My /proc/iomem contans two memory areas of 8G size which are belonging to PCI 0000:03:00.0, one of the is the BAR reported by dmesg [ 0.312692] [ T1] pci 0000:03:00.0: BAR 0 [mem 0xfc00000000-0xfdffffffff 64bit pref] the other one is "afe00000000-affffffffff : 0000:03:00.0" (in the case without nokaslr) which shifts to "3ffe00000000-3fffffffffff : 0000:03:00.0" in the case with nokaslr.
Here's /proc/iomem in the case without nokaslr: 00000000-00000fff : Reserved 00001000-0009ffff : System RAM 000a0000-000fffff : Reserved 000a0000-000dffff : PCI Bus 0000:00 000f0000-000fffff : System ROM 00100000-09bfefff : System RAM 09bff000-0a000fff : Reserved 0a001000-0a1fffff : System RAM 0a200000-0a20efff : ACPI Non-volatile Storage 0a20f000-e62edfff : System RAM e62ee000-e63e1fff : Reserved e63e2000-e87cafff : System RAM e87cb000-e87cbfff : Reserved e87cc000-e9e1ffff : System RAM e9e20000-eb33efff : Reserved eb31e000-eb321fff : MSFT0101:00 eb322000-eb325fff : MSFT0101:00 eb33f000-eb39efff : ACPI Tables eb39f000-eb556fff : ACPI Non-volatile Storage eb557000-ed1fefff : Reserved ed1ff000-edffffff : System RAM ee000000-efffffff : Reserved f0000000-fcffffff : PCI Bus 0000:00 f0000000-f7ffffff : PCI ECAM 0000 [bus 00-7f] f0000000-f7ffffff : pnp 00:00 fc500000-fc9fffff : PCI Bus 0000:08 fc500000-fc5fffff : 0000:08:00.7 fc500000-fc5fffff : pcie_mp2_amd fc600000-fc6fffff : 0000:08:00.4 fc600000-fc6fffff : xhci-hcd fc700000-fc7fffff : 0000:08:00.3 fc700000-fc7fffff : xhci-hcd fc800000-fc8fffff : 0000:08:00.2 fc800000-fc8fffff : ccp fc900000-fc97ffff : 0000:08:00.0 fc980000-fc9bffff : 0000:08:00.5 fc980000-fc9bffff : AMD ACP3x audio fc980000-fc990200 : acp_pdm_iomem fc9c0000-fc9c7fff : 0000:08:00.6 fc9c0000-fc9c7fff : ICH HD audio fc9c8000-fc9cbfff : 0000:08:00.1 fc9c8000-fc9cbfff : ICH HD audio fc9cc000-fc9cdfff : 0000:08:00.7 fc9ce000-fc9cffff : 0000:08:00.2 fc9ce000-fc9cffff : ccp fca00000-fccfffff : PCI Bus 0000:01 fca00000-fcbfffff : PCI Bus 0000:02 fca00000-fcbfffff : PCI Bus 0000:03 fca00000-fcafffff : 0000:03:00.0 fcb00000-fcb1ffff : 0000:03:00.0 fcb20000-fcb23fff : 0000:03:00.1 fcb20000-fcb23fff : ICH HD audio fcc00000-fcc03fff : 0000:01:00.0 fcd00000-fcdfffff : PCI Bus 0000:07 fcd00000-fcd03fff : 0000:07:00.0 fcd00000-fcd03fff : nvme fce00000-fcefffff : PCI Bus 0000:06 fce00000-fce03fff : 0000:06:00.0 fce00000-fce03fff : nvme fcf00000-fcffffff : PCI Bus 0000:05 fcf00000-fcf03fff : 0000:05:00.0 fcf04000-fcf04fff : 0000:05:00.0 fcf04000-fcf04fff : r8169 fd300000-fd37ffff : amd_iommu fec00000-fec003ff : IOAPIC 0 fec01000-fec013ff : IOAPIC 1 fec10000-fec10fff : Reserved fec10000-fec10fff : pnp 00:04 fed00000-fed00fff : Reserved fed00000-fed003ff : HPET 0 fed00000-fed003ff : PNP0103:00 fed40000-fed44fff : Reserved fed80000-fed8ffff : Reserved fed81200-fed812ff : AMDI0030:00 fed81500-fed818ff : AMDI0030:00 fed81500-fed818ff : AMDI0030:00 AMDI0030:00 fedc0000-fedc0fff : pnp 00:04 fedc4000-fedc9fff : Reserved fedc5000-fedc5fff : AMDI0010:03 fedc5000-fedc5fff : AMDI0010:03 AMDI0010:03 fedcc000-fedcefff : Reserved fedd5000-fedd5fff : Reserved fee00000-fee00fff : pnp 00:04 ff000000-ffffffff : pnp 00:04 100000000-fee2fffff : System RAM 825600000-8261fa1b1 : Kernel code 826200000-82663dfff : Kernel rodata 826800000-82692ef3f : Kernel data 826eaf000-826ffffff : Kernel bss fee300000-100fffffff : Reserved 1010000000-ffffffffff : PCI Bus 0000:00 fc00000000-fe0fffffff : PCI Bus 0000:01 fc00000000-fe0fffffff : PCI Bus 0000:02 fc00000000-fe0fffffff : PCI Bus 0000:03 fc00000000-fdffffffff : 0000:03:00.0 This is the usual BAR reported by dmesg (and lspci -vv) fe00000000-fe0fffffff : 0000:03:00.0 fe20000000-fe301fffff : PCI Bus 0000:08 fe20000000-fe2fffffff : 0000:08:00.0 fe30000000-fe301fffff : 0000:08:00.0 fe30300000-fe304fffff : PCI Bus 0000:04 fe30300000-fe303fffff : 0000:04:00.0 fe30300000-fe303fffff : 0000:04:00.0 fe30400000-fe30403fff : 0000:04:00.0 fe30404000-fe30404fff : 0000:04:00.0 afe00000000-affffffffff : 0000:03:00.0 This is the memory which shifts with nokaslr Bert Karwatzki