Kernel Plug And Play In Windows Vista Allen

Kernel Plug And Play In Windows Vista Allen Marshall Lead Program Manager Windows Core Platform Architecture Microsoft Corporation

Agenda Enhanced scenario support Device custom properties Device ejection support Asynchronous Pn. P operations Kernel Pn. P diagnostic tracing Supporting hardware evolution Legacy reduction Interrupt enhancements Large system support Multilevel rebalance Machine. inf logistics Common BIOS errata that impact Pn. P

Background Windows Vista features continued advancement of Windows kernel Pn. P support, driven by Evolving hardware technologies PCI Express NUMA relations in many systems Mainstream adoption of advanced server configurations Hot add memory Continued development to enhance existing and enable new scenarios Enabling faster system startup Improved diagnostics, manageability

Enhanced Scenario Support Device properties in Windows Today, Windows provides the kernel DDI Io. Open. Device. Registry. Key() Returns a device or driver registry key Drivers can access registry data using standard registry DDIs Setup information Name of the device’s PDO Use of a DDI is preferred to accessing the registry directly Allows better abstraction in the operating system Backing store location may change in the future Windows Vista will extend this to allow custom device properties to be both set and retrieved for a device node

Enhanced Scenario Support Custom property DDIs in Windows Vista This offers several practical applications The device’s bus driver can set these custom device properties on the device’s devnode The device may store useful information in its firmware, and make this available to the OS Icon image Device description string Manufacturer’s web site URL Device driver Kernel-mode Io. Set. Device. Property. Data() Io. Get. Device. Property. Data() User-mode Setup. Di…()

Enhanced Scenario Support Device custom property DDIs Function prototypes are declared in wdm. h Bus drivers should not call these DDIs until they have received a IRP_MN_QUERY_RESOURCE_REQUIREMENTS IRP This will ensure that Pn. P has created and initialized the device node associated with the PDO Calling too early results in bug check 0 x. CA PNP_DETECTED_FATAL_ERROR Callers must be running at IRQL == PASSIVE_LEVEL Locale-neutral property replace any existing locale-specific properties If you have a locale specific property, be sure to set this property for all relevant locales

Enhanced Scenario Support Device custom property DDIs NTSTATUS Io. Set. Device. Property. Data ( __in PDEVICE_OBJECT __in CONST DEVPROPKEY __in_LCID __in ULONG __in DEVPROPTYPE __in ULONG __in_opt PVOID ) Pdo, *Property. Key, Lcid, Flags, Type, Size, Data Pdo – pointer to the physical device object Property. Key – pointer to the property key identifying the property Lcid – language identifier Flags PLUGPLAY_PROPERTY_PERSISTENT – Property should be persisted across boots Type – custom property type Size – custom property data size Data – pointer to the custom property data

Enhanced Scenario Support Device custom property DDIs Deleting custom device data If Data is NULL, the specified property will be deleted If Data is NULL and LCID is specified, then the property data for the specified LCID will be deleted If Data is NULL and LCID is LOCALE_NEUTRAL, then property data for all languages will be deleted

Enhanced Scenario Support Device custom property DDIs Io. Get. Device. Property. Data ( __in PDEVICE_OBJECT __in CONST DEVPROPKEY __in LCID __reserved ULONG __in ULONG __out PVOID __out PULONG __out PDEVPROPTYPE ) Pdo, *Property. Key, Lcid, Flags, Size, Data, Required. Size, Type Pdo – pointer to the physical device object Property. Key – pointer to the property key identifying the property Lcid – language identifier Flags – reserved Size – custom property data size Data – pointer to the custom property data Required. Size – pointer that receives the required size for getting the data Type – pointer that receives the custom property data type

Enhanced Scenario Support Device custom property DDIs The PCI driver in Windows Vista will expose certain properties for a PCI root bus and PCI bridges and devices using these DDIs These properties are available to other kernel mode and user mode components once the root bus or a PCI device is started Not shown in Windows Vista UI Function drivers can retrieve custom properties for PCI devices once the PDO completes the Start IRP If a property is not applicable to a PCI device, then it will not be set and cannot be retrieved These properties are volatile and are automatically refreshed across reboots or change of device location These are read-only properties, and may not be modified Any modification to these properties from user or kernel mode will not change the operational behavior of a root bus or a device

Enhanced Scenario Support Device custom property DDIs Examples PCI root bus Secondary side characteristics Secondary side speed and mode Available when the platform defines _DSM method function 4 for the PCI host bridge PCI device Device current speed and mode Applicable for PCI Conventional and PCI-X devices Device Base. Class, Sub. Class

Enhanced Scenario Support Device ejection DDIs Windows today provides the Io. Device. Eject. Request() DDI Typically called by a bus driver to notify the Pn. P manager that a hardware device eject button for one of the bus driver’s child devices has been pressed Callers of this API have no elegant way to know if the device eject has succeeded This can lead to unnecessary complication in driver code, such as polling or other undesirable workarounds Asynchronous behavior Returns no NTSTATUS code (returns VOID)

Enhanced Scenario Support Device ejection DDIs In order to better enable hardware evolution and enhance diagnostics, Windows Vista introduces an improved device eject DDI Io. Device. Eject. Request. Ex() Supersedes Io. Device. Eject. Request() Provides an asynchronous callback mechanism Allows the caller to determine if and when the actual device ejection has completed successfully Other software actions may be taken, e. g. Update a management console; illuminate eject complete indicator Allows callers to pass in a callback and context to be invoked upon successful completion of the hardware eject operation Enables synchronous ejection behavior

Enhanced Scenario Support Device ejection DDIs Providing an asynchronous callback leads to less complexity in 3 rd party driver code Allows platform firmware a deterministic means to know ejection completion status via _OST Improves stability, reliability Fosters easier development and debugging, etc.

Enhanced Scenario Support Device ejection DDIs NTSTATUS Io. Request. Device. Eject. Ex( __in PDEVICE_OBJECT Physical. Device. Object, __in_opt PIO_DEVICE_EJECT_CALLBACK Callback, __in_opt PVOID Context ); Physical. Device. Object – pointer to the PDO of the device to eject Callback – pointer to the caller's callback if they want to find out the ultimate status of the eject operation Context – context value passed to the callback Return Value – standard NTSTATUS codes If this function succeeds, it does *not* mean that the eject has succeeded rather, it means that the eject was successfully queued up and that the caller's callback will be called with the final status If this function fails, the caller's callback is not called

Enhanced Scenario Support Interrupt DDIs With the advent of PCI Express MSI/MSI-X, Windows Vista includes several interrupt architecture enhancements Kernel Pn. P exports a new DDI for connecting to interrupts: Io. Connect. Interrupt. Ex() Required for devices that support Message-signaled interrupts For details, refer to the white paper “Interrupt Architecture Enhancements in Windows”

Enhanced Scenario Support Asynchronous Pn. P operations Two of the slowest Pn. P operations are Starting a device IRP_MN_START_DEVICE Enumerating a bus IRP_MN_QUERY_RELATIONS – Bus. Relations Historically, Pn. P serialized these operations In Windows Vista, these operations are overlapped Offers substantive savings on consumer desktops ≈ 1 to 3 seconds by overlapping PATA/SATA enumeration Huge gains possible on systems with large number of slow devices

Enhanced Scenario Support Asynchronous Pn. P operations Driver participation is required to enable parallelism Drivers should pend these IRPs IRP_MN_QUERY_RELATIONS (Bus. Relations) IRP_MN_START_DEVICE Pn. P manager will dispatch other operations while the IRP is in a pended state This only works if drivers participate On older versions of Windows, pending an IRP has no net effect Pn. P manager will wait for the pended IRP to complete Pn. P will provide tracing data Allows driver writers to determine how long it takes to complete these IRPs Indicates if the IRP was pended

Enhanced Scenario Support Asynchronous Pn. P operations Drivers having start order dependencies will not work E. g. , PS/2 mouse and keyboard Avoid these types of dependencies in your designs Plug and play will serialize operations around drivers known to have such dependencies Avoid exposing any start order-dependent information Network connection numbers Disk numbers COM port numbers

Enhanced Scenario Support Kernel Pn. P diagnostic tracing Windows Vista contains diagnostic tracing hooks around plug and play operations Allows tracing failed Pn. P operations such as Ejection failures Code 10 failures (device failed to start) Data may be utilized for Identifying problematic systems or devices Discovering failure trends

Enhanced Scenario Support Kernel Pn. P diagnostic tracing Tracing is visible in Event Viewer Ejection failures will appear in the System channel by default More detailed tracing can be enabled for the Kernel-Pn. P Diagnostic provider Refer to WHDC for additional details

Enhanced Scenario Support Kernel Pn. P diagnostic tracing

Hardware Evolution Support Legacy reduction Microsoft is continuing to eliminate legacy platform support as new technologies mature Reduces platform complexity while increasing flexibility Improves system reliability Reduces firmware code size Future legacy reduction efforts will be communicated in the Windows Hardware Newsletter

Hardware Evolution Support Legacy reduction ACPI support is required in Windows Vista Only the ACPI HAL and multiprocessor kernel are provided APM, MPS, PNPBIOS support has been removed No ISAPn. P enumeration support isapnp. sys is not installed by default Requires reference in your device’s. inf Minimal functionality preserved in msisadrv. sys Contains routines to manage an ISA bridge Allows exporting an interrupt translator interface from the HAL Required to support PS/2 keyboards and mice

Hardware Evolution Support Large resource descriptors Previous versions of Windows operating systems limited the length of a single address range descriptor to 4 GB Ranges > 4 GB had to be broken up into n contiguous 4 GB ranges Windows XP and Windows Server 2003 will bug check if they encounter resource descriptors > 4 GB Windows Vista introduces support for large memory descriptors BIOS ASL can use QWORD resource descriptors to describe ranges > 4 GB

Hardware Evolution Support Large resource descriptors Windows Vista defines new large memory resource types Defined in wdm. h Used internally in Windows Vista to support Hot Add memory, large PCI Express BARs Used by: acpi. sys, pci. sys These memory types should only be accessed using the DDIs provided Details will be published in the WDK

Hardware Evolution Support Large resource descriptors Structure Maximum Length (approx) Granularity Memory 40 1 TB 256 B Memory 48 256 TB 64 KB Memory 64 16777215 TB 4 GB

Hardware Evolution Support Large resource descriptors NTSTATUS Rtl. Io. Encode. Mem. Io. Resource ( __in PIO_RESOURCE_DESCRIPTOR Descriptor, __in UCHAR Type, __in ULONG Length, __in ULONG Alignment, __in ULONG Minimum. Address, __in ULONG Maximum. Address ); NTSTATUS Rtl. Cm. Encode. Mem. Io. Resource ( __in PCM_PARTIAL_RESOURCE_DESCRIPTOR Descriptor, __in UCHAR Type, __in ULONG Length, __in ULONG Start ); ULONG Rtl. Io. Decode. Mem. Io. Resource ( __in PIO_RESOURCE_DESCRIPTOR Descriptor, __out_opt PULONG Alignment, __out_opt PULONG Minimum. Address, __out_opt PULONG Maximum. Address ); ULONG Rtl. Cm. Decode. Mem. Io. Resource ( __in PCM_PARTIAL_RESOURCE_DESCRIPTOR Descriptor, __out_opt PULONG Start );

Hardware Evolution Support Describing resource domains A resource domain starts with either An ACPI module device A PCI root bridge (PCI Express root port) All child resources within a resource domain must be claimed by the root For a subtractive PCI bridge, subtractive resources must be reported Positive decode resources must be correctly reported by the PCI bridge All PCI bus numbers must be accurately reported

Hardware Evolution Support NUMA support Windows Server Longhorn will make use of platform-reported proximity relationships Correlates devices with temporal memory and processor resources Key driver routines are invoked on the closest processor, so memory will be allocated from NUMA local memory Requires no driver changes Add. Device, IRP_MN_QUERY_DEVICE_RELATIONS-Bus. Relations The platform should include _PXM in the appropriate scope in the system hierarchy _PXM must correlate to either SRAT or ACPI namespace information for memory and processor

Hardware Evolution Support Resource allocation Windows Vista introduces several changes to resource allocation to better support PCI bridges Partial arbitration Support for both pure and partially subtractive PCI bridges Windows Vista has reduced the default sizes for PCI bridge windows On a large server system, previous default bridge window sizes could lead to resources being over-committed I/O windows are limited to 4 K PCI Express endpoints may not use I/O Memory windows are limited to 1 MB

Hardware Evolution Support Resource allocation If a critical device is a peer of a non-boot configured device, the parent PCI bridge won’t get rebalanced Example devices that will limit rebalance Debugger devices (USB or 1394) VGA Mass storage device Partially boot configured bridges will not be rebalanced Bridge windows can’t be expanded Devices behind the bridge may not be functional due to resource conflicts or failures Platform must boot configure required boot devices If devices requiring boot configuration are behind a bridge, boot configure all devices behind the bridge

Hardware Evolution Support Multilevel resource rebalance is a mechanism used by Pn. P to dynamically reconfigure a device hierarchy that has already been assigned resources Allows for optimal resource assignment for a newly added device BIOS solution may over-commit resources Allows Windows Vista to dynamically respond to events like docking or hot add of devices Multilevel rebalance has implications for devices behind PCI bridges and BIOS configuration of bridges and devices This will allow dynamic adjustment of PCI bridge resources Resource rebalance is transparent to applications

Hardware Evolution Support Multilevel resource rebalance Rebalance event flow Resource rebalance is triggered by a hardware event Plug and play attempts to stop devices New resource assignments are computed using devices that can be stopped Plug and play stops devices that can be stopped Plug and play restarts stopped devices with new resource assignments

Hardware Evolution Support Multilevel resource rebalance Example driver events that will trigger resource rebalance Plug and play cannot assign resources to a newly added device For instance, a PCI Express. Card device is inserted and the memory range for the parent PCI bridge cannot accommodate the device’s memory requirements Driver reports that its resource requirements have changed Device driver calls Io. Invalidate. Device. State() and reports PNP_DEVICE_RESOURCE_REQUIREMENTS_CHANGED in the subsequent IRP_MN_QUERY_PNP_DEVICE_STATE Allows a driver to relinquish unused resources back to the system

Hardware Evolution Support Multilevel resource rebalance Started State IRP_MN_QUERY_STOP_DEVICE (1) IRP_MN_CANCEL_STOP_DEVICE (4) Stop-Pending State IRP_MN_STOP_DEVICE (2) IRP_MN_START_DEVICE (3) Stopped State Failed Restart (5)

Hardware Evolution Support Multilevel Resource Rebalance Handling Resource Rebalance Requests Plug and play will send IRP_MN_QUERY_STOP_DEVICE to drivers Devices that succeed this IRP will participate Succeed this IRP as much as possible If succeeded, plug and play will send IRP_MN_STOP_DEVICE IRP_MN_START_DEVICE With new set of resources If a child device fails this IRP, its parent cannot be stopped Failing this IRP can cause resource rebalance to fail Some device will not work in the system Code 12 – CM_PROB_NORMAL_CONFLICT If you fail IRP_MN_QUERY_STOP_DEVICE, you will receive IRP_MN_CANCEL_STOP_DEVICE

Hardware Evolution Support Multilevel resource rebalance When you receive IRP_MN_STOP_DEVICE, drivers must Queue all I/O requests (do not fail I/O) Release all hardware resources Disconnect interrupts Unmap I/O, memory and disable hardware decodes Do not put the device into D 3 Do not reset I/O queues When you receive a IRP_MN_START_DEVICE after a IRP_MN_STOP_DEVICE, drivers must Treat the resources as new resources Reconnect new interrupts Map new I/O, memory and enable hardware decodes Do not re-initialize IO queues Resume handling I/O

Hardware Evolution Support Multilevel resource rebalance Be prepared to handle resource rebalance in your device drivers You may see IRP_MN_SURPRISE_REMOVAL immediately after IRP_MN_STOP_DEVICE If a parent device failed its IRP_MN_START_DEVICE during rebalance You may see a IRP_MN_CANCEL_STOP_DEVICE without seeing a IRP_MN_QUERY_STOP_DEVICE This can happen if someone above you in the stack fails IRP_MN_QUERY_STOP_DEVICE and completes the IRP

Hardware Evolution Support Multilevel resource rebalance Test your driver for resource rebalance requests Enable driver verifier Run pnpdtest. exe to attempt resource rebalance on your device Pnpdtest. exe is available in the WDK

Avoiding Pn. P Problems MCFG resource conflicts Claim MCFG resources as a motherboard resource devnode As a peer of your root PCI bus Correctly report subtractive decode resources Properly report resources for subtractive bridges All subtractive devices must be accounted for at the hierarchy root Correct use of motherboard resource devnodes Claim resources at the proper level in the device hierarchy E. g. , ISA resources should be under the PCI-ISA bridge Should represent real addresses not discoverable by the OS Provide an _DIS method for devices claiming resources not decoded by actual hardware

Machine. inf Logistics Machine. inf is the INF file used by the Windows operating system To map core chipset hardware and BIOSenumerated device identifiers (IDs) during the Windows startup process Machine. inf requires updates When new chipsets evolve When system manufacturers change device description strings for their current chipsets Updates are incorporated into the latest Windows build on a quarterly basis

Machine. inf Logistics Submissions for Windows Vista will be accepted up until the Release Candidate 1 (RC 1) milestone You are required to provide two test hardware systems to Microsoft Use care with NO_DRV versus PCI_DRV. inf directives System can become inoperative if NO_DRV is specified on PCI bridges with child devices For details, refer to the white paper Machine. inf Update Submission Procedure

Call To Action Continue driving deprecation of unnecessary legacy BIOS features Firmware developers should start using large resource descriptors for systems running Windows Vista Take advantage of the enhanced ejection infrastructure in Windows Vista Test and report issues to Microsoft Driver developers should begin using Io. Connect. Interrupt. Ex() Driver developers must properly design and test for to support changes in Pn. P Asynchronous operations – measure start performance improvements Multilevel resource rebalance New Pn. P DDIs

Additional Resources Web Resources Plug and Play – Architecture and Driver Support http: //www. microsoft. com/whdc/system/pnppwr/pnp/default. mspx White Papers Firmware Allocation of PCI Device Resources in Windows http: //www. microsoft. com/whdc/system/bus/pci/PCI-rsc. mspx Interrupt Architecture Enhancements in Windows http: //www. microsoft. com/whdc/system/bus/PCI/MSI. mspx PCI Multi-level Rebalance in Windows Longhorn http: //www. microsoft. com/whdc/system/bus/PCI/multilevel-rebal. mspx Supporting Subtractive PCI-to-PCI Bridges in Windows http: //www. microsoft. com/whdc/system/bus/pci/PCIbridge-subtr. mspx Machine. inf Update Submission Procedure http: //www. microsoft. com/whdc/system/CEC/machine_inf. mspx Related Sessions CPA 0070 PCI Express In-Depth for Windows Vista CPA 002 ACPI in Windows Vista Kernel Pn. P support questions Ntpnp @ microsoft. com

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