Yes you are right when you are in user space. However in a kernel module this would be physical address.
Nope. Unless you are using some really strange processor that I am not familiar with, a memory read is a memory read. *pReg is going to read what's at virtual address 0xc0000000 regardless of whether you are executing in user or kernel context. I know it's going to work this way on a PC with an Intel x86 processor.
OK, but how do you explain I can read 0xC0000000 and I get kicked out if I try 0x00100000.
The 0xC0000000 falls under PCI address range. I guess on a PC Linux just doesn't map this address range or it maps it one2one (phys==virt) I can dereference this address and I get something plausible.
On most 32 bit Intel processors running "standard" Linux 0xC0000000 is the first address of kernel VM. This is a function of kernel configuration, but it's this way by default. It's still a virtual address. So yes, on your PC virtual address 0xC0000000 is mapped to physical RAM.
Would this mean by reading the 0xC0000000 I am reading the Linux code not PCI registers? Thanks, Stephan.