[Xen-devel] [PATCH] efi: Reallocate memory map if ExitBootServices() fails

[Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>]

If calling ExitBootServices() fails, the memory map size may have
increased, so determine the new size and reallocate the memory map
before calling GetMemoryMap() again.

This was seen on the following machine when using the iscsidxe UEFI
driver. The machine would consistently fail the first call to
ExitBootServices().
System Information
        Manufacturer: Supermicro
        Product Name: X10SLE-F/HF
BIOS Information
        Vendor: American Megatrends Inc.
        Version: 2.00
        Release Date: 04/24/2014

Signed-off-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
---
 xen/common/efi/boot.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/xen/common/efi/boot.c b/xen/common/efi/boot.c
index ef8476c..078f9b8 100644
--- a/xen/common/efi/boot.c
+++ b/xen/common/efi/boot.c
@@ -1053,14 +1053,14 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE 
*SystemTable)
             efi_arch_video_init(gop, info_size, mode_info);
     }
 
-    efi_bs->GetMemoryMap(&efi_memmap_size, NULL, &map_key,
-                         &efi_mdesc_size, &mdesc_ver);
-    efi_memmap = efi_arch_allocate_mmap_buffer(&efi_memmap_size);
-    if ( !efi_memmap )
-        blexit(L"Unable to allocate memory for EFI memory map");
-
     for ( retry = 0; ; retry = 1 )
     {
+        efi_bs->GetMemoryMap(&efi_memmap_size, NULL, &map_key,
+                             &efi_mdesc_size, &mdesc_ver);
+        efi_memmap = efi_arch_allocate_mmap_buffer(&efi_memmap_size);
+        if ( !efi_memmap )
+            blexit(L"Unable to allocate memory for EFI memory map");
+
         status = efi_bs->GetMemoryMap(&efi_memmap_size, efi_memmap, &map_key,
                                       &efi_mdesc_size, &mdesc_ver);
         if ( EFI_ERROR(status) )
-- 
2.1.0


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