[edk2-devel] [PATCH v2 06/23] OvmfPkg/BaseMemEncryptSevLib: Calculate memory size for Page State Change

["Lendacky, Thomas via groups.io" <thomas.lendacky=amd.com@groups.io>]

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4654

Calculate the amount of memory that can be use to build the Page State
Change data (SNP_PAGE_STATE_CHANGE_INFO) instead of using a hard-coded
size. This allows for changes to the GHCB shared buffer size without
having to make changes to the page state change code.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
 OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c
index 6a11adb06efb..60b176ab14b8 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c
@@ -133,23 +133,26 @@ BuildPageStateBuffer (
   IN EFI_PHYSICAL_ADDRESS        EndAddress,
   IN SEV_SNP_PAGE_STATE          State,
   IN BOOLEAN                     UseLargeEntry,
-  IN SNP_PAGE_STATE_CHANGE_INFO  *Info
+  IN SNP_PAGE_STATE_CHANGE_INFO  *Info,
+  IN UINTN                       InfoSize
   )
 {
   EFI_PHYSICAL_ADDRESS  NextAddress;
   UINTN                 RmpPageSize;
   UINTN                 Index;
+  UINTN                 IndexMax;
 
   // Clear the page state structure
-  SetMem (Info, sizeof (*Info), 0);
+  SetMem (Info, InfoSize, 0);
 
   Index       = 0;
+  IndexMax    = (InfoSize - sizeof (Info->Header)) / sizeof (Info->Entry[0]);
   NextAddress = EndAddress;
 
   //
   // Populate the page state entry structure
   //
-  while ((BaseAddress < EndAddress) && (Index < SNP_PAGE_STATE_MAX_ENTRY)) {
+  while ((BaseAddress < EndAddress) && (Index < IndexMax)) {
     //
     // Is this a 2MB aligned page? Check if we can use the Large RMP entry.
     //
@@ -265,7 +268,8 @@ InternalSetPageState (
                     EndAddress,
                     State,
                     UseLargeEntry,
-                    Info
+                    Info,
+                    sizeof (Ghcb->SharedBuffer)
                     );
 
     //
-- 
2.42.0



-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#115841): https://edk2.groups.io/g/devel/message/115841
Mute This Topic: https://groups.io/mt/104512944/7686176
Group Owner: devel+owner@edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/unsub [rebecca@openfw.io]
-=-=-=-=-=-=-=-=-=-=-=-