Kmalloc returns which address

Hi,

I am porting MPC8280 driver from vxWorks to Linux.

I want know the address return by kmalloc function? is it physical address
or kernel virtual address.

For Tx and Rx, hardware uses buffers, so I have to allocate buffers and pass
the pointer to hardware. Can I pass the pointer returned kmalloc?  or  I
should convert it into physical address?

If it returns kernel virtual address, then how to convert into physical?

Thanks & Regards-
Suresh