[edk2-devel] [PATCH v3 20/24] OvmfPkg/BaseMemEncryptSevLib: Maximize Page State Change efficiency

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

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

Similar to the Page State Change optimization added previously, also take
into account the possiblity of using the SVSM for PVALIDATE instructions.
Conditionally adjust the maximum number of entries based on how many
entries the SVSM calling area can support.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Michael Roth <michael.roth@amd.com>
Cc: Min Xu <min.m.xu@intel.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
 OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c
index c8c0c4ef0e95..e073f3937c41 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c
@@ -18,6 +18,7 @@
 
 #include <Register/Amd/Ghcb.h>
 #include <Register/Amd/Msr.h>
+#include <Register/Amd/Svsm.h>
 
 #include "SnpPageStateChange.h"
 
@@ -78,6 +79,7 @@ BuildPageStateBuffer (
   UINTN                 Index;
   UINTN                 IndexMax;
   UINTN                 PscIndexMax;
+  UINTN                 SvsmIndexMax;
 
   // Clear the page state structure
   SetMem (Info, InfoSize, 0);
@@ -96,6 +98,11 @@ BuildPageStateBuffer (
     IndexMax = MIN (IndexMax, PscIndexMax);
   }
 
+  SvsmIndexMax = (IndexMax / SVSM_PVALIDATE_MAX_ENTRY) * SVSM_PVALIDATE_MAX_ENTRY;
+  if (SvsmIndexMax > 0) {
+    IndexMax = MIN (IndexMax, SvsmIndexMax);
+  }
+
   //
   // Populate the page state entry structure
   //
-- 
2.43.2



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