OvmfPkg/PlatformBootManagerLib: Introduce support for fw_cfg for UEFI Shell

usage: qemu -fw_cfg name=opt/org.tianocore/EFIShellSupport,string=no

Signed-off-by: Luigi Leonardi <leonardi@redhat.com>

OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c

@@ -15,6 +15,8 @@
 #include <Library/Tcg2PhysicalPresenceLib.h>
 #include <Library/XenPlatformLib.h>
 
+#include <Library/QemuFwCfgSimpleParserLib.h>
+
 //
 // Global data
 //
@@ -1843,6 +1845,18 @@ PlatformBootManagerAfterConsole (
     EfiBootManagerRefreshAllBootOption ();
   }
 
+  BOOLEAN        ShellEnabled;
+  RETURN_STATUS  RetStatus;
+
+  RetStatus = QemuFwCfgParseBool (
+                "opt/org.tianocore/EFIShellSupport",
+                &ShellEnabled
+                );
+
+  if (RETURN_ERROR (RetStatus)) {
+    ShellEnabled = TRUE;
+  }
+
   //
   // Register UEFI Shell
   //
@@ -1850,7 +1864,7 @@ PlatformBootManagerAfterConsole (
     &gUefiShellFileGuid,
     L"EFI Internal Shell",
     LOAD_OPTION_ACTIVE,
-    TRUE
+    ShellEnabled
     );
 
   //

OvmfPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf

@@ -56,6 +56,7 @@
   PlatformBmPrintScLib
   Tcg2PhysicalPresenceLib
   XenPlatformLib
+  QemuFwCfgSimpleParserLib
 
 [Pcd]
   gUefiOvmfPkgTokenSpaceGuid.PcdEmuVariableEvent

OvmfPkg/OvmfXen.dsc

@@ -168,6 +168,7 @@
   UefiUsbLib|MdePkg/Library/UefiUsbLib/UefiUsbLib.inf
   SerializeVariablesLib|OvmfPkg/Library/SerializeVariablesLib/SerializeVariablesLib.inf
   QemuFwCfgLib|OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxeLib.inf
+  QemuFwCfgSimpleParserLib|OvmfPkg/Library/QemuFwCfgSimpleParserLib/QemuFwCfgSimpleParserLib.inf
   QemuLoadImageLib|OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.inf
   MemEncryptSevLib|OvmfPkg/Library/BaseMemEncryptSevLib/DxeMemEncryptSevLib.inf
   LockBoxLib|OvmfPkg/Library/LockBoxLib/LockBoxBaseLib.inf