From ee0ca422f17da55350c4da25ef9ca38127d79e3f Mon Sep 17 00:00:00 2001
From: Ashish Kalra <ashish.kalra@amd.com>
Date: Thu, 19 Aug 2021 13:04:56 +0000
Subject: [PATCH 41/46] OvmfPkg/BaseMemEncryptLib: Invoke page encryption state
 change hypercall

Invoke the hypercall API to notify hypervisor when the page's
encryption state changes.

Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Change-Id: Ia61155777fe3bf66f1d059978c0e8b1d1c833ef7
---
 .../X64/PeiDxeVirtualMemory.c                 | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
index 6726010..0b67577 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
@@ -582,10 +582,13 @@ SetMemoryEncDec (
   PAGE_MAP_AND_DIRECTORY_POINTER *PageDirectoryPointerEntry;
   PAGE_TABLE_1G_ENTRY            *PageDirectory1GEntry;
   PAGE_TABLE_ENTRY               *PageDirectory2MEntry;
+  PHYSICAL_ADDRESS               OrigPhysicalAddress;
   PAGE_TABLE_4K_ENTRY            *PageTableEntry;
   UINT64                         PgTableMask;
   UINT64                         AddressEncMask;
   BOOLEAN                        IsWpEnabled;
+  BOOLEAN                        CBitChanged;
+  UINTN                          OrigLength;
   RETURN_STATUS                  Status;
   PHYSICAL_ADDRESS               PageAddress;
   UINTN                          PageNum;
@@ -642,6 +645,9 @@ SetMemoryEncDec (
   }
 
   Status = EFI_SUCCESS;
+  OrigLength = Length;
+  CBitChanged = FALSE;
+  OrigPhysicalAddress = PhysicalAddress;
 
   while (Length != 0)
   {
@@ -702,6 +708,7 @@ SetMemoryEncDec (
           ));
         PhysicalAddress += BIT30;
         Length -= BIT30;
+        CBitChanged = TRUE;
       } else {
         //
         // We must split the page
@@ -756,6 +763,7 @@ SetMemoryEncDec (
           SetOrClearCBit (&PageDirectory2MEntry->Uint64, Mode);
           PhysicalAddress += BIT21;
           Length -= BIT21;
+          CBitChanged = TRUE;
         } else {
           //
           // We must split up this page into 4K pages
@@ -798,6 +806,7 @@ SetMemoryEncDec (
         SetOrClearCBit (&PageTableEntry->Uint64, Mode);
         PhysicalAddress += EFI_PAGE_SIZE;
         Length -= EFI_PAGE_SIZE;
+        CBitChanged = TRUE;
       }
     }
   }
@@ -815,6 +824,17 @@ SetMemoryEncDec (
   //
   CpuFlushTlb();
 
+  //
+  // Notify Hypervisor on C-bit status
+  //
+  if (CBitChanged) {
+    Status = SetMemoryEncDecHypercall3 (
+               OrigPhysicalAddress,
+               EFI_SIZE_TO_PAGES (OrigLength),
+               (Mode == SetCBit) ? TRUE : FALSE
+               );
+  }
+
 Done:
   //
   // Restore page table write protection, if any.
-- 
2.17.1