diff mbox

[RFC,11/14] OvmfPkg/XenOvmf: Adding XenTimerLocalApic

Message ID 20161208153340.2285-12-anthony.perard@citrix.com (mailing list archive)
State New, archived
Headers show

Commit Message

Anthony PERARD Dec. 8, 2016, 3:33 p.m. UTC
And replacing the ACPI Timer by this one based on the local APIC.

ACPI Timer does not work in a PVH guest, but local APIC works on both
PVH and HVM.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
---
 OvmfPkg/XenOvmf.dsc                             |  18 +-
 OvmfPkg/XenOvmf.fdf                             |   2 +-
 OvmfPkg/XenTimerLocalApic/Timer.h               | 191 ++++++++++++
 OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.c   | 386 ++++++++++++++++++++++++
 OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.inf |  51 ++++
 5 files changed, 640 insertions(+), 8 deletions(-)
 create mode 100644 OvmfPkg/XenTimerLocalApic/Timer.h
 create mode 100644 OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.c
 create mode 100644 OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.inf

Comments

Laszlo Ersek Jan. 5, 2017, 11:26 a.m. UTC | #1
On 12/08/16 16:33, Anthony PERARD wrote:
> And replacing the ACPI Timer by this one based on the local APIC.
> 
> ACPI Timer does not work in a PVH guest, but local APIC works on both
> PVH and HVM.
> 
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
> ---
>  OvmfPkg/XenOvmf.dsc                             |  18 +-
>  OvmfPkg/XenOvmf.fdf                             |   2 +-
>  OvmfPkg/XenTimerLocalApic/Timer.h               | 191 ++++++++++++
>  OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.c   | 386 ++++++++++++++++++++++++
>  OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.inf |  51 ++++
>  5 files changed, 640 insertions(+), 8 deletions(-)
>  create mode 100644 OvmfPkg/XenTimerLocalApic/Timer.h
>  create mode 100644 OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.c
>  create mode 100644 OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.inf

comments below:

> diff --git a/OvmfPkg/XenOvmf.dsc b/OvmfPkg/XenOvmf.dsc
> index ef32c33..31a2185 100644
> --- a/OvmfPkg/XenOvmf.dsc
> +++ b/OvmfPkg/XenOvmf.dsc
> @@ -81,7 +81,7 @@
>  ################################################################################
>  [LibraryClasses]
>    PcdLib|MdePkg/Library/BasePcdLibNull/BasePcdLibNull.inf
> -  TimerLib|OvmfPkg/Library/AcpiTimerLib/BaseAcpiTimerLib.inf
> +  TimerLib|MdePkg/Library/SecPeiDxeTimerLibCpu/SecPeiDxeTimerLibCpu.inf
>    PrintLib|MdePkg/Library/BasePrintLib/BasePrintLib.inf
>    BaseMemoryLib|MdePkg/Library/BaseMemoryLibRepStr/BaseMemoryLibRepStr.inf
>    BaseLib|MdePkg/Library/BaseLib/BaseLib.inf
> @@ -175,7 +175,7 @@
>  !endif
>  
>  [LibraryClasses.common.SEC]
> -  TimerLib|OvmfPkg/Library/AcpiTimerLib/BaseRomAcpiTimerLib.inf
> +  TimerLib|MdePkg/Library/SecPeiDxeTimerLibCpu/SecPeiDxeTimerLibCpu.inf
>    QemuFwCfgLib|OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSecLib.inf
>  !ifdef $(DEBUG_ON_SERIAL_PORT)
>    DebugLib|MdePkg/Library/BaseDebugLibSerialPort/BaseDebugLibSerialPort.inf
> @@ -251,7 +251,7 @@
>  
>  [LibraryClasses.common.DXE_RUNTIME_DRIVER]
>    PcdLib|MdePkg/Library/DxePcdLib/DxePcdLib.inf
> -  TimerLib|OvmfPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.inf
> +  TimerLib|MdePkg/Library/SecPeiDxeTimerLibCpu/SecPeiDxeTimerLibCpu.inf
>    HobLib|MdePkg/Library/DxeHobLib/DxeHobLib.inf
>    DxeCoreEntryPoint|MdePkg/Library/DxeCoreEntryPoint/DxeCoreEntryPoint.inf
>    MemoryAllocationLib|MdePkg/Library/UefiMemoryAllocationLib/UefiMemoryAllocationLib.inf
> @@ -269,7 +269,7 @@
>  
>  [LibraryClasses.common.UEFI_DRIVER]
>    PcdLib|MdePkg/Library/DxePcdLib/DxePcdLib.inf
> -  TimerLib|OvmfPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.inf
> +  TimerLib|MdePkg/Library/SecPeiDxeTimerLibCpu/SecPeiDxeTimerLibCpu.inf
>    HobLib|MdePkg/Library/DxeHobLib/DxeHobLib.inf
>    DxeCoreEntryPoint|MdePkg/Library/DxeCoreEntryPoint/DxeCoreEntryPoint.inf
>    MemoryAllocationLib|MdePkg/Library/UefiMemoryAllocationLib/UefiMemoryAllocationLib.inf
> @@ -284,7 +284,7 @@
>  
>  [LibraryClasses.common.DXE_DRIVER]
>    PcdLib|MdePkg/Library/DxePcdLib/DxePcdLib.inf
> -  TimerLib|OvmfPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.inf
> +  TimerLib|MdePkg/Library/SecPeiDxeTimerLibCpu/SecPeiDxeTimerLibCpu.inf
>    HobLib|MdePkg/Library/DxeHobLib/DxeHobLib.inf
>    MemoryAllocationLib|MdePkg/Library/UefiMemoryAllocationLib/UefiMemoryAllocationLib.inf
>    ReportStatusCodeLib|MdeModulePkg/Library/DxeReportStatusCodeLib/DxeReportStatusCodeLib.inf
> @@ -314,7 +314,7 @@
>  
>  [LibraryClasses.common.UEFI_APPLICATION]
>    PcdLib|MdePkg/Library/DxePcdLib/DxePcdLib.inf
> -  TimerLib|OvmfPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.inf
> +  TimerLib|MdePkg/Library/SecPeiDxeTimerLibCpu/SecPeiDxeTimerLibCpu.inf
>    HobLib|MdePkg/Library/DxeHobLib/DxeHobLib.inf
>    MemoryAllocationLib|MdePkg/Library/UefiMemoryAllocationLib/UefiMemoryAllocationLib.inf
>    ReportStatusCodeLib|MdeModulePkg/Library/DxeReportStatusCodeLib/DxeReportStatusCodeLib.inf

(1) I suggest to split this patch if possible. In the first half, the
TimerLib class resolutions should be flipped, with the argument given in
the second paragraph of the commit message.

The subject line for the first patch should be something like

  OvmfPkg/XenOvmf: use a TimerLib instance that depends only on the CPU

> @@ -546,7 +546,11 @@
>  !endif
>  
>    MdeModulePkg/Universal/EbcDxe/EbcDxe.inf
> -  PcAtChipsetPkg/8259InterruptControllerDxe/8259.inf
> +  OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.inf

(2) The second patch should introduce the new DXE_DRIVER module:

  OvmfPkg/XenOvmf: introduce XenTimerDxe

The commit message should document that
"PcAtChipsetPkg/8259InterruptControllerDxe/8259.inf" is replaced with a
Xen-specific EFI_TIMER_ARCH_PROTOCOL implementation.

(3) The new DXE_DRIVER module should be located under "OvmfPkg/XenTimerDxe".

> +  #{
> +  #<LibraryClasses>
> +    #LocalApicLib|UefiCpuPkg/Library/BaseXApicX2ApicLib/BaseXApicX2ApicLib.inf
> +  #}

(4) Please don't just comment out unnecessary stuff; it's better to
remove those lines.

>    UefiCpuPkg/CpuIo2Dxe/CpuIo2Dxe.inf
>    UefiCpuPkg/CpuDxe/CpuDxe.inf
>    PcAtChipsetPkg/8254TimerDxe/8254Timer.inf
> diff --git a/OvmfPkg/XenOvmf.fdf b/OvmfPkg/XenOvmf.fdf
> index c211f61..f6876d7 100644
> --- a/OvmfPkg/XenOvmf.fdf
> +++ b/OvmfPkg/XenOvmf.fdf
> @@ -207,7 +207,7 @@ INF  MdeModulePkg/Universal/PCD/Dxe/Pcd.inf
>  INF  MdeModulePkg/Core/RuntimeDxe/RuntimeDxe.inf
>  INF  MdeModulePkg/Universal/SecurityStubDxe/SecurityStubDxe.inf
>  INF  MdeModulePkg/Universal/EbcDxe/EbcDxe.inf
> -INF  PcAtChipsetPkg/8259InterruptControllerDxe/8259.inf
> +INF  OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.inf
>  INF  UefiCpuPkg/CpuIo2Dxe/CpuIo2Dxe.inf
>  INF  UefiCpuPkg/CpuDxe/CpuDxe.inf
>  INF  PcAtChipsetPkg/8254TimerDxe/8254Timer.inf
> diff --git a/OvmfPkg/XenTimerLocalApic/Timer.h b/OvmfPkg/XenTimerLocalApic/Timer.h
> new file mode 100644
> index 0000000..8d6f37c
> --- /dev/null
> +++ b/OvmfPkg/XenTimerLocalApic/Timer.h
> @@ -0,0 +1,191 @@
> +/** @file
> +  Private data structures
> +
> +Copyright (c) 2005 - 2016, Intel Corporation. All rights reserved.<BR>
> +This program and the accompanying materials
> +are licensed and made available under the terms and conditions of the BSD License
> +which accompanies this distribution.  The full text of the license may be found at
> +http://opensource.org/licenses/bsd-license.php
> +
> +THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
> +WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +**/

(5) You might want to add a Citrix copyright notice to the new files.

> +
> +#ifndef _TIMER_H_
> +#define _TIMER_H_
> +
> +#include <PiDxe.h>
> +
> +#include <Protocol/Cpu.h>
> +#include <Protocol/Legacy8259.h>
> +#include <Protocol/Timer.h>
> +
> +#include <Library/UefiBootServicesTableLib.h>
> +#include <Library/BaseLib.h>
> +#include <Library/DebugLib.h>
> +#include <Library/IoLib.h>
> +
> +//
> +// The PCAT 8253/8254 has an input clock at 1.193182 MHz and Timer 0 is
> +// initialized as a 16 bit free running counter that generates an interrupt(IRQ0)
> +// each time the counter rolls over.
> +//
> +//   65536 counts
> +// ---------------- * 1,000,000 uS/S = 54925.4 uS = 549254 * 100 ns
> +//   1,193,182 Hz
> +//
> +
> +//
> +// The maximum tick duration for 8254 timer
> +//
> +#define MAX_TIMER_TICK_DURATION     549254
> +//
> +// The default timer tick duration is set to 10 ms = 100000 100 ns units
> +//
> +#define DEFAULT_TIMER_TICK_DURATION 100000
> +#define TIMER_CONTROL_PORT          0x43
> +#define TIMER0_COUNT_PORT           0x40
> +
> +//
> +// Function Prototypes
> +//
> +/**
> +  Initialize the Timer Architectural Protocol driver
> +
> +  @param ImageHandle     ImageHandle of the loaded driver
> +  @param SystemTable     Pointer to the System Table
> +
> +  @retval EFI_SUCCESS            Timer Architectural Protocol created
> +  @retval EFI_OUT_OF_RESOURCES   Not enough resources available to initialize driver.
> +  @retval EFI_DEVICE_ERROR       A device error occured attempting to initialize the driver.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +TimerDriverInitialize (
> +  IN EFI_HANDLE        ImageHandle,
> +  IN EFI_SYSTEM_TABLE  *SystemTable
> +  )
> +;
> +
> +/**
> +
> +  This function adjusts the period of timer interrupts to the value specified
> +  by TimerPeriod.  If the timer period is updated, then the selected timer
> +  period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned.  If
> +  the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
> +  If an error occurs while attempting to update the timer period, then the
> +  timer hardware will be put back in its state prior to this call, and
> +  EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the timer interrupt
> +  is disabled.  This is not the same as disabling the CPU's interrupts.
> +  Instead, it must either turn off the timer hardware, or it must adjust the
> +  interrupt controller so that a CPU interrupt is not generated when the timer
> +  interrupt fires.
> +
> +
> +  @param This            The EFI_TIMER_ARCH_PROTOCOL instance.
> +  @param NotifyFunction  The rate to program the timer interrupt in 100 nS units.  If
> +                         the timer hardware is not programmable, then EFI_UNSUPPORTED is
> +                         returned.  If the timer is programmable, then the timer period
> +                         will be rounded up to the nearest timer period that is supported
> +                         by the timer hardware.  If TimerPeriod is set to 0, then the
> +                         timer interrupts will be disabled.
> +
> +  @retval        EFI_SUCCESS       The timer period was changed.
> +  @retval        EFI_UNSUPPORTED   The platform cannot change the period of the timer interrupt.
> +  @retval        EFI_DEVICE_ERROR  The timer period could not be changed due to a device error.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +TimerDriverRegisterHandler (
> +  IN EFI_TIMER_ARCH_PROTOCOL  *This,
> +  IN EFI_TIMER_NOTIFY         NotifyFunction
> +  )
> +;
> +
> +/**
> +
> +  This function adjusts the period of timer interrupts to the value specified
> +  by TimerPeriod.  If the timer period is updated, then the selected timer
> +  period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned.  If
> +  the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
> +  If an error occurs while attempting to update the timer period, then the
> +  timer hardware will be put back in its state prior to this call, and
> +  EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the timer interrupt
> +  is disabled.  This is not the same as disabling the CPU's interrupts.
> +  Instead, it must either turn off the timer hardware, or it must adjust the
> +  interrupt controller so that a CPU interrupt is not generated when the timer
> +  interrupt fires.
> +
> +
> +  @param This            The EFI_TIMER_ARCH_PROTOCOL instance.
> +  @param TimerPeriod     The rate to program the timer interrupt in 100 nS units.  If
> +                         the timer hardware is not programmable, then EFI_UNSUPPORTED is
> +                         returned.  If the timer is programmable, then the timer period
> +                         will be rounded up to the nearest timer period that is supported
> +                         by the timer hardware.  If TimerPeriod is set to 0, then the
> +                         timer interrupts will be disabled.
> +
> +  @retval        EFI_SUCCESS       The timer period was changed.
> +  @retval        EFI_UNSUPPORTED   The platform cannot change the period of the timer interrupt.
> +  @retval        EFI_DEVICE_ERROR  The timer period could not be changed due to a device error.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +TimerDriverSetTimerPeriod (
> +  IN EFI_TIMER_ARCH_PROTOCOL  *This,
> +  IN UINT64                   TimerPeriod
> +  )
> +;
> +
> +/**
> +
> +  This function retrieves the period of timer interrupts in 100 ns units,
> +  returns that value in TimerPeriod, and returns EFI_SUCCESS.  If TimerPeriod
> +  is NULL, then EFI_INVALID_PARAMETER is returned.  If a TimerPeriod of 0 is
> +  returned, then the timer is currently disabled.
> +
> +
> +  @param This            The EFI_TIMER_ARCH_PROTOCOL instance.
> +  @param TimerPeriod     A pointer to the timer period to retrieve in 100 ns units.  If
> +                         0 is returned, then the timer is currently disabled.
> +
> +  @retval EFI_SUCCESS            The timer period was returned in TimerPeriod.
> +  @retval EFI_INVALID_PARAMETER  TimerPeriod is NULL.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +TimerDriverGetTimerPeriod (
> +  IN EFI_TIMER_ARCH_PROTOCOL   *This,
> +  OUT UINT64                   *TimerPeriod
> +  )
> +;
> +
> +/**
> +
> +  This function generates a soft timer interrupt. If the platform does not support soft
> +  timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned.
> +  If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()
> +  service, then a soft timer interrupt will be generated. If the timer interrupt is
> +  enabled when this service is called, then the registered handler will be invoked. The
> +  registered handler should not be able to distinguish a hardware-generated timer
> +  interrupt from a software-generated timer interrupt.
> +
> +
> +  @param This              The EFI_TIMER_ARCH_PROTOCOL instance.
> +
> +  @retval EFI_SUCCESS       The soft timer interrupt was generated.
> +  @retval EFI_UNSUPPORTED   The platform does not support the generation of soft timer interrupts.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +TimerDriverGenerateSoftInterrupt (
> +  IN EFI_TIMER_ARCH_PROTOCOL  *This
> +  )
> +;
> +
> +#endif
> diff --git a/OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.c b/OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.c
> new file mode 100644
> index 0000000..7f3a8f0
> --- /dev/null
> +++ b/OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.c
> @@ -0,0 +1,386 @@
> +/** @file
> +  Timer Architectural Protocol as defined in the DXE CIS
> +
> +Copyright (c) 2005 - 2016, Intel Corporation. All rights reserved.<BR>
> +This program and the accompanying materials
> +are licensed and made available under the terms and conditions of the BSD License
> +which accompanies this distribution.  The full text of the license may be found at
> +http://opensource.org/licenses/bsd-license.php
> +
> +THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
> +WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +
> +**/
> +
> +#include <Register/LocalApic.h>
> +#include <Library/LocalApicLib.h>
> +#include <Library/PcdLib.h>
> +#include "Timer.h"
> +
> +//
> +// The handle onto which the Timer Architectural Protocol will be installed
> +//
> +EFI_HANDLE                mTimerHandle = NULL;
> +
> +//
> +// The Timer Architectural Protocol that this driver produces
> +//
> +EFI_TIMER_ARCH_PROTOCOL   mTimer = {
> +  TimerDriverRegisterHandler,
> +  TimerDriverSetTimerPeriod,
> +  TimerDriverGetTimerPeriod,
> +  TimerDriverGenerateSoftInterrupt
> +};
> +
> +//
> +// Pointer to the CPU Architectural Protocol instance
> +//
> +EFI_CPU_ARCH_PROTOCOL     *mCpu;
> +
> +//
> +// The notification function to call on every timer interrupt.
> +// A bug in the compiler prevents us from initializing this here.
> +//
> +EFI_TIMER_NOTIFY mTimerNotifyFunction;
> +
> +//
> +// The current period of the timer interrupt
> +//
> +volatile UINT64           mTimerPeriod = 0;
> +
> +//
> +// Worker Functions
> +//
> +/**
> +  8254 Timer #0 Interrupt Handler.
> +
> +  @param InterruptType    The type of interrupt that occured
> +  @param SystemContext    A pointer to the system context when the interrupt occured
> +**/
> +VOID
> +EFIAPI
> +TimerInterruptHandler (
> +  IN EFI_EXCEPTION_TYPE   InterruptType,
> +  IN EFI_SYSTEM_CONTEXT   SystemContext
> +  )
> +{
> +  EFI_TPL OriginalTPL;
> +
> +  OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);
> +
> +  /* mLegacy8259->EndOfInterrupt (mLegacy8259, Efi8259Irq0); */

(6) Please remove this instead.

> +
> +  if (mTimerNotifyFunction != NULL) {
> +    //
> +    // @bug : This does not handle missed timer interrupts
> +    //
> +    mTimerNotifyFunction (mTimerPeriod);
> +  }
> +  SendApicEoi();
> +
> +  gBS->RestoreTPL (OriginalTPL);
> +}
> +
> +/**
> +
> +  This function registers the handler NotifyFunction so it is called every time
> +  the timer interrupt fires.  It also passes the amount of time since the last
> +  handler call to the NotifyFunction.  If NotifyFunction is NULL, then the
> +  handler is unregistered.  If the handler is registered, then EFI_SUCCESS is
> +  returned.  If the CPU does not support registering a timer interrupt handler,
> +  then EFI_UNSUPPORTED is returned.  If an attempt is made to register a handler
> +  when a handler is already registered, then EFI_ALREADY_STARTED is returned.
> +  If an attempt is made to unregister a handler when a handler is not registered,
> +  then EFI_INVALID_PARAMETER is returned.  If an error occurs attempting to
> +  register the NotifyFunction with the timer interrupt, then EFI_DEVICE_ERROR
> +  is returned.
> +
> +
> +  @param This             The EFI_TIMER_ARCH_PROTOCOL instance.
> +  @param NotifyFunction   The function to call when a timer interrupt fires.  This
> +                          function executes at TPL_HIGH_LEVEL.  The DXE Core will
> +                          register a handler for the timer interrupt, so it can know
> +                          how much time has passed.  This information is used to
> +                          signal timer based events.  NULL will unregister the handler.
> +
> +  @retval        EFI_SUCCESS            The timer handler was registered.
> +  @retval        EFI_UNSUPPORTED        The platform does not support timer interrupts.
> +  @retval        EFI_ALREADY_STARTED    NotifyFunction is not NULL, and a handler is already
> +                                        registered.
> +  @retval        EFI_INVALID_PARAMETER  NotifyFunction is NULL, and a handler was not
> +                                        previously registered.
> +  @retval        EFI_DEVICE_ERROR       The timer handler could not be registered.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +TimerDriverRegisterHandler (
> +  IN EFI_TIMER_ARCH_PROTOCOL  *This,
> +  IN EFI_TIMER_NOTIFY         NotifyFunction
> +  )
> +{
> +  //
> +  // Check for invalid parameters
> +  //
> +  DEBUG((EFI_D_ERROR, "%a %d\n", __FUNCTION__, __LINE__));

(7) This should either be removed, or turned into a DEBUG_VERBOSE message.

> +  if (NotifyFunction == NULL && mTimerNotifyFunction == NULL) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (NotifyFunction != NULL && mTimerNotifyFunction != NULL) {
> +    return EFI_ALREADY_STARTED;
> +  }
> +  DEBUG((EFI_D_ERROR, "%a %d\n", __FUNCTION__, __LINE__));

(8) Ditto.

> +
> +  mTimerNotifyFunction = NotifyFunction;
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +
> +  This function adjusts the period of timer interrupts to the value specified
> +  by TimerPeriod.  If the timer period is updated, then the selected timer
> +  period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned.  If
> +  the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
> +  If an error occurs while attempting to update the timer period, then the
> +  timer hardware will be put back in its state prior to this call, and
> +  EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the timer interrupt
> +  is disabled.  This is not the same as disabling the CPU's interrupts.
> +  Instead, it must either turn off the timer hardware, or it must adjust the
> +  interrupt controller so that a CPU interrupt is not generated when the timer
> +  interrupt fires.
> +
> +
> +  @param This            The EFI_TIMER_ARCH_PROTOCOL instance.
> +  @param TimerPeriod     The rate to program the timer interrupt in 100 nS units.  If
> +                         the timer hardware is not programmable, then EFI_UNSUPPORTED is
> +                         returned.  If the timer is programmable, then the timer period
> +                         will be rounded up to the nearest timer period that is supported
> +                         by the timer hardware.  If TimerPeriod is set to 0, then the
> +                         timer interrupts will be disabled.
> +
> +  @retval        EFI_SUCCESS       The timer period was changed.
> +  @retval        EFI_UNSUPPORTED   The platform cannot change the period of the timer interrupt.
> +  @retval        EFI_DEVICE_ERROR  The timer period could not be changed due to a device error.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +TimerDriverSetTimerPeriod (
> +  IN EFI_TIMER_ARCH_PROTOCOL  *This,
> +  IN UINT64                   TimerPeriod
> +  )
> +{
> +  UINT64  TimerCount;
> +  UINT32  TimerFrequency;
> +  UINTN   DivideValue;
> +
> +  GetApicTimerState(&DivideValue, NULL, NULL);
> +
> +  // XXX rework comment, copy from other lib

(9) Stale comment?

> +  //
> +  //  The basic clock is 1.19318 MHz or 0.119318 ticks per 100 ns.
> +  //  TimerPeriod * 0.119318 = 8254 timer divisor. Using integer arithmetic
> +  //  TimerCount = (TimerPeriod * 119318)/1000000.
> +  //
> +  //  Round up to next highest integer. This guarantees that the timer is
> +  //  equal to or slightly longer than the requested time.
> +  //  TimerCount = ((TimerPeriod * 119318) + 500000)/1000000
> +  //
> +  // Note that a TimerCount of 0 is equivalent to a count of 65,536
> +  //
> +  if (TimerPeriod == 0) {
> +    //
> +    // Disable timer interrupt for a TimerPeriod of 0
> +    //
> +    DisableApicTimerInterrupt();
> +  } else {
> +    TimerFrequency = PcdGet32(PcdFSBClock) / DivideValue;
> +
> +    DEBUG((EFI_D_ERROR, "%a %d, fsbclock %d, freq %d\n",
> +           __FUNCTION__, __LINE__,
> +           PcdGet32(PcdFSBClock),
> +           TimerFrequency));

(10) Should be logged on DEBUG_VERBOSE or DEBUG_INFO level, I think.

Also, please keep a space between the function / macro name, and the
paren that opens the argument list.

> +
> +    //
> +    // Convert TimerPeriod into local apic counts
> +    //
> +
> +    TimerCount = DivU64x32 (MultU64x32 (TimerFrequency,
> +                                        (UINT32) TimerPeriod) + 500000,
> +                            1000000);
> +
> +    DEBUG((EFI_D_ERROR, "%a %d, new init val: %d\n", __FUNCTION__, __LINE__, TimerCount));

(11) DEBUG_VERBOSE or DEBUG_INFO, and spacing.

> +
> +    //
> +    // Program the timer with the new count value
> +    //
> +    WriteLocalApicReg (XAPIC_TIMER_INIT_COUNT_OFFSET, TimerCount);
> +
> +    //
> +    // Enable timer interrupt
> +    //
> +    EnableApicTimerInterrupt();
> +  }
> +  //
> +  // Save the new timer period
> +  //
> +  mTimerPeriod = TimerPeriod;
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +
> +  This function retrieves the period of timer interrupts in 100 ns units,
> +  returns that value in TimerPeriod, and returns EFI_SUCCESS.  If TimerPeriod
> +  is NULL, then EFI_INVALID_PARAMETER is returned.  If a TimerPeriod of 0 is
> +  returned, then the timer is currently disabled.
> +
> +
> +  @param This            The EFI_TIMER_ARCH_PROTOCOL instance.
> +  @param TimerPeriod     A pointer to the timer period to retrieve in 100 ns units.  If
> +                         0 is returned, then the timer is currently disabled.
> +
> +  @retval EFI_SUCCESS            The timer period was returned in TimerPeriod.
> +  @retval EFI_INVALID_PARAMETER  TimerPeriod is NULL.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +TimerDriverGetTimerPeriod (
> +  IN EFI_TIMER_ARCH_PROTOCOL   *This,
> +  OUT UINT64                   *TimerPeriod
> +  )
> +{
> +  if (TimerPeriod == NULL) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  *TimerPeriod = mTimerPeriod;
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +
> +  This function generates a soft timer interrupt. If the platform does not support soft
> +  timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned.
> +  If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()
> +  service, then a soft timer interrupt will be generated. If the timer interrupt is
> +  enabled when this service is called, then the registered handler will be invoked. The
> +  registered handler should not be able to distinguish a hardware-generated timer
> +  interrupt from a software-generated timer interrupt.
> +
> +
> +  @param This              The EFI_TIMER_ARCH_PROTOCOL instance.
> +
> +  @retval EFI_SUCCESS       The soft timer interrupt was generated.
> +  @retval EFI_UNSUPPORTED   The platform does not support the generation of soft timer interrupts.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +TimerDriverGenerateSoftInterrupt (
> +  IN EFI_TIMER_ARCH_PROTOCOL  *This
> +  )
> +{
> +  EFI_TPL     OriginalTPL;
> +
> +  if (GetApicTimerInterruptState()) {
> +    //
> +    // Invoke the registered handler
> +    //
> +    OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);
> +
> +    DisableApicTimerInterrupt();
> +    if (mTimerNotifyFunction != NULL) {
> +      //
> +      // @bug : This does not handle missed timer interrupts
> +      //
> +      mTimerNotifyFunction (mTimerPeriod);
> +    }
> +
> +    gBS->RestoreTPL (OriginalTPL);
> +  } else {
> +    return EFI_UNSUPPORTED;
> +  }
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Initialize the Timer Architectural Protocol driver
> +
> +  @param ImageHandle     ImageHandle of the loaded driver
> +  @param SystemTable     Pointer to the System Table
> +
> +  @retval EFI_SUCCESS            Timer Architectural Protocol created
> +  @retval EFI_OUT_OF_RESOURCES   Not enough resources available to initialize driver.
> +  @retval EFI_DEVICE_ERROR       A device error occured attempting to initialize the driver.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +TimerDriverInitialize (
> +  IN EFI_HANDLE        ImageHandle,
> +  IN EFI_SYSTEM_TABLE  *SystemTable
> +  )
> +{
> +  EFI_STATUS  Status;
> +  UINT32      TimerVector;
> +
> +  //
> +  // Initialize the pointer to our notify function.
> +  //
> +  mTimerNotifyFunction = NULL;
> +
> +  //
> +  // Make sure the Timer Architectural Protocol is not already installed in the system
> +  //
> +  ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiTimerArchProtocolGuid);
> +
> +  //
> +  // Find the CPU architectural protocol.
> +  //
> +  Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, (VOID **) &mCpu);
> +  ASSERT_EFI_ERROR (Status);
> +
> +
> +  //
> +  // Force the timer to be disabled
> +  //
> +  DisableApicTimerInterrupt();
> +
> +  //
> +  // Get the interrupt vector number corresponding to IRQ0 from the 8259 driver
> +  //
> +  TimerVector = 32;
> +  InitializeApicTimer(2, 0, 1, TimerVector);
> +
> +  //
> +  // Install interrupt handler for 8254 Timer #0 (ISA IRQ0)
> +  //
> +  Status = mCpu->RegisterInterruptHandler (mCpu, TimerVector, TimerInterruptHandler);
> +  ASSERT_EFI_ERROR (Status);
> +
> +  //
> +  // Force the timer to be enabled at its default period
> +  //
> +  Status = TimerDriverSetTimerPeriod (&mTimer, DEFAULT_TIMER_TICK_DURATION);
> +  ASSERT_EFI_ERROR (Status);
> +
> +  //
> +  // Install the Timer Architectural Protocol onto a new handle
> +  //
> +  Status = gBS->InstallMultipleProtocolInterfaces (
> +                  &mTimerHandle,
> +                  &gEfiTimerArchProtocolGuid, &mTimer,
> +                  NULL
> +                  );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  return Status;
> +}
> +
> diff --git a/OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.inf b/OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.inf
> new file mode 100644
> index 0000000..43e137c
> --- /dev/null
> +++ b/OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.inf
> @@ -0,0 +1,51 @@
> +## @file
> +# 8254 timer driver that provides Timer Arch protocol.
> +#
> +# Copyright (c) 2005 - 2014, Intel Corporation. All rights reserved.<BR>
> +# This program and the accompanying materials
> +# are licensed and made available under the terms and conditions of the BSD License
> +# which accompanies this distribution.  The full text of the license may be found at
> +# http://opensource.org/licenses/bsd-license.php
> +#
> +# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
> +# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +#
> +##
> +
> +[Defines]
> +  INF_VERSION                    = 0x00010005
> +  BASE_NAME                      = ApicTimer
> +  FILE_GUID                      = 52fe8196-f9de-4d07-b22f-51f77a0e7c41
> +  MODULE_TYPE                    = DXE_DRIVER
> +  VERSION_STRING                 = 1.0
> +
> +  ENTRY_POINT                    = TimerDriverInitialize
> +
> +[Packages]
> +  MdePkg/MdePkg.dec
> +  IntelFrameworkPkg/IntelFrameworkPkg.dec
> +  UefiCpuPkg/UefiCpuPkg.dec
> +  OvmfPkg/OvmfPkg.dec
> +
> +[LibraryClasses]
> +  UefiBootServicesTableLib
> +  BaseLib
> +  DebugLib
> +  UefiDriverEntryPoint
> +  IoLib
> +  LocalApicLib
> +
> +[Sources]
> +  Timer.h
> +  XenTimerLocalApic.c
> +
> +[Protocols]
> +  gEfiCpuArchProtocolGuid       ## CONSUMES
> +  gEfiTimerArchProtocolGuid     ## PRODUCES
> +[Pcd.IA32, Pcd.X64]
> +  gEfiMdePkgTokenSpaceGuid.PcdFSBClock  ## CONSUMES

(12) Any particular reason for not using just [Pcd]?

> +
> +[Depex]
> +  gEfiCpuArchProtocolGuid# AND gEfiLegacy8259ProtocolGuid
> +#[UserExtensions.TianoCore."ExtraFiles"]
> +  #TimerExtra.uni
> 

(13) Since gEfiLegacy8259ProtocolGuid is not consumed, please remove it
from the depex fully, don't just comment it out.

Same for the ExtraFiles section.

Thanks
Laszlo
diff mbox

Patch

diff --git a/OvmfPkg/XenOvmf.dsc b/OvmfPkg/XenOvmf.dsc
index ef32c33..31a2185 100644
--- a/OvmfPkg/XenOvmf.dsc
+++ b/OvmfPkg/XenOvmf.dsc
@@ -81,7 +81,7 @@ 
 ################################################################################
 [LibraryClasses]
   PcdLib|MdePkg/Library/BasePcdLibNull/BasePcdLibNull.inf
-  TimerLib|OvmfPkg/Library/AcpiTimerLib/BaseAcpiTimerLib.inf
+  TimerLib|MdePkg/Library/SecPeiDxeTimerLibCpu/SecPeiDxeTimerLibCpu.inf
   PrintLib|MdePkg/Library/BasePrintLib/BasePrintLib.inf
   BaseMemoryLib|MdePkg/Library/BaseMemoryLibRepStr/BaseMemoryLibRepStr.inf
   BaseLib|MdePkg/Library/BaseLib/BaseLib.inf
@@ -175,7 +175,7 @@ 
 !endif
 
 [LibraryClasses.common.SEC]
-  TimerLib|OvmfPkg/Library/AcpiTimerLib/BaseRomAcpiTimerLib.inf
+  TimerLib|MdePkg/Library/SecPeiDxeTimerLibCpu/SecPeiDxeTimerLibCpu.inf
   QemuFwCfgLib|OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSecLib.inf
 !ifdef $(DEBUG_ON_SERIAL_PORT)
   DebugLib|MdePkg/Library/BaseDebugLibSerialPort/BaseDebugLibSerialPort.inf
@@ -251,7 +251,7 @@ 
 
 [LibraryClasses.common.DXE_RUNTIME_DRIVER]
   PcdLib|MdePkg/Library/DxePcdLib/DxePcdLib.inf
-  TimerLib|OvmfPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.inf
+  TimerLib|MdePkg/Library/SecPeiDxeTimerLibCpu/SecPeiDxeTimerLibCpu.inf
   HobLib|MdePkg/Library/DxeHobLib/DxeHobLib.inf
   DxeCoreEntryPoint|MdePkg/Library/DxeCoreEntryPoint/DxeCoreEntryPoint.inf
   MemoryAllocationLib|MdePkg/Library/UefiMemoryAllocationLib/UefiMemoryAllocationLib.inf
@@ -269,7 +269,7 @@ 
 
 [LibraryClasses.common.UEFI_DRIVER]
   PcdLib|MdePkg/Library/DxePcdLib/DxePcdLib.inf
-  TimerLib|OvmfPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.inf
+  TimerLib|MdePkg/Library/SecPeiDxeTimerLibCpu/SecPeiDxeTimerLibCpu.inf
   HobLib|MdePkg/Library/DxeHobLib/DxeHobLib.inf
   DxeCoreEntryPoint|MdePkg/Library/DxeCoreEntryPoint/DxeCoreEntryPoint.inf
   MemoryAllocationLib|MdePkg/Library/UefiMemoryAllocationLib/UefiMemoryAllocationLib.inf
@@ -284,7 +284,7 @@ 
 
 [LibraryClasses.common.DXE_DRIVER]
   PcdLib|MdePkg/Library/DxePcdLib/DxePcdLib.inf
-  TimerLib|OvmfPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.inf
+  TimerLib|MdePkg/Library/SecPeiDxeTimerLibCpu/SecPeiDxeTimerLibCpu.inf
   HobLib|MdePkg/Library/DxeHobLib/DxeHobLib.inf
   MemoryAllocationLib|MdePkg/Library/UefiMemoryAllocationLib/UefiMemoryAllocationLib.inf
   ReportStatusCodeLib|MdeModulePkg/Library/DxeReportStatusCodeLib/DxeReportStatusCodeLib.inf
@@ -314,7 +314,7 @@ 
 
 [LibraryClasses.common.UEFI_APPLICATION]
   PcdLib|MdePkg/Library/DxePcdLib/DxePcdLib.inf
-  TimerLib|OvmfPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.inf
+  TimerLib|MdePkg/Library/SecPeiDxeTimerLibCpu/SecPeiDxeTimerLibCpu.inf
   HobLib|MdePkg/Library/DxeHobLib/DxeHobLib.inf
   MemoryAllocationLib|MdePkg/Library/UefiMemoryAllocationLib/UefiMemoryAllocationLib.inf
   ReportStatusCodeLib|MdeModulePkg/Library/DxeReportStatusCodeLib/DxeReportStatusCodeLib.inf
@@ -546,7 +546,11 @@ 
 !endif
 
   MdeModulePkg/Universal/EbcDxe/EbcDxe.inf
-  PcAtChipsetPkg/8259InterruptControllerDxe/8259.inf
+  OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.inf
+  #{
+  #<LibraryClasses>
+    #LocalApicLib|UefiCpuPkg/Library/BaseXApicX2ApicLib/BaseXApicX2ApicLib.inf
+  #}
   UefiCpuPkg/CpuIo2Dxe/CpuIo2Dxe.inf
   UefiCpuPkg/CpuDxe/CpuDxe.inf
   PcAtChipsetPkg/8254TimerDxe/8254Timer.inf
diff --git a/OvmfPkg/XenOvmf.fdf b/OvmfPkg/XenOvmf.fdf
index c211f61..f6876d7 100644
--- a/OvmfPkg/XenOvmf.fdf
+++ b/OvmfPkg/XenOvmf.fdf
@@ -207,7 +207,7 @@  INF  MdeModulePkg/Universal/PCD/Dxe/Pcd.inf
 INF  MdeModulePkg/Core/RuntimeDxe/RuntimeDxe.inf
 INF  MdeModulePkg/Universal/SecurityStubDxe/SecurityStubDxe.inf
 INF  MdeModulePkg/Universal/EbcDxe/EbcDxe.inf
-INF  PcAtChipsetPkg/8259InterruptControllerDxe/8259.inf
+INF  OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.inf
 INF  UefiCpuPkg/CpuIo2Dxe/CpuIo2Dxe.inf
 INF  UefiCpuPkg/CpuDxe/CpuDxe.inf
 INF  PcAtChipsetPkg/8254TimerDxe/8254Timer.inf
diff --git a/OvmfPkg/XenTimerLocalApic/Timer.h b/OvmfPkg/XenTimerLocalApic/Timer.h
new file mode 100644
index 0000000..8d6f37c
--- /dev/null
+++ b/OvmfPkg/XenTimerLocalApic/Timer.h
@@ -0,0 +1,191 @@ 
+/** @file
+  Private data structures
+
+Copyright (c) 2005 - 2016, Intel Corporation. All rights reserved.<BR>
+This program and the accompanying materials
+are licensed and made available under the terms and conditions of the BSD License
+which accompanies this distribution.  The full text of the license may be found at
+http://opensource.org/licenses/bsd-license.php
+
+THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+**/
+
+#ifndef _TIMER_H_
+#define _TIMER_H_
+
+#include <PiDxe.h>
+
+#include <Protocol/Cpu.h>
+#include <Protocol/Legacy8259.h>
+#include <Protocol/Timer.h>
+
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/IoLib.h>
+
+//
+// The PCAT 8253/8254 has an input clock at 1.193182 MHz and Timer 0 is
+// initialized as a 16 bit free running counter that generates an interrupt(IRQ0)
+// each time the counter rolls over.
+//
+//   65536 counts
+// ---------------- * 1,000,000 uS/S = 54925.4 uS = 549254 * 100 ns
+//   1,193,182 Hz
+//
+
+//
+// The maximum tick duration for 8254 timer
+//
+#define MAX_TIMER_TICK_DURATION     549254
+//
+// The default timer tick duration is set to 10 ms = 100000 100 ns units
+//
+#define DEFAULT_TIMER_TICK_DURATION 100000
+#define TIMER_CONTROL_PORT          0x43
+#define TIMER0_COUNT_PORT           0x40
+
+//
+// Function Prototypes
+//
+/**
+  Initialize the Timer Architectural Protocol driver
+
+  @param ImageHandle     ImageHandle of the loaded driver
+  @param SystemTable     Pointer to the System Table
+
+  @retval EFI_SUCCESS            Timer Architectural Protocol created
+  @retval EFI_OUT_OF_RESOURCES   Not enough resources available to initialize driver.
+  @retval EFI_DEVICE_ERROR       A device error occured attempting to initialize the driver.
+
+**/
+EFI_STATUS
+EFIAPI
+TimerDriverInitialize (
+  IN EFI_HANDLE        ImageHandle,
+  IN EFI_SYSTEM_TABLE  *SystemTable
+  )
+;
+
+/**
+
+  This function adjusts the period of timer interrupts to the value specified
+  by TimerPeriod.  If the timer period is updated, then the selected timer
+  period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned.  If
+  the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
+  If an error occurs while attempting to update the timer period, then the
+  timer hardware will be put back in its state prior to this call, and
+  EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the timer interrupt
+  is disabled.  This is not the same as disabling the CPU's interrupts.
+  Instead, it must either turn off the timer hardware, or it must adjust the
+  interrupt controller so that a CPU interrupt is not generated when the timer
+  interrupt fires.
+
+
+  @param This            The EFI_TIMER_ARCH_PROTOCOL instance.
+  @param NotifyFunction  The rate to program the timer interrupt in 100 nS units.  If
+                         the timer hardware is not programmable, then EFI_UNSUPPORTED is
+                         returned.  If the timer is programmable, then the timer period
+                         will be rounded up to the nearest timer period that is supported
+                         by the timer hardware.  If TimerPeriod is set to 0, then the
+                         timer interrupts will be disabled.
+
+  @retval        EFI_SUCCESS       The timer period was changed.
+  @retval        EFI_UNSUPPORTED   The platform cannot change the period of the timer interrupt.
+  @retval        EFI_DEVICE_ERROR  The timer period could not be changed due to a device error.
+
+**/
+EFI_STATUS
+EFIAPI
+TimerDriverRegisterHandler (
+  IN EFI_TIMER_ARCH_PROTOCOL  *This,
+  IN EFI_TIMER_NOTIFY         NotifyFunction
+  )
+;
+
+/**
+
+  This function adjusts the period of timer interrupts to the value specified
+  by TimerPeriod.  If the timer period is updated, then the selected timer
+  period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned.  If
+  the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
+  If an error occurs while attempting to update the timer period, then the
+  timer hardware will be put back in its state prior to this call, and
+  EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the timer interrupt
+  is disabled.  This is not the same as disabling the CPU's interrupts.
+  Instead, it must either turn off the timer hardware, or it must adjust the
+  interrupt controller so that a CPU interrupt is not generated when the timer
+  interrupt fires.
+
+
+  @param This            The EFI_TIMER_ARCH_PROTOCOL instance.
+  @param TimerPeriod     The rate to program the timer interrupt in 100 nS units.  If
+                         the timer hardware is not programmable, then EFI_UNSUPPORTED is
+                         returned.  If the timer is programmable, then the timer period
+                         will be rounded up to the nearest timer period that is supported
+                         by the timer hardware.  If TimerPeriod is set to 0, then the
+                         timer interrupts will be disabled.
+
+  @retval        EFI_SUCCESS       The timer period was changed.
+  @retval        EFI_UNSUPPORTED   The platform cannot change the period of the timer interrupt.
+  @retval        EFI_DEVICE_ERROR  The timer period could not be changed due to a device error.
+
+**/
+EFI_STATUS
+EFIAPI
+TimerDriverSetTimerPeriod (
+  IN EFI_TIMER_ARCH_PROTOCOL  *This,
+  IN UINT64                   TimerPeriod
+  )
+;
+
+/**
+
+  This function retrieves the period of timer interrupts in 100 ns units,
+  returns that value in TimerPeriod, and returns EFI_SUCCESS.  If TimerPeriod
+  is NULL, then EFI_INVALID_PARAMETER is returned.  If a TimerPeriod of 0 is
+  returned, then the timer is currently disabled.
+
+
+  @param This            The EFI_TIMER_ARCH_PROTOCOL instance.
+  @param TimerPeriod     A pointer to the timer period to retrieve in 100 ns units.  If
+                         0 is returned, then the timer is currently disabled.
+
+  @retval EFI_SUCCESS            The timer period was returned in TimerPeriod.
+  @retval EFI_INVALID_PARAMETER  TimerPeriod is NULL.
+
+**/
+EFI_STATUS
+EFIAPI
+TimerDriverGetTimerPeriod (
+  IN EFI_TIMER_ARCH_PROTOCOL   *This,
+  OUT UINT64                   *TimerPeriod
+  )
+;
+
+/**
+
+  This function generates a soft timer interrupt. If the platform does not support soft
+  timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned.
+  If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()
+  service, then a soft timer interrupt will be generated. If the timer interrupt is
+  enabled when this service is called, then the registered handler will be invoked. The
+  registered handler should not be able to distinguish a hardware-generated timer
+  interrupt from a software-generated timer interrupt.
+
+
+  @param This              The EFI_TIMER_ARCH_PROTOCOL instance.
+
+  @retval EFI_SUCCESS       The soft timer interrupt was generated.
+  @retval EFI_UNSUPPORTED   The platform does not support the generation of soft timer interrupts.
+
+**/
+EFI_STATUS
+EFIAPI
+TimerDriverGenerateSoftInterrupt (
+  IN EFI_TIMER_ARCH_PROTOCOL  *This
+  )
+;
+
+#endif
diff --git a/OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.c b/OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.c
new file mode 100644
index 0000000..7f3a8f0
--- /dev/null
+++ b/OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.c
@@ -0,0 +1,386 @@ 
+/** @file
+  Timer Architectural Protocol as defined in the DXE CIS
+
+Copyright (c) 2005 - 2016, Intel Corporation. All rights reserved.<BR>
+This program and the accompanying materials
+are licensed and made available under the terms and conditions of the BSD License
+which accompanies this distribution.  The full text of the license may be found at
+http://opensource.org/licenses/bsd-license.php
+
+THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include <Register/LocalApic.h>
+#include <Library/LocalApicLib.h>
+#include <Library/PcdLib.h>
+#include "Timer.h"
+
+//
+// The handle onto which the Timer Architectural Protocol will be installed
+//
+EFI_HANDLE                mTimerHandle = NULL;
+
+//
+// The Timer Architectural Protocol that this driver produces
+//
+EFI_TIMER_ARCH_PROTOCOL   mTimer = {
+  TimerDriverRegisterHandler,
+  TimerDriverSetTimerPeriod,
+  TimerDriverGetTimerPeriod,
+  TimerDriverGenerateSoftInterrupt
+};
+
+//
+// Pointer to the CPU Architectural Protocol instance
+//
+EFI_CPU_ARCH_PROTOCOL     *mCpu;
+
+//
+// The notification function to call on every timer interrupt.
+// A bug in the compiler prevents us from initializing this here.
+//
+EFI_TIMER_NOTIFY mTimerNotifyFunction;
+
+//
+// The current period of the timer interrupt
+//
+volatile UINT64           mTimerPeriod = 0;
+
+//
+// Worker Functions
+//
+/**
+  8254 Timer #0 Interrupt Handler.
+
+  @param InterruptType    The type of interrupt that occured
+  @param SystemContext    A pointer to the system context when the interrupt occured
+**/
+VOID
+EFIAPI
+TimerInterruptHandler (
+  IN EFI_EXCEPTION_TYPE   InterruptType,
+  IN EFI_SYSTEM_CONTEXT   SystemContext
+  )
+{
+  EFI_TPL OriginalTPL;
+
+  OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);
+
+  /* mLegacy8259->EndOfInterrupt (mLegacy8259, Efi8259Irq0); */
+
+  if (mTimerNotifyFunction != NULL) {
+    //
+    // @bug : This does not handle missed timer interrupts
+    //
+    mTimerNotifyFunction (mTimerPeriod);
+  }
+  SendApicEoi();
+
+  gBS->RestoreTPL (OriginalTPL);
+}
+
+/**
+
+  This function registers the handler NotifyFunction so it is called every time
+  the timer interrupt fires.  It also passes the amount of time since the last
+  handler call to the NotifyFunction.  If NotifyFunction is NULL, then the
+  handler is unregistered.  If the handler is registered, then EFI_SUCCESS is
+  returned.  If the CPU does not support registering a timer interrupt handler,
+  then EFI_UNSUPPORTED is returned.  If an attempt is made to register a handler
+  when a handler is already registered, then EFI_ALREADY_STARTED is returned.
+  If an attempt is made to unregister a handler when a handler is not registered,
+  then EFI_INVALID_PARAMETER is returned.  If an error occurs attempting to
+  register the NotifyFunction with the timer interrupt, then EFI_DEVICE_ERROR
+  is returned.
+
+
+  @param This             The EFI_TIMER_ARCH_PROTOCOL instance.
+  @param NotifyFunction   The function to call when a timer interrupt fires.  This
+                          function executes at TPL_HIGH_LEVEL.  The DXE Core will
+                          register a handler for the timer interrupt, so it can know
+                          how much time has passed.  This information is used to
+                          signal timer based events.  NULL will unregister the handler.
+
+  @retval        EFI_SUCCESS            The timer handler was registered.
+  @retval        EFI_UNSUPPORTED        The platform does not support timer interrupts.
+  @retval        EFI_ALREADY_STARTED    NotifyFunction is not NULL, and a handler is already
+                                        registered.
+  @retval        EFI_INVALID_PARAMETER  NotifyFunction is NULL, and a handler was not
+                                        previously registered.
+  @retval        EFI_DEVICE_ERROR       The timer handler could not be registered.
+
+**/
+EFI_STATUS
+EFIAPI
+TimerDriverRegisterHandler (
+  IN EFI_TIMER_ARCH_PROTOCOL  *This,
+  IN EFI_TIMER_NOTIFY         NotifyFunction
+  )
+{
+  //
+  // Check for invalid parameters
+  //
+  DEBUG((EFI_D_ERROR, "%a %d\n", __FUNCTION__, __LINE__));
+  if (NotifyFunction == NULL && mTimerNotifyFunction == NULL) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  if (NotifyFunction != NULL && mTimerNotifyFunction != NULL) {
+    return EFI_ALREADY_STARTED;
+  }
+  DEBUG((EFI_D_ERROR, "%a %d\n", __FUNCTION__, __LINE__));
+
+  mTimerNotifyFunction = NotifyFunction;
+
+  return EFI_SUCCESS;
+}
+
+/**
+
+  This function adjusts the period of timer interrupts to the value specified
+  by TimerPeriod.  If the timer period is updated, then the selected timer
+  period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned.  If
+  the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
+  If an error occurs while attempting to update the timer period, then the
+  timer hardware will be put back in its state prior to this call, and
+  EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the timer interrupt
+  is disabled.  This is not the same as disabling the CPU's interrupts.
+  Instead, it must either turn off the timer hardware, or it must adjust the
+  interrupt controller so that a CPU interrupt is not generated when the timer
+  interrupt fires.
+
+
+  @param This            The EFI_TIMER_ARCH_PROTOCOL instance.
+  @param TimerPeriod     The rate to program the timer interrupt in 100 nS units.  If
+                         the timer hardware is not programmable, then EFI_UNSUPPORTED is
+                         returned.  If the timer is programmable, then the timer period
+                         will be rounded up to the nearest timer period that is supported
+                         by the timer hardware.  If TimerPeriod is set to 0, then the
+                         timer interrupts will be disabled.
+
+  @retval        EFI_SUCCESS       The timer period was changed.
+  @retval        EFI_UNSUPPORTED   The platform cannot change the period of the timer interrupt.
+  @retval        EFI_DEVICE_ERROR  The timer period could not be changed due to a device error.
+
+**/
+EFI_STATUS
+EFIAPI
+TimerDriverSetTimerPeriod (
+  IN EFI_TIMER_ARCH_PROTOCOL  *This,
+  IN UINT64                   TimerPeriod
+  )
+{
+  UINT64  TimerCount;
+  UINT32  TimerFrequency;
+  UINTN   DivideValue;
+
+  GetApicTimerState(&DivideValue, NULL, NULL);
+
+  // XXX rework comment, copy from other lib
+  //
+  //  The basic clock is 1.19318 MHz or 0.119318 ticks per 100 ns.
+  //  TimerPeriod * 0.119318 = 8254 timer divisor. Using integer arithmetic
+  //  TimerCount = (TimerPeriod * 119318)/1000000.
+  //
+  //  Round up to next highest integer. This guarantees that the timer is
+  //  equal to or slightly longer than the requested time.
+  //  TimerCount = ((TimerPeriod * 119318) + 500000)/1000000
+  //
+  // Note that a TimerCount of 0 is equivalent to a count of 65,536
+  //
+  if (TimerPeriod == 0) {
+    //
+    // Disable timer interrupt for a TimerPeriod of 0
+    //
+    DisableApicTimerInterrupt();
+  } else {
+    TimerFrequency = PcdGet32(PcdFSBClock) / DivideValue;
+
+    DEBUG((EFI_D_ERROR, "%a %d, fsbclock %d, freq %d\n",
+           __FUNCTION__, __LINE__,
+           PcdGet32(PcdFSBClock),
+           TimerFrequency));
+
+    //
+    // Convert TimerPeriod into local apic counts
+    //
+
+    TimerCount = DivU64x32 (MultU64x32 (TimerFrequency,
+                                        (UINT32) TimerPeriod) + 500000,
+                            1000000);
+
+    DEBUG((EFI_D_ERROR, "%a %d, new init val: %d\n", __FUNCTION__, __LINE__, TimerCount));
+
+    //
+    // Program the timer with the new count value
+    //
+    WriteLocalApicReg (XAPIC_TIMER_INIT_COUNT_OFFSET, TimerCount);
+
+    //
+    // Enable timer interrupt
+    //
+    EnableApicTimerInterrupt();
+  }
+  //
+  // Save the new timer period
+  //
+  mTimerPeriod = TimerPeriod;
+
+  return EFI_SUCCESS;
+}
+
+/**
+
+  This function retrieves the period of timer interrupts in 100 ns units,
+  returns that value in TimerPeriod, and returns EFI_SUCCESS.  If TimerPeriod
+  is NULL, then EFI_INVALID_PARAMETER is returned.  If a TimerPeriod of 0 is
+  returned, then the timer is currently disabled.
+
+
+  @param This            The EFI_TIMER_ARCH_PROTOCOL instance.
+  @param TimerPeriod     A pointer to the timer period to retrieve in 100 ns units.  If
+                         0 is returned, then the timer is currently disabled.
+
+  @retval EFI_SUCCESS            The timer period was returned in TimerPeriod.
+  @retval EFI_INVALID_PARAMETER  TimerPeriod is NULL.
+
+**/
+EFI_STATUS
+EFIAPI
+TimerDriverGetTimerPeriod (
+  IN EFI_TIMER_ARCH_PROTOCOL   *This,
+  OUT UINT64                   *TimerPeriod
+  )
+{
+  if (TimerPeriod == NULL) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  *TimerPeriod = mTimerPeriod;
+
+  return EFI_SUCCESS;
+}
+
+/**
+
+  This function generates a soft timer interrupt. If the platform does not support soft
+  timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned.
+  If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()
+  service, then a soft timer interrupt will be generated. If the timer interrupt is
+  enabled when this service is called, then the registered handler will be invoked. The
+  registered handler should not be able to distinguish a hardware-generated timer
+  interrupt from a software-generated timer interrupt.
+
+
+  @param This              The EFI_TIMER_ARCH_PROTOCOL instance.
+
+  @retval EFI_SUCCESS       The soft timer interrupt was generated.
+  @retval EFI_UNSUPPORTED   The platform does not support the generation of soft timer interrupts.
+
+**/
+EFI_STATUS
+EFIAPI
+TimerDriverGenerateSoftInterrupt (
+  IN EFI_TIMER_ARCH_PROTOCOL  *This
+  )
+{
+  EFI_TPL     OriginalTPL;
+
+  if (GetApicTimerInterruptState()) {
+    //
+    // Invoke the registered handler
+    //
+    OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);
+
+    DisableApicTimerInterrupt();
+    if (mTimerNotifyFunction != NULL) {
+      //
+      // @bug : This does not handle missed timer interrupts
+      //
+      mTimerNotifyFunction (mTimerPeriod);
+    }
+
+    gBS->RestoreTPL (OriginalTPL);
+  } else {
+    return EFI_UNSUPPORTED;
+  }
+
+  return EFI_SUCCESS;
+}
+
+/**
+  Initialize the Timer Architectural Protocol driver
+
+  @param ImageHandle     ImageHandle of the loaded driver
+  @param SystemTable     Pointer to the System Table
+
+  @retval EFI_SUCCESS            Timer Architectural Protocol created
+  @retval EFI_OUT_OF_RESOURCES   Not enough resources available to initialize driver.
+  @retval EFI_DEVICE_ERROR       A device error occured attempting to initialize the driver.
+
+**/
+EFI_STATUS
+EFIAPI
+TimerDriverInitialize (
+  IN EFI_HANDLE        ImageHandle,
+  IN EFI_SYSTEM_TABLE  *SystemTable
+  )
+{
+  EFI_STATUS  Status;
+  UINT32      TimerVector;
+
+  //
+  // Initialize the pointer to our notify function.
+  //
+  mTimerNotifyFunction = NULL;
+
+  //
+  // Make sure the Timer Architectural Protocol is not already installed in the system
+  //
+  ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiTimerArchProtocolGuid);
+
+  //
+  // Find the CPU architectural protocol.
+  //
+  Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, (VOID **) &mCpu);
+  ASSERT_EFI_ERROR (Status);
+
+
+  //
+  // Force the timer to be disabled
+  //
+  DisableApicTimerInterrupt();
+
+  //
+  // Get the interrupt vector number corresponding to IRQ0 from the 8259 driver
+  //
+  TimerVector = 32;
+  InitializeApicTimer(2, 0, 1, TimerVector);
+
+  //
+  // Install interrupt handler for 8254 Timer #0 (ISA IRQ0)
+  //
+  Status = mCpu->RegisterInterruptHandler (mCpu, TimerVector, TimerInterruptHandler);
+  ASSERT_EFI_ERROR (Status);
+
+  //
+  // Force the timer to be enabled at its default period
+  //
+  Status = TimerDriverSetTimerPeriod (&mTimer, DEFAULT_TIMER_TICK_DURATION);
+  ASSERT_EFI_ERROR (Status);
+
+  //
+  // Install the Timer Architectural Protocol onto a new handle
+  //
+  Status = gBS->InstallMultipleProtocolInterfaces (
+                  &mTimerHandle,
+                  &gEfiTimerArchProtocolGuid, &mTimer,
+                  NULL
+                  );
+  ASSERT_EFI_ERROR (Status);
+
+  return Status;
+}
+
diff --git a/OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.inf b/OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.inf
new file mode 100644
index 0000000..43e137c
--- /dev/null
+++ b/OvmfPkg/XenTimerLocalApic/XenTimerLocalApic.inf
@@ -0,0 +1,51 @@ 
+## @file
+# 8254 timer driver that provides Timer Arch protocol.
+#
+# Copyright (c) 2005 - 2014, Intel Corporation. All rights reserved.<BR>
+# This program and the accompanying materials
+# are licensed and made available under the terms and conditions of the BSD License
+# which accompanies this distribution.  The full text of the license may be found at
+# http://opensource.org/licenses/bsd-license.php
+#
+# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = ApicTimer
+  FILE_GUID                      = 52fe8196-f9de-4d07-b22f-51f77a0e7c41
+  MODULE_TYPE                    = DXE_DRIVER
+  VERSION_STRING                 = 1.0
+
+  ENTRY_POINT                    = TimerDriverInitialize
+
+[Packages]
+  MdePkg/MdePkg.dec
+  IntelFrameworkPkg/IntelFrameworkPkg.dec
+  UefiCpuPkg/UefiCpuPkg.dec
+  OvmfPkg/OvmfPkg.dec
+
+[LibraryClasses]
+  UefiBootServicesTableLib
+  BaseLib
+  DebugLib
+  UefiDriverEntryPoint
+  IoLib
+  LocalApicLib
+
+[Sources]
+  Timer.h
+  XenTimerLocalApic.c
+
+[Protocols]
+  gEfiCpuArchProtocolGuid       ## CONSUMES
+  gEfiTimerArchProtocolGuid     ## PRODUCES
+[Pcd.IA32, Pcd.X64]
+  gEfiMdePkgTokenSpaceGuid.PcdFSBClock  ## CONSUMES
+
+[Depex]
+  gEfiCpuArchProtocolGuid# AND gEfiLegacy8259ProtocolGuid
+#[UserExtensions.TianoCore."ExtraFiles"]
+  #TimerExtra.uni