Re: [edk2-devel] [PATCH] ArmVirtPkg: Allow EFI memory attributes protocol to be disabled

["Gerd Hoffmann" <kraxel@redhat.com>]

> > We can disable the protocol via this method but how would you set it
> > to =n by default?
> 
> if (Status != EFI_SUCCESS) 
>     // opt/org.tiabocode/MemAttrProtocol not present on the qemu cmdline
>     MemAttrProtocol = ThisBuildsDefault
> }

FYI: Below is what I'll add to the fedora builds.

Rough plan:  Keep this until we have a fixed shim.efi and release media
with that (hopefully Fedora 40 next spring).  At that point flip default
to TRUE and keep it that way for a year or two.  Then drop the patch.

take care,
  Gerd

------------------------------- cut here ----------------------------
From c174197c65d2346f519418ded2e645d57423be41 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Wed, 6 Dec 2023 13:00:53 +0100
Subject: [PATCH 1/1] ArmVirtPkg: add runtime option to enable/disable
 MemoryAttributesProtocol

Based on a patch by Ard Biesheuvel <ardb@google.com>

Usage:
    qemu-system-aarch64 $args \
    -fw_cfg name=opt/org.tianocore/MemAttrProtocol,string=y

Default to 'n' (disabled) for now.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 .../PlatformBootManagerLib.inf                |  2 +
 .../PlatformBootManagerLib/PlatformBm.c       | 69 +++++++++++++++++++
 2 files changed, 71 insertions(+)

diff --git a/ArmVirtPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf b/ArmVirtPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf
index 997eb1a4429f..facd81a5d036 100644
--- a/ArmVirtPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf
+++ b/ArmVirtPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf
@@ -46,6 +46,7 @@ [LibraryClasses]
   PcdLib
   PlatformBmPrintScLib
   QemuBootOrderLib
+  QemuFwCfgSimpleParserLib
   QemuLoadImageLib
   ReportStatusCodeLib
   TpmPlatformHierarchyLib
@@ -73,5 +74,6 @@ [Guids]
 [Protocols]
   gEfiFirmwareVolume2ProtocolGuid
   gEfiGraphicsOutputProtocolGuid
+  gEfiMemoryAttributeProtocolGuid
   gEfiPciRootBridgeIoProtocolGuid
   gVirtioDeviceProtocolGuid
diff --git a/ArmVirtPkg/Library/PlatformBootManagerLib/PlatformBm.c b/ArmVirtPkg/Library/PlatformBootManagerLib/PlatformBm.c
index 85c01351b09d..a50b9aec0f2c 100644
--- a/ArmVirtPkg/Library/PlatformBootManagerLib/PlatformBm.c
+++ b/ArmVirtPkg/Library/PlatformBootManagerLib/PlatformBm.c
@@ -16,6 +16,7 @@
 #include <Library/PcdLib.h>
 #include <Library/PlatformBmPrintScLib.h>
 #include <Library/QemuBootOrderLib.h>
+#include <Library/QemuFwCfgSimpleParserLib.h>
 #include <Library/TpmPlatformHierarchyLib.h>
 #include <Library/UefiBootManagerLib.h>
 #include <Protocol/DevicePath.h>
@@ -1111,6 +1112,49 @@ PlatformBootManagerBeforeConsole (
   FilterAndProcess (&gEfiPciIoProtocolGuid, IsVirtioPciSerial, SetupVirtioSerial);
 }
 
+/**
+  Uninstall the EFI memory attribute protocol if it exists.
+**/
+STATIC
+VOID
+UninstallEfiMemoryAttributesProtocol (
+  VOID
+  )
+{
+  EFI_STATUS  Status;
+  EFI_HANDLE  Handle;
+  UINTN       Size;
+  VOID        *MemoryAttributeProtocol;
+
+  Size   = sizeof (Handle);
+  Status = gBS->LocateHandle (
+                  ByProtocol,
+                  &gEfiMemoryAttributeProtocolGuid,
+                  NULL,
+                  &Size,
+                  &Handle
+                  );
+
+  if (EFI_ERROR (Status)) {
+    ASSERT (Status == EFI_NOT_FOUND);
+    return;
+  }
+
+  Status = gBS->HandleProtocol (
+                  Handle,
+                  &gEfiMemoryAttributeProtocolGuid,
+                  &MemoryAttributeProtocol
+                  );
+  ASSERT_EFI_ERROR (Status);
+
+  Status = gBS->UninstallProtocolInterface (
+                  Handle,
+                  &gEfiMemoryAttributeProtocolGuid,
+                  MemoryAttributeProtocol
+                  );
+  ASSERT_EFI_ERROR (Status);
+}
+
 /**
   Do the platform specific action after the console is ready
   Possible things that can be done in PlatformBootManagerAfterConsole:
@@ -1129,12 +1173,37 @@ PlatformBootManagerAfterConsole (
   )
 {
   RETURN_STATUS  Status;
+  BOOLEAN        MemAttrProtocol;
 
   //
   // Show the splash screen.
   //
   BootLogoEnableLogo ();
 
+  //
+  // Work around shim's terminally broken use of the EFI memory attributes
+  // protocol, by just uninstalling it when requested on the QEMU command line.
+  //
+  Status = QemuFwCfgParseBool (
+             "opt/org.tianocore/MemAttrProtocol",
+             &MemAttrProtocol
+             );
+  if (RETURN_ERROR (Status)) {
+    // default
+    MemAttrProtocol = FALSE;
+  }
+
+  DEBUG ((
+    DEBUG_ERROR,
+    "%a: MemAttrProtocol = %a\n",
+    __func__,
+    MemAttrProtocol ? "yes" : "no"
+    ));
+
+  if (!MemAttrProtocol) {
+    UninstallEfiMemoryAttributesProtocol ();
+  }
+
   //
   // Process QEMU's -kernel command line option. The kernel booted this way
   // will receive ACPI tables: in PlatformBootManagerBeforeConsole(), we
-- 
2.43.0



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