OVMF is crashing for me in master

["Andrew Fish" <afish@apple.com>]

[-- Attachment #1: Type: text/plain, Size: 7568 bytes --]

This is my flavor of OVMF:  build -p OvmfPkg/OvmfPkgX64.dsc -a X64 -t XCODE5

It looks like I took an exception? Is it expected that an unhandled exception just hang in a dead loop? I would have expected some serial  output about the failure? 

Looks like a divide by zero exception. The exception context has PC and FP so I can manually walk the stack. Yikes I see PlatformBootManagerWaitCallback() will fault if PcdPlatformBootTimeOut is zero? 
/Volumes/Case/UDK2018(master)>git grep PcdPlatformBootTimeOut -- *.dsc
ArmVirtPkg/ArmVirtQemu.dsc:194:  gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|3
ArmVirtPkg/ArmVirtQemuKernel.dsc:191:  gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|3
ArmVirtPkg/ArmVirtXen.dsc:122:  gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|3
EmulatorPkg/EmulatorPkg.dsc:236:  gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|L"Timeout"|gEfiGlobalVariableGuid|0x0|10
OvmfPkg/OvmfPkgIa32.dsc:541:  gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|0
OvmfPkg/OvmfPkgIa32X64.dsc:553:  gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|0
OvmfPkg/OvmfPkgX64.dsc:552:  gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|0
OvmfPkg/OvmfXen.dsc:470:  gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|0
UefiPayloadPkg/UefiPayloadPkgIa32.dsc:344:  gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|3
UefiPayloadPkg/UefiPayloadPkgIa32X64.dsc:345:  gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|3

OK PcdPlatformBootTimeOut is zero on Ovmf, so how did this ever work?

Ahhh gotom.... 
/Volumes/Case/UDK2018(master)>git blame -L344,344  /Volumes/Case/UDK2018/MdeModulePkg/Universal/BdsDxe/BdsEntry.c 
2de1f611be0 (Pete Batard 2019-09-25 23:50:05 +0800 344)   PlatformBootManagerWaitCallback (0);

This call causes a divide by zero if PcdPlatformBootTimeOut == 0. 

This fixes my crash:
diff --git a/OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c b/OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c
index 70df6b841a..d6ae43e900 100644
--- a/OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c
+++ b/OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c
@@ -1634,6 +1634,11 @@ PlatformBootManagerWaitCallback (
   UINT16                              Timeout;
 
   Timeout = PcdGet16 (PcdPlatformBootTimeOut);
+  if (Timeout ==  0) {
+    Timeout = 100;
+  } else {
+    Timeout = (Timeout - TimeoutRemain) * 100 / Timeout;
+  }
 
   Black.Raw = 0x00000000;
   White.Raw = 0x00FFFFFF;
@@ -1643,7 +1648,7 @@ PlatformBootManagerWaitCallback (
     Black.Pixel,
     L"Start boot option",
     White.Pixel,
-    (Timeout - TimeoutRemain) * 100 / Timeout,
+    Timeout,
     0
     );
 }


lldb debugger output:

(lldb) bt
* thread #1, stop reason = signal SIGTRAP
  * frame #0: 0x0000000007b58a70 CpuDxe.dll:CpuDeadLoop() + 13 at /Volumes/Case/UDK2018/MdePkg/Library/BaseLib/CpuDeadLoop.c:31
    frame #1: 0x0000000007b61222 CpuDxe.dll:CommonExceptionHandlerWorker() + 674 at /Volumes/Case/UDK2018/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiDxeSmmCpuException.c:115
    frame #2: 0x0000000007b61624 CpuDxe.dll:CommonExceptionHandler() + 36 at /Volumes/Case/UDK2018/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeException.c:40
    frame #3: 0x0000000007b5ff26 CpuDxe.dll:HasErrorCode() + 230
(lldb) fr sel 1
frame #1: 0x0000000007b61222 CpuDxe.dll:CommonExceptionHandlerWorker() + 674 at /Volumes/Case/UDK2018/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiDxeSmmCpuException.c:115
   91  	    (ExternalInterruptHandler[ExceptionType]) (ExceptionType, SystemContext);
   92  	  } else if (ExceptionType < CPU_EXCEPTION_NUM) {
   93  	    //
   94  	    // Get Spinlock to display CPU information
   95  	    //
   96  	    while (!AcquireSpinLockOrFail (&ExceptionHandlerData->DisplayMessageSpinLock)) {
   97  	      CpuPause ();
   98  	    }
   99  	    //
   100 	    // Initialize the serial port before dumping.
   101 	    //
   102 	    SerialPortInitialize ();
   103 	    //
   104 	    // Display ExceptionType, CPU information and Image information
   105 	    //
   106 	    DumpImageAndCpuContent (ExceptionType, SystemContext);
   107 	    //
   108 	    // Release Spinlock of output message
   109 	    //
   110 	    ReleaseSpinLock (&ExceptionHandlerData->DisplayMessageSpinLock);
   111 	    //
   112 	    // Enter a dead loop if needn't to execute old IDT handler further
   113 	    //
   114 	    if (ReservedVectors[ExceptionType].Attribute != EFI_VECTOR_HANDOFF_HOOK_BEFORE) {
-> 115 	      CpuDeadLoop ();
   116 	    }
   117 	  }
   118 	}
   119 	
(lldb) p ExceptionType
(EFI_EXCEPTION_TYPE) $0 = 0
(lldb) p SystemContext.SystemContextX64->Rip
(UINT64) $1 = 0x0000000007a9cc38
(lldb) p SystemContext.SystemContextX64->Rbp
(UINT64) $2 = 0x0000000007e8fc20
(lldb) efi_backtrace --pc 0x0000000007a9cc38 --frame 0x0000000007e8fc20 --symbols
  frame  0: 0x07a9cc38 BdsDxe:PlatformBootManagerWaitCallback + 35 at /Volumes/Case/UDK2018/OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c:1646:37
  frame  1: 0x07a9e744 BdsDxe:BdsWait + 269 at /Volumes/Case/UDK2018/MdeModulePkg/Universal/BdsDxe/BdsEntry.c:344:3
  frame  2: 0x07a9dff9 BdsDxe:BdsEntry + 2620 at /Volumes/Case/UDK2018/MdeModulePkg/Universal/BdsDxe/BdsEntry.c:1002:5
  frame  3: 0x07eb367d DxeCore:DxeMain + 2680 at /Volumes/Case/UDK2018/MdeModulePkg/Core/Dxe/DxeMain/DxeMain.c:544:3
  frame  4: 0x07e943cb DxeCore:_ModuleEntryPoint + 20 at /Volumes/Case/UDK2018/MdePkg/Library/DxeCoreEntryPoint/DxeCoreEntryPoint.c:48:3
  frame  5: 0x07edc947 DxeIpl.dll`AsmEnableCache
  frame  6: 0x07ee1e4e DxeIpl:HandOffToDxeCore + 509 at /Volumes/Case/UDK2018/MdeModulePkg/Core/DxeIplPeim/X64/DxeLoadFunc.c:113:3
  frame  7: 0x07ee0604 DxeIpl:DxeLoadCore + 1354 at /Volumes/Case/UDK2018/MdeModulePkg/Core/DxeIplPeim/DxeLoad.c:449:3
  frame  8: 0x07eeff2f PeiCore.dll`PeiCore.cold.3 + 847
  frame  9: 0x07ee9d04 PeiCore:PeiCore + 163 at /Volumes/Case/UDK2018/MdeModulePkg/Core/Pei/PeiMain/PeiMain.c:502:3
  frame 10: 0x0082c387 0x0082c387
  frame 11: 0x00825dd7 0x00825dd7
  frame 12: 0x0082ad27 0x0082ad27
  frame 13: 0x0082b3a8 0x0082b3a8
  frame 14: 0x0082bf23 0x0082bf23
  frame 15: 0x00825e24 0x00825e24
  frame 16: 0x00823af2 0x00823af2
  frame 17: 0xfffd1db8 SecMain:SecStartupPhase2 + 67 at /Volumes/Case/UDK2018/OvmfPkg/Sec/SecMain.c:858:3
  frame 18: 0xfffd1d67 SecMain:SecCoreStartupWithStack + 420 at /Volumes/Case/UDK2018/OvmfPkg/Sec/SecMain.c:821:3
  frame 19: 0xfffd1e14 SecMain:ProcessLibraryConstructorList + 0 at /Volumes/Case/UDK2018/Build/OvmfX64/DEBUG_XCODE5/X64/OvmfPkg/Sec/SecMain/DEBUG/AutoGen.c:201

(lldb) l /Volumes/Case/UDK2018/OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c:1646
   1646	    (Timeout - TimeoutRemain) * 100 / Timeout,
   1647	    0
   1648	    );
   1649	}
   1650	
   1651	/**
   1652	  The function is called when no boot option could be launched,
   1653	  including platform recovery options and options pointing to applications
   1654	  built into firmware volumes.
   1655	
(lldb) l /Volumes/Case/UDK2018/MdeModulePkg/Universal/BdsDxe/BdsEntry.c:344
   344 	  PlatformBootManagerWaitCallback (0);
   345 	  DEBUG ((EFI_D_INFO, "[Bds]Exit the waiting!\n"));
   346 	}
   347 	
   348 	/**
   349 	  Attempt to boot each boot option in the BootOptions array.
   350 	
   351 	  @param BootOptions       Input boot option array.
   352 	  @param BootOptionCount   Input boot option count.
   353 	  @param BootManagerMenu   Input boot manager menu.
   354 	


Thanks,

Andrew Fish


[-- Attachment #2: Type: text/html, Size: 49849 bytes --]