Dual-mode sideband interface for smart network interface controller

An information handling system may include a host system including a first root complex, a management controller including a second root complex, a network interface controller, and at least one switching circuit. The information handling system may be configured to, in response to the host system being powered on: couple the network interface controller to the management controller via the first root complex; and wherein the information handling system is further configured to, in response to the host system being powered off: activate the at least one switching circuit to couple the network interface controller to the management controller via the second root complex.

TECHNICAL FIELD

The present disclosure relates in general to information handling systems, and more particularly to methods and systems for coupling to a smart network interface controller while a host system is offline.

BACKGROUND

In some computing applications, an information handling system may include a hypervisor for hosting one or more virtual resources such as virtual machines (VMs). A hypervisor may comprise software and/or firmware generally operable to allow multiple virtual machines and/or operating systems to run on a single information handling system at the same time. This operability is generally allowed via virtualization, a technique for hiding the physical characteristics of computing system resources (e.g., physical hardware of the computing system) from the way in which other systems, applications, or end users interact with those resources. Thus, a virtual machine may comprise any program of executable instructions, or aggregation of programs of executable instructions, configured to execute a guest operating system on a hypervisor or host operating system in order to act through or in connection with the hypervisor/host operating system to manage and/or control the allocation and usage of hardware resources such as memory, central processing unit time, disk space, and input and output devices, and provide an interface between such hardware resources and application programs hosted by the guest operating system.

In other applications, an information handling system may be used in a “bare metal” configuration in which only one operating system is installed, and the hypervisor and virtual resources are not needed.

In either scenario, a network interface of the information handling system may comprise a smart network interface card or “SmartNIC” and/or a data processing unit (DPU), which may offer capabilities not found in traditional NICs. For purposes of this disclosure, the terms “SmartNIC” and “DPU” may be used interchangeably.

There are currently several ways to establish a sideband connection between a SmartNIC and a management controller such as a baseboard management controller (BMC). For example, a network controller sideband interface (NC-SI) connection may be established over reduced media-independent interface (RMII) based transport (RBT), over Peripheral Component Interconnect Express (PCIe) vendor defined message (VDM), over System Management Bus (SMBus), etc.

A SmartNIC is an advanced network controller which may be configured to run programs to communicate with a management controller such as a BMC via NC-SI even when the host system is powered off. Currently, a management controller and one or more SmartNICs are often connected by NC-SI over management component transport protocol (MCTP) based on PCIe VDMs to overcome various limitations of NC-SI over RBT and NC-SI over SMBus. However, PCIe VDM is not generally available after powering off the host system, because the host's PCIe root complex is then also offline. Thus the SmartNIC may lose its connection with the management controller even if power is still being applied to both the management controller and to the PCIe slot housing the SmartNIC.

This disclosure thus presents a way of establishing a dual-mode connection between the management controller and one or more SmartNICs for use in both a power-on and a power-off scenario for the host.

It should be noted that the discussion of a technique in the Background section of this disclosure does not constitute an admission of prior-art status. No such admissions are made herein, unless clearly and unambiguously identified as such.

SUMMARY

In accordance with the teachings of the present disclosure, the disadvantages and problems associated with existing SmartNIC technology within an information handling system may be reduced or eliminated.

In accordance with embodiments of the present disclosure, an information handling system may include a host system including a first root complex, a management controller including a second root complex, a network interface controller, and at least one switching circuit. The information handling system may be configured to, in response to the host system being powered on: couple the network interface controller to the management controller via the first root complex; and wherein the information handling system is further configured to, in response to the host system being powered off: activate the at least one switching circuit to couple the network interface controller to the management controller via the second root complex.

In accordance with these and other embodiments of the present disclosure, a method may include, while a host system that includes a first root complex is powered on, coupling a network interface controller to a management controller via the first root complex, wherein the management controller includes a second root complex; and in response to the host system being powered off, activate at least one switching circuit to couple the network interface controller to the management controller via the second root complex.

In accordance with these and other embodiments of the present disclosure, an article of manufacture may include a non-transitory, computer-readable medium having instructions thereon that are executable by a processor of an information handling system for: while a host system that includes a first root complex is powered on, coupling a network interface controller to a management controller via the first root complex, wherein the management controller includes a second root complex; and in response to the host system being powered off, activate at least one switching circuit to couple the network interface controller to the management controller via the second root complex.

DETAILED DESCRIPTION

Preferred embodiments and their advantages are best understood by reference toFIGS.1through2C, wherein like numbers are used to indicate like and corresponding parts.

For purposes of this disclosure, when two or more elements are referred to as “coupled” to one another, such term indicates that such two or more elements are in electronic communication or mechanical communication, as applicable, whether connected directly or indirectly, with or without intervening elements.

When two or more elements are referred to as “coupleable” to one another, such term indicates that they are capable of being coupled together.

For the purposes of this disclosure, the term “computer-readable medium” (e.g., transitory or non-transitory computer-readable medium) may include any instrumentality or aggregation of instrumentalities that may retain data and/or instructions for a period of time. Computer-readable media may include, without limitation, storage media such as a direct access storage device (e.g., a hard disk drive or floppy disk), a sequential access storage device (e.g., a tape disk drive), compact disk, CD-ROM, DVD, random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), and/or flash memory; communications media such as wires, optical fibers, microwaves, radio waves, and other electromagnetic and/or optical carriers; and/or any combination of the foregoing. Physical computer-readable media such as disk drives, solid-state drives, non-volatile memory, etc. may also be referred to herein as “physical storage resources.”

For the purposes of this disclosure, the term “management controller” may broadly refer to an information handling system that provides management functionality (typically out-of-band management functionality) to one or more other information handling systems. In some embodiments, a management controller may be (or may be an integral part of) a service processor, a baseboard management controller (BMC), a chassis management controller (CMC), or a remote access controller (e.g., a Dell Remote Access Controller (DRAC) or Integrated Dell Remote Access Controller (iDRAC)).

FIG.1illustrates a block diagram of selected components of an example information handling system100having a plurality of host systems102, in accordance with embodiments of the present disclosure. As shown inFIG.1, information handling system100may include a plurality of host systems102coupled to one another via an internal network110.

In some embodiments, information handling system100may include a single chassis housing a plurality of host systems102. In other embodiments, information handling system100may include a cluster of multiple chassis, each with one or more host systems102. In yet other embodiments, host systems102may be entirely separate information handling systems, and they may be coupled together via an internal network or an external network such as the Internet.

In some embodiments, a host system102may comprise a server (e.g., embodied in a “sled” form factor). In these and other embodiments, a host system102may comprise a personal computer. In other embodiments, a host system102may be a portable computing device (e.g., a laptop, notebook, tablet, handheld, smart phone, personal digital assistant, etc.). As depicted inFIG.1, information handling system102may include a processor103, a memory104communicatively coupled to processor103, and a network interface106communicatively coupled to processor103. For the purposes of clarity and exposition, inFIG.1, each host system102is shown as comprising only a single processor103, single memory104, and single network interface106. However, a host system102may comprise any suitable number of processors103, memories104, and network interfaces106.

As shown inFIG.1, a memory104may have stored thereon a hypervisor116and one or more guest operating systems (OS)118. In some embodiments, hypervisor116and one or more of guest OSes118may be stored in a computer-readable medium (e.g., a local or remote hard disk drive) other than a memory104which is accessible to processor103. Each guest OS118may also be referred to as a “virtual machine.”

A hypervisor116may comprise software and/or firmware generally operable to allow multiple virtual machines and/or operating systems to run on a single computing system (e.g., an information handling system102) at the same time. This operability is generally allowed via virtualization, a technique for hiding the physical characteristics of computing system resources (e.g., physical hardware of the computing system) from the way in which other systems, applications, or end users interact with those resources. A hypervisor116may be one of a variety of proprietary and/or commercially available virtualization platforms, including without limitation, VIRTUALLOGIX VLX FOR EMBEDDED SYSTEMS, IBM's Z/VM, XEN, ORACLE VM, VMWARE's ESX SERVER, L4 MICROKERNEL, TRANGO, MICROSOFT's HYPER-V, SUN's LOGICAL DOMAINS, HITACHI's VIRTAGE, KVM, VMWARE SERVER, VMWARE WORKSTATION, VMWARE FUSION, QEMU, MICROSOFT's VIRTUAL PC and VIRTUAL SERVER, INNOTEK's VIRTUALBOX, and SWSOFT's PARALLELS WORKSTATION and PARALLELS DESKTOP.

In one embodiment, a hypervisor116may comprise a specially-designed OS with native virtualization capabilities. In another embodiment, a hypervisor116may comprise a standard OS with an incorporated virtualization component for performing virtualization.

In another embodiment, a hypervisor116may comprise a standard OS running alongside a separate virtualization application. In this embodiment, the virtualization application of the hypervisor116may be an application running above the OS and interacting with computing system resources only through the OS. Alternatively, the virtualization application of a hypervisor116may, on some levels, interact indirectly with computing system resources via the OS, and, on other levels, interact directly with computing system resources (e.g., similar to the way the OS interacts directly with computing system resources, or as firmware running on computing system resources). As a further alternative, the virtualization application of a hypervisor116may, on all levels, interact directly with computing system resources (e.g., similar to the way the OS interacts directly with computing system resources, or as firmware running on computing system resources) without utilizing the OS, although still interacting with the OS to coordinate use of computing system resources.

As stated above, a hypervisor116may instantiate one or more virtual machines. A virtual machine may comprise any program of executable instructions, or aggregation of programs of executable instructions, configured to execute a guest OS118in order to act through or in connection with a hypervisor116to manage and/or control the allocation and usage of hardware resources such as memory, CPU time, disk space, and input and output devices, and provide an interface between such hardware resources and application programs hosted by the guest OS118. In some embodiments, a guest OS118may be a general-purpose OS such as WINDOWS or LINUX, for example. In other embodiments, a guest OS118may comprise a specific- and/or limited-purpose OS, configured so as to perform application-specific functionality (e.g., persistent storage).

At least one host system102in information handling system100may have stored within its memory104a virtual machine manager120. A virtual machine manager120may comprise software and/or firmware generally operable to manage individual hypervisors116and the guest OSes118instantiated on each hypervisor116, including controlling migration of guest OSes118between hypervisors116. AlthoughFIG.1shows virtual machine manager120instantiated on a host system102on which a hypervisor116is also instantiated, in some embodiments virtual machine manager120may be instantiated on a dedicated host system102within information handling system100, or a host system102of another information handling system100.

A network interface106may include any suitable system, apparatus, or device operable to serve as an interface between an associated information handling system102and internal network110. A network interface106may enable its associated information handling system102to communicate with internal network110using any suitable transmission protocol (e.g., TCP/IP) and/or standard (e.g., IEEE 802.11, Wi-Fi). In certain embodiments, a network interface106may include a physical network interface card (NIC). In the same or alternative embodiments, a network interface106may be configured to communicate via wireless transmissions. In the same or alternative embodiments, a network interface106may provide physical access to a networking medium and/or provide a low-level addressing system (e.g., through the use of Media Access Control addresses). In some embodiments, a network interface106may be implemented as a local area network (“LAN”) on motherboard (“LOM”) interface. A network interface106may comprise one or more suitable NICs, including without limitation, mezzanine cards, network daughter cards, etc.

In some embodiments, a network interface106may comprise a SmartNIC and/or a DPU. In addition to the stateful and custom offloads a SmartNIC or DPU may provide, it may have an independent management domain with a separate operating system, independent credentials, and independent remote access. Accordingly, network interface106may include its own specialized processor and memory.

In addition to processor103, memory104, and network interface106, a host system102may include one or more other information handling resources.

Internal network110may be a network and/or fabric configured to communicatively couple information handling systems to each other. In certain embodiments, internal network110may include a communication infrastructure, which provides physical connections, and a management layer, which organizes the physical connections of host systems102and other devices coupled to internal network110. Internal network110may be implemented as, or may be a part of, a storage area network (SAN), personal area network (PAN), local area network (LAN), a metropolitan area network (MAN), a wide area network (WAN), a wireless local area network (WLAN), a virtual private network (VPN), an intranet, the Internet or any other appropriate architecture or system that facilitates the communication of signals, data and/or messages (generally referred to as data). Internal network110may transmit data using any storage and/or communication protocol, including without limitation, Fibre Channel, Fibre Channel over Ethernet (FCoE), Small Computer System Interface (SCSI), Internet SCSI (iSCSI), Frame Relay, Ethernet Asynchronous Transfer Mode (ATM), Internet protocol (IP), or other packet-based protocol, and/or any combination thereof. Network110and its various components may be implemented using hardware, software, or any combination thereof.

Turning now toFIGS.2A,2B, and2C, block diagrams of selected components of an information handling system200are shown, according to some embodiments. In particular,FIG.2Aillustrates an overview of the relevant components of information handling system200,FIG.2Billustrates information handling system200in operation while its host system is powered on, andFIG.2Cillustrates information handling system200in operation while its host system is powered off.

Information handling system200may include a host system that includes PCIe root complex210, which is communicatively coupled to one or more network interfaces206(e.g., SmartNICs). For simplicity, the other components of the host system (e.g., processor(s), memory, storage, etc.) are omitted in these drawings. Network interfaces206may be SmartNICs in some embodiments. Information handling system200may also include a management controller212such as a BMC.

As shown inFIG.2A, management controller212may operate both as a PCIe endpoint and as a root complex by virtue of multiplexer (MUX) circuitry included therein. Embodiments of this disclosure allow for the PCIe slots of the host system (e.g., slots housing one or more network adapters206) to be accessed either via the host PCIe root complex210or via the PCIe root complex embedded in management controller212. This may be accomplished via MUX214, PCIe switch216, and one or more MUXes218.

When the host is powered on, management controller212is coupled to PCIe root complex210of the host as a PCIe endpoint. Management controller212and network interfaces206may communicate via PCIe root complex210using NC-SI over MCTP based on PCIe VDM. A service may execute on network interface206to access management controller212through the network which is set by NC-SI. Network interfaces206may also provide an in-band access ability for management controller212on their data ports.

When the host is powered off, a new sideband path is activated via MUX214, PCIe switch216, and MUX218, such that management controller212couples its internal PCIe root complex to the PCIe ports housing network interfaces206. Network interfaces206are thus coupled to management controller212through the PCIe bus and may register a NIC port for side-band communication.

In one embodiment, when the host powers down, circuitry (e.g., circuitry within management controller212, on the host motherboard, or in any other suitable location) may detect the loss of power and implement the necessary changes in state to allow management controller212to communicate with network interfaces206via the new sideband interface. For example, management controller212may begin operating as a PCIe root complex device instead of a PCIe endpoint. Management controller212may then initialize the sideband PCIe bus. MUX214may decouple management controller212from PCIe root complex210and couple it instead to PCIe switch216. PCIe switch216may allow management controller212to communicate with more than one network interface206, if more than one such interface is present. And MUX218may decouple network interface206from PCIe root complex210and couple it instead to PCIe switch216.

As shown, the PCIe link width need not be the same for both data paths. The PCIe link from PCIe root complex210is shown as an x16 sink in one embodiment, while the PCIe link from management controller212is shown as an x1 link.

Once the change-over has occurred, network interface206may register a NIC port on management controller212, bridging this NIC port with its NC-SI port. When the initiation is finished, management controller212may bind its NC-SI port and all attached PCIe NICs to the same Ethernet bridge and transfer the IP address of the NC-SI port to this bridge. This arrangement may allow the network topology between management controller212and network interfaces206to be unchanged on both layers 2 and 3 of the network according to the Open Systems Interconnection (OSI) model. Thus for the services which need to access management controller212both inside and outside, network interface206can keep running seamlessly.

Although various possible advantages with respect to embodiments of this disclosure have been described, one of ordinary skill in the art with the benefit of this disclosure will understand that in any particular embodiment, not all of such advantages may be applicable. In any particular embodiment, some, all, or even none of the listed advantages may apply.

Unless otherwise specifically noted, articles depicted in the drawings are not necessarily drawn to scale. However, in some embodiments, articles depicted in the drawings may be to scale.

Further, reciting in the appended claims that a structure is “configured to” or “operable to” perform one or more tasks is expressly intended not to invoke 35 U.S.C. § 112(f) for that claim element. Accordingly, none of the claims in this application as filed are intended to be interpreted as having means-plus-function elements. Should Applicant wish to invoke § 112(f) during prosecution, Applicant will recite claim elements using the “means for [performing a function]” construct.