[xen stable-4.12] xen/arm: during efi boot, improve the check for usable memory

[patchbot@xxxxxxx]

commit 524e739a49f5a62f2bfc8248b44ea4ec9f9d81f9
Author:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
AuthorDate: Tue Jan 14 15:31:55 2020 -0800
Commit:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
CommitDate: Fri Apr 10 09:34:05 2020 -0700

    xen/arm: during efi boot, improve the check for usable memory
    
    When booting via EFI, the EFI memory map has information about memory
    regions and their type. Improve the check for the type and attribute of
    each memory region to figure out whether it is usable memory or not.
    This patch brings the check on par with Linux v5.5-rc6 and makes more
    memory reusable as normal memory by Xen (except that Linux also reuses
    EFI_PERSISTENT_MEMORY, which we do not).
    
    Specifically, this patch also reuses memory marked as
    EfiLoaderCode/Data, and it uses both Attribute and Type for the check
    (Attribute needs to be EFI_MEMORY_WB).
    
    Reported-by: Roman Shaposhnik <roman@xxxxxxxxxx>
    Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
    Acked-by: Julien Grall <julien@xxxxxxx>
    (cherry picked from commit b31666c8912bf18d9eff963b06d856e7e818ff34)
---
 xen/arch/arm/efi/efi-boot.h | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/xen/arch/arm/efi/efi-boot.h b/xen/arch/arm/efi/efi-boot.h
index ca655ff003..3c0772d3f2 100644
--- a/xen/arch/arm/efi/efi-boot.h
+++ b/xen/arch/arm/efi/efi-boot.h
@@ -149,10 +149,13 @@ static EFI_STATUS __init 
efi_process_memory_map_bootinfo(EFI_MEMORY_DESCRIPTOR *
 
     for ( Index = 0; Index < (mmap_size / desc_size); Index++ )
     {
-        if ( desc_ptr->Type == EfiConventionalMemory ||
-             (!map_bs &&
-              (desc_ptr->Type == EfiBootServicesCode ||
-               desc_ptr->Type == EfiBootServicesData)) )
+        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) )
             {
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.12