[xen stable-4.16] EFI: don't convert memory marked for runtime use to ordinary RAM

[patchbot@xxxxxxx]

commit 54f8ed80c8308e65c3f57ae6cbd130f43f5ecbbd
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Mon Oct 31 13:22:17 2022 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Oct 31 13:22:17 2022 +0100

    EFI: don't convert memory marked for runtime use to ordinary RAM
    
    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 in theory the same would
    apply to EfiACPIReclaimMemory, we don't actually "reclaim" or clobber
    that memory (converted to E820_ACPI on x86) there (and it would be a bug
    if the Dom0 kernel tried to reclaim the range, bypassing Xen's memory
    management, plus it would be at least bogus if it clobbered that space),
    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>
    Acked-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx>
    master commit: f324300c8347b6aa6f9c0b18e0a90bbf44011a9a
    master date: 2022-10-21 12:30:24 +0200
---
 xen/arch/arm/efi/efi-boot.h | 3 ++-
 xen/arch/x86/efi/efi-boot.h | 4 +++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/efi/efi-boot.h b/xen/arch/arm/efi/efi-boot.h
index 9f26798239..849071fe53 100644
--- a/xen/arch/arm/efi/efi-boot.h
+++ b/xen/arch/arm/efi/efi-boot.h
@@ -194,7 +194,8 @@ static EFI_STATUS __init 
efi_process_memory_map_bootinfo(EFI_MEMORY_DESCRIPTOR *
 
     for ( Index = 0; Index < (mmap_size / desc_size); Index++ )
     {
-        if ( desc_ptr->Attribute & EFI_MEMORY_WB &&
+        if ( !(desc_ptr->Attribute & EFI_MEMORY_RUNTIME) &&
+             (desc_ptr->Attribute & EFI_MEMORY_WB) &&
              (desc_ptr->Type == EfiConventionalMemory ||
               desc_ptr->Type == EfiLoaderCode ||
               desc_ptr->Type == EfiLoaderData ||
diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
index 4ee77fb9bf..d996016223 100644
--- 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_memory_map(EFI_SYSTEM_TABLE *SystemTable,
             /* 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:
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.16