From 5c7a61135326d7f7f564e4bd11dcf78fe0ce1759 Mon Sep 17 00:00:00 2001
From: Min M Xu <min.m.xu@intel.com>
Date: Wed, 18 Jan 2023 07:52:32 +0800
Subject: OvmfPkg/BaseMemEncryptTdxLib: Refactor error handle of
 SetOrClearSharedBit

The previous implementation of SetOrClearSharedBit doesn't handle the
error correctly. In this patch SetOrClearSharedBit is changed to return
error code so that the caller can handle it.

Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Michael Roth <michael.roth@amd.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>
---
 .../BaseMemEncryptTdxLib/MemoryEncryption.c        | 48 ++++++++++++++++++----
 1 file changed, 40 insertions(+), 8 deletions(-)

(limited to 'OvmfPkg')

diff --git a/OvmfPkg/Library/BaseMemEncryptTdxLib/MemoryEncryption.c b/OvmfPkg/Library/BaseMemEncryptTdxLib/MemoryEncryption.c
index 503f626d75..5b13042512 100644
--- a/OvmfPkg/Library/BaseMemEncryptTdxLib/MemoryEncryption.c
+++ b/OvmfPkg/Library/BaseMemEncryptTdxLib/MemoryEncryption.c
@@ -510,8 +510,11 @@ Split1GPageTo2M (
   @param[in]      PagetablePoint        Page table entry pointer (PTE).
   @param[in]      Mode                  Set or Clear shared bit
 
+  @retval         EFI_SUCCESS           Successfully set or clear the memory shared bit
+  @retval         Others                Other error as indicated
 **/
-STATIC VOID
+STATIC
+EFI_STATUS
 SetOrClearSharedBit (
   IN   OUT     UINT64              *PageTablePointer,
   IN           TDX_PAGETABLE_MODE  Mode,
@@ -520,7 +523,8 @@ SetOrClearSharedBit (
   )
 {
   UINT64                        AddressEncMask;
-  UINT64                        Status;
+  UINT64                        TdStatus;
+  EFI_STATUS                    Status;
   EDKII_MEMORY_ACCEPT_PROTOCOL  *MemoryAcceptProtocol;
 
   AddressEncMask = GetMemEncryptionAddressMask ();
@@ -536,16 +540,30 @@ SetOrClearSharedBit (
     PhysicalAddress   &= ~AddressEncMask;
   }
 
-  Status = TdVmCall (TDVMCALL_MAPGPA, PhysicalAddress, Length, 0, 0, NULL);
+  TdStatus = TdVmCall (TDVMCALL_MAPGPA, PhysicalAddress, Length, 0, 0, NULL);
+  if (TdStatus != 0) {
+    DEBUG ((DEBUG_ERROR, "%a: TdVmcall(MAPGPA) failed with %llx\n", __FUNCTION__, TdStatus));
+    ASSERT (FALSE);
+    return EFI_DEVICE_ERROR;
+  }
 
   //
   // If changing shared to private, must accept-page again
   //
   if (Mode == ClearSharedBit) {
     Status = gBS->LocateProtocol (&gEdkiiMemoryAcceptProtocolGuid, NULL, (VOID **)&MemoryAcceptProtocol);
-    ASSERT (!EFI_ERROR (Status));
+    if (EFI_ERROR (Status)) {
+      DEBUG ((DEBUG_ERROR, "%a: Failed to locate MemoryAcceptProtocol with %r\n", __FUNCTION__, Status));
+      ASSERT (FALSE);
+      return Status;
+    }
+
     Status = MemoryAcceptProtocol->AcceptMemory (MemoryAcceptProtocol, PhysicalAddress, Length);
-    ASSERT (!EFI_ERROR (Status));
+    if (EFI_ERROR (Status)) {
+      DEBUG ((DEBUG_ERROR, "%a: Failed to AcceptMemory with %r\n", __FUNCTION__, Status));
+      ASSERT (FALSE);
+      return Status;
+    }
   }
 
   DEBUG ((
@@ -558,6 +576,8 @@ SetOrClearSharedBit (
     Mode,
     Status
     ));
+
+  return EFI_SUCCESS;
 }
 
 /**
@@ -747,7 +767,11 @@ SetMemorySharedOrPrivate (
       // If we have at least 1GB to go, we can just update this entry
       //
       if (!(PhysicalAddress & (BIT30 - 1)) && (Length >= BIT30)) {
-        SetOrClearSharedBit (&PageDirectory1GEntry->Uint64, Mode, PhysicalAddress, BIT30);
+        Status = SetOrClearSharedBit (&PageDirectory1GEntry->Uint64, Mode, PhysicalAddress, BIT30);
+        if (EFI_ERROR (Status)) {
+          goto Done;
+        }
+
         DEBUG ((
           DEBUG_VERBOSE,
           "%a:%a: updated 1GB entry for Physical=0x%Lx\n",
@@ -809,7 +833,11 @@ SetMemorySharedOrPrivate (
         // If we have at least 2MB left to go, we can just update this entry
         //
         if (!(PhysicalAddress & (BIT21-1)) && (Length >= BIT21)) {
-          SetOrClearSharedBit (&PageDirectory2MEntry->Uint64, Mode, PhysicalAddress, BIT21);
+          Status = SetOrClearSharedBit (&PageDirectory2MEntry->Uint64, Mode, PhysicalAddress, BIT21);
+          if (EFI_ERROR (Status)) {
+            goto Done;
+          }
+
           PhysicalAddress += BIT21;
           Length          -= BIT21;
         } else {
@@ -856,7 +884,11 @@ SetMemorySharedOrPrivate (
           goto Done;
         }
 
-        SetOrClearSharedBit (&PageTableEntry->Uint64, Mode, PhysicalAddress, EFI_PAGE_SIZE);
+        Status = SetOrClearSharedBit (&PageTableEntry->Uint64, Mode, PhysicalAddress, EFI_PAGE_SIZE);
+        if (EFI_ERROR (Status)) {
+          goto Done;
+        }
+
         PhysicalAddress += EFI_PAGE_SIZE;
         Length          -= EFI_PAGE_SIZE;
       }
-- 
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