1 files changed, 49 insertions, 0 deletions
diff --git a/OvmfPkg/XenResetVector/Ia32/XenPVHMain.asm b/OvmfPkg/XenResetVector/Ia32/XenPVHMain.asm
new file mode 100644
index 0000000000..2a17fed52f
--- /dev/null
+++ b/OvmfPkg/XenResetVector/Ia32/XenPVHMain.asm
@@ -0,0 +1,49 @@
+;------------------------------------------------------------------------------
+; @file
+; An entry point use by Xen when a guest is started in PVH mode.
+;
+; Copyright (c) 2019, Citrix Systems, Inc.
+;
+; SPDX-License-Identifier: BSD-2-Clause-Patent
+;
+;------------------------------------------------------------------------------
+
+BITS    32
+
+xenPVHMain:
+    ;
+    ; 'BP' to indicate boot-strap processor
+    ;
+    mov     di, 'BP'
+
+    ;
+    ; ESP will be used as initial value of the EAX register
+    ; in Main.asm
+    ;
+    xor     esp, esp
+
+    mov     ebx, ADDR_OF(gdtr)
+    lgdt    [ebx]
+
+    mov     eax, SEC_DEFAULT_CR0
+    mov     cr0, eax
+
+    jmp     LINEAR_CODE_SEL:ADDR_OF(.jmpToNewCodeSeg)
+.jmpToNewCodeSeg:
+
+    mov     eax, SEC_DEFAULT_CR4
+    mov     cr4, eax
+
+    mov     ax, LINEAR_SEL
+    mov     ds, ax
+    mov     es, ax
+    mov     fs, ax
+    mov     gs, ax
+    mov     ss, ax
+
+    ;
+    ; Jump to the main routine of the pre-SEC code
+    ; skiping the 16-bit part of the routine and
+    ; into the 32-bit flat mode part
+    ;
+    OneTimeCallRet TransitionFromReal16To32BitFlat