Indicates the offset of the first virtual function (VF) for the physical function (PF). PF0 always resides at Offset 0, and PF1 always resides at Offset 1. Six virtual functions are available in the Gen3 Integrated Block for PCIe core and reside at the function number range 64–69.
Virtual functions are mapped sequentially with VFs for PF0 taking precedence. For example, if PF0 has two virtual functions and PF1 has three, the following mapping occurs:
The PFx_FIRST_VF_OFFSET is calculated by taking the first offset of the virtual function and subtracting that from the offset of the physical function.
PFx_FIRST_VF_OFFSET = (PFx first VF offset - PFx offset)
In the example above, the following offsets are used:
PF0_FIRST_VF_OFFSET = (64 - 0) = 64
PF1_FIRST_VF_OFFSET = (66 - 1) = 65
PF0 is always 64 assuming that PF0 has one or more virtual functions. The initial offset for PF1 is a function of how many VFs are attached to PF0 and is defined in the following pseudo code:
PF1_FIRST_VF_OFFSET = 63 + NUM_PF0_VFS