Infinite boot retries (#347)

## Description

This is a draft of infinite boot retries based on a newly created PCD.
When true, the system will never stop retrying the boot options.

PCD default is FALSE to match existing functionality. 


For each item, place an "x" in between `[` and `]` if true. Example:
`[x]`.
_(you can also check items in the GitHub UI)_

- [X] Impacts functionality?
- **Functionality** - Does the change ultimately impact how firmware
functions?
- Examples: Add a new library, publish a new PPI, update an algorithm,
...
- [ ] Impacts security?
- **Security** - Does the change have a direct security impact on an
application,
    flow, or firmware?
  - Examples: Crypto algorithm change, buffer overflow fix, parameter
    validation improvement, ...
- [ ] Breaking change?
- **Breaking change** - Will anyone consuming this change experience a
break
    in build or boot behavior?
- Examples: Add a new library class, move a module to a different repo,
call
    a function in a new library class in a pre-existing module, ...
- [ ] Includes tests?
  - **Tests** - Does the change include any explicit test code?
  - Examples: Unit tests, integration tests, robot tests, ...
- [ ] Includes documentation?
- **Documentation** - Does the change contain explicit documentation
additions
    outside direct code modifications (and comments)?
- Examples: Update readme file, add feature readme file, link to
documentation
    on an a separate Web page, ...

## How This Was Tested


## Integration Instructions

n/a

Author: apop5

MdeModulePkg/MdeModulePkg.dec

@@ -1272,6 +1272,15 @@
   gEfiMdeModulePkgTokenSpaceGuid.PcdSupportAlternativeQueueSize|FALSE|BOOLEAN|0x40000151
   # MU_CHANGE [END]
 
+  # MU_CHANGE [BEGIN] - Support indefinite boot retries
+  # # Some platforms require that all EfiLoadOptions are retried until one of the options 
+  # # succeeds. When True, this Pcd will force Bds to retry all the valid EfiLoadOptions 
+  # # indefinitely until one of the options succeeds. 
+  # #   TRUE  - Efi boot options will be retried indefinitely.
+  # #   FALSE - Efi boot options will not be retried.
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSupportInfiniteBootRetries|FALSE|BOOLEAN|0x40000152
+  # MU_CHANGE [END]
+
 [PcdsFixedAtBuild, PcdsPatchableInModule]
   ## Dynamic type PCD can be registered callback function for Pcd setting action.
   #  PcdMaxPeiPcdCallBackNumberPerPcdEntry indicates the maximum number of callback function

MdeModulePkg/Universal/BdsDxe/BdsDxe.inf

@@ -97,6 +97,7 @@
   gEfiMdeModulePkgTokenSpaceGuid.PcdTestKeyUsed                       ## CONSUMES
   gEfiMdeModulePkgTokenSpaceGuid.PcdCapsuleOnDiskSupport              ## CONSUMES
   gEfiMdeModulePkgTokenSpaceGuid.PcdPlatformRecoverySupport           ## CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSupportInfiniteBootRetries	      ## CONSUMES // MU_CHANGE
 
 [Depex]
   TRUE

MdeModulePkg/Universal/BdsDxe/BdsEntry.c

@@ -417,16 +417,38 @@ BootBootOptions (
 
     PlatformBootManagerProcessBootCompletion (&BootOptions[Index]);        // MSCHANGE 00076 - record boot status
 
-    //
-    // If the boot via Boot#### returns with a status of EFI_SUCCESS, platform firmware
-    // supports boot manager menu, and if firmware is configured to boot in an
-    // interactive mode, the boot manager will stop processing the BootOrder variable and
-    // present a boot manager menu to the user.
-    //
-    if ((BootManagerMenu != NULL) && (BootOptions[Index].Status == EFI_SUCCESS)) {
-      EfiBootManagerBoot (BootManagerMenu);
-      break;
+    // MU_CHANGE [BEGIN] - Support infinite boot retries
+    //  Changes for PcdSupportInfiniteBootRetries are meant to minimize upkeep in mu repos.
+    //   If/when upstreaming this change, refactoring calling loop in BdsEntry() would be
+    //   better location.
+    if (!PcdGetBool (PcdSupportInfiniteBootRetries)) {
+      // MU_CHANGE [END] - Support infinite boot retries
+
+      //
+      // If the boot via Boot#### returns with a status of EFI_SUCCESS, platform firmware
+      // supports boot manager menu, and if firmware is configured to boot in an
+      // interactive mode, the boot manager will stop processing the BootOrder variable and
+      // present a boot manager menu to the user.
+      //
+      if ((BootManagerMenu != NULL) && (BootOptions[Index].Status == EFI_SUCCESS)) {
+        EfiBootManagerBoot (BootManagerMenu);
+        break;
+      }
+
+      // MU_CHANGE [BEGIN]- Support infinite boot retries
+      //  Changes for PcdSupportInfiniteBootRetries are meant to minimize upkeep in mu repos.
+      //   If/when upstreaming this change, refactoring calling loop in BdsEntry() would be
+      //   better location.
+    }
+
+    if (PcdGetBool (PcdSupportInfiniteBootRetries)) {
+      if (Index == (BootOptionCount - 1)) {
+        // Resetting index back to -1 so loop increment will result in Index 0 for next iteration
+        Index = (UINTN)-1;
+      }
     }
+
+    // MU_CHANGE [END]- Support infinite boot retries
   }
 
   return (BOOLEAN)(Index < BootOptionCount);