[PATCH v2][4.17] EFI: don't convert memory marked for runtime use to ordinary RAM

[Jan Beulich <jbeulich@xxxxxxxx>]

efi_init_memory() in both relevant places is treating EFI_MEMORY_RUNTIME
higher priority than the type of the range. To avoid accessing memory at
runtime which was re-used for other purposes, make
efi_arch_process_memory_map() follow suit. While on x86 in theory the
same would apply to EfiACPIReclaimMemory, we don't actually "reclaim"
E820_ACPI memory there (and it would be a bug if the Dom0 kernel tried
to do so, bypassing Xen's memory management), hence that type's handling
can be left alone.

Fixes: bf6501a62e80 ("x86-64: EFI boot code")
Fixes: facac0af87ef ("x86-64: EFI runtime code")
Fixes: 6d70ea10d49f ("Add ARM EFI boot support")
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Reviewed-by: Luca Fancellu <luca.fancellu@xxxxxxx> # Arm
Tested-By: Luca Fancellu <luca.fancellu@xxxxxxx> # Arm
Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx> #arm
---
v2: Amend description.

--- a/xen/arch/arm/efi/efi-boot.h
+++ b/xen/arch/arm/efi/efi-boot.h
@@ -183,13 +183,15 @@ static EFI_STATUS __init efi_process_mem
 
     for ( Index = 0; Index < (mmap_size / desc_size); Index++ )
     {
-        if ( desc_ptr->Attribute & EFI_MEMORY_WB &&
-             (desc_ptr->Type == EfiConventionalMemory ||
-              desc_ptr->Type == EfiLoaderCode ||
-              desc_ptr->Type == EfiLoaderData ||
-              (!map_bs &&
-               (desc_ptr->Type == EfiBootServicesCode ||
-                desc_ptr->Type == EfiBootServicesData))) )
+        if ( desc_ptr->Attribute & EFI_MEMORY_RUNTIME )
+            /* nothing */;
+        else if ( (desc_ptr->Attribute & EFI_MEMORY_WB) &&
+                  (desc_ptr->Type == EfiConventionalMemory ||
+                   desc_ptr->Type == EfiLoaderCode ||
+                   desc_ptr->Type == EfiLoaderData ||
+                   (!map_bs &&
+                    (desc_ptr->Type == EfiBootServicesCode ||
+                     desc_ptr->Type == EfiBootServicesData))) )
         {
             if ( !meminfo_add_bank(&bootinfo.mem, desc_ptr) )
             {
--- a/xen/arch/x86/efi/efi-boot.h
+++ b/xen/arch/x86/efi/efi-boot.h
@@ -185,7 +185,9 @@ static void __init efi_arch_process_memo
             /* fall through */
         case EfiLoaderCode:
         case EfiLoaderData:
-            if ( desc->Attribute & EFI_MEMORY_WB )
+            if ( desc->Attribute & EFI_MEMORY_RUNTIME )
+                type = E820_RESERVED;
+            else if ( desc->Attribute & EFI_MEMORY_WB )
                 type = E820_RAM;
             else
         case EfiUnusableMemory: