From 99e4c8ea93fa0e98bc1bdb968e9d5bb42ff5d39c Mon Sep 17 00:00:00 2001
From: Chao Li <lichao@loongson.cn>
Date: Tue, 27 Aug 2024 10:30:36 +0800
Subject: [PATCH] OvmfPkg/LoongArchVirt: Clear the PGD series registers

Since the PGD series registers are in an unknown state when reset, some
simulators will hang when restarting if these registers are not cleared,
so they are cleared in this patch.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Chao Li <lichao@loongson.cn>
---
 OvmfPkg/LoongArchVirt/Library/CpuMmuInitLib/CpuMmuInit.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/OvmfPkg/LoongArchVirt/Library/CpuMmuInitLib/CpuMmuInit.c b/OvmfPkg/LoongArchVirt/Library/CpuMmuInitLib/CpuMmuInit.c
index be2d98cc9a..9091b70c01 100644
--- a/OvmfPkg/LoongArchVirt/Library/CpuMmuInitLib/CpuMmuInit.c
+++ b/OvmfPkg/LoongArchVirt/Library/CpuMmuInitLib/CpuMmuInit.c
@@ -141,6 +141,12 @@ ConfigureMemoryManagementUnit (
     return EFI_UNSUPPORTED;
   }
 
+  //
+  // Clear PGD series registers.
+  //
+  CsrWrite (LOONGARCH_CSR_PGDL, 0x0);
+  CsrWrite (LOONGARCH_CSR_PGDH, 0x0);
+
   PageTable = 0;
   while (MemoryTable->NumberOfPages != 0) {
     DEBUG ((