This protocol is used to add or remove all PCI child devices on the PCI root bridge.
Include/Protocol/PciHotPlugRequest.h

PROTOCOL Information

PROTOCOL's Guid Name	PROTOCOL's Guid
gEfiPciHotPlugRequestProtocolGuid	{ 0x19CB87AB, 0x2CB9, 0x4665, { 0x83, 0x60, 0xDD, 0xCF, 0x60, 0x54, 0xF7, 0x9D }}

Refer to Header File