All mappings in a memory-space can be viewed with the <memory-space>.map command. Example:
simics> phys_io0.map base object fn offs length 0x0000040000400000 chmmu0 0 0x0 0x48 0x000004000c000000 schizo24 0 0x0 0x800000 0x000004000c800000 schizo25 0 0x0 0x800000 0x000007fff0000000 serengeti_cpuprom 0 0x0 0xbd3b0 0x000007fff0102000 serengeti_fpost_code 0 0x0 0x2000 0x000007fff0104000 fpost_data0 0 0x0 0x2000 0x000007fff0800060 empty0_0 0 0x60 0x10 0x000007fff091e000 empty1_0 0 0x0 0x120
Another useful command is devs, that lists all mapped devices in the system.
simics> devs
Count Device Space Range Func
0 chmmu0 phys_io0 0x0000040000400000 - 0x0000040000400047 0
0 e2bus24B_1 bus_pcicfg24B 0x0000000000000800 - 0x00000000000008ff 255
0 empty0_0 phys_io0 0x000007fff0800060 - 0x000007fff080006f 0
0 empty1_0 phys_io0 0x000007fff091e000 - 0x000007fff091e11f 0
0 fpost_data0 phys_io0 0x000007fff0104000 - 0x000007fff0105fff 0
0 glm0 bus_pcicfg25B 0x0000000000001000 - 0x00000000000010ff 255
...