Direct-attached storage device software raid boot system

An Information Handling System (IHS), comprising:

• a processing system;
• and
• a memory system that is coupled to the processing system and that includes instructions that, when executed by the processing system, cause the processing system to provide a software Redundant Array of Independent Disk (RAID) engine that is configured to:
• identify, from a plurality of Peripheral Component Interconnect express (PCIe) subsystems that are coupled to the processing system, a first PCIe subsystem that is not claimed by a Unified Extensible Firmware Interface (UEFI) driver provided by a UEFI subsystem that is coupled to the processing system;
• and
• determine that the first PCIe subsystem is one of a PCIe bridge device or a PCIe root device and, in response:
• claim the first PCIe subsystem;
• install a RAID protocol on the first PCIe subsystem;
• attach, to the first PCIe subsystem, at least one RAID logical storage subsystem provided by at least one PCIe endpoint device that is included in the plurality of PCIe subsystems;
• and
• present, to the UEFI subsystem, a PCIe controller device that is included in the first PCIe subsystem as connected to the at least RAID logical storage subsystem.

A method for booting a direct-attached storage device software Redundant Array of Independent Disk (RAID), comprising:

• identifying, by a software Redundant Array of Independent Disk (RAID) subsystem from a plurality of Peripheral Component Interconnect express (PCIe) subsystems, a first PCIe subsystem that is not claimed by a Unified Extensible Firmware Interface (UEFI) driver provided by a UEFI subsystem;
• and
• determining, by the software RAID subsystem, that the first PCIe subsystem is one of a PCIe bridge device or a PCIe root device and, in response:
• claiming, by the software RAID subsystem, the first PCIe subsystem;
• installing, by the software RAID subsystem, a RAID protocol on the first PCIe subsystem;
• attaching, by the software RAID subsystem to the first PCIe subsystem, at least one RAID logical storage subsystem provided by at least one PCIe endpoint device that is included in the plurality of PCIe subsystems;
• and
• presenting, by the software RAID subsystem to the UEFI subsystem, a PCIe controller device that is included in the first PCIe subsystem as connected to the at least RAID logical storage subsystem.