From a7e155d9d0be18b9db31dd7135e9da2bc955e6b4 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Wed, 11 Jan 2023 19:00:23 +0100
Subject: [PATCH 1/2] OvmfPkg/VirtNorFlashDxe: map flash memory as uncacheable

RH-Author: Gerd Hoffmann <kraxel@redhat.com>
RH-MergeRequest: 21: OvmfPkg/VirtNorFlashDxe: map flash memory as uncacheable
RH-Bugzilla: 2158173
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
RH-Acked-by: Oliver Steffen <osteffen@redhat.com>
RH-Commit: [1/1] 819cd72096fa9f253eef7b532122183b608c0064 (kraxel/centos-edk2)

Switching from the ArmPlatformPkg/NorFlashDxe driver to the
OvmfPkg/VirtNorFlashDxe driver had the side effect that flash address
space got registered as EFI_MEMORY_WC instead of EFI_MEMORY_UC.

That confuses the linux kernel's numa code, seems this makes kernel
consider the flash being node memory.  "lsmem" changes from ...

    RANGE                                 SIZE  STATE REMOVABLE BLOCK
    0x0000000040000000-0x000000013fffffff   4G online       yes  8-39

... to ...

    RANGE                                  SIZE  STATE REMOVABLE BLOCK
    0x0000000000000000-0x0000000007ffffff  128M online       yes     0
    0x0000000040000000-0x000000013fffffff    4G online       yes  8-39

... and in the kernel log got new error lines:

    NUMA: Warning: invalid memblk node 512 [mem 0x0000000004000000-0x0000000007ffffff]
    NUMA: Faking a node at [mem 0x0000000004000000-0x000000013fffffff]

Changing the attributes back to EFI_MEMORY_UC fixes this.

Fixes: b92298af8218 ("ArmVirtPkg/ArmVirtQemu: migrate to OVMF's VirtNorFlashDxe")
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
(cherry picked from commit e5ec3ba409b5baa9cf429cc25fdf3c8d1b8dcef0)
---
 OvmfPkg/VirtNorFlashDxe/VirtNorFlashDxe.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/OvmfPkg/VirtNorFlashDxe/VirtNorFlashDxe.c b/OvmfPkg/VirtNorFlashDxe/VirtNorFlashDxe.c
index ff3121af2a..f9a41f6aab 100644
--- a/OvmfPkg/VirtNorFlashDxe/VirtNorFlashDxe.c
+++ b/OvmfPkg/VirtNorFlashDxe/VirtNorFlashDxe.c
@@ -394,14 +394,14 @@ NorFlashFvbInitialize (
                   EfiGcdMemoryTypeMemoryMappedIo,
                   Instance->DeviceBaseAddress,
                   RuntimeMmioRegionSize,
-                  EFI_MEMORY_WC | EFI_MEMORY_RUNTIME
+                  EFI_MEMORY_UC | EFI_MEMORY_RUNTIME
                   );
   ASSERT_EFI_ERROR (Status);
 
   Status = gDS->SetMemorySpaceAttributes (
                   Instance->DeviceBaseAddress,
                   RuntimeMmioRegionSize,
-                  EFI_MEMORY_WC | EFI_MEMORY_RUNTIME
+                  EFI_MEMORY_UC | EFI_MEMORY_RUNTIME
                   );
   ASSERT_EFI_ERROR (Status);
 
-- 
2.31.1