci=realloc pci=nocrs isn't set: ubuntu@testbox01:~$ sudo cat /proc/iomem 00000000-00000fff : Reserved 00001000-0009ffff : System RAM 000a0000-000bffff : PCI Bus 0000:00 000f0000-000fffff : System ROM 00100000-7e317017 : System RAM 7e317018-7e349057 : System RAM 7e349058-7ed3efff : System RAM 7ed3f000-7edfffff : Reserved 7ee00000-7f8ecfff : System RAM 7f8ed000-7fb6cfff : Reserved 7fb6d000-7fb7efff : ACPI Tables 7fb7f000-7fbfefff : ACPI Non-volatile Storage 7fbff000-7ff7bfff : System RAM 7ff7c000-7fffffff : Reserved 80000000-dfffffff : PCI Bus 0000:00 80000000-801fffff : PCI Bus 0000:0e 80200000-803fffff : PCI Bus 0000:0d 80400000-805fffff : PCI Bus 0000:0c 80600000-807fffff : PCI Bus 0000:0b 80600000-80600fff : 0000:0b:00.0 80800000-809fffff : PCI Bus 0000:0a 80a00000-80bfffff : PCI Bus 0000:09 80c00000-80dfffff : PCI Bus 0000:08 80e00000-80ffffff : PCI Bus 0000:07 81000000-811fffff : PCI Bus 0000:06 81200000-813fffff : PCI Bus 0000:05 81200000-81200fff : 0000:05:00.0 81400000-815fffff : PCI Bus 0000:04 81400000-81400fff : 0000:04:00.0 81600000-817fffff : PCI Bus 0000:03 81600000-81600fff : 0000:03:00.0 81800000-819fffff : PCI Bus 0000:02 81800000-81803fff : 0000:02:00.0 81800000-81803fff : xhci-hcd 81a00000-81bfffff : PCI Bus 0000:01 81a00000-81a00fff : 0000:01:00.0 81a80000-81afffff : 0000:01:00.0 81c80000-81c80fff : 0000:00:1f.2 81c80000-81c80fff : ahci 81c81000-81c81fff : 0000:00:02.5 81c82000-81c82fff : 0000:00:02.4 81c83000-81c83fff : 0000:00:02.3 81c84000-81c84fff : 0000:00:02.2 81c85000-81c85fff : 0000:00:02.1 81c86000-81c86fff : 0000:00:02.0 81c87000-81c87fff : 0000:00:01.7 81c88000-81c88fff : 0000:00:01.6 81c89000-81c89fff : 0000:00:01.5 81c8a000-81c8afff : 0000:00:01.4 81c8b000-81c8bfff : 0000:00:01.3 81c8c000-81c8cfff : 0000:00:01.2 81c8d000-81c8dfff : 0000:00:01.1 81c8e000-81c8efff : 0000:00:01.0 e0000000-efffffff : PCI MMCONFIG 0000 [bus 00-ff] e0000000-efffffff : Reserved e0000000-efffffff : pnp 00:04 f0000000-febfffff : PCI Bus 0000:00 fec00000-fec003ff : IOAPIC 0 fed40000-fed40fff : MSFT0101:00 fed40000-fed40fff : MSFT0101:00 fee00000-fee00fff : Local APIC feffc000-feffffff : Reserved ffc00000-ffffffff : Reserved 100000000-e6dfffffff : System RAM 1384c00000-1385c022c1 : Kernel code 1385e00000-13868b4fff : Kernel rodata 1386a00000-1386e4b4ff : Kernel data 13871bd000-13883fffff : Kernel bss e800000000-efffffffff : PCI Bus 0000:00 e800000000-e8000fffff : PCI Bus 0000:01 e800000000-e800003fff : 0000:01:00.0 e800000000-e800003fff : virtio-pci-modern e800100000-e8001fffff : PCI Bus 0000:03 e800100000-e800103fff : 0000:03:00.0 e800100000-e800103fff : virtio-pci-modern e800200000-e8002fffff : PCI Bus 0000:04 e800200000-e800203fff : 0000:04:00.0 e800200000-e800203fff : virtio-pci-modern e800300000-e8003fffff : PCI Bus 0000:05 e800300000-e800303fff : 0000:05:00.0 e800300000-e800303fff : virtio-pci-modern e800400000-e8004fffff : PCI Bus 0000:0a e800400000-e800403fff : 0000:0a:00.0 e800400000-e800403fff : virtio-pci-modern e800500000-e8005fffff : PCI Bus 0000:0b e800500000-e800503fff : 0000:0b:00.0 e800500000-e800503fff : virtio-pci-modern e800600000-e8007fffff : PCI Bus 0000:0e e800800000-e8009fffff : PCI Bus 0000:0d e800a00000-e800bfffff : PCI Bus 0000:0c e800c00000-e800dfffff : PCI Bus 0000:02 Same guest, but with `pci=realloc pci=nocrs`: ubuntu@testbox01:~$ sudo cat /proc/iomem 00000000-00000fff : Reserved 00001000-0009ffff : System RAM 000f0000-000fffff : System ROM 00100000-7e319017 : System RAM 7e319018-7e34b057 : System RAM 7e34b058-7ed3efff : System RAM 7ed3f000-7edfffff : Reserved 7ee00000-7f8ecfff : System RAM 7f8ed000-7fb6cfff : Reserved 7fb6d000-7fb7efff : ACPI Tables 7fb7f000-7fbfefff : ACPI Non-volatile Storage 7fbff000-7ff7bfff : System RAM 7ff7c000-7fffffff : Reserved 80000000-801fffff : PCI Bus 0000:0e 80200000-803fffff : PCI Bus 0000:0d 80400000-805fffff : PCI Bus 0000:0c 80600000-807fffff : PCI Bus 0000:0b 80600000-80600fff : 0000:0b:00.0 80800000-809fffff : PCI Bus 0000:0a 80a00000-80bfffff : PCI Bus 0000:09 80c00000-80dfffff : PCI Bus 0000:08 80e00000-80ffffff : PCI Bus 0000:07 81000000-811fffff : PCI Bus 0000:06 81200000-813fffff : PCI Bus 0000:05 81200000-81200fff : 0000:05:00.0 81400000-815fffff : PCI Bus 0000:04 81400000-81400fff : 0000:04:00.0 81600000-817fffff : PCI Bus 0000:03 81600000-81600fff : 0000:03:00.0 81800000-819fffff : PCI Bus 0000:02 81800000-81803fff : 0000:02:00.0 81800000-81803fff : xhci-hcd 81a00000-81bfffff : PCI Bus 0000:01 81a00000-81a00fff : 0000:01:00.0 81a80000-81afffff : 0000:01:00.0 81c80000-81c80fff : 0000:00:1f.2 81c80000-81c80fff : ahci 81c81000-81c81fff : 0000:00:02.5 81c82000-81c82fff : 0000:00:02.4 81c83000-81c83fff : 0000:00:02.3 81c84000-81c84fff : 0000:00:02.2 81c85000-81c85fff : 0000:00:02.1 81c86000-81c86fff : 0000:00:02.0 81c87000-81c87fff : 0000:00:01.7 81c88000-81c88fff : 0000:00:01.6 81c89000-81c89fff : 0000:00:01.5 81c8a000-81c8afff : 0000:00:01.4 81c8b000-81c8bfff : 0000:00:01.3 81c8c000-81c8cfff : 0000:00:01.2 81c8d000-81c8dfff : 0000:00:01.1 81c8e000-81c8efff : 0000:00:01.0 e0000000-efffffff : PCI MMCONFIG 0000 [bus 00-ff] e0000000-efffffff : Reserved e0000000-efffffff : pnp 00:04 fec00000-fec003ff : IOAPIC 0 fed40000-fed40fff : MSFT0101:00 fed40000-fed40fff : MSFT0101:00 fee00000-fee00fff : Local APIC feffc000-feffffff : Reserved ffc00000-ffffffff : Reserved 100000000-e6dfffffff : System RAM 1162e00000-1163e022c1 : Kernel code 1164000000-1164ab4fff : Kernel rodata 1164c00000-116504b4ff : Kernel data 11653bd000-11665fffff : Kernel bss e6e0000000-e6e01fffff : PCI Bus 0000:02 e6e0200000-e6e03fffff : PCI Bus 0000:0c e6e0400000-e6e05fffff : PCI Bus 0000:0d e6e0600000-e6e07fffff : PCI Bus 0000:0e e800000000-e8000fffff : PCI Bus 0000:01 e800000000-e800003fff : 0000:01:00.0 e800000000-e800003fff : virtio-pci-modern e800100000-e8001fffff : PCI Bus 0000:03 e800100000-e800103fff : 0000:03:00.0 e800100000-e800103fff : virtio-pci-modern e800200000-e8002fffff : PCI Bus 0000:04 e800200000-e800203fff : 0000:04:00.0 e800200000-e800203fff : virtio-pci-modern e800300000-e8003fffff : PCI Bus 0000:05 e800300000-e800303fff : 0000:05:00.0 e800300000-e800303fff : virtio-pci-modern e800400000-e8004fffff : PCI Bus 0000:0a e800400000-e800403fff : 0000:0a:00.0 e800400000-e800403fff : virtio-pci-modern e800500000-e8005fffff : PCI Bus 0000:0b e800500000-e800503fff : 0000:0b:00.0 e800500000-e800503fff : virtio-pci-modern f000000000-11fffffffff : PCI Bus 0000:06 f000000000-f001ffffff : 0000:06:00.0 f002000000-f002ffffff : 0000:06:00.0 10000000000-11fffffffff : 0000:06:00.0 12000000000-14fffffffff : PCI Bus 0000:07 12000000000-13fffffffff : 0000:07:00.0 14000000000-14001ffffff : 0000:07:00.0 14002000000-14002ffffff : 0000:07:00.0 15000000000-17fffffffff : PCI Bus 0000:08 15000000000-15001ffffff : 0000:08:00.0 15002000000-15002ffffff : 0000:08:00.0 16000000000-17fffffffff : 0000:08:00.0 18000000000-1afffffffff : PCI Bus 0000:09 18000000000-19fffffffff : 0000:09:00.0 1a000000000-1a001ffffff : 0000:09:00.0 1a002000000-1a002ffffff : 0000:09:00.0