[PATCH] ArmPkg/PlatformBootManagerLib: regenerate boot options on boot failure

["Ard Biesheuvel" <ard.biesheuvel@arm.com>]

One of the side effects of the recent changes to PlatformBootManagerLib
changes to avoid connecting all devices on every boot is that we no
longer default to network boot on a virgin boot, but end up in the
UiApp menu. At this point, the autogenerated boot options that we used
to rely on will be instantiated too, but it does break the unattended
boot case where devices are expected to attempt a network boot on the
very first power on.

Let's work around this by refreshing all boot options explicitly in
the UnableToBoot() handler, and rebooting the system if doing so
resulted in a change to the total number of configured boot options.
This way, we ultimately end up in the UiApp as before if no boot
options could be started, but only after all the autogenerated ones
have been attempted as well.

Cc: Pete Batard <pete@akeo.ie>
Cc: Andrei Warkentin (awarkentin@vmware.com) <awarkentin@vmware.com>
Cc: Samer El-Haj-Mahmoud <Samer.El-Haj-Mahmoud@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
---
 ArmPkg/Library/PlatformBootManagerLib/PlatformBm.c | 34 ++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/ArmPkg/Library/PlatformBootManagerLib/PlatformBm.c b/ArmPkg/Library/PlatformBootManagerLib/PlatformBm.c
index 15c5cac1bea0..9905cad22908 100644
--- a/ArmPkg/Library/PlatformBootManagerLib/PlatformBm.c
+++ b/ArmPkg/Library/PlatformBootManagerLib/PlatformBm.c
@@ -820,6 +820,40 @@ PlatformBootManagerUnableToBoot (
 {
   EFI_STATUS                   Status;
   EFI_BOOT_MANAGER_LOAD_OPTION BootManagerMenu;
+  EFI_BOOT_MANAGER_LOAD_OPTION *BootOptions;
+  UINTN                        OldBootOptionCount;
+  UINTN                        NewBootOptionCount;
+
+  //
+  // Record the total number of boot configured boot options
+  //
+  BootOptions = EfiBootManagerGetLoadOptions (&OldBootOptionCount,
+                  LoadOptionTypeBoot);
+  EfiBootManagerFreeLoadOptions (BootOptions, OldBootOptionCount);
+
+  //
+  // Connect all devices, and regenerate all boot options
+  //
+  EfiBootManagerConnectAll ();
+  EfiBootManagerRefreshAllBootOption ();
+
+  //
+  // Record the updated number of boot configured boot options
+  //
+  BootOptions = EfiBootManagerGetLoadOptions (&NewBootOptionCount,
+                  LoadOptionTypeBoot);
+  EfiBootManagerFreeLoadOptions (BootOptions, NewBootOptionCount);
+
+  //
+  // If the number of configured boot options has changed, reboot
+  // the system so the new boot options will be taken into account
+  // while executing the ordinary BDS bootflow sequence.
+  //
+  if (NewBootOptionCount != OldBootOptionCount) {
+    DEBUG ((DEBUG_WARN, "%a: rebooting after refreshing all boot options\n",
+      __FUNCTION__));
+    gRT->ResetSystem (EfiResetCold, EFI_SUCCESS, 0, NULL);
+  }
 
   Status = EfiBootManagerGetBootManagerMenu (&BootManagerMenu);
   if (EFI_ERROR (Status)) {
-- 
2.27.0