OvmfPkg/PlatformPei: handle non-power-of-two spare size for emu variables

In commit b24fca05751f ("OvmfPkg: introduce 4MB flash image (mainly) for
Windows HCK", 2017-04-29), I changed PcdFlashNvStorageFtwSpareSize to
264KB, in the then-new default 4MB build.

While PcdFlashNvStorageFtwSpareSize remains exactly half of the entire
non-volatile store (which is 528KB), 264KB isn't itself a power of two.
This triggers an assertion failure in AllocateAlignedRuntimePages() when
PlatformPei calls it from the ReserveEmuVariableNvStore() function,
passing PcdFlashNvStorageFtwSpareSize as the Alignment parameter:

> ASSERT MdePkg/Library/PeiMemoryAllocationLib/MemoryAllocationLib.c(196):
> (Alignment & (Alignment - 1)) == 0

Round up the alignment to the next power of two if necessary.

Fixes: b24fca05751f8222acf264853709012e0ab7bf49
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

1 files changed, 14 insertions, 3 deletions

diff --git a/OvmfPkg/PlatformPei/Platform.c b/OvmfPkg/PlatformPei/Platform.c
index 77a8a16c15..5e983a8dce 100644
--- a/OvmfPkg/PlatformPei/Platform.c
+++ b/OvmfPkg/PlatformPei/Platform.c
@@ -504,6 +504,7 @@ ReserveEmuVariableNvStore (
 {

   EFI_PHYSICAL_ADDRESS VariableStore;

   RETURN_STATUS        PcdStatus;

+  UINT32               Alignment;

 

   //

   // Allocate storage for NV variables early on so it will be

@@ -511,16 +512,26 @@ ReserveEmuVariableNvStore (
   // across reboots, this allows the NV variable storage to survive

   // a VM reboot.

   //

+  Alignment = PcdGet32 (PcdFlashNvStorageFtwSpareSize);

+  if ((Alignment & (Alignment - 1)) != 0) {

+    //

+    // Round up Alignment to the next power of two.

+    //

+    Alignment = GetPowerOfTwo32 (Alignment) << 1;

+  }

+

   VariableStore =

     (EFI_PHYSICAL_ADDRESS)(UINTN)

       AllocateAlignedRuntimePages (

         EFI_SIZE_TO_PAGES (2 * PcdGet32 (PcdFlashNvStorageFtwSpareSize)),

-        PcdGet32 (PcdFlashNvStorageFtwSpareSize)

+        Alignment

         );

   DEBUG ((EFI_D_INFO,

-          "Reserved variable store memory: 0x%lX; size: %dkb\n",

+          "Reserved variable store memory: 0x%lX; size: %dkb, "

+          "alignment: 0x%x\n",

           VariableStore,

-          (2 * PcdGet32 (PcdFlashNvStorageFtwSpareSize)) / 1024

+          (2 * PcdGet32 (PcdFlashNvStorageFtwSpareSize)) / 1024,

+          Alignment

         ));

   PcdStatus = PcdSet64S (PcdEmuVariableNvStoreReserved, VariableStore);

   ASSERT_RETURN_ERROR (PcdStatus);