From b7b88720312be7daa5a7d955f7b5816a41e87485 Mon Sep 17 00:00:00 2001
From: Brijesh Singh <brijesh.singh@amd.com>
Date: Thu, 9 Dec 2021 11:27:57 +0800
Subject: [PATCH] OvmfPkg/MemEncryptSevLib: skip page state change for Mmio
 address

The SetMemoryEncDec() is used by the higher level routines to set or clear
the page encryption mask for system RAM and Mmio address. When SEV-SNP is
active, in addition to set/clear page mask it also updates the RMP table.
The RMP table updates are required for the system RAM address and not
the Mmio address.

Add a new parameter in SetMemoryEncDec() to tell whether the specified
address is Mmio. If its Mmio then skip the page state change in the RMP
table.

Cc: Michael Roth <michael.roth@amd.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Min Xu <min.m.xu@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Jiewen Yao <Jiewen.yao@intel.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 .../X64/PeiDxeVirtualMemory.c                 | 20 ++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
index 814f814035..b9c0a5b25a 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
@@ -671,6 +671,7 @@ Done:
   @param[in]  Mode                    Set or Clear mode
   @param[in]  CacheFlush              Flush the caches before applying the
                                       encryption mask
+  @param[in]  Mmio                    The physical address specified is Mmio
 
   @retval RETURN_SUCCESS              The attributes were cleared for the
                                       memory region.
@@ -686,7 +687,8 @@ SetMemoryEncDec (
   IN    PHYSICAL_ADDRESS  PhysicalAddress,
   IN    UINTN             Length,
   IN    MAP_RANGE_MODE    Mode,
-  IN    BOOLEAN           CacheFlush
+  IN    BOOLEAN           CacheFlush,
+  IN    BOOLEAN           Mmio
   )
 {
   PAGE_MAP_AND_DIRECTORY_POINTER  *PageMapLevel4Entry;
@@ -709,14 +711,15 @@ SetMemoryEncDec (
 
   DEBUG ((
     DEBUG_VERBOSE,
-    "%a:%a: Cr3Base=0x%Lx Physical=0x%Lx Length=0x%Lx Mode=%a CacheFlush=%u\n",
+    "%a:%a: Cr3Base=0x%Lx Physical=0x%Lx Length=0x%Lx Mode=%a CacheFlush=%u Mmio=%u\n",
     gEfiCallerBaseName,
     __FUNCTION__,
     Cr3BaseAddress,
     PhysicalAddress,
     (UINT64)Length,
     (Mode == SetCBit) ? "Encrypt" : "Decrypt",
-    (UINT32)CacheFlush
+    (UINT32)CacheFlush,
+    (UINT32)Mmio
     ));
 
   //
@@ -758,7 +761,7 @@ SetMemoryEncDec (
   //
   // The InternalSetPageState() is used for setting the page state in the RMP table.
   //
-  if ((Mode == ClearCBit) && MemEncryptSevSnpIsEnabled ()) {
+  if (!Mmio && (Mode == ClearCBit) && MemEncryptSevSnpIsEnabled ()) {
     InternalSetPageState (PhysicalAddress, EFI_SIZE_TO_PAGES (Length), SevSnpPageShared, FALSE);
   }
 
@@ -996,7 +999,8 @@ InternalMemEncryptSevSetMemoryDecrypted (
            PhysicalAddress,
            Length,
            ClearCBit,
-           TRUE
+           TRUE,
+           FALSE
            );
 }
 
@@ -1029,7 +1033,8 @@ InternalMemEncryptSevSetMemoryEncrypted (
            PhysicalAddress,
            Length,
            SetCBit,
-           TRUE
+           TRUE,
+           FALSE
            );
 }
 
@@ -1062,6 +1067,7 @@ InternalMemEncryptSevClearMmioPageEncMask (
            PhysicalAddress,
            Length,
            ClearCBit,
-           FALSE
+           FALSE,
+           TRUE
            );
 }