[PATCH v2 27/31] OvmfPkg/XenOvmf: Introduce XenTimerDxe

["Anthony PERARD" <anthony.perard@citrix.com>]

"PcAtChipsetPkg/8254TimerDxe" is replaced with a Xen-specific
EFI_TIMER_ARCH_PROTOCOL implementation. Also remove
8259InterruptControllerDxe as it is not used anymore.

This Timer uses the local APIC timer as time source as it can work on
both a Xen PVH guest and an HVM one.

Based on the "PcAtChipsetPkg/8254TimerDxe" implementation.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
---

Notes:
    v2:
    - Use InitializeApicTimer instead of WriteLocalApicReg
    - rework comments (remove many that don't apply)
    - remove unused includes, and libs
    - have a macro to the timervector.
    - cleanup, copyright
    - rework calculation of TimerCount, value to be use by the APIC timer
    - check for overflow of TimerPeriod, with the apic timer, the period can
      be up to about 42s on Xen (or even higher by changing the DivideValue).

 OvmfPkg/XenOvmf.dsc                                                              |   3 +-
 OvmfPkg/XenOvmf.fdf                                                              |   3 +-
 PcAtChipsetPkg/8254TimerDxe/8254Timer.inf => OvmfPkg/XenTimerDxe/XenTimerDxe.inf |  27 +++---
 PcAtChipsetPkg/8254TimerDxe/Timer.h => OvmfPkg/XenTimerDxe/XenTimerDxe.h         |  32 +++----
 PcAtChipsetPkg/8254TimerDxe/Timer.c => OvmfPkg/XenTimerDxe/XenTimerDxe.c         | 100 ++++++--------------
 5 files changed, 55 insertions(+), 110 deletions(-)

diff --git a/OvmfPkg/XenOvmf.dsc b/OvmfPkg/XenOvmf.dsc
index 54601c697f..35af05715b 100644
--- a/OvmfPkg/XenOvmf.dsc
+++ b/OvmfPkg/XenOvmf.dsc
@@ -560,10 +560,9 @@ [Components]
   MdeModulePkg/Universal/SecurityStubDxe/SecurityStubDxe.inf
 
   MdeModulePkg/Universal/EbcDxe/EbcDxe.inf
-  PcAtChipsetPkg/8259InterruptControllerDxe/8259.inf
+  OvmfPkg/XenTimerDxe/XenTimerDxe.inf
   UefiCpuPkg/CpuIo2Dxe/CpuIo2Dxe.inf
   UefiCpuPkg/CpuDxe/CpuDxe.inf
-  PcAtChipsetPkg/8254TimerDxe/8254Timer.inf
   OvmfPkg/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.inf
   OvmfPkg/PciHotPlugInitDxe/PciHotPlugInit.inf
   MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridgeDxe.inf {
diff --git a/OvmfPkg/XenOvmf.fdf b/OvmfPkg/XenOvmf.fdf
index f9e58befd6..d614bdce1d 100644
--- a/OvmfPkg/XenOvmf.fdf
+++ b/OvmfPkg/XenOvmf.fdf
@@ -284,10 +284,9 @@ [FV.DXEFV]
 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/XenTimerDxe/XenTimerDxe.inf
 INF  UefiCpuPkg/CpuIo2Dxe/CpuIo2Dxe.inf
 INF  UefiCpuPkg/CpuDxe/CpuDxe.inf
-INF  PcAtChipsetPkg/8254TimerDxe/8254Timer.inf
 INF  OvmfPkg/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.inf
 INF  OvmfPkg/PciHotPlugInitDxe/PciHotPlugInit.inf
 INF  MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridgeDxe.inf
diff --git a/PcAtChipsetPkg/8254TimerDxe/8254Timer.inf b/OvmfPkg/XenTimerDxe/XenTimerDxe.inf
similarity index 64%
copy from PcAtChipsetPkg/8254TimerDxe/8254Timer.inf
copy to OvmfPkg/XenTimerDxe/XenTimerDxe.inf
index 46cf01de39..5ad80b9368 100644
--- a/PcAtChipsetPkg/8254TimerDxe/8254Timer.inf
+++ b/OvmfPkg/XenTimerDxe/XenTimerDxe.inf
@@ -1,7 +1,9 @@
 ## @file
-# 8254 timer driver that provides Timer Arch protocol.
+# Local APIC timer driver that provides Timer Arch protocol.
+#
+# Copyright (c) 2005 - 2014, Intel Corporation. All rights reserved.<BR>
+# Copyright (c) 2019, Citrix Systems, Inc.
 #
-# Copyright (c) 2005 - 2018, 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
@@ -14,9 +16,8 @@
 
 [Defines]
   INF_VERSION                    = 0x00010005
-  BASE_NAME                      = Timer
-  MODULE_UNI_FILE                = Timer.uni
-  FILE_GUID                      = f2765dec-6b41-11d5-8e71-00902707b35e
+  BASE_NAME                      = XenTimerDxe
+  FILE_GUID                      = 52fe8196-f9de-4d07-b22f-51f77a0e7c41
   MODULE_TYPE                    = DXE_DRIVER
   VERSION_STRING                 = 1.0
 
@@ -25,24 +26,24 @@ [Defines]
 [Packages]
   MdePkg/MdePkg.dec
   IntelFrameworkPkg/IntelFrameworkPkg.dec
+  UefiCpuPkg/UefiCpuPkg.dec
+  OvmfPkg/OvmfPkg.dec
 
 [LibraryClasses]
   UefiBootServicesTableLib
   BaseLib
   DebugLib
   UefiDriverEntryPoint
-  IoLib
+  LocalApicLib
 
 [Sources]
-  Timer.h
-  Timer.c
+  XenTimerDxe.h
+  XenTimerDxe.c
 
 [Protocols]
   gEfiCpuArchProtocolGuid       ## CONSUMES
-  gEfiLegacy8259ProtocolGuid    ## CONSUMES
   gEfiTimerArchProtocolGuid     ## PRODUCES
-
+[Pcd]
+  gEfiMdePkgTokenSpaceGuid.PcdFSBClock  ## CONSUMES
 [Depex]
-  gEfiCpuArchProtocolGuid AND gEfiLegacy8259ProtocolGuid
-[UserExtensions.TianoCore."ExtraFiles"]
-  TimerExtra.uni
+  gEfiCpuArchProtocolGuid
diff --git a/PcAtChipsetPkg/8254TimerDxe/Timer.h b/OvmfPkg/XenTimerDxe/XenTimerDxe.h
similarity index 89%
copy from PcAtChipsetPkg/8254TimerDxe/Timer.h
copy to OvmfPkg/XenTimerDxe/XenTimerDxe.h
index 9d70e3aa19..747259c162 100644
--- a/PcAtChipsetPkg/8254TimerDxe/Timer.h
+++ b/OvmfPkg/XenTimerDxe/XenTimerDxe.h
@@ -1,7 +1,9 @@
 /** @file
   Private data structures
 
-Copyright (c) 2005 - 2018, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2005 - 2016, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2019, Citrix Systems, Inc.
+
 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
@@ -17,34 +19,24 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 #include <PiDxe.h>
 
 #include <Protocol/Cpu.h>
-#include <Protocol/Legacy8259.h>
 #include <Protocol/Timer.h>
 
+#include <Register/LocalApic.h>
+
 #include <Library/UefiBootServicesTableLib.h>
 #include <Library/BaseLib.h>
 #include <Library/DebugLib.h>
-#include <Library/IoLib.h>
+#include <Library/LocalApicLib.h>
+#include <Library/PcdLib.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
+
+//
+// The Timer Vector use for interrupt
+//
+#define LOCAL_APIC_TIMER_VECTOR 32
 
 //
 // Function Prototypes
diff --git a/PcAtChipsetPkg/8254TimerDxe/Timer.c b/OvmfPkg/XenTimerDxe/XenTimerDxe.c
similarity index 77%
copy from PcAtChipsetPkg/8254TimerDxe/Timer.c
copy to OvmfPkg/XenTimerDxe/XenTimerDxe.c
index 60799aadd3..fb39ce0cd3 100644
--- a/PcAtChipsetPkg/8254TimerDxe/Timer.c
+++ b/OvmfPkg/XenTimerDxe/XenTimerDxe.c
@@ -1,7 +1,9 @@
 /** @file
   Timer Architectural Protocol as defined in the DXE CIS
 
-Copyright (c) 2005 - 2018, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2005 - 2016, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2019, Citrix Systems, Inc.
+
 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
@@ -12,7 +14,7 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 
 **/
 
-#include "Timer.h"
+#include "XenTimerDxe.h"
 
 //
 // The handle onto which the Timer Architectural Protocol will be installed
@@ -34,11 +36,6 @@ EFI_TIMER_ARCH_PROTOCOL   mTimer = {
 //
 EFI_CPU_ARCH_PROTOCOL     *mCpu;
 
-//
-// Pointer to the Legacy 8259 Protocol instance
-//
-EFI_LEGACY_8259_PROTOCOL  *mLegacy8259;
-
 //
 // The notification function to call on every timer interrupt.
 // A bug in the compiler prevents us from initializing this here.
@@ -54,22 +51,7 @@ volatile UINT64           mTimerPeriod = 0;
 // Worker Functions
 //
 /**
-  Sets the counter value for Timer #0 in a legacy 8254 timer.
-
-  @param Count    The 16-bit counter value to program into Timer #0 of the legacy 8254 timer.
-**/
-VOID
-SetPitCount (
-  IN UINT16  Count
-  )
-{
-  IoWrite8 (TIMER_CONTROL_PORT, 0x36);
-  IoWrite8 (TIMER0_COUNT_PORT, (UINT8)(Count & 0xff));
-  IoWrite8 (TIMER0_COUNT_PORT, (UINT8)((Count >> 8) & 0xff));
-}
-
-/**
-  8254 Timer #0 Interrupt Handler.
+  Interrupt Handler.
 
   @param InterruptType    The type of interrupt that occurred
   @param SystemContext    A pointer to the system context when the interrupt occurred
@@ -85,7 +67,7 @@ TimerInterruptHandler (
 
   OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);
 
-  mLegacy8259->EndOfInterrupt (mLegacy8259, Efi8259Irq0);
+  SendApicEoi();
 
   if (mTimerNotifyFunction != NULL) {
     //
@@ -187,49 +169,41 @@ TimerDriverSetTimerPeriod (
   )
 {
   UINT64  TimerCount;
+  UINT32  TimerFrequency;
+  UINTN   DivideValue = 1;
 
-  //
-  //  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
-  //
-  // Since TimerCount is limited to 16 bits for IA32, TimerPeriod is limited
-  // to 20 bits.
-  //
   if (TimerPeriod == 0) {
     //
     // Disable timer interrupt for a TimerPeriod of 0
     //
-    mLegacy8259->DisableIrq (mLegacy8259, Efi8259Irq0);
+    DisableApicTimerInterrupt();
   } else {
+    TimerFrequency = PcdGet32(PcdFSBClock) / DivideValue;
 
     //
-    // Convert TimerPeriod into 8254 counts
+    // Convert TimerPeriod into local APIC counts
     //
-    TimerCount = DivU64x32 (MultU64x32 (119318, (UINT32) TimerPeriod) + 500000, 1000000);
+    // TimerPeriod is in 100ns
+    // TimerPeriod/10000000 will be in seconds.
+    TimerCount = DivU64x32 (MultU64x32 (TimerPeriod, TimerFrequency),
+                            10000000);
 
-    //
     // Check for overflow
-    //
-    if (TimerCount >= 65536) {
-      TimerCount = 0;
-      TimerPeriod = MAX_TIMER_TICK_DURATION;
+    if (TimerCount > MAX_UINT32) {
+      TimerCount = MAX_UINT32;
+      /* TimerPeriod = (MAX_UINT32 / TimerFrequency) * 10000000; */
+      TimerPeriod = 429496730;
     }
+
     //
-    // Program the 8254 timer with the new count value
+    // Program the timer with the new count value
     //
-    SetPitCount ((UINT16) TimerCount);
+    InitializeApicTimer(DivideValue, TimerCount, TRUE, LOCAL_APIC_TIMER_VECTOR);
 
     //
     // Enable timer interrupt
     //
-    mLegacy8259->EnableIrq (mLegacy8259, Efi8259Irq0, FALSE);
+    EnableApicTimerInterrupt();
   }
   //
   // Save the new timer period
@@ -294,16 +268,9 @@ TimerDriverGenerateSoftInterrupt (
   IN EFI_TIMER_ARCH_PROTOCOL  *This
   )
 {
-  EFI_STATUS  Status;
-  UINT16      IRQMask;
   EFI_TPL     OriginalTPL;
 
-  //
-  // If the timer interrupt is enabled, then the registered handler will be invoked.
-  //
-  Status = mLegacy8259->GetMask (mLegacy8259, NULL, NULL, &IRQMask, NULL);
-  ASSERT_EFI_ERROR (Status);
-  if ((IRQMask & 0x1) == 0) {
+  if (GetApicTimerInterruptState()) {
     //
     // Invoke the registered handler
     //
@@ -343,7 +310,6 @@ TimerDriverInitialize (
   )
 {
   EFI_STATUS  Status;
-  UINT32      TimerVector;
 
   //
   // Initialize the pointer to our notify function.
@@ -361,12 +327,6 @@ TimerDriverInitialize (
   Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, (VOID **) &mCpu);
   ASSERT_EFI_ERROR (Status);
 
-  //
-  // Find the Legacy8259 protocol.
-  //
-  Status = gBS->LocateProtocol (&gEfiLegacy8259ProtocolGuid, NULL, (VOID **) &mLegacy8259);
-  ASSERT_EFI_ERROR (Status);
-
   //
   // Force the timer to be disabled
   //
@@ -374,16 +334,10 @@ TimerDriverInitialize (
   ASSERT_EFI_ERROR (Status);
 
   //
-  // Get the interrupt vector number corresponding to IRQ0 from the 8259 driver
+  // Install interrupt handler for Local APIC Timer
   //
-  TimerVector = 0;
-  Status      = mLegacy8259->GetVector (mLegacy8259, Efi8259Irq0, (UINT8 *) &TimerVector);
-  ASSERT_EFI_ERROR (Status);
-
-  //
-  // Install interrupt handler for 8254 Timer #0 (ISA IRQ0)
-  //
-  Status = mCpu->RegisterInterruptHandler (mCpu, TimerVector, TimerInterruptHandler);
+  Status = mCpu->RegisterInterruptHandler (mCpu, LOCAL_APIC_TIMER_VECTOR,
+                                           TimerInterruptHandler);
   ASSERT_EFI_ERROR (Status);
 
   //
-- 
Anthony PERARD