x86/efi: Dump the EFI page table

This is very useful for debugging issues with the recently added
pagetable switching code for EFI virtual mode.

Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 321a52c..61bd2ad 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -81,6 +81,15 @@
 	  kernel.
 	  If in doubt, say "N"
 
+config EFI_PGT_DUMP
+	bool "Dump the EFI pagetable"
+	depends on EFI && X86_PTDUMP
+	---help---
+	  Enable this if you want to dump the EFI page table before
+	  enabling virtual mode. This can be used to debug miscellaneous
+	  issues with the mapping of the EFI runtime regions into that
+	  table.
+
 config DEBUG_RODATA
 	bool "Write protect kernel read-only data structures"
 	default y