Patent Application
20240028363
A data center is a facility that houses servers, data storage devices, and/or other associated components such as backup power supplies, redundant data communications connections, environmental controls such as air conditioning and/or fire suppression, and/or various security systems. A data center may be maintained by an information technology (IT) service provider. An enterprise may utilize data storage and/or data processing services from the provider in order to run applications that handle the enterprises' core business and operational data. The applications may be proprietary and used exclusively by the enterprise or made available through a network for anyone to access and use.
Virtual computing instances (VCIs), such as virtual machines and containers, have been introduced to lower data center capital investment in facilities and operational expenses and reduce energy consumption. A VCI is a software implementation of a computer that executes application software analogously to a physical computer. VCIs have the advantage of not being bound to physical resources, which allows VCIs to be moved around and scaled to meet changing demands of an enterprise without affecting the use of the enterprise's applications. In a software-defined data center, storage resources may be allocated to VCIs in various ways, such as through network attached storage (NAS), a storage area network (SAN) such as fiber channel and/or Internet small computer system interface (iSCSI), a virtual SAN, and/or raw device mappings, among others.
The term “virtual computing instance” (VCI) refers generally to an isolated user space instance, which can be executed within a virtualized environment. Other technologies aside from hardware virtualization can provide isolated user space instances, also referred to as data compute nodes. Data compute nodes may include non-virtualized physical hosts, VCIs, containers that run on top of a host operating system without a hypervisor or separate operating system, and/or hypervisor kernel network interface modules, among others. Hypervisor kernel network interface modules are non-VCI data compute nodes that include a network stack with a hypervisor kernel network interface and receive/transmit threads.
VCIs, in some embodiments, operate with their own guest operating systems on a host using resources of the host virtualized by virtualization software (e.g., a hypervisor, virtual machine monitor, etc.). The tenant (i.e., the owner of the VCI) can choose which applications to operate on top of the guest operating system. Some containers, on the other hand, are constructs that run on top of a host operating system without the need for a hypervisor or separate guest operating system. The host operating system can use name spaces to isolate the containers from each other and therefore can provide operating-system level segregation of the different groups of applications that operate within different containers. This segregation is akin to the VCI segregation that may be offered in hypervisor-virtualized environments that virtualize system hardware, and thus can be viewed as a form of virtualization that isolates different groups of applications that operate in different containers. Such containers may be more lightweight than VCIs.
While the specification refers generally to VCIs, the examples given could be any type of data compute node, including physical hosts, VCIs, non-VCI containers, and hypervisor kernel network interface modules. Embodiments of the present disclosure can include combinations of different types of data compute nodes.
VCIs can be granted access to hardware devices. More specifically, a guest operating system (OS) running on a VCI can be granted direct access to physical Peripheral Component Interconnect (PCI) functions on platforms with an I/O Memory Management Unit. PCI passthrough, as it is commonly referred to, allows guests to have exclusive access to PCI devices for a range of tasks. PCI passthrough allows PCI devices to appear and behave as if they were physically attached to the guest OS. PCI devices are known to those of skill in the art and include, for example, storage devices, networking devices, graphics devices (e.g., graphics cards, graphics processing units (GPUs), etc.), and others.
In previous approaches, the availability of a VCI may be jeopardized by some failure associated with a configured passthrough device. A “failure” associated with a passthrough device, as referred to herein, is an error or a fault originating at, or caused by, that passthrough device. For example, if a PCI Express (PCIe) uncorrectable error occurs because of a passthrough device, the hypervisor is at risk of crashing. Additionally, if a passthrough device causes an input-output memory management unit (IOMMU) fault, the VCI may be terminated as a matter of course. Such failures cause undesirable downtime in previous approaches.
Embodiments of the present disclosure can handle such failures without the undesirable outcomes of hypervisor crash and/or VCI termination. In some embodiments, a PCIe uncorrectable error or an IOMMU fault can be addressed in less than one second and availability of the VCI can be provided. As discussed further below, some embodiments include detecting a failure associated with a passthrough device and simulating a “surprise hot removal” of the device from the VCI. When the device has been successfully reset and is back to an accessible state it can be “hot added” back to the VCI and resume its function as a passthrough device.
As used herein, the singular forms “a”, “an”, and “the” include singular and plural referents unless the content clearly dictates otherwise. Furthermore, the word “may” is used throughout this application in a permissive sense (i.e., having the potential to, being able to), not in a mandatory sense (i.e., must). The term “include,” and derivations thereof, mean “including, but not limited to.” The term “coupled” means directly or indirectly connected.
The figures herein follow a numbering convention in which the first digit or digits correspond to the drawing figure number and the remaining digits identify an element or component in the drawing. Analogous elements within a Figure may be referenced with a hyphen and extra numeral or letter. Such analogous elements may be generally referenced without the hyphen and extra numeral or letter. For example, elements 108-1, 108-2, and 108-N in
The host 102 can incorporate a hypervisor 104 that can execute a number of virtual computing instances 106-1, 106-2, . . . , 106-N (referred to generally herein as “VCIs 106”). The VCIs can be provisioned with processing resources 108 and/or memory resources 110 and can communicate via the network interface 112. The processing resources 108 and the memory resources 110 provisioned to the VCIs can be local and/or remote to the host 102. For example, in a software defined data center, the VCIs 106 can be provisioned with resources that are generally available to the software defined data center and not tied to any particular hardware device. By way of example, the memory resources 110 can include volatile and/or non-volatile memory available to the VCIs 106. The VCIs 106 can be moved to different hosts (not specifically illustrated), such that a different hypervisor manages the VCIs 106. The host 102 can be in communication with the availability system 114. In some embodiments, the availability system 114 can be deployed on a server, such as a web server. The availability system 114 can include computing resources (e.g., processing resources and/or memory resources in the form of hardware, circuitry, and/or logic, etc.) to perform various operations to provide availability of passthrough devices configured on VCIs, as described in more detail herein.
As shown in
The OS layer 218 can a Portable Operating System Interface (POSIX)-like OS. It acts as a liaison between the VCI 208 and the physical hardware that supports it, such as hosts and/or the device(s) of the hardware layer 220. A VCI may utilize the OS layer 218 to communicate with the host server, for instance. As shown in
The hardware layer can include one or more passthrough devices. As shown in
A PCIe error from the PCI device 236 can be isolated from the guest OS 222 by the OS layer 218. In some embodiments, when a PCIe error is detected (e.g., by the PCI device 236) platform firmware (e.g., the availability system 114, previously described in connection with
When an IOMMU fault is caused by a passthrough device, the fault may be isolated from the guest OS 222 by the OS layer 218. An IOMMU fault may be caused by some failure in the IOMMU 238, for instance. When such a fault is caused, platform firmware can send an IOMMU fault interrupt to the OS layer 218. The IOMMU driver 234 can read and log details associated with the fault. The IOMMU driver 234 can send a hot remove event to the device manager 230. In some embodiments, the device manager 230, upon receiving the hot remove event, calls the passthrough driver 232 to detach from the PCI device 236. The passthrough driver 232 can send the hot remove event to the VMX 224 and the host agent 226. Responsive to receiving the hot remove event, the VMX 224 can send a PCIe hot remove interrupt to the guest OS 222. In some embodiments, the guest OS 222 handles the hot remove interrupt, unloads drivers associated with the PCI device 236, and removes the device 236. The IOMMU driver 234 can reset the PCI device 236 and wait for the device 236 to return to an accessible state. The IOMMU driver 234 can post a hot add event to the device manager 230. The device manager 230, upon receiving the hot add event, can scan the bus and rediscover the device 236. The IOMMU driver 234 can post the hot add event to the VMX 224 and the host agent 226. The VMX can send a PCIe hot add interrupt to the guest OS 222. In some embodiments, the guest OS 222 handles the hot add interrupt, rediscovers the device 236, and loads drivers associated with the device 236, rendering the device 236 again a passthrough device.
In some embodiments, the passthrough driver 232, rather than the PCIe error handling driver 228 or the IOMMU driver 234, can perform the reset of the device 236. In such embodiments, the device manager 230 may not be involved in the process.
The number of engines can include a combination of hardware and program instructions that is configured to perform a number of functions described herein. The program instructions (e.g., software, firmware, etc.) can be stored in a memory resource (e.g., machine-readable medium) as well as hard-wired program (e.g., logic). Hard-wired program instructions (e.g., logic) can be considered as both program instructions and hardware.
In some embodiments, the failure engine 452 can include a combination of hardware and program instructions that is configured to receive a notification of a failure associated with a passthrough device configured on a VCI. In some embodiments, the event engine 454 can include a combination of hardware and program instructions that is configured to communicate a hot remove event to a configuration file and a host agent of the VCI. In some embodiments, the interrupt engine 456 can include a combination of hardware and program instructions that is configured to communicate, by the configuration file, a hot remove interrupt to a guest OS running on the VCI. In some embodiments, the removal engine 458 can include a combination of hardware and program instructions that is configured to remove the device by the guest OS responsive to receiving the hot remove interrupt. In some embodiments, the reset engine 460 can include a combination of hardware and program instructions that is configured to reset the device. In some embodiments, the add event engine 462 can include a combination of hardware and program instructions that is configured to communicate a hot add event to the configuration file. In some embodiments, the add interrupt engine 464 can include a combination of hardware and program instructions that is configured to communicate, by the configuration file, a hot add interrupt to the guest OS. In some embodiments, the add engine 466 can include a combination of hardware and program instructions that is configured to add the device, by the guest OS, responsive to receiving the hot add interrupt.
Memory resources 510 can be non-transitory and can include volatile and/or non-volatile memory. Volatile memory can include memory that depends upon power to store information, such as various types of dynamic random access memory (DRAM) among others. Non-volatile memory can include memory that does not depend upon power to store information. Examples of non-volatile memory can include solid state media such as flash memory, electrically erasable programmable read-only memory (EEPROM), phase change memory (PCM), 3D cross-point, ferroelectric transistor random access memory (FeTRAM), ferroelectric random access memory (FeRAM), magneto random access memory (MRAM), Spin Transfer Torque (STT)-MRAM, conductive bridging RAM (CBRAM), resistive random access memory (RRAM), oxide based RRAM (OxRAM), negative-or (NOR) flash memory, magnetic memory, optical memory, and/or a solid state drive (SSD), etc., as well as other types of machine-readable media.
The processing resources 508 can be coupled to the memory resources 510 via a communication path 570. The communication path 570 can be local or remote to the machine 568. Examples of a local communication path 570 can include an electronic bus internal to a machine, where the memory resources 510 are in communication with the processing resources 408 via the electronic bus. Examples of such electronic buses can include Industry Standard Architecture (ISA), Peripheral Component Interconnect (PCI), Advanced Technology Attachment (ATA), Small Computer System Interface (SCSI), Universal Serial Bus (USB), among other types of electronic buses and variants thereof. The communication path 570 can be such that the memory resources 510 are remote from the processing resources 508, such as in a network connection between the memory resources 510 and the processing resources 508. That is, the communication path 570 can be a network connection. Examples of such a network connection can include a local area network (LAN), wide area network (WAN), personal area network (PAN), and the Internet, among others.
As shown in
Each of the number of modules 552, 554, 556, 558, 560, 562, 564, 566 can include program instructions and/or a combination of hardware and program instructions that, when executed by a processing resource 508, can function as a corresponding engine as described with respect to
The machine 568 can include a failure module 552, which can include instructions to receive a notification of a failure associated with a passthrough device configured on a VCI. The machine 568 can include an event module 554, which can include instructions to communicate a hot remove event to a configuration file and a host agent of the VCI. The machine 568 can include an interrupt module 556, which can include instructions to communicate, by the configuration file, a hot remove interrupt to a guest OS running on the VCI. The machine 568 can include a removal module 558, which can include instructions to remove the device by the guest OS responsive to receiving the hot remove interrupt. The machine 568 can include a reset module 560, which can include instructions to reset the device. The machine 568 can include an add event module 562, which can include instructions to communicate a hot add event to the configuration file. The machine 568 can include an add interrupt module 564, which can include instructions to communicate, by the configuration file, a hot add interrupt to the guest OS. The machine 568 can include an add module 566, which can include instructions to add the device, by the guest OS, responsive to receiving the hot add interrupt.
Although specific embodiments have been described above, these embodiments are not intended to limit the scope of the present disclosure, even where only a single embodiment is described with respect to a particular feature. Examples of features provided in the disclosure are intended to be illustrative rather than restrictive unless stated otherwise. The above description is intended to cover such alternatives, modifications, and equivalents as would be apparent to a person skilled in the art having the benefit of this disclosure.
The scope of the present disclosure includes any feature or combination of features disclosed herein (either explicitly or implicitly), or any generalization thereof, whether or not it mitigates any or all of the problems addressed herein. Various advantages of the present disclosure have been described herein, but embodiments may provide some, all, or none of such advantages, or may provide other advantages.
In the foregoing Detailed Description, some features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the disclosed embodiments of the present disclosure have to use more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.
