diff --git a/OvmfPkg/AmdSevDxe/AmdSevDxe.c b/OvmfPkg/AmdSevDxe/AmdSevDxe.c
index 80831b81fa..c66c4e9b92 100644
--- a/OvmfPkg/AmdSevDxe/AmdSevDxe.c
+++ b/OvmfPkg/AmdSevDxe/AmdSevDxe.c
@@ -120,8 +120,7 @@ AmdSevDxeEntryPoint (
     Status = MemEncryptSevClearPageEncMask (
                0,             // Cr3BaseAddress -- use current CR3
                MapPagesBase,  // BaseAddress
-               MapPagesCount, // NumPages
-               TRUE           // Flush
+               MapPagesCount  // NumPages
                );
     if (EFI_ERROR (Status)) {
       DEBUG ((DEBUG_ERROR, "%a: MemEncryptSevClearPageEncMask(): %r\n",
diff --git a/OvmfPkg/Include/Library/MemEncryptSevLib.h b/OvmfPkg/Include/Library/MemEncryptSevLib.h
index b91490d5d4..76d06c206c 100644
--- a/OvmfPkg/Include/Library/MemEncryptSevLib.h
+++ b/OvmfPkg/Include/Library/MemEncryptSevLib.h
@@ -100,8 +100,6 @@ MemEncryptSevIsEnabled (
                                       address of a memory region.
   @param[in]  NumPages                The number of pages from start memory
                                       region.
-  @param[in]  Flush                   Flush the caches before clearing the bit
-                                      (mostly TRUE except MMIO addresses)
 
   @retval RETURN_SUCCESS              The attributes were cleared for the
                                       memory region.
@@ -114,8 +112,7 @@ EFIAPI
 MemEncryptSevClearPageEncMask (
   IN PHYSICAL_ADDRESS         Cr3BaseAddress,
   IN PHYSICAL_ADDRESS         BaseAddress,
-  IN UINTN                    NumPages,
-  IN BOOLEAN                  Flush
+  IN UINTN                    NumPages
   );
 
 /**
@@ -128,8 +125,6 @@ MemEncryptSevClearPageEncMask (
                                       address of a memory region.
   @param[in]  NumPages                The number of pages from start memory
                                       region.
-  @param[in]  Flush                   Flush the caches before setting the bit
-                                      (mostly TRUE except MMIO addresses)
 
   @retval RETURN_SUCCESS              The attributes were set for the memory
                                       region.
@@ -142,8 +137,7 @@ EFIAPI
 MemEncryptSevSetPageEncMask (
   IN PHYSICAL_ADDRESS         Cr3BaseAddress,
   IN PHYSICAL_ADDRESS         BaseAddress,
-  IN UINTN                    NumPages,
-  IN BOOLEAN                  Flush
+  IN UINTN                    NumPages
   );
 
 
diff --git a/OvmfPkg/IoMmuDxe/AmdSevIoMmu.c b/OvmfPkg/IoMmuDxe/AmdSevIoMmu.c
index 49ffa24488..b30628078f 100644
--- a/OvmfPkg/IoMmuDxe/AmdSevIoMmu.c
+++ b/OvmfPkg/IoMmuDxe/AmdSevIoMmu.c
@@ -252,8 +252,7 @@ IoMmuMap (
   Status = MemEncryptSevClearPageEncMask (
              0,
              MapInfo->PlainTextAddress,
-             MapInfo->NumberOfPages,
-             TRUE
+             MapInfo->NumberOfPages
              );
   ASSERT_EFI_ERROR (Status);
   if (EFI_ERROR (Status)) {
@@ -407,8 +406,7 @@ IoMmuUnmapWorker (
   Status = MemEncryptSevSetPageEncMask (
              0,
              MapInfo->PlainTextAddress,
-             MapInfo->NumberOfPages,
-             TRUE
+             MapInfo->NumberOfPages
              );
   ASSERT_EFI_ERROR (Status);
   if (EFI_ERROR (Status)) {
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/MemEncryptSevLib.c b/OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/MemEncryptSevLib.c
index 169d3118e4..be260e0d10 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/MemEncryptSevLib.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/MemEncryptSevLib.c
@@ -25,8 +25,6 @@
                                       address of a memory region.
   @param[in]  NumPages                The number of pages from start memory
                                       region.
-  @param[in]  Flush                   Flush the caches before clearing the bit
-                                      (mostly TRUE except MMIO addresses)
 
   @retval RETURN_SUCCESS              The attributes were cleared for the
                                       memory region.
@@ -39,8 +37,7 @@ EFIAPI
 MemEncryptSevClearPageEncMask (
   IN PHYSICAL_ADDRESS         Cr3BaseAddress,
   IN PHYSICAL_ADDRESS         BaseAddress,
-  IN UINTN                    NumPages,
-  IN BOOLEAN                  Flush
+  IN UINTN                    NumPages
   )
 {
   //
@@ -59,8 +56,6 @@ MemEncryptSevClearPageEncMask (
                                       address of a memory region.
   @param[in]  NumPages                The number of pages from start memory
                                       region.
-  @param[in]  Flush                   Flush the caches before setting the bit
-                                      (mostly TRUE except MMIO addresses)
 
   @retval RETURN_SUCCESS              The attributes were set for the memory
                                       region.
@@ -73,8 +68,7 @@ EFIAPI
 MemEncryptSevSetPageEncMask (
   IN PHYSICAL_ADDRESS         Cr3BaseAddress,
   IN PHYSICAL_ADDRESS         BaseAddress,
-  IN UINTN                    NumPages,
-  IN BOOLEAN                  Flush
+  IN UINTN                    NumPages
   )
 {
   //
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/MemEncryptSevLib.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/MemEncryptSevLib.c
index a2bf698bcd..a57e8fd37f 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/MemEncryptSevLib.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/MemEncryptSevLib.c
@@ -27,8 +27,6 @@
                                       address of a memory region.
   @param[in]  NumPages                The number of pages from start memory
                                       region.
-  @param[in]  Flush                   Flush the caches before clearing the bit
-                                      (mostly TRUE except MMIO addresses)
 
   @retval RETURN_SUCCESS              The attributes were cleared for the
                                       memory region.
@@ -41,15 +39,13 @@ EFIAPI
 MemEncryptSevClearPageEncMask (
   IN PHYSICAL_ADDRESS         Cr3BaseAddress,
   IN PHYSICAL_ADDRESS         BaseAddress,
-  IN UINTN                    NumPages,
-  IN BOOLEAN                  Flush
+  IN UINTN                    NumPages
   )
 {
   return InternalMemEncryptSevSetMemoryDecrypted (
            Cr3BaseAddress,
            BaseAddress,
-           EFI_PAGES_TO_SIZE (NumPages),
-           Flush
+           EFI_PAGES_TO_SIZE (NumPages)
            );
 }
 
@@ -63,8 +59,6 @@ MemEncryptSevClearPageEncMask (
                                       address of a memory region.
   @param[in]  NumPages                The number of pages from start memory
                                       region.
-  @param[in]  Flush                   Flush the caches before setting the bit
-                                      (mostly TRUE except MMIO addresses)
 
   @retval RETURN_SUCCESS              The attributes were set for the memory
                                       region.
@@ -77,15 +71,13 @@ EFIAPI
 MemEncryptSevSetPageEncMask (
   IN PHYSICAL_ADDRESS         Cr3BaseAddress,
   IN PHYSICAL_ADDRESS         BaseAddress,
-  IN UINTN                    NumPages,
-  IN BOOLEAN                  Flush
+  IN UINTN                    NumPages
   )
 {
   return InternalMemEncryptSevSetMemoryEncrypted (
            Cr3BaseAddress,
            BaseAddress,
-           EFI_PAGES_TO_SIZE (NumPages),
-           Flush
+           EFI_PAGES_TO_SIZE (NumPages)
            );
 }
 
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
index a18d336a87..c696745f9d 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
@@ -828,8 +828,6 @@ Done:
   @param[in]  PhysicalAddress         The physical address that is the start
                                       address of a memory region.
   @param[in]  Length                  The length of memory region
-  @param[in]  Flush                   Flush the caches before applying the
-                                      encryption mask
 
   @retval RETURN_SUCCESS              The attributes were cleared for the
                                       memory region.
@@ -842,8 +840,7 @@ EFIAPI
 InternalMemEncryptSevSetMemoryDecrypted (
   IN  PHYSICAL_ADDRESS        Cr3BaseAddress,
   IN  PHYSICAL_ADDRESS        PhysicalAddress,
-  IN  UINTN                   Length,
-  IN  BOOLEAN                 Flush
+  IN  UINTN                   Length
   )
 {
 
@@ -852,7 +849,7 @@ InternalMemEncryptSevSetMemoryDecrypted (
            PhysicalAddress,
            Length,
            ClearCBit,
-           Flush
+           TRUE
            );
 }
 
@@ -865,8 +862,6 @@ InternalMemEncryptSevSetMemoryDecrypted (
   @param[in]  PhysicalAddress         The physical address that is the start
                                       address of a memory region.
   @param[in]  Length                  The length of memory region
-  @param[in]  Flush                   Flush the caches before applying the
-                                      encryption mask
 
   @retval RETURN_SUCCESS              The attributes were set for the memory
                                       region.
@@ -879,8 +874,7 @@ EFIAPI
 InternalMemEncryptSevSetMemoryEncrypted (
   IN  PHYSICAL_ADDRESS        Cr3BaseAddress,
   IN  PHYSICAL_ADDRESS        PhysicalAddress,
-  IN  UINTN                   Length,
-  IN  BOOLEAN                 Flush
+  IN  UINTN                   Length
   )
 {
   return SetMemoryEncDec (
@@ -888,7 +882,7 @@ InternalMemEncryptSevSetMemoryEncrypted (
            PhysicalAddress,
            Length,
            SetCBit,
-           Flush
+           TRUE
            );
 }
 
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SecVirtualMemory.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SecVirtualMemory.c
index e0d3a15e85..a155c8729b 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SecVirtualMemory.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SecVirtualMemory.c
@@ -42,8 +42,6 @@ InternalGetMemEncryptionAddressMask (
   @param[in]  PhysicalAddress         The physical address that is the start
                                       address of a memory region.
   @param[in]  Length                  The length of memory region
-  @param[in]  Flush                   Flush the caches before applying the
-                                      encryption mask
 
   @retval RETURN_SUCCESS              The attributes were cleared for the
                                       memory region.
@@ -56,8 +54,7 @@ EFIAPI
 InternalMemEncryptSevSetMemoryDecrypted (
   IN  PHYSICAL_ADDRESS        Cr3BaseAddress,
   IN  PHYSICAL_ADDRESS        PhysicalAddress,
-  IN  UINTN                   Length,
-  IN  BOOLEAN                 Flush
+  IN  UINTN                   Length
   )
 {
   //
@@ -89,8 +86,7 @@ EFIAPI
 InternalMemEncryptSevSetMemoryEncrypted (
   IN  PHYSICAL_ADDRESS        Cr3BaseAddress,
   IN  PHYSICAL_ADDRESS        PhysicalAddress,
-  IN  UINTN                   Length,
-  IN  BOOLEAN                 Flush
+  IN  UINTN                   Length
   )
 {
   //
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.h b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.h
index 8dc39e647b..21bbbd1c4f 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.h
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.h
@@ -58,8 +58,6 @@ InternalGetMemEncryptionAddressMask (
   @param[in]  PhysicalAddress         The physical address that is the start
                                       address of a memory region.
   @param[in]  Length                  The length of memory region
-  @param[in]  Flush                   Flush the caches before applying the
-                                      encryption mask
 
   @retval RETURN_SUCCESS              The attributes were cleared for the
                                       memory region.
@@ -72,8 +70,7 @@ EFIAPI
 InternalMemEncryptSevSetMemoryDecrypted (
   IN  PHYSICAL_ADDRESS        Cr3BaseAddress,
   IN  PHYSICAL_ADDRESS        PhysicalAddress,
-  IN  UINTN                   Length,
-  IN  BOOLEAN                 Flush
+  IN  UINTN                   Length
   );
 
 /**
@@ -85,8 +82,6 @@ InternalMemEncryptSevSetMemoryDecrypted (
   @param[in]  PhysicalAddress         The physical address that is the start
                                       address of a memory region.
   @param[in]  Length                  The length of memory region
-  @param[in]  Flush                   Flush the caches before applying the
-                                      encryption mask
 
   @retval RETURN_SUCCESS              The attributes were set for the memory
                                       region.
@@ -99,8 +94,7 @@ EFIAPI
 InternalMemEncryptSevSetMemoryEncrypted (
   IN  PHYSICAL_ADDRESS        Cr3BaseAddress,
   IN  PHYSICAL_ADDRESS        PhysicalAddress,
-  IN  UINTN                   Length,
-  IN  BOOLEAN                 Flush
+  IN  UINTN                   Length
   );
 
 /**
diff --git a/OvmfPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLib.c b/OvmfPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLib.c
index fdf2380974..c7cc5b0389 100644
--- a/OvmfPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLib.c
+++ b/OvmfPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLib.c
@@ -283,8 +283,7 @@ SmmCpuFeaturesSmmRelocationComplete (
   Status = MemEncryptSevSetPageEncMask (
              0,             // Cr3BaseAddress -- use current CR3
              MapPagesBase,  // BaseAddress
-             MapPagesCount, // NumPages
-             TRUE           // Flush
+             MapPagesCount  // NumPages
              );
   if (EFI_ERROR (Status)) {
     DEBUG ((DEBUG_ERROR, "%a: MemEncryptSevSetPageEncMask(): %r\n",
diff --git a/OvmfPkg/PlatformPei/AmdSev.c b/OvmfPkg/PlatformPei/AmdSev.c
index dddffdebda..a8bf610022 100644
--- a/OvmfPkg/PlatformPei/AmdSev.c
+++ b/OvmfPkg/PlatformPei/AmdSev.c
@@ -72,8 +72,7 @@ AmdSevEsInitialize (
     DecryptStatus = MemEncryptSevClearPageEncMask (
       0,
       GhcbBasePa + EFI_PAGES_TO_SIZE (PageCount),
-      1,
-      TRUE
+      1
       );
     ASSERT_RETURN_ERROR (DecryptStatus);
   }