Patent Publication Number: US-7913251-B2

Title: Hypervisor virtualization of OS console and operator panel

Description:
This application is a divisional of application Ser. No. 10/735,403, filed Dec. 12, 2003, now U.S. Pat. No. 7,100,163, status allowed, which is herein incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates generally to the field of computer architecture and, more specifically, to methods and systems for allowing multiple operating system images within a logically partitioned data processing system to interact with a console and operator panel. 
     2. Description of Related Art 
     A logical partitioning option (LPAR) within a data processing system allows multiple copies of a single operating system (OS) or multiple heterogeneous operating systems to be simultaneously run on a single data processing system platform. A partition, within which an operating system image runs, is assigned a non-overlapping sub-set of the platform&#39;s resources. These platform allocable resources include one or more architecturally distinct processors with their interrupt management area, regions of system memory, and I/O adapter bus slots. The partition&#39;s resources are represented by its own open firmware device tree to the OS image. 
     Each distinct OS or image of an OS running within the platform are protected from each other such that software errors on one logical partition cannot affect the correct operation of any of the other partitions. This is provided by allocating a disjoint set of platform resources to be directly managed by each OS image and by providing mechanisms for ensuring that the various images cannot control any resources that have not been allocated to it. Furthermore, software errors in the control of an OS&#39;s allocated resources are prevented from affecting the resources of any other image. Thus, each image of the OS (or each different OS) directly controls a distinct set of allocable resources within the platform. 
     There are certain resources within many server platforms that exist singly, yet each distinct OS within the platform must interact with these resources. For example, the RS/6000, a product of International Business Machines Corporation of Armonk, N.Y., includes a console and an operator panel for allowing a system administrator to detect and correct problems within the platform. However, each of these resources exists singly within the platform and it is impractical to duplicate these resources. While present architectures often do not preclude the sharing of allocable resources of this type between partitions, there is no current architectural support for such sharing. Therefore, a method, system, and computer program product for providing the sharing of allocable resources within a logically partitioned platform is desirable. 
     SUMMARY OF THE INVENTION 
     The present invention provides a logically partitioned data processing system in which shared resources are emulated to provide each partition a separate copy of the shared resource. In one embodiment, the logically partitioned data processing system includes a plurality of logical partitions, a plurality of operating systems executing within the data processing system and a plurality of assignable resources. Each of the plurality of operating systems is assigned to a separate one of the plurality of logical partitions, such that no more than one operating system is assigned to any given logical partition. Each of the plurality of assignable resources is assigned to a single one of the plurality of logical partitions. The logically partitioned data processing system also includes a hypervisor. The hypervisor emulates shared resources, such as an operator panel and a system console, and provides a virtual copy of these shared resources to each of the plurality of logical partitions. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: 
         FIG. 1  depicts a pictorial representation of a distributed data processing system in which the present invention may be implemented; 
         FIG. 2 , a block diagram of a data processing system in accordance with the present invention is illustrated; 
         FIG. 3  depicts a block diagram of a data processing system, which may be implemented as a logically partitioned server, in accordance with the present invention; 
         FIG. 4  depicts a block diagram illustrating a prior art logically partitioned platform in accordance with the present invention; 
         FIG. 5  depicts a block diagram of a logically partitioned platform in which the present invention may be implemented; 
         FIGS. 6A-6B  depict high-level flowcharts illustrating exemplary processes, performed for example, in hypervisor  510 , for emulating a console and operator platform in accordance with the present invention; 
         FIG. 7  depicts a high level flowchart illustrating an exemplary process on a hardware system console for presenting the information from the various OS images to an operator in accordance with the present invention; and 
         FIG. 8  depicts a high level flowchart illustrating an exemplary process on a hardware system console for sending messages to various ones of multiple OS images running on a logically partitioned platform in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference now to the figures, and in particular with reference to  FIG. 1 , a pictorial representation of a distributed data processing system is depicted in which the present invention may be implemented. 
     Distributed data processing system  100  is a network of computers in which the present invention may be implemented. Distributed data processing system  100  contains network  102 , which is the medium used to provide communications links between various devices and computers connected within distributed data processing system  100 . Network  102  may include permanent connections, such as wire or fiber optic cables, or temporary connections made through telephone connections. 
     In the depicted example, server  104  is connected to hardware system console  150 . Server  104  is also connected to network  102 , along with storage unit  106 . In addition, clients  108 ,  110  and  112  are also connected to network  102 . These clients,  108 ,  110  and  112 , may be, for example, personal computers or network computers. For purposes of this application, a network computer is any computer coupled to a network that receives a program or other application from another computer coupled to the network. In the depicted example, server  104  is a logically partitioned platform and provides data, such as boot files, operating system images and applications, to clients  108 - 112 . Hardware system console  150  may be a laptop computer and is used to display messages to an operator from each operating system image running on server  104 , as well as to send input information, received from the operator, to server  104 . Clients  108 ,  110  and  112  are clients to server  104 . Distributed data processing system  100  may include additional servers, clients, and other devices not shown. Distributed data processing system  100  also includes printers  114 ,  116  and  118 . A client, such as client  110 , may print directly to printer  114 . Clients such as client  108  and client  112  do not have directly attached printers. These clients may print to printer  116 , which is attached to server  104 , or to printer  118 , which is a network printer that does not require connection to a computer for printing documents. Client  110 , alternatively, may print to printer  116  or printer  118 , depending on the printer type and the document requirements. 
     In the depicted example, distributed data processing system  100  is the Internet, with network  102  representing a worldwide collection of networks and gateways that use the TCP/IP suite of protocols to communicate with one another. At the heart of the Internet is a backbone of high-speed data communication lines between major nodes or host computers consisting of thousands of commercial, government, education, and other computer systems that route data and messages. Of course, distributed data processing system  100  also may be implemented as a number of different types of networks such as, for example, an intranet or a local area network. 
       FIG. 1  is intended as an example and not as an architectural limitation for the processes of the present invention. 
     With reference now to  FIG. 2 , a block diagram of a data processing system in accordance with the present invention is illustrated. Data processing system  200  is an example of a hardware system console, such as hardware system console  150  depicted in  FIG. 1 . Data processing system  200  employs a peripheral component interconnect (PCI) local bus architecture. Although the depicted example employs a PCI bus, other bus architectures, such as Micro Channel and ISA, may be used. Processor  202  and main memory  204  are connected to PCI local bus  206  through PCI bridge  208 . PCI bridge  208  may also include an integrated memory controller and cache memory for processor  202 . Additional connections to PCI local bus  206  may be made through direct component interconnection or through add-in boards. In the depicted example, local area network (LAN) adapter  210 , SCSI host bus adapter  212 , and expansion bus interface  214  are connected to PCI local bus  206  by a direct component connection. In contrast, audio adapter  216 , graphics adapter  218 , and audio/video adapter (A/V)  219  are connected to PCI local bus  206  by add-in boards inserted into expansion slots. Expansion bus interface  214  provides a connection for a keyboard and mouse adapter  220 , modem  222 , and additional memory  224 . In the depicted example, SCSI host bus adapter  212  provides a connection for hard disk drive  226 , tape drive  228 , CD-ROM drive  230 , and digital video disc read only memory drive (DVD-ROM)  232 . Typical PCI local bus implementations will support three or four PCI expansion slots or add-in connectors. 
     An operating system runs on processor  202  and is used to coordinate and provide control of various components within data processing system  200  in  FIG. 2 . The operating system may be a commercially available operating system, such as OS/2, which is available from International Business Machines Corporation. “OS/2” is a trademark of International Business Machines Corporation. An object-oriented programming system, such as Java, may run in conjunction with the operating system, providing calls to the operating system from Java programs or applications executing on data processing system  200 . Instructions for the operating system, the object-oriented operating system, and applications or programs are located on a storage device, such as hard disk drive  226 , and may be loaded into main memory  204  for execution by processor  202 . 
     Those of ordinary skill in the art will appreciate that the hardware in  FIG. 2  may vary depending on the implementation. For example, other peripheral devices, such as optical disk drives and the like, may be used in addition to or in place of the hardware depicted in  FIG. 2 . The depicted example is not meant to imply architectural limitations with respect to the present invention. For example, the processes of the present invention may be applied to multiprocessor data processing systems. 
     With reference now to  FIG. 3 , a block diagram of a data processing system, which may be implemented as a logically partitioned server, such as server  104  in  FIG. 1 , is depicted in accordance with the present invention. Data processing system  300  may be a symmetric multiprocessor (SMP) system including a plurality of processors  301 ,  302 ,  303 , and  304  connected to system bus  306 . For example, data processing system  300  may be an IBM RS/6000, a product of International Business Machines Corporation in Armonk, N.Y. Alternatively, a single processor system may be employed. Also connected to system bus  306  is memory controller/cache  308 , which provides an interface to a plurality of local memories  360 - 363 . I/O bus bridge  310  is connected to system bus  306  and provides an interface to I/O bus  312 . Memory controller/cache  308  and I/O bus bridge  310  may be integrated as depicted. 
     Data processing system  300  is a logically partitioned data processing system. Thus, data processing system  300  may have multiple heterogeneous operating systems (or multiple instances of a single operating system) running simultaneously. Each of these multiple operating systems may have any number of software programs executing within in it. Data processing system  300  is logically partitioned such that different I/O adapters  320 - 321 ,  328 - 329 ,  336 - 337 , and  346 - 347  may be assigned to different logical partitions. 
     Thus, for example, suppose data processing system  300  is divided into three logical partitions, P 1 , P 2 , and P 3 . Each of I/O adapters  320 - 321 ,  328 - 329 , and  336 - 337 , each of processors  301 - 304 , and each of local memories  360 - 363  is assigned to one of the three partitions. For example, processor  301 , memory  360 , and I/O adapters  320 ,  328 , and  329  may be assigned to logical partition P 1 ; processors  302 - 303 , memory  361 , and I/O adapters  321  and  337  may be assigned to partition P 2 ; and processor  304 , memories  362 - 363 , and I/O adapters  336  and  346 - 347  may be assigned to logical partition P 3 . 
     Each operating system executing within data processing system  300  is assigned to a different logical partition. Thus, each operating system executing within data processing system  300  may access only those I/O units that are within its logical partition. Thus, for example, one instance of the Advanced Interactive Executive (AIX) operating system may be executing within partition P 1 , a second instance (image) of the AIX operating system may be executing within partition P 2 , and a Windows 2000™ operating system may be operating within logical partition P 1 . Windows 2000 is a product and trademark of Microsoft Corporation of Redmond, Wash. 
     Peripheral component interconnect (PCI) Host bridge  314  connected to I/O bus  312  provides an interface to PCI local bus  315 . A number of Terminal Bridges  316 - 317  may be connected to PCI bus  315 . Typical PCI bus implementations will support four Terminal Bridges for providing expansion slots or add-in connectors. Each of Terminal Bridges  316 - 317  is connected to a PCI/I/O Adapter  320 - 321  through a PCI Bus  318 - 319 . Each I/O Adapter  320 - 321  provides an interface between data processing system  300  and input/output devices such as, for example, other network computers, which are clients to server  300 . Only a single I/O adapter  320 - 321  may be connected to each terminal bridge  316 - 317 . Each of terminal bridges  316 - 317  is configured to prevent the propagation of errors up into the PCI Host Bridge  314  and into higher levels of data processing system  300 . By doing so, an error received by any of terminal bridges  316 - 317  is isolated from the shared buses  315  and  312  of the other I/O adapters  321 ,  328 - 329 , and  336 - 337  that may be in different partitions. Therefore, an error occurring within an I/O device in one partition is not “seen” by the operating system of another partition. Thus, the integrity of the operating system in one partition is not effected by an error occurring in another logical partition. Without such isolation of errors, an error occurring within an I/O device of one partition may cause the operating systems or application programs of another partition to cease to operate or to cease to operate correctly. 
     Additional PCI host bridges  322 ,  330 , and  340  provide interfaces for additional PCI buses  323 ,  331 , and  341 . Each of additional PCI buses  323 ,  331 , and  341  are connected to a plurality of terminal bridges  324 - 325 ,  332 - 333 , and  342 - 343  which are each connected to a PCI I/O adapter  328 - 329 ,  336 - 337 , and  346 - 347  by a PCI bus  326 - 327 ,  334 - 335 , and  344 - 345 . Thus, additional I/O devices, such as, for example, modems or network adapters may be supported through each of PCI I/O adapters  328 - 329 ,  336 - 337 , and  346 - 347 . In this manner, server  300  allows connections to multiple network computers. A memory mapped graphics adapter  348  and hard disk  350  may also be connected to I/O bus  312  as depicted, either directly or indirectly. Hard disk  350  may be logically partitioned between various partitions without the need for additional hard disks. However, additional hard disks may be utilized if desired. 
     Those of ordinary skill in the art will appreciate that the hardware depicted in  FIG. 3  may vary. For example, other peripheral devices, such as optical disk drives and the like, also may be used in addition to or in place of the hardware depicted. The depicted example is not meant to imply architectural limitations with respect to the present invention. 
     With reference now to  FIG. 4 , a block diagram illustrating a prior art logically partitioned platform is depicted in accordance with the present invention. Logically partitioned platform  400  is an example of a platform that, in prior art systems, may have been implemented as server  104  in  FIG. 1 . Logically partitioned platform  400  includes partitioned hardware  430 , shared single hardware  420 , and operating systems  402 - 408 . Operating systems  402 - 408  may be multiple copies of a single operating system or multiple heterogeneous operating systems simultaneously run on platform  400 . 
     Partitioned hardware  430  includes a plurality of processors  432 - 438 , a plurality of system memory units  440 - 446 , a plurality of input/output (I/O) adapters  448 - 462 , and a storage unit  470 . Each of the processors  432 - 438 , memory units  440 - 446 , and I/O adapters  448 - 462  may be assigned to one of multiple partitions within logically partitioned platform  400 , each of which corresponds to one of operating systems  402 - 408 . 
     Shared single hardware unit  420  includes console  422  and operator panel  424 . Shared single hardware unit  420  may also include other shared devices not depicted in  FIG. 4 . Console  422  typically includes a display and data entry device such as a keyboard. Console  422  allows an operator to respond to and correct errors displayed on operator panel  424 . Operator panel  424  is typically a panel display, such as an LCD display, on the front of the physical chassis of the server in which text messages are displayed alerting an operator of potential problems within platform  400  or within a particular OS  402 - 408  running on platform  400 . 
     Each operating system image  402 - 408  must share access to resources within shared single hardware  420 . Therefore, some of the benefits of a logically partitioned platform are lost, since each partition may access and change the contents of shared resources, thus affecting other partitions within the platform. One alternative to allowing each partition to share access to shared single hardware  420  is to duplicate these hardware devices and have a separate operator panel and console for each partition. However, such a solution is bulky and, often cost prohibitive. 
     With reference now to  FIG. 5 , a block diagram of an exemplary logically partitioned platform is depicted in which the present invention may be implemented. The hardware in logically partitioned platform  500  may be implemented as, for example, server  200  in  FIG. 2 . Logically partitioned platform  500  is similar to logically partitioned platform  400  in  FIG. 4 . However, Hypervisor  510 , implemented as firmware, has been added. Firmware is “hard software” stored in a memory chip that holds its content without electrical power, such as, for example, read-only memory (ROM), programmable ROM (PROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), and non-volatile random access memory (non-volatile RAM). 
     Hypervisor  510  provides the OS images  402 - 408  running in multiple logical partitions each a virtual copy of a console and operator panel. The interface to the console is changed from an asynchronous teletype port device driver, as in the prior art, to a set of hypervisor firmware calls that emulate a port device driver. The hypervisor  510  encapsulates the data from the various OS images onto a message stream that is transferred to a computer  580 , known as a hardware system console  580 . 
     Hardware system console  580  is connected directly to logically partitioned platform  500  as illustrated in  FIG. 5 , or may be connected to logically partitioned platform through a network, such as, for example, network  102  in  FIG. 1 . Hardware system console  580  may be, for example, a desktop or laptop computer, and may be implemented as data processing system  200  in  FIG. 2 . Hardware system console  580  decodes the message stream and displays the information from the various OS images  402 - 408  in separate windows, at least one per OS image. Similarly, keyboard input information from the operator is packaged by the hardware system console, sent to logically partitioned platform  500  where it is decoded and delivered to the appropriate OS image via the hypervisor  510  emulated port device driver associated with the then active window on the hardware system console  580 . 
     Those of ordinary skill in the art will appreciate that the hardware and software depicted in  FIG. 5  may vary. For example, more or fewer processors and/or more or fewer operating system images may be used than those depicted in  FIG. 5 . The depicted example is not meant to imply architectural limitations with respect to the present invention. 
     With reference now to  FIGS. 6A-6B , high-level flowcharts illustrating exemplary processes, performed for example, in hypervisor  510 , for emulating a console and operator platform is depicted in accordance with the present invention. The operating systems, such as, for example, OS  402 - 408  in  FIG. 4 , call the hypervisor through a single entry point. One thread of execution illustrated in  FIG. 6A  gets data from a per partition buffer and sends data to the hardware system console while a separate thread of execution illustrated in  FIG. 6B  receives data from the hardware system console. 
     In the first thread of execution depicted in  FIG. 6A , the hypervisor receives a request from an operating system to get or send data (step  601 ). The hypervisor determines whether the request is a request to send or get data (step  602 ). If the request is a request to send data, then the hypervisor determines from which OS image (partition) the received data originated (step  604 ). The received data is then encapsulated onto a message stream (step  606 ). The encapsulated data includes the message or information received from the OS as well as the identity of the OS. The hypervisor then sends the message stream to the hardware system console (step  608 ). If the request is a request to get data, then the hypervisor determines which OS partition requested the data (step  610 ). Each partition is assigned a data buffer for storing data received from the hardware system console until retrieved by the partition&#39;s OS. Thus, the hypervisor determines whether the requesting partition&#39;s data buffer is empty (step  612 ). If the data buffers for the requesting partition is empty, then the hypervisor sends a NULL message to the requesting OS image indicating that there is no data from the hardware system console for the OS image to receive (step  616 ). If the data buffer is not empty, then the message data from the partition&#39;s data buffer is sent to the requesting OS image (step  614 ). 
     In the second thread of execution depicted in  FIG. 6B , the hypervisor receives and decodes data from the hardware system console (step  618 ). The hypervisor then places the decoded data into the buffer corresponding to the appropriate partition such that it may be retrieved and sent to the appropriate partition&#39;s OS image upon request (step  620 ). 
     With reference now to  FIG. 7 , a high level flowchart illustrating an exemplary process on a hardware system console for presenting the information from the various OS images to an operator is depicted in accordance with the present invention. To begin, the hardware system console receives a message stream from the hypervisor (step  702 ). The hardware system console decodes the message stream (step  704 ) and determines to which OS image the received data corresponds (step  706 ). Next, the hardware system console determines which window within the display corresponds to the determined OS image (step  708 ) and displays the received data to an operator in the window corresponding to the proper OS image (step  710 ). 
     With reference now to  FIG. 8 , a high level flowchart illustrating an exemplary process on a hardware system console for sending messages to various ones of multiple OS images running on a logically partitioned platform is depicted in accordance with the present invention. To begin, the hardware system console receives input from an operator from an input device, such as, for example, a keyboard (step  802 ). The hardware system console then determines which OS image corresponds to the active window from which the input was received (step  804 ). The data input, along with the OS image it corresponds with, are encapsulated into a message stream (step  806 ). The message stream is then sent to the hypervisor (step  808 ). 
     It is important to note that while the present invention has been described in the context of a fully functioning data processing system, those of ordinary skill in the art will appreciate that the processes of the present invention are capable of being distributed in the form of a computer readable medium of instructions and a variety of forms and that the present invention applies equally regardless of the particular type of signal bearing media actually used to carry out the distribution. Examples of computer readable media include recordable-type media such as a floppy disc, a hard disk drive, a RAM, and CD-ROMs and transmission-type media such as digital and analog communications links. 
     The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to best explain the principles of the invention, the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.