From 9af96e21d8bc47fc89d44a6480fcc962bc511c21 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Thu, 26 Oct 2023 14:05:42 +0200
Subject: [PATCH] OvmfPkg: add PcdQemuVarsRequire

Add PcdQemuVarsRequire FeaturePcd, so firmware code can figure whenever
the given build is supposed to use the qemu uefi variable service.

Skip the emulated variable store setup in case PcdQemuVarsRequire is
true.  This is needed to make secure boot work.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 OvmfPkg/OvmfPkg.dec                 | 3 +++
 OvmfPkg/OvmfPkgX64.dsc              | 1 +
 OvmfPkg/PlatformPei/Platform.c      | 4 ++++
 OvmfPkg/PlatformPei/PlatformPei.inf | 1 +
 4 files changed, 9 insertions(+)

diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec
index 1703f50637..10de89916a 100644
--- a/OvmfPkg/OvmfPkg.dec
+++ b/OvmfPkg/OvmfPkg.dec
@@ -464,3 +464,6 @@
   #  framebuffer. This might be required on platforms that do not tolerate
   #  misaligned accesses otherwise.
   gUefiOvmfPkgTokenSpaceGuid.PcdRemapFrameBufferWriteCombine|FALSE|BOOLEAN|0x75
+
+  ## This feature flag indicates the firmware build needs the qemu variable service.
+  gUefiOvmfPkgTokenSpaceGuid.PcdQemuVarsRequire|FALSE|BOOLEAN|0x77
diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc
index 6212d994e8..60fccc19d2 100644
--- a/OvmfPkg/OvmfPkgX64.dsc
+++ b/OvmfPkg/OvmfPkgX64.dsc
@@ -502,6 +502,7 @@
   gEfiMdeModulePkgTokenSpaceGuid.PcdEnableVariableRuntimeCache|FALSE
 !endif
 !if $(QEMU_PV_VARS) == TRUE
+  gUefiOvmfPkgTokenSpaceGuid.PcdQemuVarsRequire|TRUE
   gEfiMdeModulePkgTokenSpaceGuid.PcdEnableVariableRuntimeCache|FALSE
 !endif
 !if $(SECURE_BOOT_ENABLE) == TRUE
diff --git a/OvmfPkg/PlatformPei/Platform.c b/OvmfPkg/PlatformPei/Platform.c
index d22c525677..a354e0641f 100644
--- a/OvmfPkg/PlatformPei/Platform.c
+++ b/OvmfPkg/PlatformPei/Platform.c
@@ -221,6 +221,10 @@ ReserveEmuVariableNvStore (
   EFI_PHYSICAL_ADDRESS  VariableStore;
   RETURN_STATUS         PcdStatus;
 
+  if (FeaturePcdGet (PcdQemuVarsRequire)) {
+    return;
+  }
+
   VariableStore = (EFI_PHYSICAL_ADDRESS)(UINTN)PlatformReserveEmuVariableNvStore ();
   PcdStatus     = PcdSet64S (PcdEmuVariableNvStoreReserved, VariableStore);
 
diff --git a/OvmfPkg/PlatformPei/PlatformPei.inf b/OvmfPkg/PlatformPei/PlatformPei.inf
index c20ac6b35e..1b2af6f3e6 100644
--- a/OvmfPkg/PlatformPei/PlatformPei.inf
+++ b/OvmfPkg/PlatformPei/PlatformPei.inf
@@ -143,6 +143,7 @@
 
 [FeaturePcd]
   gUefiOvmfPkgTokenSpaceGuid.PcdSmmSmramRequire
+  gUefiOvmfPkgTokenSpaceGuid.PcdQemuVarsRequire
 
 [Ppis]
   gEfiPeiMasterBootModePpiGuid